Merge remote-tracking branch 'origin/master'

2025-02-13 20:02:57 +08:00 · 2020-02-22 20:41:26 +08:00 · 2020-02-22 20:41:26 +08:00 · e9c794296d
commit e9c794296d
parent 5847ac855c 7e3ede0de7
64 changed files with 1524 additions and 368 deletions
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -2,6 +2,37 @@

 开发版本. 频繁更新, 不保证高稳定性

+## `0.19.1` 2020/2/21
+
+### mirai-core
+- 支持机器人撤回群消息 (含自己发送的消息): `Group.recall`, `MessageReceipt.recall`
+- 支持一定时间后自动撤回: `Group.recallIn`, `MessageReceipt.recallIn`
+- `sendMessage` 返回 `MessageReceipt` 以实现撤回功能
+- 添加 `MessageChain.addOrRemove`
+- 添加 `ContactList.firstOrNull`, `ContactList.first`
+- 新的异步事件监听方式: `subscribingGetAsync` 启动一个协程并从一个事件从获取返回值到 `Deferred`.
+- 新的线性事件监听方式: `subscribingGet` 挂起当前协程并从一个事件从获取返回值.
+
+##### 新的线性消息连续处理: `nextMessage` 挂起当前协程并等待下一条消息:
+使用该示例, 发送两条消息, 一条为 "禁言", 另一条包含一个 At
+```kotlin
+case("禁言") {
+    val value: At = nextMessage { message.any(At) }[At]
+    value.member().mute(10)
+}
+```
+示例 2:
+```kotlin
+case("复读下一条") {
+    reply(nextMessage().message)
+}
+```
+
+### mirai-core-qqandroid
+- 修复一些情况下 `At` 无法发送的问题
+- 统一 ImageId: 群消息收到的 ImageId 均为 `{xxxxxxxx-xxxx-xxxx-xxxxxxxxxxxx}.jpg` 形式（固定长度 37）
+- 支持成员主动离开事件的解析 (#51)
+
 ## `0.18.0` 2020/2/20

 ### mirai-core
@ -212,7 +243,7 @@ TIMPC
 ## `0.10.0`  *2019/12/23*
 **事件优化**  
 更快的监听过程  
-现在监听不再是 `suspend`, 而必须显式指定 `CoroutineScope`. 详见 [`Subscribers.kt`](mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/Subscribers.kt#L69)  
+现在监听不再是 `suspend`, 而必须显式指定 `CoroutineScope`. 详见 `Subscribers.kt`  
 删除原本的 bot.subscribe 等监听模式.

 **其他**  
--- a/build.gradle
+++ b/build.gradle
@ -1,6 +1,7 @@
 buildscript {
    repositories {
        mavenLocal()
+        maven { url "https://mirrors.huaweicloud.com/repository/maven" }
        jcenter()
        mavenCentral()
        google()
@ -9,7 +10,6 @@ buildscript {
    }

    dependencies {
-        // Do try to waste your time.
        classpath 'com.android.tools.build:gradle:3.5.3'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion"
        classpath("com.github.jengelman.gradle.plugins:shadow:5.2.0")
@ -32,14 +32,10 @@ allprojects {
    group = "net.mamoe"
    version = getProperty("mirai_version")

-//    tasks.withType(KotlinCompile).all { task ->
-//        task.kotlinOptions{
-//            jvmTarget = '1.6'
-//        }
-//    }

    repositories {
        mavenLocal()
+        maven { url "https://mirrors.huaweicloud.com/repository/maven" }
        jcenter()
        mavenCentral()
        google()
--- a/docs/guide_build_for_mirai.md
+++ b/docs/guide_build_for_mirai.md
@ -0,0 +1,186 @@
+# Mirai Guide - Build For Mirai
+
+由于Mirai项目在快速推进中，因此内容时有变动，本文档的最后更新日期为```2020-02-22```，对应版本```0.19.1```
+
+本页面采用Kotlin作为开发语言，**若你希望使用 Java 开发**, 请参阅: [mirai-japt](mirai-japt/README.md)
+
+本页面是[Mirai Guide - Subscribe Events](/docs/guide_subscribe_events.md)的后续Guide
+
+## build.gradle
+
+我们首先来看一下完整的```build.gradle```文件
+
+```groovy
+plugins {
+    id 'java'
+    id 'org.jetbrains.kotlin.jvm' version '1.3.61'
+}
+
+group 'test'
+version '1.0-SNAPSHOT'
+
+sourceCompatibility = 1.8
+
+repositories {
+    mavenCentral()
+    jcenter()
+}
+
+dependencies {
+    implementation 'net.mamoe:mirai-core-qqandroid-jvm:0.19.1'
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+    testCompile group: 'junit', name: 'junit', version: '4.12'
+}
+
+compileKotlin {
+    kotlinOptions.jvmTarget = "1.8"
+}
+compileTestKotlin {
+    kotlinOptions.jvmTarget = "1.8"
+}
+```
+
+使用gradle直接打包，不会将依赖也打包进去
+
+因此，我们引入一些插件进行打包
+
+### ShadowJar
+
+shadowJar支持将依赖也打包到Jar内，下面介绍用法。
+
+#### 1.buildscript
+
+首先声明buildScript
+
+```groovy
+buildscript {
+    repositories {
+        jcenter()
+    }
+    dependencies {
+        classpath 'com.github.jengelman.gradle.plugins:shadow:5.2.0'
+    }
+}
+```
+
+在plugin前加入以上语句
+
+
+
+#### 2.在plugins中进行插件的使用
+
+将原本的plugins
+
+```groovy
+plugins {
+    id 'java'
+    id 'org.jetbrains.kotlin.jvm' version '1.3.61'
+}
+```
+
+覆盖为
+
+```groovy
+plugins {
+    id 'java'
+    id 'org.jetbrains.kotlin.jvm' version '1.3.61'
+    id 'com.github.johnrengelman.shadow' version '5.2.0'//使用shadow对依赖进行打包
+}
+
+apply plugin: 'com.github.johnrengelman.shadow'
+apply plugin: 'java'
+```
+
+
+
+#### 3.添加shadowJar
+
+在文件底部添加
+
+```groovy
+shadowJar {
+    // 生成包的命名规则： baseName-version-classifier.jar
+    manifest {
+        attributes(
+                'Main-Class': 'net.mamoe.mirai.simpleloader.MyLoaderKt'//入口点
+        )
+    }
+
+    // 将 build.gradle 打入到 jar 中, 方便查看依赖包版本
+    from("./"){
+        include 'build.gradle'
+    }
+}
+```
+
+
+
+#### 4.运行build
+
+在IDEA中点击```ShadowJar```左侧的run按钮(绿色小三角)，build完成后在```build\libs```中找到jar
+
+
+
+至此，build.gradle内的内容是
+
+```groovy
+buildscript {
+    repositories {
+        jcenter()
+    }
+    dependencies {
+        classpath 'com.github.jengelman.gradle.plugins:shadow:5.2.0'
+    }
+}
+
+
+plugins {
+    id 'java'
+    id 'org.jetbrains.kotlin.jvm' version '1.3.61'
+    id 'com.github.johnrengelman.shadow' version '5.2.0'//使用shadow对依赖进行打包
+}
+
+apply plugin: 'com.github.johnrengelman.shadow'
+apply plugin: 'java'
+
+group 'test'
+version '1.0-SNAPSHOT'
+
+sourceCompatibility = 1.8
+
+
+repositories {
+    mavenCentral()
+    jcenter()
+}
+
+dependencies {
+    implementation 'net.mamoe:mirai-core-qqandroid-jvm:0.19.1'
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+    testCompile group: 'junit', name: 'junit', version: '4.12'
+}
+
+
+compileKotlin {
+    kotlinOptions.jvmTarget = "1.8"
+}
+compileTestKotlin {
+    kotlinOptions.jvmTarget = "1.8"
+}
+
+shadowJar {
+    // 生成包的命名规则： baseName-version-classifier.jar
+    manifest {
+        attributes(
+                'Main-Class': 'net.mamoe.mirai.simpleloader.MyLoaderKt'
+        )
+    }
+
+    // 将 build.gradle 打入到 jar 中, 方便查看依赖包版本
+    from("./"){
+        include 'build.gradle'
+    }
+}
+
+```
+
--- a/docs/guide_getting_started.md
+++ b/docs/guide_getting_started.md
@ -26,6 +26,8 @@ JDK要求6以上

 ### 2 新建Gradle项目

+*使用gradle项目可能需要代理，在IDEA的```settings```->```proxy settings```中可以设置
+
 - 在```File->new project```中选择```Gradle```
 - 在面板中的```Additional Libraries and Frameworks```中勾选```Java```以及```Kotlin/JVM```
 - 点击```next```，填入```GroupId```与```ArtifactId```(对于测试项目来说，可随意填写)
@ -69,7 +71,7 @@ JDK要求6以上
 ### 4 Try Bot

 - 在src/main文件夹下新建文件夹，命名为```kotlin```
- 在```kotlin```下新建包(在```kotlin```文件夹上右键-```New```-```Packages```) 包名为```net.mamoe.mirai.simpleloader```
+- 在```kotlin```下新建包(在```kotlin```文件夹上右键-```New```-```Package```) 包名为```net.mamoe.mirai.simpleloader```

 - 在包下新建kotlin文件```MyLoader.kt```

@ -103,9 +105,9 @@ suspend fun main() {
 - 本例的功能中，在任意群内任意成员发送包含“舔”字或“刘老板”字样的消息，MiraiBot会回复“刘老板太强了”


-
 至此，简单的入门已经结束，下面可根据不同的需求参阅wiki进行功能的添加。

+下面，可以尝试对不同事件进行监听[Mirai Guide - Subscribe Events](/docs/guide_subscribe_events.md)

 ### 此外，还可以使用Maven作为包管理工具
 本项目推荐使用gradle，因此不提供详细入门指导
--- a/docs/guide_subscribe_events.md
+++ b/docs/guide_subscribe_events.md
@ -0,0 +1,116 @@
+# Mirai Guide - Subscribe Events
+
+由于Mirai项目在快速推进中，因此内容时有变动，本文档的最后更新日期为```2020-02-21```，对应版本```0.17.0```
+
+本页面采用Kotlin作为开发语言，**若你希望使用 Java 开发**, 请参阅: [mirai-japt](mirai-japt/README.md)
+
+本页面是[Mirai Guide - Getting Started](/docs/guide_getting_started.md)的后续Guide
+
+## 消息事件-Message Event
+
+首先我们来回顾上一个Guide的源码
+
+```kotlin
+suspend fun main() {
+    val qqId = 10000L//Bot的QQ号，需为Long类型，在结尾处添加大写L
+    val password = "your_password"//Bot的密码
+    val miraiBot = Bot(qqId, password).alsoLogin()//新建Bot并登录
+    miraiBot.subscribeMessages {
+        "你好" reply "你好!"
+        case("at me") {
+            reply(sender.at() + " 给爷爬 ")
+        }
+
+        (contains("舔") or contains("刘老板")) {
+            "刘老板太强了".reply()
+        }
+    }
+    miraiBot.join() // 等待 Bot 离线, 避免主线程退出
+}
+```
+
+在本例中，```miraiBot```是一个Bot对象，让其登录，然后对```Message Event```进行了监听。
+
+对于``````Message Event``````，```Mirai```提供了较其他Event更强大的[MessageSubscribersBuilder](https://github.com/mamoe/mirai/wiki/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/MessageSubscribers.kt#L140)，本例也采用了[MessageSubscribersBuilder](https://github.com/mamoe/mirai/wiki/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/MessageSubscribers.kt#L140)。其他具体使用方法可以参考[Wiki:Message Event](https://github.com/mamoe/mirai/wiki/Development-Guide---Kotlin#Message-Event)部分。
+
+
+
+## 事件-Event
+
+上一节中提到的```Message Event```仅仅是众多```Event```的这一种，其他```Event```有群员加入群，离开群，私聊等等...
+
+具体doc暂不提供，现可翻阅源码[**BotEvents.kt**](https://github.com/mamoe/mirai/blob/master/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/events/BotEvents.kt)，查看注释。当前事件仍在扩充中，可能有一定不足。
+
+下面我们开始示例对一些事件进行监听。
+
+
+
+## 尝试监听事件-Try Subscribing Events
+
+### 监听加群事件
+
+在代码中的```miraiBot.join()```前添加
+
+```kotlin
+miraiBot.subscribeAlways<MemberJoinEvent> {
+        it.group.sendMessage("欢迎 ${it.member.nameCardOrNick} 加入本群！")
+}
+```
+
+本段语句监听了加入群的事件。
+
+### 监听禁言事件
+
+在代码中添加
+
+```kotlin
+miraiBot.subscribeAlways<MemberMuteEvent> (){
+        it.group.sendMessage("恭喜老哥 ${it.member.nameCardOrNick} 喜提禁言套餐一份")
+}
+```
+
+在被禁言后，Bot将发送恭喜语句。
+
+### 添加后的可执行代码
+
+至此，当前的代码为
+
+```kotlin
+package net.mamoe.mirai.simpleloader
+
+import kotlinx.coroutines.*
+import net.mamoe.mirai.Bot
+import net.mamoe.mirai.alsoLogin
+import net.mamoe.mirai.event.subscribeMessages
+import net.mamoe.mirai.contact.nameCardOrNick
+import net.mamoe.mirai.contact.sendMessage
+import net.mamoe.mirai.event.events.MemberJoinEvent
+import net.mamoe.mirai.event.events.MemberMuteEvent
+import net.mamoe.mirai.event.subscribeAlways
+
+suspend fun main() {
+    val qqId = 10000L//Bot的QQ号，需为Long类型，在结尾处添加大写L
+    val password = "your_password"//Bot的密码
+    val miraiBot = Bot(qqId, password).alsoLogin()//新建Bot并登录
+    miraiBot.subscribeMessages {
+        "你好" reply "你好!"
+        case("at me") {
+            reply(sender.at() + " 给爷爬 ")
+        }
+
+        (contains("舔") or contains("刘老板")) {
+            "刘老板太强了".reply()
+        }
+    }
+    miraiBot.subscribeAlways<MemberJoinEvent> {
+        it.group.sendMessage("欢迎 ${it.member.nameCardOrNick} 加入本群！")
+    }
+    miraiBot.subscribeAlways<MemberMuteEvent> (){
+        it.group.sendMessage("恭喜老哥 ${it.member.nameCardOrNick} 喜提禁言套餐一份")
+    }
+    miraiBot.join() // 等待 Bot 离线, 避免主线程退出
+}
+```
+
+下面可以参阅[Mirai Guide - Build For Mirai](/docs/guide_build_for_mirai.md)，对你的Mirai应用进行打包
+
--- a/gradle.properties
+++ b/gradle.properties
@ -1,7 +1,7 @@
 # style guide
 kotlin.code.style=official
 # config
-mirai_version=0.18.0
+mirai_version=0.19.1
 mirai_japt_version=1.0.1
 kotlin.incremental.multiplatform=true
 kotlin.parallel.tasks.in.project=true
--- a/mirai-api-http/EventType_CH.md
+++ b/mirai-api-http/EventType_CH.md
--- a/mirai-api-http/README_CH.md
+++ b/mirai-api-http/README_CH.md
@ -408,7 +408,7 @@ Content-Type：multipart/form-data


 ### 事件类型一览
-[事件类型一览](./EventType_CN.md)
+[事件类型一览](EventType_CH.md)

 > 事件为Bot被动接收的信息，无法主动构建

@ -430,13 +430,13 @@ Content-Type：multipart/form-data
 ```json5
 {
    "type": "Source",
-    "uid": 123456
+    "id": 123456
 }
 ```

 | 名字 | 类型 | 说明                                                         |
 | ---- | ---- | ------------------------------------------------------------ |
-| uid  | Long | 消息的识别号，用于引用回复（Source类型只在群消息中返回，且永远为chain的第一个元素） |
+| id   | Long | 消息的识别号，用于引用回复（Source类型只在群消息中返回，且永远为chain的第一个元素） |

 #### At

--- a/mirai-api-http/src/main/kotlin/net/mamoe/mirai/api/http/data/StateCode.kt
+++ b/mirai-api-http/src/main/kotlin/net/mamoe/mirai/api/http/data/StateCode.kt
@ -1,9 +1,10 @@
 package net.mamoe.mirai.api.http.data

 import kotlinx.serialization.Serializable
+import net.mamoe.mirai.api.http.data.common.DTO

@Serializable
-open class StateCode(val code: Int, var msg: String) {
+open class StateCode(val code: Int, var msg: String) : DTO {
    object Success : StateCode(0, "success") // 成功
    object NoBot : StateCode(2, "指定Bot不存在")
    object IllegalSession : StateCode(3, "Session失效或不存在")
--- a/mirai-api-http/src/main/kotlin/net/mamoe/mirai/api/http/data/common/MessageDTO.kt
+++ b/mirai-api-http/src/main/kotlin/net/mamoe/mirai/api/http/data/common/MessageDTO.kt
@ -36,7 +36,7 @@ data class GroupMessagePacketDTO(val sender: MemberDTO) : MessagePacketDTO()
 // Message
@Serializable
@SerialName("Source")
-data class MessageSourceDTO(val uid: Long) : MessageDTO()
+data class MessageSourceDTO(val id: Long) : MessageDTO()

@Serializable
@SerialName("At")
@ -64,7 +64,7 @@ data class XmlDTO(val xml: String) : MessageDTO()

@Serializable
@SerialName("Unknown")
-data class UnknownMessageDTO(val text: String) : MessageDTO()
+object UnknownMessageDTO : MessageDTO()

 /*
 *   Abstract Class
@ -88,24 +88,29 @@ fun MessagePacket<*, *>.toDTO() = when (this) {
    is GroupMessage -> GroupMessagePacketDTO(MemberDTO(sender))
    else -> IgnoreEventDTO
 }.apply {
-    if (this is MessagePacketDTO) {
-        messageChain = mutableListOf<MessageDTO>().also { ls -> message.foreachContent { ls.add(it.toDTO()) } }
-    }
+    if (this is MessagePacketDTO) { messageChain = message.toDTOChain() }
+    // else: `this` is bot event
+}
+
+fun MessageChain.toDTOChain() = mutableListOf(this[MessageSource].toDTO()).apply {
+    foreachContent { content -> content.toDTO().takeUnless { it == UnknownMessageDTO }?.let(::add) }
 }

 fun MessageChainDTO.toMessageChain(contact: Contact) =
    MessageChain().apply { this@toMessageChain.forEach { add(it.toMessage(contact)) } }

+internal fun MessageSource.calMessageId() = (messageUid.toLong() shl 32) or (sequenceId.toLong() and 0xFFFFFFFF)
+
@UseExperimental(ExperimentalUnsignedTypes::class)
 fun Message.toDTO() = when (this) {
-    is MessageSource -> MessageSourceDTO(messageUid)
+    is MessageSource -> MessageSourceDTO(calMessageId())
    is At -> AtDTO(target, display)
    is AtAll -> AtAllDTO(0L)
    is Face -> FaceDTO(id)
    is PlainText -> PlainDTO(stringValue)
    is Image -> ImageDTO(imageId)
    is XMLMessage -> XmlDTO(stringValue)
-    else -> UnknownMessageDTO("未知消息类型")
+    else -> UnknownMessageDTO
 }

@UseExperimental(ExperimentalUnsignedTypes::class, MiraiInternalAPI::class)
--- a/mirai-api-http/src/main/kotlin/net/mamoe/mirai/api/http/queue/MessageQueue.kt
+++ b/mirai-api-http/src/main/kotlin/net/mamoe/mirai/api/http/queue/MessageQueue.kt
@ -11,20 +11,22 @@ package net.mamoe.mirai.api.http.queue

 import net.mamoe.mirai.api.http.data.common.EventDTO
 import net.mamoe.mirai.api.http.data.common.IgnoreEventDTO
+import net.mamoe.mirai.api.http.data.common.calMessageId
 import net.mamoe.mirai.api.http.data.common.toDTO
 import net.mamoe.mirai.event.events.BotEvent
 import net.mamoe.mirai.message.GroupMessage
 import net.mamoe.mirai.message.data.MessageSource
-import java.util.concurrent.ConcurrentHashMap
+import net.mamoe.mirai.utils.firstKey
 import java.util.concurrent.ConcurrentLinkedDeque

 class MessageQueue : ConcurrentLinkedDeque<BotEvent>() {

-    val quoteCache = ConcurrentHashMap<Long, GroupMessage>()
+    val quoteCacheSize = 4096
+    val quoteCache = LinkedHashMap<Long, GroupMessage>()

    fun fetch(size: Int): List<EventDTO> {
        var count = size
-        quoteCache.clear()
+
        val ret = ArrayList<EventDTO>(count)
        while (!this.isEmpty() && count > 0) {
            val event = pop()
@ -36,14 +38,18 @@ class MessageQueue : ConcurrentLinkedDeque<BotEvent>() {
                }
            }

+            // TODO: 等FriendMessage支持quote
            if (event is GroupMessage) {
-                addCache(event)
+                addQuoteCache(event)
            }
        }
        return ret
    }

-    private fun addCache(msg: GroupMessage) {
-        quoteCache[msg.message[MessageSource].messageUid] = msg
+    private fun addQuoteCache(msg: GroupMessage) {
+        quoteCache[msg.message[MessageSource].calMessageId()] = msg
+        if (quoteCache.size > quoteCacheSize) {
+            quoteCache.remove(quoteCache.firstKey())
+        }
    }
 }
--- a/mirai-api-http/src/main/kotlin/net/mamoe/mirai/api/http/route/BaseRoute.kt
+++ b/mirai-api-http/src/main/kotlin/net/mamoe/mirai/api/http/route/BaseRoute.kt
@ -21,6 +21,7 @@ import io.ktor.http.HttpStatusCode
 import io.ktor.http.content.PartData
 import io.ktor.request.receive
 import io.ktor.response.defaultTextContentType
+import io.ktor.response.respond
 import io.ktor.response.respondText
 import io.ktor.routing.Route
 import io.ktor.routing.route
@ -141,6 +142,9 @@ internal inline fun Route.intercept(crossinline blk: suspend PipelineContext<Uni
        call.respondStateCode(StateCode.PermissionDenied)
    } catch (e: IllegalAccessException) {
        call.respondStateCode(StateCode(400, e.message), HttpStatusCode.BadRequest)
+    } catch (e: Throwable) {
+        e.printStackTrace()
+        call.respond(HttpStatusCode.InternalServerError, e.message!!)
    }
 }

--- a/mirai-api-http/src/main/kotlin/net/mamoe/mirai/api/http/route/SendMessageRouteModule.kt
+++ b/mirai-api-http/src/main/kotlin/net/mamoe/mirai/api/http/route/SendMessageRouteModule.kt
@ -11,19 +11,21 @@ package net.mamoe.mirai.api.http.route

 import io.ktor.application.Application
 import io.ktor.application.call
+import io.ktor.http.HttpStatusCode
 import io.ktor.http.content.readAllParts
 import io.ktor.http.content.streamProvider
 import io.ktor.request.receiveMultipart
+import io.ktor.response.respond
 import io.ktor.response.respondText
 import io.ktor.routing.post
 import io.ktor.routing.routing
 import kotlinx.serialization.Serializable
+import kotlinx.serialization.Transient
 import net.mamoe.mirai.api.http.AuthedSession
 import net.mamoe.mirai.api.http.SessionManager
 import net.mamoe.mirai.api.http.data.*
 import net.mamoe.mirai.api.http.data.common.MessageChainDTO
 import net.mamoe.mirai.api.http.data.common.VerifyDTO
-import net.mamoe.mirai.api.http.data.common.toDTO
 import net.mamoe.mirai.api.http.data.common.toMessageChain
 import net.mamoe.mirai.api.http.util.toJson
 import net.mamoe.mirai.contact.toList
@ -45,14 +47,12 @@ fun Application.messageModule() {
            it.session.bot.getFriend(it.target).apply {
                sendMessage(it.messageChain.toMessageChain(this)) // this aka QQ
            }
-            call.respondStateCode(StateCode.Success)
        }

        miraiVerify<SendDTO>("/sendGroupMessage") {
            it.session.bot.getGroup(it.target).apply {
                sendMessage(it.messageChain.toMessageChain(this)) // this aka Group
            }
-            call.respondStateCode(StateCode.Success)
        }

        miraiVerify<SendDTO>("/quoteMessage") {
@ -100,6 +100,11 @@ fun Application.messageModule() {
                } ?: throw IllegalAccessException("图片上传错误")
            } ?: throw IllegalAccessException("未知错误")
        }
+
+        miraiVerify<RecallDTO>("recall") {
+            // TODO
+            call.respond(HttpStatusCode.NotFound, "未完成")
+        }
    }
 }

@ -119,3 +124,15 @@ private data class SendImageDTO(
    val urls: List<String>
 ) : VerifyDTO()

+@Serializable
+private class SendRetDTO(
+    val messageId: Long,
+    @Transient val stateCode: StateCode = Success
+) : StateCode(stateCode.code, stateCode.msg)
+
+@Serializable
+private data class RecallDTO(
+    override val sessionKey: String,
+    val target: Long,
+    val sender: Long
+) : VerifyDTO()
--- a/mirai-console-graphical/src/main/kotlin/net/mamoe/mirai/console/graphical/controller/MiraiGraphicalUIController.kt
+++ b/mirai-console-graphical/src/main/kotlin/net/mamoe/mirai/console/graphical/controller/MiraiGraphicalUIController.kt
@ -1,6 +1,7 @@
 package net.mamoe.mirai.console.graphical.controller

 import javafx.application.Platform
+import javafx.collections.ObservableList
 import javafx.stage.Modality
 import kotlinx.io.core.IoBuffer
 import net.mamoe.mirai.Bot
@ -8,6 +9,7 @@ import net.mamoe.mirai.console.MiraiConsole
 import net.mamoe.mirai.console.MiraiConsoleUI
 import net.mamoe.mirai.console.graphical.model.BotModel
 import net.mamoe.mirai.console.graphical.model.ConsoleInfo
+import net.mamoe.mirai.console.graphical.model.PluginModel
 import net.mamoe.mirai.console.graphical.model.VerificationCodeModel
 import net.mamoe.mirai.console.graphical.view.VerificationCodeFragment
 import net.mamoe.mirai.utils.LoginSolver
@ -21,13 +23,21 @@ class MiraiGraphicalUIController : Controller(), MiraiConsoleUI {
    private val loginSolver = GraphicalLoginSolver()
    private val cache = mutableMapOf<Long, BotModel>()
    val mainLog = observableListOf<String>()
+
+
    val botList = observableListOf<BotModel>()
+    val pluginList: ObservableList<PluginModel> by lazy(::getPluginsFromConsole)
+
+    val consoleConfig : Map<String, Any> by lazy(::getConfigFromConsole)
+
    val consoleInfo = ConsoleInfo()

    suspend fun login(qq: String, psd: String) {
        MiraiConsole.CommandListener.commandChannel.send("/login $qq $psd")
    }

+    suspend fun sendCommand(command: String) = MiraiConsole.CommandListener.commandChannel.send(command)
+
    override fun pushLog(identity: Long, message: String) = Platform.runLater {
        when (identity) {
            0L -> mainLog.add(message)
@ -68,6 +78,13 @@ class MiraiGraphicalUIController : Controller(), MiraiConsoleUI {
    }

    override fun createLoginSolver(): LoginSolver = loginSolver
+
+    private fun getPluginsFromConsole(): ObservableList<PluginModel> {
+        // TODO
+        return observableListOf<PluginModel>()
+    }
+
+    private fun getConfigFromConsole() = MiraiConsole.MiraiProperties.config.asMap()
 }

 class GraphicalLoginSolver : LoginSolver() {
--- a/mirai-console-graphical/src/main/kotlin/net/mamoe/mirai/console/graphical/model/PluginModel.kt
+++ b/mirai-console-graphical/src/main/kotlin/net/mamoe/mirai/console/graphical/model/PluginModel.kt
@ -0,0 +1,19 @@
+package net.mamoe.mirai.console.graphical.model
+
+import com.jfoenix.controls.datamodels.treetable.RecursiveTreeObject
+import javafx.beans.property.SimpleBooleanProperty
+import javafx.beans.property.SimpleStringProperty
+import tornadofx.getValue
+import tornadofx.setValue
+
+class PluginModel : RecursiveTreeObject<PluginModel>() {
+
+    val nameProperty = SimpleStringProperty(this, "nameProperty")
+    val name by nameProperty
+
+    val descriptionProperty = SimpleStringProperty(this, "descriptionProperty")
+    val description by descriptionProperty
+
+    val enabledProperty = SimpleBooleanProperty(this, "enabledProperty")
+    var enabled by enabledProperty
+}
--- a/mirai-console-graphical/src/main/kotlin/net/mamoe/mirai/console/graphical/util/JFoenixAdaptor.kt
+++ b/mirai-console-graphical/src/main/kotlin/net/mamoe/mirai/console/graphical/util/JFoenixAdaptor.kt
@ -1,6 +1,7 @@
 package net.mamoe.mirai.console.graphical.util

 import com.jfoenix.controls.*
+import com.jfoenix.controls.datamodels.treetable.RecursiveTreeObject
 import javafx.beans.value.ObservableValue
 import javafx.collections.ObservableList
 import javafx.event.EventTarget
@ -42,3 +43,6 @@ internal fun <T> EventTarget.jfxListView(values: ObservableList<T>? = null, op:
            else it.items = values
        }
    }
+
+fun <T : RecursiveTreeObject<T>?> EventTarget.jfxTreeTableView(items: ObservableList<T>? = null, op: JFXTreeTableView<T>.() -> Unit = {})
+        = JFXTreeTableView<T>(RecursiveTreeItem(items, RecursiveTreeObject<T>::getChildren)).attachTo(this, op)
--- a/mirai-console-graphical/src/main/kotlin/net/mamoe/mirai/console/graphical/view/PluginsView.kt
+++ b/mirai-console-graphical/src/main/kotlin/net/mamoe/mirai/console/graphical/view/PluginsView.kt
@ -0,0 +1,22 @@
+package net.mamoe.mirai.console.graphical.view
+
+import com.jfoenix.controls.JFXTreeTableColumn
+import net.mamoe.mirai.console.graphical.controller.MiraiGraphicalUIController
+import net.mamoe.mirai.console.graphical.model.PluginModel
+import net.mamoe.mirai.console.graphical.util.jfxTreeTableView
+import tornadofx.View
+
+class PluginsView : View() {
+
+    private val controller = find<MiraiGraphicalUIController>()
+    val plugins = controller.pluginList
+
+    override val root = jfxTreeTableView(plugins) {
+        columns.addAll(
+            JFXTreeTableColumn<PluginModel, String>("插件名").apply {  },
+            JFXTreeTableColumn<PluginModel, String>("版本").apply {  },
+            JFXTreeTableColumn<PluginModel, String>("作者").apply {  },
+            JFXTreeTableColumn<PluginModel, String>("介绍").apply {  }
+        )
+    }
+}
--- a/mirai-console-graphical/src/main/kotlin/net/mamoe/mirai/console/graphical/view/PrimaryView.kt
+++ b/mirai-console-graphical/src/main/kotlin/net/mamoe/mirai/console/graphical/view/PrimaryView.kt
@ -5,6 +5,8 @@ import javafx.collections.ObservableList
 import javafx.scene.control.Tab
 import javafx.scene.control.TabPane
 import javafx.scene.image.Image
+import javafx.scene.input.KeyCode
+import kotlinx.coroutines.runBlocking
 import net.mamoe.mirai.console.graphical.controller.MiraiGraphicalUIController
 import net.mamoe.mirai.console.graphical.model.BotModel
 import net.mamoe.mirai.console.graphical.util.jfxListView
@ -52,17 +54,26 @@ class PrimaryView : View() {
                    }
                }
            }
+
+            // command input
+            textfield {
+                setOnKeyPressed {
+                    if (it.code == KeyCode.ENTER) {
+                        runAsync {
+                            runBlocking { controller.sendCommand(text) }
+                        }.ui { text = "" }
+                    }
+                }
+            }
        }

        center = jfxTabPane {

-            tab("Login") {
-                this += find<LoginView>().root
-            }
+            tab("Login").content = find<LoginView>().root

-            tab("Plugin")
+            tab("Plugins").content = find<PluginsView>().root

-            tab("Settings")
+            tab("Settings").content = find<SettingsView>().root

            logTab("Main", controller.mainLog)
        }
--- a/mirai-console-graphical/src/main/kotlin/net/mamoe/mirai/console/graphical/view/SettingsView.kt
+++ b/mirai-console-graphical/src/main/kotlin/net/mamoe/mirai/console/graphical/view/SettingsView.kt
@ -0,0 +1,23 @@
+package net.mamoe.mirai.console.graphical.view
+
+import net.mamoe.mirai.console.graphical.controller.MiraiGraphicalUIController
+import net.mamoe.mirai.console.graphical.util.jfxTextfield
+import tornadofx.View
+import tornadofx.field
+import tornadofx.fieldset
+import tornadofx.form
+
+class SettingsView : View() {
+
+    private val controller = find<MiraiGraphicalUIController>()
+
+    override val root = form {
+        controller.consoleConfig.forEach {
+            fieldset {
+                field(it.key) {
+                    jfxTextfield(it.value.toString()) { isEditable = false }
+                }
+            }
+        }
+    }
+}
--- a/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/ContactImpl.kt
+++ b/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/ContactImpl.kt
@ -16,14 +16,13 @@ import net.mamoe.mirai.event.broadcast
 import net.mamoe.mirai.event.events.*
 import net.mamoe.mirai.event.events.MessageSendEvent.FriendMessageSendEvent
 import net.mamoe.mirai.event.events.MessageSendEvent.GroupMessageSendEvent
-import net.mamoe.mirai.message.data.CustomFaceFromFile
-import net.mamoe.mirai.message.data.Image
-import net.mamoe.mirai.message.data.MessageChain
-import net.mamoe.mirai.message.data.NotOnlineImageFromFile
+import net.mamoe.mirai.message.MessageReceipt
+import net.mamoe.mirai.message.data.*
 import net.mamoe.mirai.qqandroid.network.highway.HighwayHelper
 import net.mamoe.mirai.qqandroid.network.highway.postImage
 import net.mamoe.mirai.qqandroid.network.protocol.data.jce.StTroopMemberInfo
 import net.mamoe.mirai.qqandroid.network.protocol.data.proto.Cmd0x352
+import net.mamoe.mirai.qqandroid.network.protocol.packet.chat.PbMessageSvc
 import net.mamoe.mirai.qqandroid.network.protocol.packet.chat.TroopManagement
 import net.mamoe.mirai.qqandroid.network.protocol.packet.chat.image.ImgStore
 import net.mamoe.mirai.qqandroid.network.protocol.packet.chat.image.LongConn
@ -66,20 +65,22 @@ internal class QQImpl(
    override val nick: String
        get() = friendInfo.nick

-    override suspend fun sendMessage(message: MessageChain) {
+    override suspend fun sendMessage(message: MessageChain): MessageReceipt<QQ> {
        val event = FriendMessageSendEvent(this, message).broadcast()
        if (event.isCancelled) {
            throw EventCancelledException("cancelled by FriendMessageSendEvent")
        }
+        lateinit var source: MessageSource
        bot.network.run {
            check(
                MessageSvc.PbSendMsg.ToFriend(
                    bot.client,
                    id,
                    event.message
-                ).sendAndExpect<MessageSvc.PbSendMsg.Response>() is MessageSvc.PbSendMsg.Response.SUCCESS
+                ) { source = it }.sendAndExpect<MessageSvc.PbSendMsg.Response>() is MessageSvc.PbSendMsg.Response.SUCCESS
            ) { "send message failed" }
        }
+        return MessageReceipt(message, source, this)
    }

    override suspend fun uploadImage(image: ExternalImage): Image = try {
@ -166,7 +167,7 @@ internal class QQImpl(
 }


-@Suppress("MemberVisibilityCanBePrivate", "DELEGATED_MEMBER_HIDES_SUPERTYPE_OVERRIDE")
+@Suppress("MemberVisibilityCanBePrivate")
 internal class MemberImpl(
    qq: QQImpl,
    group: GroupImpl,
@ -286,26 +287,39 @@ internal class MemberImpl(
        }
    }

+    override fun hashCode(): Int {
+        var result = bot.hashCode()
+        result = 31 * result + id.hashCode()
+        return result
+    }
+
+    @Suppress("DuplicatedCode")
+    override fun equals(other: Any?): Boolean { // 不要删除. trust me
+        if (this === other) return true
+        if (other !is Contact) return false
+        if (this::class != other::class) return false
+        return this.id == other.id && this.bot == other.bot
+    }
+
    override fun toString(): String {
        return "Member($id)"
    }
 }

 internal class MemberInfoImpl(
-    private val jceInfo: StTroopMemberInfo,
-    private val groupOwnerId: Long
+    jceInfo: StTroopMemberInfo,
+    groupOwnerId: Long
 ) : MemberInfo {
-    override val uin: Long get() = jceInfo.memberUin
-    override val nameCard: String get() = jceInfo.sName ?: ""
-    override val nick: String get() = jceInfo.nick
-    override val permission: MemberPermission
-        get() = when {
-            jceInfo.memberUin == groupOwnerId -> MemberPermission.OWNER
-            jceInfo.dwFlag == 1L -> MemberPermission.ADMINISTRATOR
-            else -> MemberPermission.MEMBER
-        }
-    override val specialTitle: String get() = jceInfo.sSpecialTitle ?: ""
-    override val muteTimestamp: Int get() = jceInfo.dwShutupTimestap?.toInt() ?: 0
+    override val uin: Long = jceInfo.memberUin
+    override val nameCard: String = jceInfo.sName ?: ""
+    override val nick: String = jceInfo.nick
+    override val permission: MemberPermission = when {
+        jceInfo.memberUin == groupOwnerId -> MemberPermission.OWNER
+        jceInfo.dwFlag == 1L -> MemberPermission.ADMINISTRATOR
+        else -> MemberPermission.MEMBER
+    }
+    override val specialTitle: String = jceInfo.sSpecialTitle ?: ""
+    override val muteTimestamp: Int = jceInfo.dwShutupTimestap?.toInt() ?: 0
 }

 /**
@ -325,6 +339,24 @@ internal class GroupImpl(

    override lateinit var owner: Member

+    @UseExperimental(MiraiExperimentalAPI::class)
+    override val botAsMember: Member by lazy {
+        Member(object : MemberInfo {
+            override val nameCard: String
+                get() = bot.nick // TODO: 2020/2/21 机器人在群内的昵称获取
+            override val permission: MemberPermission
+                get() = botPermission
+            override val specialTitle: String
+                get() = "" // TODO: 2020/2/21 获取机器人在群里的头衔
+            override val muteTimestamp: Int
+                get() = botMuteRemaining
+            override val uin: Long
+                get() = bot.uin
+            override val nick: String
+                get() = bot.nick
+        })
+    }
+
    @UseExperimental(MiraiExperimentalAPI::class)
    override lateinit var botPermission: MemberPermission

@ -340,6 +372,9 @@ internal class GroupImpl(
    override val members: ContactList<Member> = ContactList(members.mapNotNull {
        if (it.uin == bot.uin) {
            botPermission = it.permission
+            if (it.permission == MemberPermission.OWNER) {
+                owner = botAsMember
+            }
            null
        } else Member(it).also { member ->
            if (member.permission == MemberPermission.OWNER) {
@ -475,6 +510,20 @@ internal class GroupImpl(
        TODO("not implemented")
    }

+    override suspend fun recall(source: MessageSource) {
+        if (source.senderId != bot.uin) {
+            checkBotPermissionOperator()
+        }
+
+        source.ensureSequenceIdAvailable()
+
+        bot.network.run {
+            val response = PbMessageSvc.PbMsgWithDraw.Group(bot.client, this@GroupImpl.id, source.sequenceId, source.messageUid.toInt())
+                .sendAndExpect<PbMessageSvc.PbMsgWithDraw.Response>()
+            check(response is PbMessageSvc.PbMsgWithDraw.Response.Success) { "Failed to recall message #${source.sequenceId}: $response" }
+        }
+    }
+
    @UseExperimental(MiraiExperimentalAPI::class)
    override fun Member(memberInfo: MemberInfo): Member {
        return MemberImpl(
@ -498,22 +547,27 @@ internal class GroupImpl(
        return members.delegate.filteringGetOrNull { it.id == id }
    }

-    override suspend fun sendMessage(message: MessageChain) {
+    override suspend fun sendMessage(message: MessageChain): MessageReceipt<Group> {
        check(!isBotMuted) { "bot is muted. Remaining seconds=$botMuteRemaining" }
        val event = GroupMessageSendEvent(this, message).broadcast()
        if (event.isCancelled) {
            throw EventCancelledException("cancelled by FriendMessageSendEvent")
        }
+        lateinit var source: MessageSvc.PbSendMsg.MessageSourceFromSend
        bot.network.run {
-            val response = MessageSvc.PbSendMsg.ToGroup(
+            val response: MessageSvc.PbSendMsg.Response = MessageSvc.PbSendMsg.ToGroup(
                bot.client,
                id,
                event.message
-            ).sendAndExpect<MessageSvc.PbSendMsg.Response>()
+            ) { source = it }.sendAndExpect()
            check(
                response is MessageSvc.PbSendMsg.Response.SUCCESS
            ) { "send message failed: $response" }
        }
+
+        source.startWaitingSequenceId(this)
+
+        return MessageReceipt(message, source, this)
    }

    override suspend fun uploadImage(image: ExternalImage): Image = try {
--- a/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/message/MessageSourceFromMsg.kt
+++ b/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/message/MessageSourceFromMsg.kt
@ -10,7 +10,6 @@
 package net.mamoe.mirai.qqandroid.message

 import net.mamoe.mirai.contact.Group
-import net.mamoe.mirai.message.data.MessageChain
 import net.mamoe.mirai.message.data.MessageSource
 import net.mamoe.mirai.qqandroid.io.serialization.loadAs
 import net.mamoe.mirai.qqandroid.io.serialization.toByteArray
@ -22,8 +21,14 @@ internal inline class MessageSourceFromServer(
    val delegate: ImMsgBody.SourceMsg
 ) : MessageSource {
    override val time: Long get() = delegate.time.toLong() and 0xFFFFFFFF
-    override val messageUid: Long get() = delegate.pbReserve.loadAs(SourceMsg.ResvAttr.serializer()).origUids!!
-    override val sourceMessage: MessageChain get() = delegate.toMessageChain()
+    override val sequenceId: Int get() = delegate.origSeqs?.firstOrNull() ?: error("cannot find sequenceId from ImMsgBody.SourceMsg")
+
+    override suspend fun ensureSequenceIdAvailable() {
+        // nothing to do
+    }
+
+    override val messageUid: Int get() = delegate.pbReserve.loadAs(SourceMsg.ResvAttr.serializer()).origUids!!.toInt()
+    // override val sourceMessage: MessageChain get() = delegate.toMessageChain()
    override val senderId: Long get() = delegate.senderUin
    override val groupId: Long get() = Group.calculateGroupCodeByGroupUin(delegate.toUin)

@ -34,8 +39,13 @@ internal inline class MessageSourceFromMsg(
    val delegate: MsgComm.Msg
 ) : MessageSource {
    override val time: Long get() = delegate.msgHead.msgTime.toLong() and 0xFFFFFFFF
-    override val messageUid: Long get() = delegate.msgBody.richText.attr!!.random.toLong()
-    override val sourceMessage: MessageChain get() = delegate.toMessageChain()
+    override val sequenceId: Int get() = delegate.msgHead.msgSeq
+    override suspend fun ensureSequenceIdAvailable() {
+        // nothing to do
+    }
+
+    override val messageUid: Int get() = delegate.msgBody.richText.attr!!.random
+    // override val sourceMessage: MessageChain get() = delegate.toMessageChain()
    override val senderId: Long get() = delegate.msgHead.fromUin
    override val groupId: Long get() = delegate.msgHead.groupInfo!!.groupCode

@ -52,7 +62,7 @@ internal inline class MessageSourceFromMsg(
            type = 0,
            time = delegate.msgHead.msgTime,
            pbReserve = SourceMsg.ResvAttr(
-                origUids = messageUid
+                origUids = messageUid.toLong() and 0xffFFffFF
            ).toByteArray(SourceMsg.ResvAttr.serializer()),
            srcMsg = MsgComm.Msg(
                msgHead = MsgComm.MsgHead(
@ -62,7 +72,8 @@ internal inline class MessageSourceFromMsg(
                    c2cCmd = delegate.msgHead.c2cCmd,
                    msgSeq = delegate.msgHead.msgSeq,
                    msgTime = delegate.msgHead.msgTime,
-                    msgUid = messageUid, // ok
+                    msgUid = messageUid.toLong() and 0xffFFffFF
+                    , // ok
                    groupInfo = MsgComm.GroupInfo(groupCode = delegate.msgHead.groupInfo.groupCode),
                    isSrcMsg = true
                ),
--- a/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/message/messages.kt
+++ b/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/message/messages.kt
@ -15,6 +15,7 @@ import kotlinx.io.core.readUInt
 import net.mamoe.mirai.message.data.*
 import net.mamoe.mirai.qqandroid.network.protocol.data.proto.ImMsgBody
 import net.mamoe.mirai.qqandroid.network.protocol.data.proto.MsgComm
+import net.mamoe.mirai.utils.ExternalImage
 import net.mamoe.mirai.utils.MiraiDebugAPI
 import net.mamoe.mirai.utils.MiraiInternalAPI
 import net.mamoe.mirai.utils.io.discardExact
@ -27,12 +28,13 @@ internal fun At.toJceData(): ImMsgBody.Text {
    return ImMsgBody.Text(
        str = text,
        attr6Buf = buildPacket {
-            writeShort(1)
-            writeShort(0)
-            writeShort(text.length.toShort())
-            writeByte(1)
-            writeInt(target.toInt())
-            writeShort(0)
+            // MessageForText$AtTroopMemberInfo
+            writeShort(1) // const
+            writeShort(0) // startPos
+            writeShort(text.length.toShort()) // textLen
+            writeByte(0) // flag, may=1
+            writeInt(target.toInt()) // uin
+            writeShort(0) // const
        }.readBytes()
    )
 }
@ -206,7 +208,15 @@ notOnlineImage=NotOnlineImage#2050019814 {
 private val atAllData = ImMsgBody.Elem(
    text = ImMsgBody.Text(
        str = "@全体成员",
-        attr6Buf = "00 01 00 00 00 05 01 00 00 00 00 00 00".hexToBytes()
+        attr6Buf = buildPacket {
+            // MessageForText$AtTroopMemberInfo
+            writeShort(1) // const
+            writeShort(0) // startPos
+            writeShort("@全体成员".length.toShort()) // textLen
+            writeByte(1) // flag, may=1
+            writeInt(0) // uin
+            writeShort(0) // const
+        }.readBytes()
    )
 )

@ -224,7 +234,7 @@ internal fun MessageChain.toRichTextElems(): MutableList<ImMsgBody.Elem> {
    this.forEach {
        when (it) {
            is PlainText -> elements.add(ImMsgBody.Elem(text = ImMsgBody.Text(str = it.stringValue)))
-            is At -> elements.add(ImMsgBody.Elem(text = it.toJceData()))
+            is At -> elements.add(ImMsgBody.Elem(text = it.toJceData())).also { elements.add(ImMsgBody.Elem(text = ImMsgBody.Text(str = " "))) }
            is CustomFaceFromFile -> elements.add(ImMsgBody.Elem(customFace = it.toJceData()))
            is CustomFaceFromServer -> elements.add(ImMsgBody.Elem(customFace = it.delegate))
            is NotOnlineImageFromServer -> elements.add(ImMsgBody.Elem(notOnlineImage = it.delegate))
@ -249,7 +259,7 @@ internal fun MessageChain.toRichTextElems(): MutableList<ImMsgBody.Elem> {
 internal class CustomFaceFromServer(
    internal val delegate: ImMsgBody.CustomFace
 ) : CustomFace() {
-    override val filepath: String get() = delegate.filePath
+    override val filepath: String = delegate.filePath
    override val fileId: Int get() = delegate.fileId
    override val serverIp: Int get() = delegate.serverIp
    override val serverPort: Int get() = delegate.serverPort
@ -265,14 +275,14 @@ internal class CustomFaceFromServer(
    override val size: Int get() = delegate.size
    override val original: Int get() = delegate.origin
    override val pbReserve: ByteArray get() = delegate.pbReserve
-    override val imageId: String get() = delegate.filePath
+    override val imageId: String = ExternalImage.generateImageId(delegate.md5, imageType)

    override fun equals(other: Any?): Boolean {
        return other is CustomFaceFromServer && other.filepath == this.filepath && other.md5.contentEquals(this.md5)
    }

    override fun hashCode(): Int {
-        return filepath.hashCode() + 31 * md5.hashCode()
+        return imageId.hashCode() + 31 * md5.hashCode()
    }
 }

@ -296,7 +306,7 @@ internal class NotOnlineImageFromServer(
    }

    override fun hashCode(): Int {
-        return resourceId.hashCode() + 31 * md5.hashCode()
+        return imageId.hashCode() + 31 * md5.hashCode()
    }
 }

--- a/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/QQAndroidBotNetworkHandler.kt
+++ b/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/QQAndroidBotNetworkHandler.kt
@ -374,12 +374,12 @@ internal class QQAndroidBotNetworkHandler(bot: QQAndroidBot) : BotNetworkHandler
    // with generic type, less mistakes
    private suspend fun <P : Packet?> generifiedParsePacket(input: Input) {
        KnownPacketFactories.parseIncomingPacket(bot, input) { packetFactory: PacketFactory<P>, packet: P, commandName: String, sequenceId: Int ->
-            handlePacket(packetFactory, packet, commandName, sequenceId)
            if (packet is MultiPacket<*>) {
                packet.forEach {
                    handlePacket(null, it, commandName, sequenceId)
                }
            }
+            handlePacket(packetFactory, packet, commandName, sequenceId)
        }
    }

@ -388,29 +388,6 @@ internal class QQAndroidBotNetworkHandler(bot: QQAndroidBot) : BotNetworkHandler
     */
    suspend fun <P : Packet?> handlePacket(packetFactory: PacketFactory<P>?, packet: P, commandName: String, sequenceId: Int) {
        // highest priority: pass to listeners (attached by sendAndExpect).
-        packetListeners.forEach { listener ->
-            if (listener.filter(commandName, sequenceId) && packetListeners.remove(listener)) {
-                listener.complete(packet)
-            }
-        }
-
-        // check top-level cancelling
-        if (packet != null && PacketReceivedEvent(packet).broadcast().isCancelled) {
-            return
-        }
-
-
-        // broadcast
-        if (packet is Event) {
-            if (packet is BroadcastControllable) {
-                if (packet.shouldBroadcast) packet.broadcast()
-            } else {
-                packet.broadcast()
-            }
-
-            if (packet is CancellableEvent && packet.isCancelled) return
-        }
-
        if (packet != null && (bot.logger.isEnabled || logger.isEnabled)) {
            val logMessage = "Received: ${packet.toString().replace("\n", """\n""").replace("\r", "")}"

@ -419,12 +396,32 @@ internal class QQAndroidBotNetworkHandler(bot: QQAndroidBot) : BotNetworkHandler
            } else logger.verbose(logMessage)
        }

+        packetListeners.forEach { listener ->
+            if (listener.filter(commandName, sequenceId) && packetListeners.remove(listener)) {
+                listener.complete(packet)
+            }
+        }
+
        packetFactory?.run {
            when (this) {
                is OutgoingPacketFactory<P> -> bot.handle(packet)
                is IncomingPacketFactory<P> -> bot.handle(packet, sequenceId)?.sendWithoutExpect()
            }
        }
+
+        if (packet != null && PacketReceivedEvent(packet).broadcast().isCancelled) {
+            return
+        }
+
+        if (packet is Event) {
+            if (packet is BroadcastControllable) {
+                if (packet.shouldBroadcast) packet.broadcast()
+            } else {
+                packet.broadcast()
+            }
+
+            if (packet is CancellableEvent && packet.isCancelled) return
+        }
    }

    /**
--- a/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/protocol/data/proto/MsgRevokeUserDef.kt
+++ b/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/protocol/data/proto/MsgRevokeUserDef.kt
@ -0,0 +1,38 @@
+/*
+ * Copyright 2020 Mamoe Technologies and contributors.
+ *
+ * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
+ * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
+ *
+ * https://github.com/mamoe/mirai/blob/master/LICENSE
+ */
+
+package net.mamoe.mirai.qqandroid.network.protocol.data.proto
+
+import kotlinx.serialization.SerialId
+import kotlinx.serialization.Serializable
+import net.mamoe.mirai.qqandroid.io.ProtoBuf
+
+class MsgRevokeUserDef : ProtoBuf {
+    @Serializable
+    class MsgInfoUserDef(
+        @SerialId(1) val longMessageFlag: Int = 0,
+        @SerialId(2) val longMsgInfo: List<MsgInfoDef>? = null,
+        @SerialId(3) val fileUuid: List<String> = listOf()
+    ) : ProtoBuf {
+        @Serializable
+        class MsgInfoDef(
+            @SerialId(1) val msgSeq: Int = 0,
+            @SerialId(2) val longMsgId: Int = 0,
+            @SerialId(3) val longMsgNum: Int = 0,
+            @SerialId(4) val longMsgIndex: Int = 0
+        ) : ProtoBuf
+    }
+
+    @Serializable
+    class UinTypeUserDef(
+        @SerialId(1) val fromUinType: Int = 0,
+        @SerialId(2) val fromGroupCode: Long = 0L,
+        @SerialId(3) val fileUuid: List<String> = listOf()
+    ) : ProtoBuf
+}
--- a/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/protocol/data/proto/MsgSvc.kt
+++ b/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/protocol/data/proto/MsgSvc.kt
@ -26,7 +26,7 @@ internal class MsgSvc : ProtoBuf {
    internal class PbGetMsgResp(
        @SerialId(1) val result: Int = 0,
        @SerialId(2) val errmsg: String = "",
-        @SerialId(3) val syncCookie: ByteArray = EMPTY_BYTE_ARRAY,
+        @SerialId(3) val syncCookie: ByteArray? = EMPTY_BYTE_ARRAY,
        @SerialId(4) val syncFlag: SyncFlag,
        @SerialId(5) val uinPairMsgs: List<MsgComm.UinPairMsg>? = null,
        @SerialId(6) val bindUin: Long = 0L,
--- a/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/protocol/packet/PacketFactory.kt
+++ b/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/protocol/packet/PacketFactory.kt
@ -14,6 +14,7 @@ import kotlinx.io.pool.useInstance
 import net.mamoe.mirai.data.Packet
 import net.mamoe.mirai.event.Event
 import net.mamoe.mirai.qqandroid.QQAndroidBot
+import net.mamoe.mirai.qqandroid.network.protocol.packet.chat.PbMessageSvc
 import net.mamoe.mirai.qqandroid.network.protocol.packet.chat.TroopManagement
 import net.mamoe.mirai.qqandroid.network.protocol.packet.chat.image.ImgStore
 import net.mamoe.mirai.qqandroid.network.protocol.packet.chat.image.LongConn
@ -138,7 +139,8 @@ internal object KnownPacketFactories {
        TroopManagement.GetGroupInfo,
        TroopManagement.EditGroupNametag,
        TroopManagement.Kick,
-        Heartbeat.Alive
+        Heartbeat.Alive,
+        PbMessageSvc.PbMsgWithDraw
    )

    object IncomingFactories : List<IncomingPacketFactory<*>> by mutableListOf(
--- a/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/protocol/packet/chat/PbMessageSvc.kt
+++ b/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/protocol/packet/chat/PbMessageSvc.kt
@ -0,0 +1,91 @@
+/*
+ * Copyright 2020 Mamoe Technologies and contributors.
+ *
+ * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
+ * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
+ *
+ * https://github.com/mamoe/mirai/blob/master/LICENSE
+ */
+
+package net.mamoe.mirai.qqandroid.network.protocol.packet.chat
+
+import kotlinx.io.core.ByteReadPacket
+import net.mamoe.mirai.data.Packet
+import net.mamoe.mirai.qqandroid.QQAndroidBot
+import net.mamoe.mirai.qqandroid.io.serialization.readProtoBuf
+import net.mamoe.mirai.qqandroid.io.serialization.toByteArray
+import net.mamoe.mirai.qqandroid.io.serialization.writeProtoBuf
+import net.mamoe.mirai.qqandroid.network.QQAndroidClient
+import net.mamoe.mirai.qqandroid.network.protocol.data.proto.MsgRevokeUserDef
+import net.mamoe.mirai.qqandroid.network.protocol.data.proto.MsgSvc
+import net.mamoe.mirai.qqandroid.network.protocol.packet.OutgoingPacket
+import net.mamoe.mirai.qqandroid.network.protocol.packet.OutgoingPacketFactory
+import net.mamoe.mirai.qqandroid.network.protocol.packet.buildOutgoingUniPacket
+
+internal class PbMessageSvc {
+    object PbMsgWithDraw : OutgoingPacketFactory<PbMsgWithDraw.Response>(
+        "PbMessageSvc.PbMsgWithDraw"
+    ) {
+        sealed class Response : Packet {
+            object Success : Response() {
+                override fun toString(): String {
+                    return "PbMessageSvc.PbMsgWithDraw.Response.Success"
+                }
+            }
+
+            data class Failed(
+                val result: Int,
+                val errorMessage: String
+            ) : Response()
+        }
+
+        // 12 1A 08 01 10 00 18 E7 C1 AD B8 02 22 0A 08 BF BA 03 10 BF 81 CB B7 03 2A 02 08 00
+        fun Group(
+            client: QQAndroidClient,
+            groupCode: Long,
+            messageSequenceId: Int, // 56639
+            messageRandom: Int, // 921878719
+            messageType: Int = 0
+        ): OutgoingPacket = buildOutgoingUniPacket(client) {
+            writeProtoBuf(
+                MsgSvc.PbMsgWithDrawReq.serializer(),
+                MsgSvc.PbMsgWithDrawReq(
+                    groupWithDraw = listOf(
+                        MsgSvc.PbGroupMsgWithDrawReq(
+                            subCmd = 1,
+                            groupType = 0, // 普通群
+                            groupCode = groupCode,
+                            msgList = listOf(
+                                MsgSvc.PbGroupMsgWithDrawReq.MessageInfo(
+                                    msgSeq = messageSequenceId,
+                                    msgRandom = messageRandom,
+                                    msgType = messageType
+                                )
+                            ),
+                            userdef = MsgRevokeUserDef.MsgInfoUserDef(
+                                longMessageFlag = 0
+                            ).toByteArray(MsgRevokeUserDef.MsgInfoUserDef.serializer())
+                        )
+                    )
+                )
+            )
+        }
+
+        override suspend fun ByteReadPacket.decode(bot: QQAndroidBot): Response {
+            val resp = readProtoBuf(MsgSvc.PbMsgWithDrawResp.serializer())
+            resp.groupWithDraw?.firstOrNull()?.let {
+                if (it.result != 0) {
+                    return Response.Failed(it.result, it.errmsg)
+                }
+                return Response.Success
+            }
+            resp.c2cWithDraw?.firstOrNull()?.let {
+                if (it.result != 0) {
+                    return Response.Failed(it.result, it.errmsg)
+                }
+                return Response.Success
+            }
+            return Response.Failed(-1, "No response")
+        }
+    }
+}
--- a/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/protocol/packet/chat/receive/MessageSvc.kt
+++ b/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/protocol/packet/chat/receive/MessageSvc.kt
@ -9,8 +9,11 @@

 package net.mamoe.mirai.qqandroid.network.protocol.packet.chat.receive

+import kotlinx.coroutines.Deferred
+import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.io.core.ByteReadPacket
 import kotlinx.io.core.discardExact
+import net.mamoe.mirai.contact.Contact
 import net.mamoe.mirai.contact.Group
 import net.mamoe.mirai.contact.MemberPermission
 import net.mamoe.mirai.data.MemberInfo
@ -19,8 +22,11 @@ import net.mamoe.mirai.data.Packet
 import net.mamoe.mirai.event.events.BotJoinGroupEvent
 import net.mamoe.mirai.event.events.BotOfflineEvent
 import net.mamoe.mirai.event.events.MemberJoinEvent
+import net.mamoe.mirai.event.subscribingGetAsync
 import net.mamoe.mirai.message.FriendMessage
 import net.mamoe.mirai.message.data.MessageChain
+import net.mamoe.mirai.message.data.MessageSource
+import net.mamoe.mirai.message.data.addOrRemove
 import net.mamoe.mirai.qqandroid.GroupImpl
 import net.mamoe.mirai.qqandroid.QQAndroidBot
 import net.mamoe.mirai.qqandroid.io.serialization.decodeUniPacket
@ -256,22 +262,73 @@ internal class MessageSvc {
                override fun toString(): String = "MessageSvc.PbSendMsg.Response.SUCCESS"
            }

+            /**
+             * 121: 被限制? 个别号才不能发
+             */
            data class Failed(val resultType: Int, val errorCode: Int, val errorMessage: String) : Response() {
                override fun toString(): String =
                    "MessageSvc.PbSendMsg.Response.Failed(resultType=$resultType, errorCode=$errorCode, errorMessage=$errorMessage)"
            }
        }

+        internal class MessageSourceFromSend(
+            override val messageUid: Int,
+            override val time: Long,
+            override val senderId: Long,
+            override val groupId: Long// ,
+            // override val sourceMessage: MessageChain
+        ) : MessageSource {
+            private lateinit var sequenceIdDeferred: Deferred<Int>
+
+            @UseExperimental(MiraiExperimentalAPI::class)
+            fun startWaitingSequenceId(contact: Contact) {
+                sequenceIdDeferred = contact.subscribingGetAsync<OnlinePush.PbPushGroupMsg.SendGroupMessageReceipt, Int> {
+                    if (it.messageRandom == messageUid) {
+                        it.sequenceId
+                    } else null
+                }
+            }
+
+            @UseExperimental(ExperimentalCoroutinesApi::class)
+            override val sequenceId: Int
+                get() = sequenceIdDeferred.getCompleted()
+
+            override suspend fun ensureSequenceIdAvailable() {
+                sequenceIdDeferred.join()
+            }
+
+            override fun toString(): String {
+                return ""
+            }
+        }
+
+        inline fun ToFriend(
+            client: QQAndroidClient,
+            toUin: Long,
+            message: MessageChain,
+            crossinline sourceCallback: (MessageSource) -> Unit
+        ): OutgoingPacket {
+            val source = MessageSourceFromSend(
+                messageUid = Random.nextInt().absoluteValue,
+                senderId = client.uin,
+                time = currentTimeSeconds + client.timeDifference,
+                groupId = 0//
+                //   sourceMessage = message
+            )
+            sourceCallback(source)
+            return ToFriend(client, toUin, message, source)
+        }
+
        /**
         * 发送好友消息
         */
        @Suppress("FunctionName")
-        fun ToFriend(
+        private fun ToFriend(
            client: QQAndroidClient,
            toUin: Long,
-            message: MessageChain
+            message: MessageChain,
+            source: MessageSource
        ): OutgoingPacket = buildOutgoingUniPacket(client) {
-
            ///writeFully("0A 08 0A 06 08 89 FC A6 8C 0B 12 06 08 01 10 00 18 00 1A 1F 0A 1D 12 08 0A 06 0A 04 F0 9F 92 A9 12 11 AA 02 0E 88 01 00 9A 01 08 78 00 F8 01 00 C8 02 00 20 9B 7A 28 F4 CA 9B B8 03 32 34 08 92 C2 C4 F1 05 10 92 C2 C4 F1 05 18 E6 ED B9 C3 02 20 89 FE BE A4 06 28 89 84 F9 A2 06 48 DE 8C EA E5 0E 58 D9 BD BB A0 09 60 1D 68 92 C2 C4 F1 05 70 00 40 01".hexToBytes())

            ///return@buildOutgoingUniPacket
@ -285,13 +342,32 @@ internal class MessageSvc {
                        )
                    ),
                    msgSeq = client.atomicNextMessageSequenceId(),
-                    msgRand = Random.nextInt().absoluteValue,
-                    syncCookie = SyncCookie(time = currentTimeSeconds).toByteArray(SyncCookie.serializer())
+                    msgRand = source.messageUid,
+                    syncCookie = SyncCookie(time = source.time).toByteArray(SyncCookie.serializer())
                    // msgVia = 1
                )
            )
        }

+
+        inline fun ToGroup(
+            client: QQAndroidClient,
+            groupCode: Long,
+            message: MessageChain,
+            sourceCallback: (MessageSourceFromSend) -> Unit
+        ): OutgoingPacket {
+
+            val source = MessageSourceFromSend(
+                messageUid = Random.nextInt().absoluteValue,
+                senderId = client.uin,
+                time = currentTimeSeconds + client.timeDifference,
+                groupId = groupCode//,
+                //   sourceMessage = message
+            )
+            sourceCallback(source)
+            return ToGroup(client, groupCode, message, source)
+        }
+
        /**
         * 发送群消息
         */
@ -299,14 +375,13 @@ internal class MessageSvc {
        fun ToGroup(
            client: QQAndroidClient,
            groupCode: Long,
-            message: MessageChain
+            message: MessageChain,
+            source: MessageSource
        ): OutgoingPacket = buildOutgoingUniPacket(client) {
-
            ///writeFully("0A 08 0A 06 08 89 FC A6 8C 0B 12 06 08 01 10 00 18 00 1A 1F 0A 1D 12 08 0A 06 0A 04 F0 9F 92 A9 12 11 AA 02 0E 88 01 00 9A 01 08 78 00 F8 01 00 C8 02 00 20 9B 7A 28 F4 CA 9B B8 03 32 34 08 92 C2 C4 F1 05 10 92 C2 C4 F1 05 18 E6 ED B9 C3 02 20 89 FE BE A4 06 28 89 84 F9 A2 06 48 DE 8C EA E5 0E 58 D9 BD BB A0 09 60 1D 68 92 C2 C4 F1 05 70 00 40 01".hexToBytes())

            // DebugLogger.debug("sending group message: " + message.toRichTextElems().contentToString())

-            val seq = client.atomicNextMessageSequenceId()
            ///return@buildOutgoingUniPacket
            writeProtoBuf(
                MsgSvc.PbSendMsgReq.serializer(), MsgSvc.PbSendMsgReq(
@ -317,12 +392,14 @@ internal class MessageSvc {
                            elems = message.toRichTextElems()
                        )
                    ),
-                    msgSeq = seq,
-                    msgRand = Random.nextInt().absoluteValue,
+                    msgSeq = client.atomicNextMessageSequenceId(),
+                    msgRand = source.messageUid,
                    syncCookie = EMPTY_BYTE_ARRAY,
                    msgVia = 1
                )
            )
+
+            message.addOrRemove(source)
        }

        override suspend fun ByteReadPacket.decode(bot: QQAndroidBot): Response {
--- a/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/protocol/packet/chat/receive/OnlinePush.kt
+++ b/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/network/protocol/packet/chat/receive/OnlinePush.kt
@ -19,6 +19,7 @@ import net.mamoe.mirai.contact.MemberPermission
 import net.mamoe.mirai.data.MultiPacket
 import net.mamoe.mirai.data.NoPacket
 import net.mamoe.mirai.data.Packet
+import net.mamoe.mirai.event.Event
 import net.mamoe.mirai.event.events.*
 import net.mamoe.mirai.message.GroupMessage
 import net.mamoe.mirai.qqandroid.GroupImpl
@ -46,9 +47,18 @@ internal class OnlinePush {
    /**
     * 接受群消息
     */
-    internal object PbPushGroupMsg : IncomingPacketFactory<GroupMessage?>("OnlinePush.PbPushGroupMsg") {
+    internal object PbPushGroupMsg : IncomingPacketFactory<Packet?>("OnlinePush.PbPushGroupMsg") {
+        internal class SendGroupMessageReceipt(
+            val messageRandom: Int,
+            val sequenceId: Int
+        ) : Packet, Event {
+            override fun toString(): String {
+                return "OnlinePush.PbPushGroupMsg.SendGroupMessageReceipt(messageRandom=$messageRandom, sequenceId=$sequenceId)"
+            }
+        }
+
        @UseExperimental(ExperimentalStdlibApi::class)
-        override suspend fun ByteReadPacket.decode(bot: QQAndroidBot, sequenceId: Int): GroupMessage? {
+        override suspend fun ByteReadPacket.decode(bot: QQAndroidBot, sequenceId: Int): Packet? {
            // 00 00 02 E4 0A D5 05 0A 4F 08 A2 FF 8C F0 03 10 DD F1 92 B7 07 18 52 20 00 28 BC 3D 30 8C 82 AB F1 05 38 D2 80 E0 8C 80 80 80 80 02 4A 21 08 E7 C1 AD B8 02 10 01 18 BA 05 22 09 48 69 6D 31 38 38 6D 6F 65 30 06 38 02 42 05 4D 69 72 61 69 50 01 58 01 60 00 88 01 08 12 06 08 01 10 00 18 00 1A F9 04 0A F6 04 0A 26 08 00 10 87 82 AB F1 05 18 B7 B4 BF 30 20 00 28 0C 30 00 38 86 01 40 22 4A 0C E5 BE AE E8 BD AF E9 9B 85 E9 BB 91 12 E6 03 42 E3 03 12 2A 7B 34 45 31 38 35 38 32 32 2D 30 45 37 42 2D 46 38 30 46 2D 43 35 42 31 2D 33 34 34 38 38 33 37 34 44 33 39 43 7D 2E 6A 70 67 22 00 2A 04 03 00 00 00 32 60 15 36 20 39 36 6B 45 31 41 38 35 32 32 39 64 63 36 39 38 34 37 39 37 37 62 20 20 20 20 20 20 35 30 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 7B 34 45 31 38 35 38 32 32 2D 30 45 37 42 2D 46 38 30 46 2D 43 35 42 31 2D 33 34 34 38 38 33 37 34 44 33 39 43 7D 2E 6A 70 67 31 32 31 32 41 38 C6 BB 8A A9 08 40 FB AE 9E C2 09 48 50 50 41 5A 00 60 01 6A 10 4E 18 58 22 0E 7B F8 0F C5 B1 34 48 83 74 D3 9C 72 59 2F 67 63 68 61 74 70 69 63 5F 6E 65 77 2F 31 30 34 30 34 30 30 32 39 30 2F 36 35 35 30 35 37 31 32 37 2D 32 32 33 33 36 33 38 33 34 32 2D 34 45 31 38 35 38 32 32 30 45 37 42 46 38 30 46 43 35 42 31 33 34 34 38 38 33 37 34 44 33 39 43 2F 31 39 38 3F 74 65 72 6D 3D 32 82 01 57 2F 67 63 68 61 74 70 69 63 5F 6E 65 77 2F 31 30 34 30 34 30 30 32 39 30 2F 36 35 35 30 35 37 31 32 37 2D 32 32 33 33 36 33 38 33 34 32 2D 34 45 31 38 35 38 32 32 30 45 37 42 46 38 30 46 43 35 42 31 33 34 34 38 38 33 37 34 44 33 39 43 2F 30 3F 74 65 72 6D 3D 32 B0 01 4D B8 01 2E C8 01 FF 05 D8 01 4D E0 01 2E FA 01 59 2F 67 63 68 61 74 70 69 63 5F 6E 65 77 2F 31 30 34 30 34 30 30 32 39 30 2F 36 35 35 30 35 37 31 32 37 2D 32 32 33 33 36 33 38 33 34 32 2D 34 45 31 38 35 38 32 32 30 45 37 42 46 38 30 46 43 35 42 31 33 34 34 38 38 33 37 34 44 33 39 43 2F 34 30 30 3F 74 65 72 6D 3D 32 80 02 4D 88 02 2E 12 45 AA 02 42 50 03 60 00 68 00 9A 01 39 08 09 20 BF 50 80 01 01 C8 01 00 F0 01 00 F8 01 00 90 02 00 98 03 00 A0 03 20 B0 03 00 C0 03 00 D0 03 00 E8 03 00 8A 04 04 08 02 08 01 90 04 80 80 80 10 B8 04 00 C0 04 00 12 06 4A 04 08 00 40 01 12 14 82 01 11 0A 09 48 69 6D 31 38 38 6D 6F 65 18 06 20 08 28 03 10 8A CA 9D A1 07 1A 00
            if (!bot.firstLoginSucceed) return null
            val pbPushMsg = readProtoBuf(MsgOnlinePush.PbPushMsg.serializer())
@ -56,7 +66,7 @@ internal class OnlinePush {
            val extraInfo: ImMsgBody.ExtraInfo? = pbPushMsg.msg.msgBody.richText.elems.firstOrNull { it.extraInfo != null }?.extraInfo

            if (pbPushMsg.msg.msgHead.fromUin == bot.uin) {
-                return null
+                return SendGroupMessageReceipt(pbPushMsg.msg.msgBody.richText.attr!!.random, pbPushMsg.msg.msgHead.msgSeq)
            }

            val group = bot.getGroup(pbPushMsg.msg.msgHead.groupInfo!!.groupCode)
@ -64,8 +74,6 @@ internal class OnlinePush {
            // println(pbPushMsg.msg.msgBody.richText.contentToString())
            val flags = extraInfo?.flags ?: 0
            return GroupMessage(
-                bot = bot,
-                group = group,
                senderName = pbPushMsg.msg.msgHead.groupInfo.groupCard,
                sender = group[pbPushMsg.msg.msgHead.fromUin],
                message = pbPushMsg.msg.toMessageChain(),
--- a/mirai-core-qqandroid/src/jvmTest/kotlin/androidPacketTests/clientToServer.kt
+++ b/mirai-core-qqandroid/src/jvmTest/kotlin/androidPacketTests/clientToServer.kt
@ -107,6 +107,8 @@ fun main() {
 * 顶层方法. TCP 切掉头后直接来这里
 */
 fun ByteReadPacket.decodeMultiClientToServerPackets() {
+    DebugLogger.enable()
+    PacketLogger.enable()
    println("=======================处理客户端到服务器=======================")
    var count = 0
    while (remaining != 0L) {
--- a/mirai-core-qqandroid/src/jvmTest/kotlin/test/ProtoBufDataClassGenerator.kt
+++ b/mirai-core-qqandroid/src/jvmTest/kotlin/test/ProtoBufDataClassGenerator.kt
@ -25,7 +25,7 @@ fun main() {
    println(
        File(
            """
-            E:\Projects\QQAndroidFF\app\src\main\java\tencent\im\statsvc\getonline
+            E:\Projects\QQAndroidFF\app\src\main\java\tencent\im\msgrevoke
        """.trimIndent()
        )
            .generateUnarrangedClasses().toMutableList().arrangeClasses().joinToString("\n\n")
--- a/mirai-core/src/androidMain/kotlin/net/mamoe/mirai/message/MessagePacket.kt
+++ b/mirai-core/src/androidMain/kotlin/net/mamoe/mirai/message/MessagePacket.kt
@ -9,7 +9,6 @@

 package net.mamoe.mirai.message

-import net.mamoe.mirai.Bot
 import net.mamoe.mirai.contact.Contact
 import net.mamoe.mirai.contact.QQ
 import net.mamoe.mirai.utils.MiraiInternalAPI
@ -18,7 +17,7 @@ import net.mamoe.mirai.utils.MiraiInternalAPI
 * 平台相关扩展
 */
@UseExperimental(MiraiInternalAPI::class)
-actual abstract class MessagePacket<TSender : QQ, TSubject : Contact> actual constructor(bot: Bot) : MessagePacketBase<TSender, TSubject>(bot) {
+actual abstract class MessagePacket<TSender : QQ, TSubject : Contact> actual constructor() : MessagePacketBase<TSender, TSubject>() {
    //   suspend inline fun uploadImage(image: Bitmap): Image = subject.uploadImage(image)
    //suspend inline fun uploadImage(image: URL): Image = subject.uploadImage(image)
    //suspend inline fun uploadImage(image: Input): Image = subject.uploadImage(image)
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/Bot.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/Bot.kt
@ -84,7 +84,7 @@ abstract class Bot : CoroutineScope {
     */
    @MiraiExperimentalAPI("还未支持")
    val nick: String
-        get() = TODO("bot 昵称获取")
+        get() = ""// TODO("bot 昵称获取")

    /**
     * 日志记录器
@ -175,8 +175,6 @@ abstract class Bot : CoroutineScope {
     */
    abstract suspend fun queryGroupMemberList(groupUin: Long, groupCode: Long, ownerId: Long): Sequence<MemberInfo>

-    // TODO 目前还不能构造群对象. 这将在以后支持
-
    // endregion

    // region network
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Contact.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Contact.kt
@ -18,6 +18,7 @@ import net.mamoe.mirai.event.events.EventCancelledException
 import net.mamoe.mirai.event.events.ImageUploadEvent
 import net.mamoe.mirai.event.events.MessageSendEvent.FriendMessageSendEvent
 import net.mamoe.mirai.event.events.MessageSendEvent.GroupMessageSendEvent
+import net.mamoe.mirai.message.MessageReceipt
 import net.mamoe.mirai.message.data.*
 import net.mamoe.mirai.utils.ExternalImage
 import net.mamoe.mirai.utils.WeakRefProperty
@ -40,6 +41,9 @@ interface Contact : CoroutineScope {
     *
     * 对于 [QQ], `uin` 与 `id` 是相同的意思.
     * 对于 [Group], `groupCode` 与 `id` 是相同的意思.
+     *
+     * @see QQ.id
+     * @see Group.id
     */
    val id: Long

@ -51,8 +55,10 @@ interface Contact : CoroutineScope {
     *
     * @throws EventCancelledException 当发送消息事件被取消
     * @throws IllegalStateException 发送群消息时若 [Bot] 被禁言抛出
+     *
+     * @return 消息回执. 可 [引用回复][MessageReceipt.quote]（仅群聊）或 [撤回][MessageReceipt.recall] 这条消息.
     */
-    suspend fun sendMessage(message: MessageChain)
+    suspend fun sendMessage(message: MessageChain): MessageReceipt<out Contact>

    /**
     * 上传一个图片以备发送.
@ -88,4 +94,4 @@ interface Contact : CoroutineScope {

 suspend inline fun Contact.sendMessage(message: Message) = sendMessage(message.toChain())

-suspend inline fun Contact.sendMessage(plain: String) = sendMessage(plain.singleChain())
+suspend inline fun Contact.sendMessage(plain: String) = sendMessage(plain.toMessage())
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/ContactList.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/ContactList.kt
@ -40,6 +40,15 @@ class ContactList<C : Contact>(@MiraiInternalAPI val delegate: LockFreeLinkedLis
    fun containsAll(elements: Collection<C>): Boolean = elements.all { contains(it) }
    fun isEmpty(): Boolean = delegate.isEmpty()
    inline fun forEach(block: (C) -> Unit) = delegate.forEach(block)
+    fun first(): C {
+        forEach { return it }
+        throw NoSuchElementException()
+    }
+
+    fun firstOrNull(): C? {
+        forEach { return it }
+        return null
+    }

    override fun toString(): String = delegate.joinToString(separator = ", ", prefix = "ContactList(", postfix = ")")
 }
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Group.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Group.kt
@ -11,11 +11,21 @@

 package net.mamoe.mirai.contact

+import kotlinx.coroutines.CoroutineName
 import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.launch
 import net.mamoe.mirai.Bot
 import net.mamoe.mirai.data.MemberInfo
 import net.mamoe.mirai.event.events.*
+import net.mamoe.mirai.event.events.MessageSendEvent.FriendMessageSendEvent
+import net.mamoe.mirai.event.events.MessageSendEvent.GroupMessageSendEvent
+import net.mamoe.mirai.message.MessageReceipt
+import net.mamoe.mirai.message.data.MessageChain
+import net.mamoe.mirai.message.data.MessageSource
 import net.mamoe.mirai.utils.MiraiExperimentalAPI
+import kotlin.coroutines.CoroutineContext
+import kotlin.coroutines.EmptyCoroutineContext
 import kotlin.jvm.JvmName

 /**
@ -83,10 +93,18 @@ interface Group : Contact, CoroutineScope {
    override val id: Long

    /**
-     * 群主
+     * 群主.
+     *
+     * @return 若机器人是群主, 返回 [botAsMember]. 否则返回相应的成员
     */
    val owner: Member

+    /**
+     * [Bot] 在群内的 [Member] 实例
+     */
+    @MiraiExperimentalAPI
+    val botAsMember: Member
+
    /**
     * 机器人被禁言还剩余多少秒
     *
@ -133,6 +151,17 @@ interface Group : Contact, CoroutineScope {
    @MiraiExperimentalAPI("还未支持")
    suspend fun quit(): Boolean

+    /**
+     * 撤回这条消息.
+     *
+     * [Bot] 撤回自己的消息不需要权限.
+     * [Bot] 撤回群员的消息需要管理员权限.
+     *
+     * @throws PermissionDeniedException 当 [Bot] 无权限操作时
+     * @see Group.recall (扩展函数) 接受参数 [MessageChain]
+     */
+    suspend fun recall(source: MessageSource)
+
    /**
     * 构造一个 [Member].
     * 非特殊情况请不要使用这个函数. 优先使用 [get].
@ -142,6 +171,19 @@ interface Group : Contact, CoroutineScope {
    @JvmName("newMember")
    fun Member(memberInfo: MemberInfo): Member

+    /**
+     * 向这个对象发送消息.
+     *
+     * @see FriendMessageSendEvent 发送好友信息事件, cancellable
+     * @see GroupMessageSendEvent  发送群消息事件. cancellable
+     *
+     * @throws EventCancelledException 当发送消息事件被取消
+     * @throws IllegalStateException 发送群消息时若 [Bot] 被禁言抛出
+     *
+     * @return 消息回执. 可进行撤回 ([MessageReceipt.recall])
+     */
+    override suspend fun sendMessage(message: MessageChain): MessageReceipt<Group>
+
    companion object {

        /**
@ -184,7 +226,52 @@ interface Group : Contact, CoroutineScope {
    fun toFullString(): String = "Group(id=${this.id}, name=$name, owner=${owner.id}, members=${members.idContentString})"
 }

+/**
+ * 撤回这条消息.
+ *
+ * [Bot] 撤回自己的消息不需要权限.
+ * [Bot] 撤回群员的消息需要管理员权限.
+ *
+ * @throws PermissionDeniedException 当 [Bot] 无权限操作时
+ * @see Group.recall
+ */
+suspend inline fun Group.recall(message: MessageChain) = this.recall(message[MessageSource])
+
+/**
+ * 在一段时间后撤回这条消息.
+ *
+ * @param millis 延迟的时间, 单位为毫秒
+ * @param coroutineContext 额外的 [CoroutineContext]
+ * @see recall
+ */
+fun Group.recallIn(
+    message: MessageSource,
+    millis: Long,
+    coroutineContext: CoroutineContext = EmptyCoroutineContext
+): Job = this.launch(coroutineContext + CoroutineName("MessageRecall")) {
+    kotlinx.coroutines.delay(millis)
+    recall(message)
+}
+
+/**
+ * 在一段时间后撤回这条消息.
+ *
+ * @param millis 延迟的时间, 单位为毫秒
+ * @param coroutineContext 额外的 [CoroutineContext]
+ * @see recall
+ */
+fun Group.recallIn(
+    message: MessageChain,
+    millis: Long,
+    coroutineContext: CoroutineContext = EmptyCoroutineContext
+): Job = this.launch(coroutineContext + CoroutineName("MessageRecall")) {
+    kotlinx.coroutines.delay(millis)
+    recall(message)
+}
+
 /**
 * 返回机器人是否正在被禁言
+ *
+ * @see Group.botMuteRemaining 剩余禁言时间
 */
 val Group.isBotMuted: Boolean get() = this.botMuteRemaining != 0
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Member.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Member.kt
@ -72,6 +72,9 @@ interface Member : QQ, Contact {
    /**
     * 禁言.
     *
+     * QQ 中最小操作和显示的时间都是一分钟.
+     * 机器人可以实现精确到秒, 会被客户端显示为 1 分钟但不影响实际禁言时间.
+     *
     * 管理员可禁言成员, 群主可禁言管理员和群员.
     *
     * @param durationSeconds 持续时间. 精确到秒. 范围区间表示为 `(0s, 30days]`. 超过范围则会抛出异常.
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/QQ.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/QQ.kt
@ -16,6 +16,11 @@ import net.mamoe.mirai.Bot
 import net.mamoe.mirai.data.FriendNameRemark
 import net.mamoe.mirai.data.PreviousNameList
 import net.mamoe.mirai.data.Profile
+import net.mamoe.mirai.event.events.EventCancelledException
+import net.mamoe.mirai.event.events.MessageSendEvent.FriendMessageSendEvent
+import net.mamoe.mirai.event.events.MessageSendEvent.GroupMessageSendEvent
+import net.mamoe.mirai.message.MessageReceipt
+import net.mamoe.mirai.message.data.MessageChain
 import net.mamoe.mirai.utils.MiraiExperimentalAPI

 /**
@ -68,4 +73,17 @@ interface QQ : Contact, CoroutineScope {
     */
    @MiraiExperimentalAPI("还未支持")
    suspend fun queryRemark(): FriendNameRemark
+
+    /**
+     * 向这个对象发送消息.
+     *
+     * @see FriendMessageSendEvent 发送好友信息事件, cancellable
+     * @see GroupMessageSendEvent  发送群消息事件. cancellable
+     *
+     * @throws EventCancelledException 当发送消息事件被取消
+     * @throws IllegalStateException 发送群消息时若 [Bot] 被禁言抛出
+     *
+     * @return 消息回执. 可进行撤回 ([MessageReceipt.recall])
+     */
+    override suspend fun sendMessage(message: MessageChain): MessageReceipt<QQ>
 }
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/data/GroupInfo.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/data/GroupInfo.kt
@ -62,4 +62,15 @@ interface GroupInfo {
     * 机器人被禁言还剩时间, 秒.
     */
    val botMuteRemaining: Int
+
+    /*
+    /**
+     * 机器人的头衔
+     */
+    val botSpecialTitle: String
+
+    /**
+     * 机器人的昵称
+     */
+    val botNameCard: String*/
 }
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/Subscribable.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/Subscribable.kt
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/linear.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/linear.kt
@ -0,0 +1,112 @@
+/*
+ * Copyright 2020 Mamoe Technologies and contributors.
+ *
+ * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
+ * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
+ *
+ * https://github.com/mamoe/mirai/blob/master/LICENSE
+ */
+
+package net.mamoe.mirai.event
+
+import kotlinx.coroutines.*
+import net.mamoe.mirai.utils.MiraiExperimentalAPI
+import kotlin.coroutines.CoroutineContext
+import kotlin.coroutines.EmptyCoroutineContext
+
+/**
+ * 挂起当前协程, 监听这个事件, 并尝试从这个事件中获取一个值.
+ *
+ * 若 [filter] 抛出了一个异常, 本函数会立即抛出这个异常.
+ *
+ * @param timeoutMillis 超时. 单位为毫秒. `-1` 为不限制
+ * @param filter 过滤器. 返回非 null 则代表得到了需要的值. [subscribingGet] 会返回这个值
+ *
+ * @see subscribingGetAsync 本函数的异步版本
+ */
+@MiraiExperimentalAPI
+suspend inline fun <reified E : Event, R : Any> subscribingGet(
+    timeoutMillis: Long = -1,
+    noinline filter: E.(E) -> R? // 不要 crossinline: crossinline 后 stacktrace 会不正常
+): R {
+    require(timeoutMillis == -1L || timeoutMillis > 0) { "timeoutMillis must be -1 or > 0" }
+    return subscribingGetOrNull(timeoutMillis, filter) ?: error("timeout subscribingGet")
+}
+
+/**
+ * 挂起当前协程, 监听这个事件, 并尝试从这个事件中获取一个值.
+ *
+ * 若 [filter] 抛出了一个异常, 本函数会立即抛出这个异常.
+ *
+ * @param timeoutMillis 超时. 单位为毫秒. `-1` 为不限制
+ * @param filter 过滤器. 返回非 null 则代表得到了需要的值. [subscribingGet] 会返回这个值
+ *
+ * @see subscribingGetAsync 本函数的异步版本
+ */
+@MiraiExperimentalAPI
+suspend inline fun <reified E : Event, R : Any> subscribingGetOrNull(
+    timeoutMillis: Long = -1,
+    noinline filter: E.(E) -> R? // 不要 crossinline: crossinline 后 stacktrace 会不正常
+): R? {
+    require(timeoutMillis == -1L || timeoutMillis > 0) { "timeoutMillis must be -1 or > 0" }
+    var result: R? = null
+    var resultThrowable: Throwable? = null
+
+    if (timeoutMillis == -1L) {
+        @Suppress("DuplicatedCode") // for better performance
+        coroutineScope {
+            var listener: Listener<E>? = null
+            listener = this.subscribe {
+                val value = try {
+                    filter.invoke(this, it)
+                } catch (e: Exception) {
+                    resultThrowable = e
+                    return@subscribe ListeningStatus.STOPPED.also { listener!!.complete() }
+                }
+
+                if (value != null) {
+                    result = value
+                    return@subscribe ListeningStatus.STOPPED.also { listener!!.complete() }
+                } else return@subscribe ListeningStatus.LISTENING
+            }
+        }
+    } else {
+        withTimeoutOrNull(timeoutMillis) {
+            var listener: Listener<E>? = null
+            @Suppress("DuplicatedCode") // for better performance
+            listener = this.subscribe {
+                val value = try {
+                    filter.invoke(this, it)
+                } catch (e: Exception) {
+                    resultThrowable = e
+                    return@subscribe ListeningStatus.STOPPED.also { listener!!.complete() }
+                }
+
+                if (value != null) {
+                    result = value
+                    return@subscribe ListeningStatus.STOPPED.also { listener!!.complete() }
+                } else return@subscribe ListeningStatus.LISTENING
+            }
+        }
+    }
+    resultThrowable?.let { throw it }
+    return result
+}
+
+/**
+ * 异步监听这个事件, 并尝试从这个事件中获取一个值.
+ *
+ * 若 [filter] 抛出了一个异常, [Deferred.await] 会抛出这个异常或.
+ *
+ * @param timeoutMillis 超时. 单位为毫秒. `-1` 为不限制
+ * @param coroutineContext 额外的 [CoroutineContext]
+ * @param filter 过滤器. 返回非 null 则代表得到了需要的值. [subscribingGet] 会返回这个值
+ */
+@MiraiExperimentalAPI
+inline fun <reified E : Event, R : Any> CoroutineScope.subscribingGetAsync(
+    coroutineContext: CoroutineContext = EmptyCoroutineContext,
+    timeoutMillis: Long = -1,
+    noinline filter: E.(E) -> R? // 不要 crossinline: crossinline 后 stacktrace 会不正常
+): Deferred<R> = this.async(coroutineContext) {
+    subscribingGet(timeoutMillis, filter)
+}
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/MessageSubscribers.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/MessageSubscribers.kt
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/Subscribers.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/event/Subscribers.kt
@ -101,6 +101,9 @@ interface Listener<in E : Event> : CompletableJob {
 *
 * @param coroutineContext 给事件监听协程的额外的 [CoroutineContext]
 *
+ * @see subscribingGet 监听一个事件, 并尝试从这个事件中获取一个值.
+ * @see subscribingGetAsync 异步监听一个事件, 并尝试从这个事件中获取一个值.
+ *
 * @see subscribeAlways 一直监听
 * @see subscribeOnce   只监听一次
 *
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/FriendMessage.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/FriendMessage.kt
@ -13,12 +13,16 @@ import net.mamoe.mirai.Bot
 import net.mamoe.mirai.contact.QQ
 import net.mamoe.mirai.event.BroadcastControllable
 import net.mamoe.mirai.message.data.MessageChain
+import net.mamoe.mirai.utils.getValue
+import net.mamoe.mirai.utils.unsafeWeakRef

 class FriendMessage(
    bot: Bot,
-    override val sender: QQ,
+    sender: QQ,
    override val message: MessageChain
-) : MessagePacket<QQ, QQ>(bot), BroadcastControllable {
+) : MessagePacket<QQ, QQ>(), BroadcastControllable {
+    override val sender: QQ by sender.unsafeWeakRef()
+    override val bot: Bot get() = sender.bot
    override val subject: QQ get() = sender

    override fun toString(): String = "FriendMessage(sender=${sender.id}, message=$message)"
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/GroupMessage.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/GroupMessage.kt
@ -9,21 +9,19 @@

 package net.mamoe.mirai.message

+import kotlinx.coroutines.Job
 import net.mamoe.mirai.Bot
-import net.mamoe.mirai.contact.Group
-import net.mamoe.mirai.contact.Member
-import net.mamoe.mirai.contact.MemberPermission
+import net.mamoe.mirai.contact.*
 import net.mamoe.mirai.event.Event
 import net.mamoe.mirai.message.data.Message
 import net.mamoe.mirai.message.data.MessageChain
+import net.mamoe.mirai.message.data.MessageSource
 import net.mamoe.mirai.utils.getValue
 import net.mamoe.mirai.utils.unsafeWeakRef
 import kotlin.jvm.JvmName

@Suppress("unused", "NOTHING_TO_INLINE")
 class GroupMessage(
-    bot: Bot,
-    group: Group,
    val senderName: String,
    /**
     * 发送方权限.
@ -31,9 +29,10 @@ class GroupMessage(
    val permission: MemberPermission,
    sender: Member,
    override val message: MessageChain
-) : MessagePacket<Member, Group>(bot), Event {
-    val group: Group by group.unsafeWeakRef()
+) : MessagePacket<Member, Group>(), Event {
    override val sender: Member by sender.unsafeWeakRef()
+    val group: Group get() = sender.group
+    override val bot: Bot get() = sender.bot

    override val subject: Group get() = group

@ -45,20 +44,25 @@ class GroupMessage(
     * 对于好友消息事件, 这个方法将会给好友 ([subject]) 发送消息
     * 对于群消息事件, 这个方法将会给群 ([subject]) 发送消息
     */
-    suspend inline fun quoteReply(message: MessageChain) = reply(this.message.quote() + message)
+    suspend inline fun quoteReply(message: MessageChain): MessageReceipt<Group> = reply(this.message.quote() + message)

-    suspend inline fun quoteReply(message: Message) = reply(this.message.quote() + message)
-    suspend inline fun quoteReply(plain: String) = reply(this.message.quote() + plain)
+    suspend inline fun quoteReply(message: Message): MessageReceipt<Group> = reply(this.message.quote() + message)
+    suspend inline fun quoteReply(plain: String): MessageReceipt<Group> = reply(this.message.quote() + plain)


    @JvmName("reply2")
-    suspend inline fun String.quoteReply() = quoteReply(this)
+    suspend inline fun String.quoteReply(): MessageReceipt<Group> = quoteReply(this)

    @JvmName("reply2")
-    suspend inline fun Message.quoteReply() = quoteReply(this)
+    suspend inline fun Message.quoteReply(): MessageReceipt<Group> = quoteReply(this)

    @JvmName("reply2")
-    suspend inline fun MessageChain.quoteReply() = quoteReply(this)
+    suspend inline fun MessageChain.quoteReply(): MessageReceipt<Group> = quoteReply(this)
+
+    suspend inline fun MessageChain.recall() = group.recall(this)
+    suspend inline fun MessageSource.recall() = group.recall(this)
+    inline fun MessageSource.recallIn(delay: Long): Job = group.recallIn(this, delay)
+    inline fun MessageChain.recallIn(delay: Long): Job = group.recallIn(this, delay)

    override fun toString(): String =
        "GroupMessage(group=${group.id}, senderName=$senderName, sender=${sender.id}, permission=${permission.name}, message=$message)"
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/MessagePacket.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/MessagePacket.kt
@ -21,6 +21,8 @@ import net.mamoe.mirai.contact.Member
 import net.mamoe.mirai.contact.QQ
 import net.mamoe.mirai.data.Packet
 import net.mamoe.mirai.event.events.BotEvent
+import net.mamoe.mirai.event.subscribingGet
+import net.mamoe.mirai.event.subscribingGetAsync
 import net.mamoe.mirai.message.data.*
 import net.mamoe.mirai.utils.*
 import kotlin.jvm.JvmName
@ -30,18 +32,19 @@ import kotlin.jvm.JvmName
 * 请查看各平台的 `actual` 实现的说明.
 */
@UseExperimental(MiraiInternalAPI::class)
-expect abstract class MessagePacket<TSender : QQ, TSubject : Contact>(bot: Bot) : MessagePacketBase<TSender, TSubject>
+expect abstract class MessagePacket<TSender : QQ, TSubject : Contact>() : MessagePacketBase<TSender, TSubject>

 /**
 * 仅内部使用, 请使用 [MessagePacket]
 */ // Tips: 在 IntelliJ 中 (左侧边栏) 打开 `Structure`, 可查看类结构
-@Suppress("NOTHING_TO_INLINE")
+@Suppress("NOTHING_TO_INLINE", "UNCHECKED_CAST")
@MiraiInternalAPI
-abstract class MessagePacketBase<TSender : QQ, TSubject : Contact>(_bot: Bot) : Packet, BotEvent {
+abstract class MessagePacketBase<TSender : QQ, TSubject : Contact> : Packet, BotEvent {
    /**
     * 接受到这条消息的
     */
-    override val bot: Bot by _bot.unsafeWeakRef()
+    @WeakRefProperty
+    abstract override val bot: Bot

    /**
     * 消息事件主体.
@ -51,6 +54,7 @@ abstract class MessagePacketBase<TSender : QQ, TSubject : Contact>(_bot: Bot) :
     *
     * 在回复消息时, 可通过 [subject] 作为回复对象
     */
+    @WeakRefProperty
    abstract val subject: TSubject

    /**
@ -58,6 +62,7 @@ abstract class MessagePacketBase<TSender : QQ, TSubject : Contact>(_bot: Bot) :
     *
     * 在好友消息时为 [QQ] 的实例, 在群消息时为 [Member] 的实例
     */
+    @WeakRefProperty
    abstract val sender: TSender

    /**
@ -73,20 +78,19 @@ abstract class MessagePacketBase<TSender : QQ, TSubject : Contact>(_bot: Bot) :
     * 对于好友消息事件, 这个方法将会给好友 ([subject]) 发送消息
     * 对于群消息事件, 这个方法将会给群 ([subject]) 发送消息
     */
-    suspend inline fun reply(message: MessageChain) = subject.sendMessage(message)
+    suspend inline fun reply(message: MessageChain): MessageReceipt<TSubject> = subject.sendMessage(message) as MessageReceipt<TSubject>

-    suspend inline fun reply(message: Message) = subject.sendMessage(message.toChain())
-    suspend inline fun reply(plain: String) = subject.sendMessage(plain.singleChain())
+    suspend inline fun reply(message: Message): MessageReceipt<TSubject> = subject.sendMessage(message.toChain()) as MessageReceipt<TSubject>
+    suspend inline fun reply(plain: String): MessageReceipt<TSubject> = subject.sendMessage(plain.toMessage().toChain()) as MessageReceipt<TSubject>

    @JvmName("reply1")
-    suspend inline fun String.reply() = reply(this)
+    suspend inline fun String.reply(): MessageReceipt<TSubject> = reply(this)

    @JvmName("reply1")
-    suspend inline fun Message.reply() = reply(this)
+    suspend inline fun Message.reply(): MessageReceipt<TSubject> = reply(this)

    @JvmName("reply1")
-    suspend inline fun MessageChain.reply() = reply(this)
-
+    suspend inline fun MessageChain.reply(): MessageReceipt<TSubject> = reply(this)
    // endregion

    // region
@ -110,12 +114,16 @@ abstract class MessagePacketBase<TSender : QQ, TSubject : Contact>(_bot: Bot) :
    suspend inline fun String.send() = this.toMessage().sendTo(subject)
    // endregion

+    operator fun <M : Message> get(at: Message.Key<M>): M {
+        return this.message[at]
+    }
+
    /**
     * 创建 @ 这个账号的消息. 当且仅当消息为群消息时可用. 否则将会抛出 [IllegalArgumentException]
     */
-    inline fun QQ.at(): At = At(this as? Member ?: error("`QQ.at` can only be used in GroupMessage"))
+    fun QQ.at(): At = At(this as? Member ?: error("`QQ.at` can only be used in GroupMessage"))

-    inline fun At.member(): Member = (this@MessagePacketBase as? GroupMessage)?.group?.get(this.target) ?: error("`At.member` can only be used in GroupMessage")
+    fun At.member(): Member = (this@MessagePacketBase as? GroupMessage)?.group?.get(this.target) ?: error("`At.member` can only be used in GroupMessage")

    // endregion

@ -135,16 +143,47 @@ abstract class MessagePacketBase<TSender : QQ, TSubject : Contact>(_bot: Bot) :
     */
    suspend inline fun Image.download(): ByteReadPacket = bot.run { download() }
    // endregion
+}

-    @Deprecated(message = "这个函数有歧义, 将在不久后删除", replaceWith = ReplaceWith("bot.getFriend(this.target)"))
-    fun At.qq(): QQ = bot.getFriend(this.target)
+/**
+ * 判断两个 [MessagePacket] 的 [MessagePacket.sender] 和 [MessagePacket.subject] 是否相同
+ */
+fun MessagePacket<*, *>.isContextIdenticalWith(another: MessagePacket<*, *>): Boolean {
+    return this.sender == another.sender && this.subject == another.subject
+}

-    @Deprecated(message = "这个函数有歧义, 将在不久后删除", replaceWith = ReplaceWith("bot.getFriend(this.toLong())"))
-    fun Int.qq(): QQ = bot.getFriend(this.coerceAtLeastOrFail(0).toLong())
+/**
+ * 挂起当前协程, 等待下一条 [MessagePacket.sender] 和 [MessagePacket.subject] 与 [P] 相同且通过 [筛选][filter] 的 [MessagePacket]
+ *
+ * 若 [filter] 抛出了一个异常, 本函数会立即抛出这个异常.
+ *
+ * @param timeoutMillis 超时. 单位为毫秒. `-1` 为不限制
+ * @param filter 过滤器. 返回非 null 则代表得到了需要的值. [subscribingGet] 会返回这个值
+ *
+ * @see subscribingGetAsync 本函数的异步版本
+ */
+suspend inline fun <reified P : MessagePacket<*, *>> P.nextMessage(
+    timeoutMillis: Long = -1,
+    crossinline filter: P.(P) -> Boolean
+): MessageChain {
+    return subscribingGet<P, P>(timeoutMillis) {
+        takeIf { this.isContextIdenticalWith(this@nextMessage) }?.takeIf { filter(it, it) }
+    }.message
+}

-    @Deprecated(message = "这个函数有歧义, 将在不久后删除", replaceWith = ReplaceWith("bot.getFriend(this)"))
-    fun Long.qq(): QQ = bot.getFriend(this.coerceAtLeastOrFail(0))
-
-    @Deprecated(message = "这个函数有歧义, 将在不久后删除", replaceWith = ReplaceWith("bot.getGroup(this)"))
-    fun Long.group(): Group = bot.getGroup(this)
+/**
+ * 挂起当前协程, 等待下一条 [MessagePacket.sender] 和 [MessagePacket.subject] 与 [P] 相同的 [MessagePacket]
+ *
+ * 若 [filter] 抛出了一个异常, 本函数会立即抛出这个异常.
+ *
+ * @param timeoutMillis 超时. 单位为毫秒. `-1` 为不限制
+ *
+ * @see subscribingGetAsync 本函数的异步版本
+ */
+suspend inline fun <reified P : MessagePacket<*, *>> P.nextMessage(
+    timeoutMillis: Long = -1
+): MessageChain {
+    return subscribingGet<P, P>(timeoutMillis) {
+        takeIf { this.isContextIdenticalWith(this@nextMessage) }
+    }.message
 }
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/MessageReceipt.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/MessageReceipt.kt
@ -0,0 +1,126 @@
+/*
+ * Copyright 2020 Mamoe Technologies and contributors.
+ *
+ * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
+ * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
+ *
+ * https://github.com/mamoe/mirai/blob/master/LICENSE
+ */
+
+package net.mamoe.mirai.message
+
+import kotlinx.atomicfu.atomic
+import kotlinx.coroutines.Job
+import net.mamoe.mirai.Bot
+import net.mamoe.mirai.contact.*
+import net.mamoe.mirai.message.data.*
+import net.mamoe.mirai.utils.MiraiExperimentalAPI
+import net.mamoe.mirai.utils.getValue
+import net.mamoe.mirai.utils.unsafeWeakRef
+
+/**
+ * 发送消息后得到的回执. 可用于撤回.
+ *
+ * 此对象持有 [Contact] 的弱引用, [Bot] 离线后将会释放引用, 届时 [target] 将无法访问.
+ *
+ * @see Group.sendMessage 发送群消息, 返回回执（此对象）
+ * @see QQ.sendMessage 发送群消息, 返回回执（此对象）
+ */
+open class MessageReceipt<C : Contact>(
+    val originalMessage: MessageChain,
+    private val source: MessageSource,
+    target: C
+) {
+    init {
+        require(target is Group || target is QQ) { "target must be either Group or QQ" }
+    }
+
+    /**
+     * 发送目标, 为 [Group] 或 [QQ]
+     */
+    val target: C by target.unsafeWeakRef()
+
+    private val _isRecalled = atomic(false)
+
+    /**
+     * 撤回这条消息. [recall] 或 [recallIn] 只能被调用一次.
+     *
+     * @see Group.recall
+     * @throws IllegalStateException 当此消息已经被撤回或正计划撤回时
+     */
+    @UseExperimental(MiraiExperimentalAPI::class)
+    suspend fun recall() {
+        @Suppress("BooleanLiteralArgument")
+        if (_isRecalled.compareAndSet(false, true)) {
+            when (val contact = target) {
+                is Group -> {
+                    contact.recall(source)
+                }
+                is QQ -> {
+                    TODO()
+                }
+                else -> error("Unknown contact type")
+            }
+        } else error("message is already or planned to be recalled")
+    }
+
+    /**
+     * 撤回这条消息. [recall] 或 [recallIn] 只能被调用一次.
+     *
+     * @param millis 延迟时间, 单位为毫秒
+     *
+     * @throws IllegalStateException 当此消息已经被撤回或正计划撤回时
+     */
+    @UseExperimental(MiraiExperimentalAPI::class)
+    fun recallIn(millis: Long): Job {
+        @Suppress("BooleanLiteralArgument")
+        if (_isRecalled.compareAndSet(false, true)) {
+            when (val contact = target) {
+                is Group -> {
+                    return contact.recallIn(source, millis)
+                }
+                is QQ -> {
+                    TODO()
+                }
+                else -> error("Unknown contact type")
+            }
+        } else error("message is already or planned to be recalled")
+    }
+
+    /**
+     * 引用这条消息. 仅群消息能被引用
+     *
+     * @see MessageChain.quote 引用一条消息
+     *
+     * @throws IllegalStateException 当此消息不是群消息时
+     */
+    @MiraiExperimentalAPI("unstable")
+    open fun quote(): MessageChain {
+        val target = target
+        check(target is Group) { "quote is only available for GroupMessage" }
+        return this.source.quote(target.botAsMember)
+    }
+
+    /**
+     * 引用这条消息并回复. 仅群消息能被引用
+     *
+     * @see MessageChain.quote 引用一条消息
+     *
+     * @throws IllegalStateException 当此消息不是群消息时
+     */
+    @MiraiExperimentalAPI("unstable")
+    suspend fun quoteReply(message: MessageChain) {
+        target.sendMessage(this.quote() + message)
+    }
+}
+
+@MiraiExperimentalAPI("unstable")
+suspend inline fun MessageReceipt<out Contact>.quoteReply(message: Message) {
+    return this.quoteReply(message.toChain())
+}
+
+@MiraiExperimentalAPI("unstable")
+suspend inline fun MessageReceipt<out Contact>.quoteReply(message: String) {
+    return this.quoteReply(message.toMessage().toChain())
+}
+
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/At.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/At.kt
@ -34,10 +34,6 @@ class At @MiraiInternalAPI constructor(val target: Long, val display: String) :

    companion object Key : Message.Key<At>

-    override fun eq(other: Message): Boolean {
-        return other is At && other.target == this.target
-    }
-
    // 自动为消息补充 " "

    override fun followedBy(tail: Message): MessageChain {
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/AtAll.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/AtAll.kt
@ -16,7 +16,9 @@ import kotlin.jvm.JvmMultifileClass
 import kotlin.jvm.JvmName

 /**
- * "@全体成员"
+ * "@全体成员".
+ *
+ * 非会员每天只能发送 10 次 [AtAll]. 超出部分会被以普通文字看待.
 *
 * @see At at 单个群成员
 */
@ -26,7 +28,7 @@ object AtAll : Message, Message.Key<AtAll> {
    // 自动为消息补充 " "

    override fun followedBy(tail: Message): MessageChain {
-        if(tail is PlainText && tail.stringValue.startsWith(' ')){
+        if (tail is PlainText && tail.stringValue.startsWith(' ')) {
            return super.followedBy(tail)
        }
        return super.followedBy(PlainText(" ")) + tail
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/Face.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/Face.kt
@ -167,8 +167,4 @@ class Face(val id: Int) : Message {
        const val shouqiang: Int = 169
        const val qingwa: Int = 170
    }
-
-    override fun eq(other: Message): Boolean {
-        return other is Face && other.id == this.id
-    }
 }
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/Image.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/Image.kt
@ -49,11 +49,6 @@ sealed class Image : Message {
    final override fun toString(): String {
        return "[mirai:$imageId]"
    }
-
-    final override fun eq(other: Message): Boolean {
-        return if (other is Image) return other.imageId == this.imageId
-        else this.toString() == other.toString()
-    }
 }

 abstract class CustomFace : Image() {
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/MessageChain.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/MessageChain.kt
@ -13,9 +13,6 @@
 package net.mamoe.mirai.message.data

 import net.mamoe.mirai.message.data.NullMessageChain.toString
-import net.mamoe.mirai.utils.MiraiExperimentalAPI
-import kotlin.contracts.ExperimentalContracts
-import kotlin.contracts.contract
 import kotlin.js.JsName
 import kotlin.jvm.JvmMultifileClass
 import kotlin.jvm.JvmName
@ -60,12 +57,15 @@ interface MessageChain : Message, MutableList<Message> {
     * @param key 由各个类型消息的伴生对象持有. 如 [PlainText.Key]
     */
    operator fun <M : Message> get(key: Message.Key<M>): M = first(key)
+}

-    override fun eq(other: Message): Boolean {
-        if (other is MessageChain && other.size != this.size)
-            return false
-        return this.toString() == other.toString()
-    }
+/**
+ * 先删除同类型的消息, 再添加 [message]
+ */
+fun <T : Message> MessageChain.addOrRemove(message: T) {
+    val clazz = message::class
+    this.removeAll { clazz.isInstance(it) }
+    this.add(message)
 }

 /**
@ -132,6 +132,16 @@ fun MessageChain(vararg messages: Message): MessageChain =
    if (messages.isEmpty()) EmptyMessageChain()
    else MessageChainImpl(messages.toMutableList())

+/**
+ * 构造 [MessageChain] 的快速途径 (无 [Array] 创建)
+ * 若仅提供一个参数, 请考虑使用 [Message.toChain] 以优化性能
+ */
+@JvmName("newChain")
+@JsName("newChain")
+@Suppress("FunctionName")
+fun MessageChain(message: Message): MessageChain =
+    MessageChainImpl(mutableListOf(message))
+
 /**
 * 构造 [MessageChain]
 */
@ -141,30 +151,6 @@ fun MessageChain(vararg messages: Message): MessageChain =
 fun MessageChain(messages: Iterable<Message>): MessageChain =
    MessageChainImpl(messages.toMutableList())

-/**
- * 构造单元素的不可修改的 [MessageChain]. 内部类实现为 [SingleMessageChain]
- *
- * 参数 [delegate] 不能为 [MessageChain] 的实例, 否则将会抛出异常.
- * 使用 [Message.toChain] 将帮助提前处理这个问题.
- *
- * @param delegate 所构造的单元素 [MessageChain] 代表的 [Message]
- * @throws IllegalArgumentException 当 [delegate] 为 [MessageChain] 的实例时
- *
- * @see Message.toChain receiver 模式
- */
-@JvmName("newSingleMessageChain")
-@JsName("newChain")
-@MiraiExperimentalAPI
-@UseExperimental(ExperimentalContracts::class)
-@Suppress("FunctionName")
-fun SingleMessageChain(delegate: Message): MessageChain {
-    contract {
-        returns() implies (delegate !is MessageChain)
-    }
-    require(delegate !is MessageChain) { "delegate for SingleMessageChain should not be any instance of MessageChain" }
-    return SingleMessageChainImpl(delegate)
-}
-

 /**
 * 得到包含 [this] 的 [MessageChain].
@ -217,7 +203,7 @@ fun <M : Message> MessageChain.firstOrNull(key: Message.Key<M>): M? = when (key)
 * @throws [NoSuchElementException] 如果找不到该类型的实例
 */
@Suppress("UNCHECKED_CAST")
-fun <M : Message> MessageChain.first(key: Message.Key<M>): M = firstOrNull(key) ?: error("unknown key: $key")
+fun <M : Message> MessageChain.first(key: Message.Key<M>): M = firstOrNull(key) ?: throw NoSuchElementException("no such element: $key")

 /**
 * 获取第一个 [M] 类型的 [Message] 实例
@ -387,97 +373,3 @@ internal inline class MessageChainImpl constructor(
    // endregion
 }

-/**
- * 单个成员的不可修改的 [MessageChain].
- *
- * 在连接时将会把它当做一个普通 [Message] 看待, 但它不能被 [plusAssign]
- */
-@PublishedApi
-internal inline class SingleMessageChainImpl(
-    private val delegate: Message
-) : Message, MutableList<Message>,
-    MessageChain {
-
-    // region Message override
-    override operator fun contains(sub: String): Boolean = delegate.contains(sub)
-
-    override fun followedBy(tail: Message): MessageChain {
-        require(tail !is SingleOnly) { "SingleOnly Message cannot follow another message" }
-        return if (tail is MessageChain) tail.apply { followedBy(delegate) }
-        else MessageChain(delegate, tail)
-    }
-
-    override fun plusAssign(message: Message) =
-        throw UnsupportedOperationException("SingleMessageChainImpl cannot be plusAssigned")
-
-    override fun toString(): String = delegate.toString()
-    // endregion
-
-    // region MutableList override
-    override fun containsAll(elements: Collection<Message>): Boolean = elements.all { it == delegate }
-
-    override operator fun get(index: Int): Message = if (index == 0) delegate else throw NoSuchElementException()
-    override fun indexOf(element: Message): Int = if (delegate == element) 0 else -1
-    override fun isEmpty(): Boolean = false
-    override fun lastIndexOf(element: Message): Int = if (delegate == element) 0 else -1
-    override fun add(element: Message): Boolean = throw UnsupportedOperationException()
-    override fun add(index: Int, element: Message) = throw UnsupportedOperationException()
-    override fun addAll(index: Int, elements: Collection<Message>): Boolean = throw UnsupportedOperationException()
-    override fun addAll(elements: Collection<Message>): Boolean = throw UnsupportedOperationException()
-    override fun clear() = throw UnsupportedOperationException()
-    override fun listIterator(): MutableListIterator<Message> = object : MutableListIterator<Message> {
-        private var hasNext = true
-        override fun hasPrevious(): Boolean = !hasNext
-        override fun nextIndex(): Int = if (hasNext) 0 else -1
-        override fun previous(): Message =
-            if (hasPrevious()) {
-                hasNext = true
-                delegate
-            } else throw NoSuchElementException()
-
-        override fun previousIndex(): Int = if (!hasNext) 0 else -1
-        override fun add(element: Message) = throw UnsupportedOperationException()
-        override fun hasNext(): Boolean = hasNext
-        override fun next(): Message =
-            if (hasNext) {
-                hasNext = false
-                delegate
-            } else throw NoSuchElementException()
-
-        override fun remove() = throw UnsupportedOperationException()
-        override fun set(element: Message) = throw UnsupportedOperationException()
-    }
-
-    override fun listIterator(index: Int): MutableListIterator<Message> =
-        if (index == 0) listIterator() else throw UnsupportedOperationException()
-
-    override fun remove(element: Message): Boolean = throw UnsupportedOperationException()
-    override fun removeAll(elements: Collection<Message>): Boolean = throw UnsupportedOperationException()
-    override fun removeAt(index: Int): Message = throw UnsupportedOperationException()
-    override fun retainAll(elements: Collection<Message>): Boolean = throw UnsupportedOperationException()
-    override fun set(index: Int, element: Message): Message = throw UnsupportedOperationException()
-    override fun subList(fromIndex: Int, toIndex: Int): MutableList<Message> {
-        return if (fromIndex == 0) when (toIndex) {
-            1 -> mutableListOf<Message>(this)
-            0 -> mutableListOf()
-            else -> throw UnsupportedOperationException()
-        }
-        else throw UnsupportedOperationException()
-    }
-
-    override fun iterator(): MutableIterator<Message> = object : MutableIterator<Message> {
-        private var hasNext = true
-        override fun hasNext(): Boolean = hasNext
-        override fun next(): Message =
-            if (hasNext) {
-                hasNext = false
-                delegate
-            } else throw NoSuchElementException()
-
-        override fun remove() = throw UnsupportedOperationException()
-    }
-
-    override operator fun contains(element: Message): Boolean = element == delegate
-    override val size: Int get() = 1
-    // endregion
-}
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/MessageSource.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/MessageSource.kt
@ -26,10 +26,22 @@ import kotlin.jvm.JvmName
 interface MessageSource : Message {
    companion object Key : Message.Key<MessageSource>

+    /**
+     * 序列号. 若是机器人发出去的消息, 请先 [确保 sequenceId 可用][ensureSequenceIdAvailable]
+     */
+    val sequenceId: Int
+
+    /**
+     * 等待 [sequenceId] 获取, 确保其可用.
+     *
+     * 若原消息发送失败, 这个方法会等待最多 3 秒随后抛出 [IllegalStateException]
+     */
+    suspend fun ensureSequenceIdAvailable()
+
    /**
     * 实际上是个随机数, 但服务器确实是用它当做 uid
     */
-    val messageUid: Long
+    val messageUid: Int

    /**
     * 发送时间, 单位为秒
@ -42,17 +54,22 @@ interface MessageSource : Message {
    val senderId: Long

    /**
-     * 群号码
+     * 群号码, 为 0 时则来自好友消息
     */
    val groupId: Long

-    /**
-     * 原消息内容
-     */
-    val sourceMessage: MessageChain
-
    /**
     * 固定返回空字符串 ("")
     */
    override fun toString(): String
-}
+}
+
+/**
+ * 消息唯一标识符. 实际上是个随机数, 但服务器确实是用它当做 uid
+ */
+val MessageChain.messageUid get() = this[MessageSource].messageUid
+
+/**
+ * 消息序列号, 可能来自服务器也可以发送时赋值, 不唯一.
+ */
+val MessageChain.sequenceId get() = this[MessageSource].sequenceId
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/PlainText.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/PlainText.kt
@ -25,28 +25,10 @@ inline class PlainText(val stringValue: String) : Message {
    override fun toString(): String = stringValue

    companion object Key : Message.Key<PlainText>
-
-    override fun eq(other: Message): Boolean {
-        if (other is MessageChain) {
-            return other eq this.toString()
-        }
-        return other is PlainText && other.stringValue == this.stringValue
-    }
 }

 /**
 * 构造 [PlainText]
 */
@Suppress("NOTHING_TO_INLINE")
-inline fun String.toMessage(): PlainText = PlainText(this)
-
-/**
- * 得到包含作为 [PlainText] 的 [this] 的 [MessageChain].
- *
- * @return 唯一成员且不可修改的 [SingleMessageChainImpl]
- *
- * @see SingleMessageChain
- * @see SingleMessageChainImpl
- */
-@Suppress("NOTHING_TO_INLINE")
-inline fun String.singleChain(): MessageChain = SingleMessageChainImpl(this.toMessage())
+inline fun String.toMessage(): PlainText = PlainText(this)
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/XML.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/data/XML.kt
@ -27,10 +27,6 @@ inline class XMLMessage(val stringValue: String) : Message,
    SingleOnly {
    override fun followedBy(tail: Message): Nothing = error("XMLMessage Message cannot be followed")
    override fun toString(): String = stringValue
-
-    override fun eq(other: Message): Boolean {
-        return other is XMLMessage && other.stringValue == this.stringValue
-    }
 }

 /**
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/ExternalImage.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/ExternalImage.kt
@ -51,9 +51,39 @@ class ExternalImage(
            filename: String
        ): ExternalImage = ExternalImage(width, height, md5, format, data, data.remaining, filename)

-        fun generateUUID(md5: ByteArray): String{
+        fun generateUUID(md5: ByteArray): String {
            return "${md5[0..3]}-${md5[4..5]}-${md5[6..7]}-${md5[8..9]}-${md5[10..15]}"
        }
+
+        fun generateImageId(md5: ByteArray, imageType: Int): String {
+            return """{${generateUUID(md5)}}.${determineFormat(imageType)}"""
+        }
+
+        fun determineImageType(format: String): Int {
+            return when (format) {
+                "jpg" -> 1000
+                "png" -> 1001
+                "webp" -> 1002
+                "bmp" -> 1005
+                "gig" -> 2000
+                "apng" -> 2001
+                "sharpp" -> 1004
+                else -> 1000 // unsupported, just make it jpg
+            }
+        }
+
+        fun determineFormat(imageType: Int): String {
+            return when (imageType) {
+                1000 -> "jpg"
+                1001 -> "png"
+                1002 -> "webp"
+                1005 -> "bmp"
+                2000 -> "gig"
+                2001 -> "apng"
+                1004 -> "sharpp"
+                else -> "jpg" // unsupported, just make it jpg
+            }
+        }
    }

    val format: String =
@ -73,16 +103,7 @@ class ExternalImage(
     *  SHARPP: 1004
     */
    val imageType: Int
-        get() = when (format) {
-            "jpg" -> 1000
-            "png" -> 1001
-            "webp" -> 1002
-            "bmp" -> 1005
-            "gig" -> 2000
-            "apng" -> 2001
-            "sharpp" -> 1004
-            else -> 1000 // unsupported, just make it jpg
-        }
+        get() = determineImageType(format)

    override fun toString(): String = "[ExternalImage(${width}x$height $format)]"

--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/LockFreeLinkedList.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/LockFreeLinkedList.kt
@ -68,6 +68,10 @@ fun <E> LockFreeLinkedList<E>.asSequence(): Sequence<E> {
    }
 }

+operator fun <E> LockFreeLinkedList<E>.iterator(): Iterator<E> {
+    return asSequence().iterator()
+}
+
 /**
 * 构建链表结构然后转为 [LockFreeLinkedList]
 */
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/io/ByteArrayPool.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/io/ByteArrayPool.kt
@ -13,7 +13,7 @@ import kotlinx.io.pool.DefaultPool
 import kotlinx.io.pool.ObjectPool

 internal const val DEFAULT_BYTE_ARRAY_POOL_SIZE = 256
-internal const val DEFAULT_BYTE_ARRAY_SIZE = 81920
+internal const val DEFAULT_BYTE_ARRAY_SIZE = 81920 / 2

 val ByteArrayPool: ObjectPool<ByteArray> = ByteArrayPoolImpl

--- a/mirai-core/src/jvmMain/kotlin/net/mamoe/mirai/message/MessagePacket.kt
+++ b/mirai-core/src/jvmMain/kotlin/net/mamoe/mirai/message/MessagePacket.kt
@ -16,7 +16,6 @@ import kotlinx.coroutines.withContext
 import kotlinx.io.core.Input
 import kotlinx.io.core.use
 import kotlinx.io.streams.inputStream
-import net.mamoe.mirai.Bot
 import net.mamoe.mirai.contact.Contact
 import net.mamoe.mirai.contact.QQ
 import net.mamoe.mirai.message.data.Image
@ -35,7 +34,7 @@ import javax.imageio.ImageIO
 * JVM 平台相关扩展
 */
@UseExperimental(MiraiInternalAPI::class)
-actual abstract class MessagePacket<TSender : QQ, TSubject : Contact> actual constructor(bot: Bot) : MessagePacketBase<TSender, TSubject>(bot) {
+actual abstract class MessagePacket<TSender : QQ, TSubject : Contact> actual constructor() : MessagePacketBase<TSender, TSubject>() {
    // region 上传图片
    suspend inline fun uploadImage(image: BufferedImage): Image = subject.uploadImage(image)

--- a/mirai-demos/mirai-demo-1/src/main/java/demo/subscribe/SubscribeSamples.kt
+++ b/mirai-demos/mirai-demo-1/src/main/java/demo/subscribe/SubscribeSamples.kt
@ -16,17 +16,14 @@ import net.mamoe.mirai.Bot
 import net.mamoe.mirai.BotAccount
 import net.mamoe.mirai.alsoLogin
 import net.mamoe.mirai.contact.QQ
+import net.mamoe.mirai.contact.isOperator
 import net.mamoe.mirai.contact.sendMessage
 import net.mamoe.mirai.event.*
 import net.mamoe.mirai.message.FriendMessage
 import net.mamoe.mirai.message.GroupMessage
-import net.mamoe.mirai.message.data.AtAll
-import net.mamoe.mirai.message.data.Image
-import net.mamoe.mirai.message.data.PlainText
-import net.mamoe.mirai.message.data.firstOrNull
+import net.mamoe.mirai.message.data.*
+import net.mamoe.mirai.message.nextMessage
 import net.mamoe.mirai.message.sendAsImageTo
-import net.mamoe.mirai.qqandroid.Bot
-import net.mamoe.mirai.qqandroid.QQAndroid
 import net.mamoe.mirai.utils.FileBasedDeviceInfo
 import net.mamoe.mirai.utils.MiraiInternalAPI
 import java.io.File
@ -49,7 +46,7 @@ private fun readTestAccount(): BotAccount? {

@Suppress("UNUSED_VARIABLE")
 suspend fun main() {
-    val bot = QQAndroid.Bot( // JVM 下也可以不写 `QQAndroid.` 引用顶层函数
+    val bot = Bot( // JVM 下也可以不写 `QQAndroid.` 引用顶层函数
        123456789,
        "123456"
    ) {
@ -207,6 +204,25 @@ fun Bot.messageDSL() {
        // sender: QQ
        // it: String (来自 MessageChain.toString)
        // group: Group
+
+        case("recall") {
+            reply("😎").recallIn(3000) // 3 秒后自动撤回这条消息
+        }
+
+        case("禁言") {
+            // 挂起当前协程, 等待下一条满足条件的消息.
+            // 发送 "禁言" 后需要再发送一条消息 at 一个人.
+            val value: At = nextMessage { message.any(At) }[At]
+            value.member().mute(10)
+        }
+
+        startsWith("群名=") {
+            if (!sender.isOperator()) {
+                sender.mute(5)
+                return@startsWith
+            }
+            group.name = it
+        }
    }
 }

--- a/mirai-japt/src/main/java/net/mamoe/mirai/japt/BlockingContact.java
+++ b/mirai-japt/src/main/java/net/mamoe/mirai/japt/BlockingContact.java
@ -9,6 +9,7 @@ import net.mamoe.mirai.event.events.EventCancelledException;
 import net.mamoe.mirai.event.events.ImageUploadEvent;
 import net.mamoe.mirai.event.events.MessageSendEvent.FriendMessageSendEvent;
 import net.mamoe.mirai.event.events.MessageSendEvent.GroupMessageSendEvent;
+import net.mamoe.mirai.message.MessageReceipt;
 import net.mamoe.mirai.message.data.Image;
 import net.mamoe.mirai.message.data.Message;
 import net.mamoe.mirai.message.data.MessageChain;
@ -42,8 +43,7 @@ public interface BlockingContact {
     * @see FriendMessageSendEvent 发送好友信息事件, cancellable
     * @see GroupMessageSendEvent  发送群消息事件. cancellable
     */
-    // kotlin bug
-    void sendMessage(@NotNull MessageChain messages) throws EventCancelledException, IllegalStateException;
+    MessageReceipt<? extends Contact> sendMessage(@NotNull MessageChain messages) throws EventCancelledException, IllegalStateException;

    /**
     * 向这个对象发送消息.
@ -53,7 +53,7 @@ public interface BlockingContact {
     * @see FriendMessageSendEvent 发送好友信息事件, cancellable
     * @see GroupMessageSendEvent  发送群消息事件. cancellable
     */
-    void sendMessage(@NotNull String message) throws EventCancelledException, IllegalStateException;
+    MessageReceipt<? extends Contact> sendMessage(@NotNull String message) throws EventCancelledException, IllegalStateException;

    /**
     * 向这个对象发送消息.
@ -63,7 +63,7 @@ public interface BlockingContact {
     * @see FriendMessageSendEvent 发送好友信息事件, cancellable
     * @see GroupMessageSendEvent  发送群消息事件. cancellable
     */
-    void sendMessage(@NotNull Message message) throws EventCancelledException, IllegalStateException;
+    MessageReceipt<? extends Contact> sendMessage(@NotNull Message message) throws EventCancelledException, IllegalStateException;

    /**
     * 上传一个图片以备发送.
--- a/mirai-japt/src/main/java/net/mamoe/mirai/japt/BlockingGroup.java
+++ b/mirai-japt/src/main/java/net/mamoe/mirai/japt/BlockingGroup.java
@ -3,6 +3,9 @@ package net.mamoe.mirai.japt;
 import net.mamoe.mirai.contact.*;
 import net.mamoe.mirai.data.MemberInfo;
 import net.mamoe.mirai.event.events.*;
+import net.mamoe.mirai.message.MessageReceipt;
+import net.mamoe.mirai.message.data.Message;
+import net.mamoe.mirai.message.data.MessageChain;
 import net.mamoe.mirai.utils.MiraiExperimentalAPI;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@ -152,6 +155,36 @@ public interface BlockingGroup extends BlockingContact {
    @Nullable
    BlockingMember getMemberOrNull(long id);

+    /**
+     * 向这个对象发送消息.
+     *
+     * @throws EventCancelledException 当发送消息事件被取消
+     * @throws IllegalStateException   发送群消息时若 [Bot] 被禁言抛出
+     * @see MessageSendEvent.FriendMessageSendEvent 发送好友信息事件, cancellable
+     * @see MessageSendEvent.GroupMessageSendEvent  发送群消息事件. cancellable
+     */
+    MessageReceipt<Group> sendMessage(@NotNull MessageChain messages) throws EventCancelledException, IllegalStateException;
+
+    /**
+     * 向这个对象发送消息.
+     *
+     * @throws EventCancelledException 当发送消息事件被取消
+     * @throws IllegalStateException   发送群消息时若 [Bot] 被禁言抛出
+     * @see MessageSendEvent.FriendMessageSendEvent 发送好友信息事件, cancellable
+     * @see MessageSendEvent.GroupMessageSendEvent  发送群消息事件. cancellable
+     */
+    MessageReceipt<Group> sendMessage(@NotNull String message) throws EventCancelledException, IllegalStateException;
+
+    /**
+     * 向这个对象发送消息.
+     *
+     * @throws EventCancelledException 当发送消息事件被取消
+     * @throws IllegalStateException   发送群消息时若 [Bot] 被禁言抛出
+     * @see MessageSendEvent.FriendMessageSendEvent 发送好友信息事件, cancellable
+     * @see MessageSendEvent.GroupMessageSendEvent  发送群消息事件. cancellable
+     */
+    MessageReceipt<Group> sendMessage(@NotNull Message message) throws EventCancelledException, IllegalStateException;
+
    /**
     * 检查此 id 的群成员是否存在
     */
--- a/mirai-japt/src/main/java/net/mamoe/mirai/japt/BlockingQQ.java
+++ b/mirai-japt/src/main/java/net/mamoe/mirai/japt/BlockingQQ.java
@ -1,8 +1,14 @@
 package net.mamoe.mirai.japt;

+import net.mamoe.mirai.contact.QQ;
 import net.mamoe.mirai.data.FriendNameRemark;
 import net.mamoe.mirai.data.PreviousNameList;
 import net.mamoe.mirai.data.Profile;
+import net.mamoe.mirai.event.events.EventCancelledException;
+import net.mamoe.mirai.event.events.MessageSendEvent;
+import net.mamoe.mirai.message.MessageReceipt;
+import net.mamoe.mirai.message.data.Message;
+import net.mamoe.mirai.message.data.MessageChain;
 import net.mamoe.mirai.utils.MiraiExperimentalAPI;
 import org.jetbrains.annotations.NotNull;

@ -47,4 +53,35 @@ public interface BlockingQQ extends BlockingContact {
    @MiraiExperimentalAPI(message = "还未支持")
    @NotNull
    FriendNameRemark queryRemark();
+
+    /**
+     * 向这个对象发送消息.
+     *
+     * @throws EventCancelledException 当发送消息事件被取消
+     * @throws IllegalStateException   发送群消息时若 [Bot] 被禁言抛出
+     * @see MessageSendEvent.FriendMessageSendEvent 发送好友信息事件, cancellable
+     * @see MessageSendEvent.GroupMessageSendEvent  发送群消息事件. cancellable
+     */
+    MessageReceipt<QQ> sendMessage(@NotNull MessageChain messages) throws EventCancelledException, IllegalStateException;
+
+    /**
+     * 向这个对象发送消息.
+     *
+     * @throws EventCancelledException 当发送消息事件被取消
+     * @throws IllegalStateException   发送群消息时若 [Bot] 被禁言抛出
+     * @see MessageSendEvent.FriendMessageSendEvent 发送好友信息事件, cancellable
+     * @see MessageSendEvent.GroupMessageSendEvent  发送群消息事件. cancellable
+     */
+    MessageReceipt<QQ> sendMessage(@NotNull String message) throws EventCancelledException, IllegalStateException;
+
+    /**
+     * 向这个对象发送消息.
+     *
+     * @throws EventCancelledException 当发送消息事件被取消
+     * @throws IllegalStateException   发送群消息时若 [Bot] 被禁言抛出
+     * @see MessageSendEvent.FriendMessageSendEvent 发送好友信息事件, cancellable
+     * @see MessageSendEvent.GroupMessageSendEvent  发送群消息事件. cancellable
+     */
+    MessageReceipt<QQ> sendMessage(@NotNull Message message) throws EventCancelledException, IllegalStateException;
+
 }
--- a/mirai-japt/src/main/kotlin/net/mamoe/mirai/japt/internal/BlockingContactsImpl.kt
+++ b/mirai-japt/src/main/kotlin/net/mamoe/mirai/japt/internal/BlockingContactsImpl.kt
@ -24,6 +24,7 @@ import net.mamoe.mirai.japt.BlockingBot
 import net.mamoe.mirai.japt.BlockingGroup
 import net.mamoe.mirai.japt.BlockingMember
 import net.mamoe.mirai.japt.BlockingQQ
+import net.mamoe.mirai.message.MessageReceipt
 import net.mamoe.mirai.message.data.*
 import net.mamoe.mirai.utils.ExternalImage
 import net.mamoe.mirai.utils.MiraiExperimentalAPI
@ -35,9 +36,9 @@ internal class BlockingQQImpl(private val delegate: QQ) : BlockingQQ {
    override fun getId(): Long = delegate.id
    override fun getNick(): String = delegate.nick

-    override fun sendMessage(messages: MessageChain) = runBlocking { delegate.sendMessage(messages) }
-    override fun sendMessage(message: String) = runBlocking { delegate.sendMessage(message.toMessage().toChain()) }
-    override fun sendMessage(message: Message) = runBlocking { delegate.sendMessage(message.toChain()) }
+    override fun sendMessage(messages: MessageChain): MessageReceipt<QQ> = runBlocking { delegate.sendMessage(messages) }
+    override fun sendMessage(message: String): MessageReceipt<QQ> = runBlocking { delegate.sendMessage(message.toMessage().toChain()) }
+    override fun sendMessage(message: Message): MessageReceipt<QQ> = runBlocking { delegate.sendMessage(message.toChain()) }
    override fun uploadImage(image: ExternalImage): Image = runBlocking { delegate.uploadImage(image) }

    @MiraiExperimentalAPI
@ -51,9 +52,9 @@ internal class BlockingQQImpl(private val delegate: QQ) : BlockingQQ {
 }

 internal class BlockingGroupImpl(private val delegate: Group) : BlockingGroup {
-    override fun sendMessage(messages: MessageChain) = runBlocking { delegate.sendMessage(messages) }
-    override fun sendMessage(message: String) = runBlocking { delegate.sendMessage(message.toMessage().toChain()) }
-    override fun sendMessage(message: Message) = runBlocking { delegate.sendMessage(message.toChain()) }
+    override fun sendMessage(messages: MessageChain): MessageReceipt<Group> = runBlocking { delegate.sendMessage(messages) }
+    override fun sendMessage(message: String): MessageReceipt<Group> = runBlocking { delegate.sendMessage(message.toMessage().toChain()) }
+    override fun sendMessage(message: Message): MessageReceipt<Group> = runBlocking { delegate.sendMessage(message.toChain()) }
    override fun getOwner(): BlockingMember = delegate.owner.blocking()
    @MiraiExperimentalAPI
    override fun newMember(memberInfo: MemberInfo): Member = delegate.Member(memberInfo)