From 7a217f6f65be01411e305cfe25701a2a3891859d Mon Sep 17 00:00:00 2001
From: Him188 <Him188@mamoe.net>
Date: Sat, 22 Feb 2020 14:32:52 +0800
Subject: [PATCH] Add `MessageChain.messageUid`, `MessageChain.sequenceId`

---
 .../kotlin/net.mamoe.mirai/contact/Contact.kt        |  2 +-
 .../net.mamoe.mirai/message/data/MessageChain.kt     |  2 +-
 .../net.mamoe.mirai/message/data/MessageSource.kt    | 12 +++++++++++-
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Contact.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Contact.kt
index 68224bdd0..fb1fc8942 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Contact.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/contact/Contact.kt
@@ -48,7 +48,7 @@ interface Contact : CoroutineScope {
     val id: Long
 
     /**
-     * 向这个对象发送消息. 发送成功后 [message] 中会添加 [MessageSource], 此后可以 [引用回复][MessageReceipt.quote]（仅群聊）或 [撤回][MessageReceipt.recall] 这条消息.
+     * 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
diff --git 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
index 9a4c9ad4e..f66376bb3 100644
--- 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
@@ -209,7 +209,7 @@ 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
diff --git 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
index c0ecb35cd..d7a047a30 100644
--- 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
@@ -62,4 +62,14 @@ interface MessageSource : Message {
      * 固定返回空字符串 ("")
      */
     override fun toString(): String
-}
\ No newline at end of file
+}
+
+/**
+ * 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
\ No newline at end of file