From 3c83883c66a08135f7db8bef520c882d767ed977 Mon Sep 17 00:00:00 2001
From: Him188 <Him188@mamoe.net>
Date: Sun, 9 Feb 2020 23:35:11 +0800
Subject: [PATCH] Add space automatically if necessary

---
 .../kotlin/net.mamoe.mirai/message/MessagePacket.kt      | 2 +-
 .../commonMain/kotlin/net.mamoe.mirai/message/data/At.kt | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/MessagePacket.kt b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/MessagePacket.kt
index cbeb4f506..fa0d0f09a 100644
--- a/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/MessagePacket.kt
+++ b/mirai-core/src/commonMain/kotlin/net.mamoe.mirai/message/MessagePacket.kt
@@ -92,7 +92,7 @@ abstract class MessagePacketBase<TSender : QQ, TSubject : Contact>(_bot: Bot) :
     // region
 
     /**
-     * 引用这个消息.
+     * 引用这个消息. 当且仅当消息为群消息时可用. 否则将会抛出 [IllegalArgumentException]
      */
     inline fun MessageChain.quote(): MessageChain = this.quote(sender as? Member ?: error("only group message can be quoted"))
 
diff --git 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
index d2fe95424..4295e4961 100644
--- 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
@@ -30,6 +30,15 @@ class At @MiraiInternalAPI constructor(val target: Long, val display: String) :
     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 {
+        if(tail is PlainText && !tail.stringValue.startsWith(' ')){
+            return super.followedBy(PlainText(" ")) + tail
+        }
+        return super.followedBy(tail)
+    }
 }
 
 /**