feat: stack /clear messages (#5806)

src/messages/MessageBuilder.cpp

@@ -53,6 +53,7 @@
 #include <QDateTime>
 #include <QDebug>
 #include <QFileInfo>
+#include <QStringBuilder>
 #include <QTimeZone>
 
 #include <algorithm>
@@ -1986,6 +1987,46 @@ MessagePtr MessageBuilder::makeLowTrustUpdateMessage(
     return builder.release();
 }
 
+MessagePtrMut MessageBuilder::makeClearChatMessage(QTime now,
+                                                   const QString &actor,
+                                                   uint32_t count)
+{
+    MessageBuilder builder;
+    builder.emplace<TimestampElement>(now);
+    builder->count = count;
+    builder->parseTime = now;
+    builder.message().flags.set(MessageFlag::System,
+                                MessageFlag::DoNotTriggerNotification,
+                                MessageFlag::ClearChat);
+
+    QString messageText;
+    if (actor.isEmpty())
+    {
+        builder.emplaceSystemTextAndUpdate(
+            "Chat has been cleared by a moderator.", messageText);
+    }
+    else
+    {
+        builder.message().flags.set(MessageFlag::PubSub);
+        builder.emplace<MentionElement>(actor, actor, MessageColor::System,
+                                        MessageColor::System);
+        messageText = actor + ' ';
+        builder.emplaceSystemTextAndUpdate("cleared the chat.", messageText);
+        builder->timeoutUser = actor;
+    }
+
+    if (count > 1)
+    {
+        builder.emplaceSystemTextAndUpdate(
+            '(' % QString::number(count) % u" times)", messageText);
+    }
+
+    builder->messageText = messageText;
+    builder->searchText = messageText;
+
+    return builder.release();
+}
+
 std::pair<MessagePtrMut, HighlightAlert> MessageBuilder::makeIrcMessage(
     /* mutable */ Channel *channel, const Communi::IrcMessage *ircMessage,
     const MessageParseArgs &args, /* mutable */ QString content,

src/messages/MessageBuilder.hpp

@@ -258,6 +258,12 @@ public:
                                             const QVariantMap &tags,
                                             const QTime &time);
 
+    /// "Chat has been cleared by a moderator." or "{actor} cleared the chat."
+    /// @param actor The user who cleared the chat (empty if unknown)
+    /// @param count How many times this message has been received already
+    static MessagePtrMut makeClearChatMessage(QTime now, const QString &actor,
+                                              uint32_t count = 1);
+
 private:
     struct TextState {
         TwitchChannel *twitchChannel = nullptr;

src/messages/MessageFlag.hpp

@@ -54,6 +54,8 @@ enum class MessageFlag : std::int64_t {
     SharedMessage = (1LL << 37),
     /// AutoMod message that showed up due to containing a blocked term in the channel
     AutoModBlockedTerm = (1LL << 38),
+    /// The message is a full clear chat message (/clear)
+    ClearChat = (1LL << 39),
 };
 using MessageFlags = FlagsEnum<MessageFlag>;
 

src/messages/MessageSink.hpp

@@ -48,6 +48,11 @@ public:
     virtual void addOrReplaceTimeout(MessagePtr clearchatMessage,
                                      QTime now) = 0;
 
+    /// Adds a clear chat message (for the entire chat) or merges it into an
+    /// existing one
+    virtual void addOrReplaceClearChat(MessagePtr clearchatMessage,
+                                       QTime now) = 0;
+
     /// Flags all messages as `Disabled`
     virtual void disableAllMessages() = 0;