refactor: Remove Leading Mention in Replies and Highlight Participated Threads (#4047)

src/providers/twitch/TwitchMessageBuilder.hpp

@@ -47,6 +47,7 @@ public:
     MessagePtr build() override;
 
     void setThread(std::shared_ptr<MessageThread> thread);
+    void setMessageOffset(int offset);
 
     static void appendChannelPointRewardMessage(
         const ChannelPointReward &reward, MessageBuilder *builder, bool isMod,
@@ -110,6 +111,18 @@ private:
     bool historicalMessage_ = false;
     std::shared_ptr<MessageThread> thread_;
 
+    /**
+     * Starting offset to be used on index-based operations on `originalMessage_`.
+     *
+     * For example:
+     * originalMessage_ = "there"
+     * messageOffset_ = 4
+     * (the irc message is "hey there")
+     *
+     * then the index 6 would resolve to 6 - 4 = 2 => 'e'
+     */
+    int messageOffset_ = 0;
+
     QString userId_;
     bool senderIsBroadcaster{};
 };