[irc] Partially fix IRC colors (#1594)

Doesn't fix #1379 but it is a big step forward.

Needs some "real life" testing, but should be good.

src/messages/SharedMessageBuilder.hpp

@@ -0,0 +1,69 @@
+#include "messages/MessageBuilder.hpp"
+
+#include "common/Aliases.hpp"
+#include "common/Outcome.hpp"
+
+#include <IrcMessage>
+#include <QColor>
+
+namespace chatterino {
+
+class SharedMessageBuilder : public MessageBuilder
+{
+public:
+    SharedMessageBuilder() = delete;
+
+    explicit SharedMessageBuilder(Channel *_channel,
+                                  const Communi::IrcPrivateMessage *_ircMessage,
+                                  const MessageParseArgs &_args);
+
+    explicit SharedMessageBuilder(Channel *_channel,
+                                  const Communi::IrcMessage *_ircMessage,
+                                  const MessageParseArgs &_args,
+                                  QString content, bool isAction);
+
+    QString userName;
+
+    [[nodiscard]] virtual bool isIgnored() const;
+
+    // triggerHighlights triggers any alerts or sounds parsed by parseHighlights
+    virtual void triggerHighlights();
+    virtual MessagePtr build() = 0;
+
+protected:
+    virtual void parse();
+
+    virtual void parseUsernameColor();
+
+    virtual void parseUsername();
+
+    virtual Outcome tryAppendEmote(const EmoteName &name)
+    {
+        return Failure;
+    }
+
+    // parseHighlights only updates the visual state of the message, but leaves the playing of alerts and sounds to the triggerHighlights function
+    virtual void parseHighlights();
+
+    virtual void addTextOrEmoji(EmotePtr emote);
+    virtual void addTextOrEmoji(const QString &value);
+
+    void appendChannelName();
+
+    Channel *channel;
+    const Communi::IrcMessage *ircMessage;
+    MessageParseArgs args;
+    const QVariantMap tags;
+    QString originalMessage_;
+
+    const bool action_{};
+
+    QColor usernameColor_;
+
+    bool highlightAlert_ = false;
+    bool highlightSound_ = false;
+
+    QUrl highlightSoundUrl_;
+};
+
+}  // namespace chatterino