Separate out a base MessageContentModel.

Separate out a base `MessageContentModel` that can be extended to get the component types from different places. This is used currently for `EventMessageContentModel` but will be used later as part of the rich chat bar.

All display text is now in the text component so it never needs special casing. This also cleans up some of the model parameters so more things come from attributes including location and file data (which was already a qvariantmap anyway).

Also cleaned up the itinerary and file enhancement views,

src/messagecontent/models/eventmessagecontentmodel.h

@@ -0,0 +1,80 @@
+// SPDX-FileCopyrightText: 2024 James Graham <james.h.graham@protonmail.com>
+// SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
+
+#pragma once
+
+#include <QAbstractListModel>
+#include <QQmlEngine>
+
+#include "models/messagecontentmodel.h"
+#include "models/threadmodel.h"
+
+/**
+ * @class EventMessageContentModel
+ *
+ * Inherited from MessageContentModel this visulaises the content of a Quotient::RoomMessageEvent.
+ */
+class EventMessageContentModel : public MessageContentModel
+{
+    Q_OBJECT
+    QML_ELEMENT
+    QML_UNCREATABLE("")
+
+public:
+    enum MessageState {
+        Unknown, /**< The message state is unknown. */
+        Pending, /**< The message is a new pending message which the server has not yet acknowledged. */
+        Available, /**< The message is available and acknowledged by the server. */
+        UnAvailable, /**< The message can't be retrieved either because it doesn't exist or is blocked. */
+    };
+    Q_ENUM(MessageState)
+
+    explicit EventMessageContentModel(NeoChatRoom *room,
+                                         const QString &eventId,
+                                         bool isReply = false,
+                                         bool isPending = false,
+                                         MessageContentModel *parent = nullptr);
+
+    /**
+     * @brief Returns the thread model for the given thread root event ID.
+     *
+     * A model is created if one doesn't exist. Will return nullptr if threadRootId
+     * is empty.
+     */
+    Q_INVOKABLE ThreadModel *modelForThread(const QString &threadRootId);
+
+    static void setThreadsEnabled(bool enableThreads);
+
+Q_SIGNALS:
+    void eventUpdated();
+    void threadsEnabledChanged();
+
+private:
+    void initializeModel();
+
+    QDateTime time() const override;
+    QString timeString() const override;
+    QString authorId() const override;
+    QString threadRootId() const override;
+
+    MessageState m_currentState = Unknown;
+    bool m_isReply;
+
+    void initializeEvent();
+    void getEvent();
+
+    MessageComponent unavailableMessageComponent() const;
+    void resetModel();
+    void resetContent(bool isEditing = false, bool isThreading = false);
+    QList<MessageComponent> messageContentComponents(bool isEditing = false, bool isThreading = false);
+
+    void updateReplyModel();
+
+    QList<MessageComponent> componentsForType(MessageComponentType::Type type);
+
+    void updateItineraryModel();
+
+    void updateReactionModel();
+
+    static bool m_threadsEnabled;
+};