Disable send message when there's nothing to actually send

Now there's a way to check if the message content model has any useful
data inside of it.

BUG: 516118
FIXED-IN: 26.04

src/chatbar/SendBar.qml

@@ -208,6 +208,7 @@ RowLayout {
         icon.name: "document-send"
         text: i18nc("@action:button", "Send message")
         display: QQC2.AbstractButton.IconOnly
+        enabled: root.contentModel.hasAnyContent
 
         onClicked: root.contentModel.postMessage();
         QQC2.ToolTip.visible: hovered

src/messagecontent/models/chatbarmessagecontentmodel.cpp

@@ -60,6 +60,9 @@ ChatBarMessageContentModel::ChatBarMessageContentModel(QObject *parent)
         initializeFromCache();
     });
     connect(m_markdownHelper, &ChatMarkdownHelper::unhandledBlockFormat, this, &ChatBarMessageContentModel::insertStyleAtCursor);
+    connect(this, &ChatBarMessageContentModel::modelReset, this, &ChatBarMessageContentModel::hasAnyContentChanged);
+    connect(this, &ChatBarMessageContentModel::rowsInserted, this, &ChatBarMessageContentModel::hasAnyContentChanged);
+    connect(this, &ChatBarMessageContentModel::rowsRemoved, this, &ChatBarMessageContentModel::hasAnyContentChanged);
 
     connectCache();
     connectKeyHelper();
@@ -302,6 +305,7 @@ void ChatBarMessageContentModel::connectTextItem(ChatTextItemHelper *chattextite
     connect(chattextitemhelper, &ChatTextItemHelper::cleared, this, [this](ChatTextItemHelper *helper) {
         removeComponent(helper);
     });
+    connect(chattextitemhelper, &ChatTextItemHelper::contentsChanged, this, &ChatBarMessageContentModel::hasAnyContentChanged);
 }
 
 ChatTextItemHelper *ChatBarMessageContentModel::textItemForComponent(const MessageComponent &component) const
@@ -664,6 +668,28 @@ void ChatBarMessageContentModel::postMessage()
     refocusCurrentComponent();
 }
 
+bool ChatBarMessageContentModel::hasAnyContent() const
+{
+    // Shouldn't really be possible, but is true.
+    if (m_components.empty()) {
+        return false;
+    }
+
+    // If there's more than one component naturally there is content.
+    if (m_components.size() > 1) {
+        return true;
+    }
+
+    // There's usually at a minimum a TextComponent, we need to check if it's empty.
+    if (const auto textItem = textItemForComponent(m_components.constFirst())) {
+        if (textItem->isEmpty()) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
 std::optional<QString> ChatBarMessageContentModel::getReplyEventId()
 {
     if (!m_room) {

src/messagecontent/models/chatbarmessagecontentmodel.h

@@ -77,6 +77,11 @@ class ChatBarMessageContentModel : public MessageContentModel
      */
     Q_PROPERTY(bool sendMessageWithEnter READ sendMessageWithEnter WRITE setSendMessageWithEnter NOTIFY sendMessageWithEnterChanged)
 
+    /**
+     * @brief Whether the model has any content, ideal for checking if there is anything to send.
+     */
+    Q_PROPERTY(bool hasAnyContent READ hasAnyContent NOTIFY hasAnyContentChanged)
+
 public:
     explicit ChatBarMessageContentModel(QObject *parent = nullptr);
 
@@ -106,12 +111,15 @@ public:
 
     Q_INVOKABLE void postMessage();
 
+    bool hasAnyContent() const;
+
 Q_SIGNALS:
     void typeChanged(ChatBarType::Type oldType, ChatBarType::Type newType);
     void focusRowChanged();
     void hasRichFormattingChanged();
     void hasAttachmentChanged();
     void sendMessageWithEnterChanged();
+    void hasAnyContentChanged();
 
 private:
     ChatBarType::Type m_type = ChatBarType::None;