chatgui: add scroll-to-bottom floating button, incremental message refresh via getMessagesSince

tools/chatgui/db/db_manager.cpp

@@ -8,6 +8,17 @@
 
 /* ── helpers ── */
 
+static QByteArray parseJsonField(const QByteArray& json, const char* key) {
+    QByteArray pat = "\"" + QByteArray(key) + "\":\"";
+    int idx = json.indexOf(pat);
+    if (idx < 0) return {};
+    idx += pat.size();
+    int end = idx;
+    while (end < json.size() && !(json[end] == '"' && (end == idx || json[end - 1] != '\\'))) end++;
+    if (end > idx) return QByteArray(json.constData() + idx, end - idx);
+    return {};
+}
+
 QString DbManager::sanitizeTableName(const QString& chId) {
     QString s;
     s.reserve(chId.size());
@@ -136,17 +147,6 @@ QList<MessageRow> DbManager::getMessages(const QString& chId, int limit) const {
     sqlite3_stmt* stmt = prepareOrNull(sql.toUtf8().constData());
     if (!stmt) return list;
     sqlite3_bind_int(stmt, 1, limit);
-    /* helper: parse JSON field from data column: {"n":<id>,"ch":"<id>","ct":"<>","d":"<>"} */
-    auto parseJsonField = [](const QByteArray& json, const char* key) -> QByteArray {
-        QByteArray pat = "\"" + QByteArray(key) + "\":\"";
-        int idx = json.indexOf(pat);
-        if (idx < 0) return {};
-        idx += pat.size();
-        int end = idx;
-        while (end < json.size() && !(json[end] == '"' && (end == idx || json[end - 1] != '\\'))) end++;
-        if (end > idx) return QByteArray(json.constData() + idx, end - idx);
-        return {};
-    };
     uint64_t myId = 0;
     { sqlite3_stmt* ms = prepareOrNull("SELECT node_id FROM local_identity WHERE id=1");
       if (ms) { if (sqlite3_step(ms) == SQLITE_ROW) myId = (uint64_t)sqlite3_column_int64(ms, 0); sqlite3_finalize(ms); } }
@@ -170,6 +170,33 @@ QList<MessageRow> DbManager::getMessages(const QString& chId, int limit) const {
     return list;
 }
 
+QList<MessageRow> DbManager::getMessagesSince(const QString& chId, qint64 sinceId) const {
+    QList<MessageRow> list;
+    QString sql = QStringLiteral(
+        "SELECT id, node_id, data, timestamp, chain_hash, author_signature"
+        " FROM \"%1\" WHERE id > ? ORDER BY id ASC").arg(msgTableName(chId));
+    sqlite3_stmt* stmt = prepareOrNull(sql.toUtf8().constData());
+    if (!stmt) return list;
+    sqlite3_bind_int64(stmt, 1, sinceId);
+    uint64_t myId = m_myNodeId;
+    while (sqlite3_step(stmt) == SQLITE_ROW) {
+        MessageRow m;
+        m.id           = sqlite3_column_int64(stmt, 0);
+        m.authorNodeId = (quint64)sqlite3_column_int64(stmt, 1);
+        QByteArray jdata = colBlob(stmt, 2);
+        m.data         = parseJsonField(jdata, "d");
+        m.timestamp    = sqlite3_column_int64(stmt, 3);
+        m.datahash     = 0;
+        m.chainHash    = colBlob(stmt, 4);
+        m.signature    = colBlob(stmt, 5);
+        m.isOutgoing   = (m.authorNodeId == myId);
+        m.isRead       = true;
+        list.append(m);
+    }
+    sqlite3_finalize(stmt);
+    return list;
+}
+
 /* ── peers (UI) ── */
 
 int DbManager::getChannelMemberCount(const QString& chId) const {