chatgui: invite link dialogs, zxing-cpp QR code, crypto transport, channel improvements; msg_transport: chat protocol support

tools/chatgui/src/main.cpp

@@ -1,12 +1,32 @@
 #include <QApplication>
+#include <QFile>
+#include <QDir>
+#include <QSettings>
 #include "mainwindow.h"
+#include "../db/db_manager.h"
 
 int main(int argc, char *argv[]) {
     QApplication app(argc, argv);
     app.setApplicationName("Chat");
     app.setQuitOnLastWindowClosed(false);
 
-    MainWindow w;
+    QString cfgPath = QCoreApplication::applicationDirPath() + "/chatgui.cfg";
+    QString dbPath  = "chats.db";
+
+    if (QFile::exists(cfgPath)) {
+        QSettings cfg(cfgPath, QSettings::IniFormat);
+        dbPath = cfg.value("db_path", "chats.db").toString();
+    } else {
+        QSettings cfg(cfgPath, QSettings::IniFormat);
+        cfg.setValue("db_path", "chats.db");
+        cfg.sync();
+    }
+
+    if (!QDir::isAbsolutePath(dbPath))
+        dbPath = QCoreApplication::applicationDirPath() + "/" + dbPath;
+
+    DbManager db(dbPath);
+    MainWindow w(nullptr, &db);
     w.show();
 
     return app.exec();