chore: adjusted the project directory structure

app/main.cpp

@@ -0,0 +1,62 @@
+#include "mainwindow.h"
+#include <QApplication>
+#include <QCommandLineParser>
+#include <QDir>
+#include <QTranslator>
+#include <QUrl>
+
+// QM_FILE_INSTALL_DIR should be defined from the CMakeLists file.
+#ifndef QM_FILE_INSTALL_DIR
+#define QM_FILE_INSTALL_DIR ":/i18n/"
+#endif // QM_FILE_INSTALL_DIR
+
+int main(int argc, char *argv[])
+{
+    QApplication a(argc, argv);
+
+    QTranslator translator;
+    QString qmDir;
+#ifdef _WIN32
+    qmDir = QDir(QCoreApplication::applicationDirPath()).absoluteFilePath("translations");
+#else
+    qmDir = QT_STRINGIFY(QM_FILE_INSTALL_DIR);
+#endif
+    translator.load(QString("PineapplePictures_%1").arg(QLocale::system().name()), qmDir);
+    a.installTranslator(&translator);
+    a.setApplicationName("Pineapple Pictures");
+    a.setApplicationDisplayName(QCoreApplication::translate("main", "Pineapple Pictures"));
+
+    // parse commandline arguments
+    QCommandLineParser parser;
+    parser.addPositionalArgument("File list", QCoreApplication::translate("main", "File list."));
+    parser.addHelpOption();
+
+    parser.process(a);
+
+    QStringList urlStrList = parser.positionalArguments();
+    QList<QUrl> urlList;
+    for (const QString & str : urlStrList) {
+        QUrl url = QUrl::fromLocalFile(str);
+#ifdef Q_OS_WIN
+        // TODO: remove this workaround when M$ change the "wsl$" hostname.
+        if (Q_UNLIKELY(str.startsWith(R"(\\wsl$\)"))) {
+            url.clear();
+            url.setScheme(QStringLiteral("qtbug-86277"));
+            url.setPath(str);
+        }
+#endif // Q_OS_WIN
+        if (url.isValid()) {
+            urlList.append(url);
+        }
+    }
+
+    MainWindow w;
+    w.show();
+
+    if (!urlList.isEmpty()) {
+        w.showUrls(urlList);
+        w.adjustWindowSizeBySceneRect();
+    }
+
+    return a.exec();
+}