#!/usr/bin/gjs

imports.gi.versions.Gtk = '3.0';

const Gio = imports.gi.Gio;

const Gtk = imports.gi.Gtk;

class MessageDialogExample {

    // Create the application itself

    constructor() {

        this.application = new Gtk.Application({

            application_id: 'org.example.jsmessagedialog',

            flags: Gio.ApplicationFlags.FLAGS_NONE

        });

        // Connect 'activate' and 'startup' signals to the callback functions

        this.application.connect('activate', this._onActivate.bind(this));

        this.application.connect('startup', this._onStartup.bind(this));

    }

    // Callback function for 'activate' signal presents windows when active

    _onActivate() {

        this._window.present();

    }

    // Callback function for 'startup' signal initializes menus and builds the UI

    _onStartup() {

        this._initMenus();

        this._buildUI ();

    }

    // Build the application's UI

    _buildUI() {

        // Create the application window

        this._window = new Gtk.ApplicationWindow({

            application: this.application,

            window_position: Gtk.WindowPosition.CENTER,

            title: "Gtk.MessageDialog Example",

            default_height: 200,

            default_width: 400

        });

        // Create a silly warning message and add it to the window

        this.warningLabel = new Gtk.Label({

            label: "This application goes boom! (Not really.)"

        });

        this._window.add (this.warningLabel);

        // Show the window and all child widgets

        this._window.show_all();

    }

    // Build the application menu, including the button that calls the dialog

    _initMenus() {

        let menu = new Gio.Menu();

        menu.append("Message",'app.message');

        menu.append("Quit",'app.quit');

        this.application.set_app_menu(menu);

        // This pops up a MessageDialog when "Message" is clicked in the menu

        let messageAction = new Gio.SimpleAction ({ name: 'message' });

        messageAction.connect('activate', () => { this._showMessageDialog(); });

        this.application.add_action(messageAction);

        // This closes the window when "Quit" is clicked in the menu

        let quitAction = new Gio.SimpleAction ({ name: 'quit' });

        quitAction.connect('activate', () => { this._window.destroy(); });

        this.application.add_action(quitAction);

    }

    _showMessageDialog() {

        // Create a modal MessageDialog whose parent is the window

        this._messageDialog = new Gtk.MessageDialog ({

            transient_for: this._window,

            modal: true,

            buttons: Gtk.ButtonsType.OK_CANCEL,

            message_type: Gtk.MessageType.WARNING,

            text: "This action will cause the universe to stop existing." });

        this._messageDialog.connect ('response', this._response_cb.bind(this));

        this._messageDialog.show();

    }

    // Callback function (aka signal handler) for the response signal

    _response_cb(messagedialog, response_id) {

        // A simple switch that changes the main window's label

        switch (response_id) {

            case Gtk.ResponseType.OK:

                this.warningLabel.set_label ("*BOOM*\n");

                break;

            case Gtk.ResponseType.CANCEL:

                this.warningLabel.set_label ("Good choice!\n");

                break;

            case Gtk.ResponseType.DELETE_EVENT:

                this.warningLabel.set_label ("Dialog closed or cancelled.\n");

                break;

        }

        this._messageDialog.destroy();

    }

};

// Run the application

let app = new MessageDialogExample ();

app.application.run (ARGV);