import {BrowserWindow, Menu, MenuItem, MessageBoxOptions, app, dialog} from "electron";
import * as path from "path";

let app_references = 0;
export function reference_app() {
    app_references++;
}

export function unreference_app() {
    app_references--;
    test_app_should_exit();
}

export let is_debug: boolean;
export let allow_dev_tools: boolean;

import {Arguments, parse_arguments, process_args} from "../shared/process-arguments";
import * as updater from "./app-updater";
import * as loader from "./ui-loader";
import * as crash_handler from "../crash_handler";
import * as url from "url";
import {loadWindowBounds, startTrackWindowBounds} from "../shared/window";

// Keep a global reference of the window object, if you don't, the window will
// be closed automatically when the JavaScript object is garbage collected.
export let main_window: BrowserWindow = null;

function spawn_main_window(entry_point: string) {
    // Create the browser window.
    console.log("Spawning main window");
    reference_app(); /* main browser window references the app */
    main_window = new BrowserWindow({
        width: 800,
        height: 600,

        minHeight: 600,
        minWidth: 600,

        show: false,
        webPreferences: {
            webSecurity: false,
            nodeIntegrationInWorker: true,
            nodeIntegration: true
        },
        icon: path.join(__dirname, "..", "..", "resources", "logo.ico")
    });

    main_window.webContents.on('devtools-closed', event => {
        console.log("Dev tools destroyed!");
    });

    main_window.on('closed', () => {
        app.releaseSingleInstanceLock();
        require("./url-preview").close();
        main_window = null;

        unreference_app();
    });

    main_window.loadURL(url.pathToFileURL(loader.ui.preloading_page(entry_point)).toString());

    main_window.once('ready-to-show', () => {
        main_window.show();
        loadWindowBounds('main-window', main_window).then(() => {
            startTrackWindowBounds('main-window', main_window);

            main_window.focus();
            loader.ui.cleanup();
            if(allow_dev_tools && !main_window.webContents.isDevToolsOpened())
                main_window.webContents.openDevTools();
        });
    });

    main_window.webContents.on('new-window', (event, url_str, frameName, disposition, options, additionalFeatures) => {
        if(frameName.startsWith("__modal_external__")) {
            return;
        }

        event.preventDefault();
        try {
            let url: URL;
            try {
                url = new URL(url_str);
            } catch(error) {
                throw "failed to parse URL";
            }

            {
                let protocol = url.protocol.endsWith(":") ? url.protocol.substring(0, url.protocol.length - 1) : url.protocol;
                if(protocol !== "https" && protocol !== "http") {
                    throw "invalid protocol (" + protocol + "). HTTP(S) are only supported!";
                }
            }

            console.log("Got new window " + frameName);
            const url_preview = require("./url-preview");
            url_preview.open_preview(url_str);
        } catch(error) {
            console.error("Failed to open preview window for URL %s: %o", url_str, error);
            dialog.showErrorBox("Failed to open preview", "Failed to open preview URL: " + url_str + "\nError: " + error);
        }
    });

    main_window.webContents.on('crashed', event => {
        console.error("UI thread crashed! Closing app!");
        if(!process_args.has_flag(Arguments.DEBUG))
            main_window.close();
    });
}

function handle_ui_load_error(message: string) {
    console.log("Caught loading error: %s", message);
    //"A critical error happened while loading TeaClient!", "A critical error happened while loading TeaClient!<br>" + message
    reference_app();
    dialog.showMessageBox({
        type: "error",
        buttons: ["exit"],
        title: "A critical error happened while loading TeaClient!",
        message: (message || "no error").toString()
    }).then(unreference_app);
    loader.ui.cancel();
}

function test_app_should_exit() {
    if(app_references > 0) return;

    console.log("All windows have been closed, closing app.");
    app.quit();
}

function init_listener() {
    app.on('quit', () => {
        console.debug("Shutting down app.");
        crash_handler.finalize_handler();
        loader.ui.cleanup();
        console.log("App has been finalized.");
    });


    app.on('window-all-closed', () => {
        console.log("All windows have been closed. App reference count: %d", app_references);
        test_app_should_exit();
    });

    app.on('activate', () => {
        // On macOS it's common to re-create a window in the app when the
        // dock icon is clicked and there are no other windows open.
        if (main_window === null) {
            //spawn_loading_screen();
            //createWindow()
        }
    });

    app.on('certificate-error', (event, webContents, url, error, certificate, callback) => {
        console.log("Allowing untrusted certificate for %o", url);
        event.preventDefault();
        callback(true);
    });
}

export function execute() {
    console.log("Main app executed!");

    parse_arguments();
    is_debug = process_args.has_flag(...Arguments.DEBUG);
    allow_dev_tools = process_args.has_flag(...Arguments.DEV_TOOLS);
    if(is_debug) {
        console.log("Enabled debug!");
        console.log("Arguments: %o", process_args);
    }

    Menu.setApplicationMenu(null);
    init_listener();

    console.log("Setting up render backend");
    require("./render-backend");

    console.log("Spawn loading screen");
    loader.ui.execute_loader().then(async (entry_point: string) => {
        /* test if the updater may have an update found */
        let awaiting_update_set = false;
        while(updater.update_question_open) {
            if(!awaiting_update_set) {
                awaiting_update_set = true;
                loader.ui.show_await_update();
                console.log("Awaiting update stuff to be finished");
            }
            await new Promise(resolve => setTimeout(resolve, 100));
        }

        if(updater.update_restart_pending)
            return undefined;

        return entry_point;
    }).then((entry_point: string) => {
        reference_app(); /* because we've no windows when we close the loader UI */
        loader.ui.cleanup(); /* close the window */

        if(entry_point) //has not been canceled
            spawn_main_window(entry_point);
        else {
            handle_ui_load_error("Missing UI entry point");
        }
        unreference_app();
    }).catch(handle_ui_load_error);
}