(function () {
    // Shared Lib
    var CANVAS_ID = 'application-canvas';

    // Needed as we will have edge cases for particular versions of iOS
    // returns null if not iOS
    var getIosVersion = function () {
        if (/iP(hone|od|ad)/.test(navigator.platform)) {
            var v = (navigator.appVersion).match(/OS (\d+)_(\d+)_?(\d+)?/);
            var version = [parseInt(v[1], 10), parseInt(v[2], 10), parseInt(v[3] || 0, 10)];
            return version;
        }

        return null;
    };

    var lastWindowHeight = window.innerHeight;
    var lastWindowWidth = window.innerWidth;
    var windowSizeChangeIntervalHandler = null;

    var pcBootstrap = {
        reflowHandler: null,
        iosVersion: getIosVersion(),

        createCanvas: function () {
            var canvas = document.createElement('canvas');
            canvas.setAttribute('id', CANVAS_ID);
            canvas.setAttribute('tabindex', 0);

            // Disable I-bar cursor on click+drag
            canvas.onselectstart = function () { return false; };

            // Disable long-touch select on iOS devices
            canvas.style['-webkit-user-select'] = 'none';

            document.body.appendChild(canvas);

            return canvas;
        },


        resizeCanvas: function (app, canvas) {
            canvas.style.width = '';
            canvas.style.height = '';
            app.resizeCanvas(canvas.width, canvas.height);

            var fillMode = app._fillMode;

            if (fillMode === pc.FILLMODE_NONE || fillMode === pc.FILLMODE_KEEP_ASPECT) {
                if ((fillMode === pc.FILLMODE_NONE && canvas.clientHeight < window.innerHeight) || (canvas.clientWidth / canvas.clientHeight >= window.innerWidth / window.innerHeight)) {
                    canvas.style.marginTop = Math.floor((window.innerHeight - canvas.clientHeight) / 2) + 'px';
                } else {
                    canvas.style.marginTop = '';
                }
            }

            lastWindowHeight = window.innerHeight;
            lastWindowWidth = window.innerWidth;

            // Work around when in landscape to work on iOS 12 otherwise
            // the content is under the URL bar at the top
            if (this.iosVersion && this.iosVersion[0] <= 12) {
                window.scrollTo(0, 0);
            }
        },

        reflow: function (app, canvas) {
            this.resizeCanvas(app, canvas);

            // Poll for size changes as the window inner height can change after the resize event for iOS
            // Have one tab only, and rotate from portrait -> landscape -> portrait
            if (windowSizeChangeIntervalHandler === null) {
                windowSizeChangeIntervalHandler = setInterval(function () {
                    if (lastWindowHeight !== window.innerHeight || lastWindowWidth !== window.innerWidth) {
                        this.resizeCanvas(app, canvas);
                    }
                }.bind(this), 100);

                // Don't want to do this all the time so stop polling after some short time
                setTimeout(function () {
                    if (!!windowSizeChangeIntervalHandler) {
                        clearInterval(windowSizeChangeIntervalHandler);
                        windowSizeChangeIntervalHandler = null;
                    }
                }, 2000);
            }
        }
    };

    // Expose the reflow to users so that they can override the existing
    // reflow logic if need be
    window.pcBootstrap = pcBootstrap;
})();


(function () {
        // template varants
    var LTC_MAT_1 = [];
    var LTC_MAT_2 = [];

    // varants
    var canvas = pcBootstrap.createCanvas();
    var app = new pc.AppBase(canvas);

    function initCSS() {
        if (document.head.querySelector) {
            // css media query for aspect ratio changes
            // TODO: Change these from private properties
            var css = `@media screen and (min-aspect-ratio: ${app._width}/${app._height}) {
                #application-canvas.fill-mode-KEEP_ASPECT {
                    width: auto;
                    height: 100%;
                    margin: 0 auto;
                }
            }`;
            document.head.querySelector('style').innerHTML += css;
        }

        // Configure resolution and resize event
        if (canvas.classList) {
            canvas.classList.add(`fill-mode-${app.fillMode}`);
        }
    }

    function displayError(html) {
        var div = document.createElement('div');
        div.innerHTML = `<table style="background-color: #8CE; width: 100%; height: 100%;">
        <tr>
            <td align="center">
                <div style="display: table-cell; vertical-align: middle;">
                    <div style="">${html}</div>
                </div>
            </td>
        </tr>
    </table>`;
        document.body.appendChild(div);
    }

    function createGraphicsDevice(callback) {
        var deviceOptions = window.CONTEXT_OPTIONS ? window.CONTEXT_OPTIONS : {};

        if (typeof window.Promise === 'function') {
            var LEGACY_WEBGL = 'webgl';
            var deviceTypes = [...deviceOptions.deviceTypes, LEGACY_WEBGL];

            var gpuLibPath = window.ASSET_PREFIX ? (window.ASSET_PREFIX.replace(/\/$/g, '') + '/') : '';

            // new graphics device creation function with promises
            var gfxOptions = {
                deviceTypes: deviceTypes,
                glslangUrl: gpuLibPath + 'glslang.js',
                twgslUrl: gpuLibPath + 'twgsl.js',
                powerPreference: deviceOptions.powerPreference,
                antialias: deviceOptions.antialias !== false,
                alpha: deviceOptions.alpha === true,
                preserveDrawingBuffer: !!deviceOptions.preserveDrawingBuffer
            };
        
            pc.createGraphicsDevice(canvas, gfxOptions).then((device) => {
                callback(device);
            }).catch((e) => {
                console.error('Device creation error:', e);
                callback(null);
            })
        } else {
            var igl1 = deviceOptions.deviceTypes.indexOf('webgl1');
            var igl2 = deviceOptions.deviceTypes.indexOf('webgl2');
            
            // old webgl graphics device creation
            var options = {
                powerPreference: deviceOptions.powerPreference,
                antialias: deviceOptions.antialias !== false,
                alpha: deviceOptions.transparentCanvas !== false,
                preserveDrawingBuffer: !!deviceOptions.preserveDrawingBuffer,
                preferWebGl2: igl2 > igl1
            };

            if (pc.platform.browser && !!navigator.xr) {
                options.xrCompatible = true;
            }

            callback(new pc.WebglGraphicsDevice(canvas, options));
        }
    }

    function initApp(device) {
        try {
            var createOptions = new pc.AppOptions();
            createOptions.graphicsDevice = device;

            createOptions.componentSystems = [
                pc.RigidBodyComponentSystem,
                pc.CollisionComponentSystem,
                pc.JointComponentSystem,
                pc.AnimationComponentSystem,
                pc.AnimComponentSystem,
                pc.ModelComponentSystem,
                pc.RenderComponentSystem,
                pc.CameraComponentSystem,
                pc.LightComponentSystem,
                pc.script.legacy ? pc.ScriptLegacyComponentSystem : pc.ScriptComponentSystem,
                pc.AudioSourceComponentSystem,
                pc.SoundComponentSystem,
                pc.AudioListenerComponentSystem,
                pc.ParticleSystemComponentSystem,
                pc.ScreenComponentSystem,
                pc.ElementComponentSystem,
                pc.ButtonComponentSystem,
                pc.ScrollViewComponentSystem,
                pc.ScrollbarComponentSystem,
                pc.SpriteComponentSystem,
                pc.LayoutGroupComponentSystem,
                pc.LayoutChildComponentSystem,
                pc.ZoneComponentSystem,
                pc.GSplatComponentSystem,
            ].filter(Boolean);

            createOptions.resourceHandlers = [
                pc.RenderHandler,
                pc.AnimationHandler,
                pc.AnimClipHandler,
                pc.AnimStateGraphHandler,
                pc.ModelHandler,
                pc.MaterialHandler,
                pc.TextureHandler,
                pc.TextHandler,
                pc.JsonHandler,
                pc.AudioHandler,
                pc.ScriptHandler,
                pc.SceneHandler,
                pc.CubemapHandler,
                pc.HtmlHandler,
                pc.CssHandler,
                pc.ShaderHandler,
                pc.HierarchyHandler,
                pc.FolderHandler,
                pc.FontHandler,
                pc.BinaryHandler,
                pc.TextureAtlasHandler,
                pc.SpriteHandler,
                pc.TemplateHandler,
                pc.ContainerHandler,
                pc.GSplatHandler
            ].filter(Boolean);

            createOptions.elementInput = new pc.ElementInput(canvas, {
                useMouse: INPUT_SETTINGS.useMouse,
                useTouch: INPUT_SETTINGS.useTouch
            });
            createOptions.keyboard = INPUT_SETTINGS.useKeyboard ? new pc.Keyboard(window) : null;
            createOptions.mouse = INPUT_SETTINGS.useMouse ? new pc.Mouse(canvas) : null;
            createOptions.gamepads = INPUT_SETTINGS.useGamepads ? new pc.GamePads() : null;
            createOptions.touch = INPUT_SETTINGS.useTouch && pc.platform.touch ? new pc.TouchDevice(canvas) : null;
            createOptions.assetPrefix = window.ASSET_PREFIX || '';
            createOptions.scriptPrefix = window.SCRIPT_PREFIX || '';
            createOptions.scriptsOrder = window.SCRIPTS || [];
            createOptions.soundManager = new pc.SoundManager();
            createOptions.lightmapper = pc.Lightmapper;
            createOptions.batchManager = pc.BatchManager;
            createOptions.xr = pc.XrManager;

            app.init(createOptions);
            return true;

        } catch (e) {
            displayError('Could not initialize application. Error: ' + e);
            console.error(e);
            return false;
        }
    }

    function configure() {
        app.configure(window.CONFIG_FILENAME, (err) => {
            if (err) {
                console.error(err);
                return;
            }

            initCSS(canvas, app._fillMode, app._width, app._height);

            if (LTC_MAT_1.length && LTC_MAT_2.length && app.setAreaLightLuts.length === 2) {
                app.setAreaLightLuts(LTC_MAT_1, LTC_MAT_2);
            }

            // do the first reflow after a timeout because of
            // iOS showing a squished iframe sometimes
            setTimeout(() => {
                pcBootstrap.reflow(app, canvas);
                pcBootstrap.reflowHandler = function () {
                    pcBootstrap.reflow(app, canvas);
                };
        
                window.addEventListener('resize', pcBootstrap.reflowHandler, false);
                window.addEventListener('orientationchange', pcBootstrap.reflowHandler, false);

                app.preload(() => {
                    app.scenes.loadScene(window.SCENE_PATH, (err) => {
                        if (err) {
                            console.error(err);
                            return;
                        }

                        app.start();
                    })
                })
            });
        });
    }

    function main() {
        createGraphicsDevice((device) => {
            if (!device) {
                return;
            }

            if (!initApp(device)) {
                return;
            }

            if (window.PRELOAD_MODULES.length) {
                loadModules(window.PRELOAD_MODULES, window.ASSET_PREFIX, () => {
                    configure(() => {
                        console.timeEnd('start');
                    });
                })
            } else {
                configure();
            }
        });
    }
    main();
})(); // Add scope to avoid polluting window scope