var WebGLFullscreen = {
    WebGLFullscreenInject: function () {
        document.setFullScreenByElement = function (container, canvas, keepAspectRatio) {
            // set fullscreen
            var setFullScreen = function (element) {
                (element.webkitRequestFullscreen ||
                    element.requestFullscreen ||
                    element.mozRequestFullScreen ||
                    element.msRequestFullscreen).call(element)
            }

            // get fullscreen state
            var getFullscreen = function () {
                var doc = window.document;
                var objFullScreen = doc.fullscreenElement || doc.mozFullScreenElement || doc.webkitFullscreenElement || doc.msFullscreenElement;
                return (objFullScreen);
            }

            // add fullscreenchange event handle
            var addEventFullscreenChange = function (callback) {
                document.addEventListener("fullscreenchange", callback, false);
                document.addEventListener("webkitfullscreenchange", callback, false);
                document.addEventListener("mozfullscreenchange", callback, false);
                document.addEventListener("MSFullscreenChange", callback, false);
            }

            // remove fullscreenchange event handle
            var removeEventFullscreenChange = function (callback) {
                document.removeEventListener("fullscreenchange", callback, false);
                document.removeEventListener("webkitfullscreenchange", callback, false);
                document.removeEventListener("mozfullscreenchange", callback, false);
                document.removeEventListener("MSFullscreenChange", callback, false);
            }

            var beforeStyle = canvas.style;
            var beforeWidth = parseInt(beforeStyle.width);
            var beforeHeight = parseInt(beforeStyle.height);

            // recv fullscreen function
            var fullscreenFunc = function () {
                if (getFullscreen()) {
                    if (keepAspectRatio) {
                        var ratio = Math.min(window.screen.width / beforeWidth, window.screen.height / beforeHeight);
                        var width = Math.floor(beforeWidth * ratio);
                        var height = Math.floor(beforeHeight * ratio);

                        canvas.style.width = width + 'px';
                        canvas.style.height = height + 'px';;
                    } else {
                        canvas.style.width = window.screen.width + 'px';;
                        canvas.style.height = window.screen.height + 'px';;
                    }
                } else {
                    canvas.style.width = beforeWidth + 'px';;
                    canvas.style.height = beforeHeight + 'px';;

                    // remove this function
                    removeEventFullscreenChange(fullscreenFunc);
                }
            }

            // listener fullscreen event
            addEventFullscreenChange(fullscreenFunc);

            // fullscreen
            setFullScreen(container)
        }
        document.setFullscreen = function (containerId, canvasId, keepAspectRatio) {
            var container = document.getElementById(containerId);
            var canvas = document.getElementById(canvasId);
            document.setFullScreenByElement(container, canvas, keepAspectRatio)
        }
    },
    WebGLSetFullscreen: function () {
        var container = document.getElementById('unity-container');
        var canvas = document.getElementById('unity-canvas');
        var keepAspectRatio = false;
        document.setFullScreenByElement(container, canvas, keepAspectRatio);
    },
    WebGLSetFullscreen2019: function () {
        document.makeFullscreen('unityContainer');
    },
}

mergeInto(LibraryManager.library, WebGLFullscreen);