/**
 * html5调用摄像头扫码
 */
;(function (win, doc) {
    function QRScan(div_id) {
        this.div_id = div_id;
        this.div_can = null;
        this.videos = [];
        this.medioConfig = {};
        this.can_open = false;
        this.init();
    }

    QRScan.prototype = {
        init: function () {
            win.URL = (win.URL || win.webkitURL || win.mozURL || win.msURL);
            var promisifiedOldGUM = function(constraints) {
                var getUserMedia = (navigator.getUserMedia ||
                    navigator.webkitGetUserMedia || navigator.mozGetUserMedia);
                if (!getUserMedia) {
                    return Promise.reject(new Error('getUserMedia is not implemented in this browser'));
                }
                return new Promise(function (resolve, reject) {
                    getUserMedia.call(navigator, constraints, resolve, reject);
                });
            };
            if(navigator.mediaDevices === undefined) {
                navigator.mediaDevices = {};
            }
            if(navigator.mediaDevices.getUserMedia === undefined) {
                navigator.mediaDevices.getUserMedia = promisifiedOldGUM;
            }

            var self = this;
            self.div_can = doc.getElementById(self.div_id);
            navigator.mediaDevices.enumerateDevices().then(function(devices) {
                devices.forEach(function (dv) {
                    var kind = dv.kind;
                    if (kind.match(/^video.*/)) {
                        self.videos.push(dv.deviceId);
                        console.log(dv);
                    }
                });
                var len = self.videos.length;
                self.can_open = true;
                self.medioConfig = {
                    audio: false,
                    video: { deviceId: self.videos[len - 1] }
                }
            });
        },
        openScan: function () {
            var self = this;
            if (self.can_open) {
                var vd = doc.createElement('video');
                vd.setAttribute('id', 'video_id');
                navigator.mediaDevices.getUserMedia(self.medioConfig).then(function (stream) {
                    vd.src = win.URL.createObjectURL(stream);
                    //  vd.srcObject = stream  在新的浏览器中需使用此代替createObjectURL
                    self.div_can.appendChild(vd);
                }).catch(function (err) {
                    var p = doc.createElement('p');
                    p.innerHTML = 'ERROR: ' + err.name +
                                  '<br>该浏览器不支持调用摄像头，请使用夸克浏览器';
                    self.div_can.appendChild(p);
                });
                vd.play();
            }
        },

        closeScan: function () {
            this.div_can.innerHTML = '';
        },
        // 截图上传
        getImgDecode: function (func) {
            var self = this;
            var video = doc.getElementById('video_id');
            var canvas = doc.createElement('canvas');
            canvas.width = 340;
            canvas.height = 305;
            var ctx = canvas.getContext('2d');
            ctx.drawImage(video, 0, 0, 340, 305);
            if (canvas.toBlob === undefined) {
                var base64 = canvas.toDataURL();
                var blob = self.Base64ToBlob(base64);
                self.sendBlob(blob, func);
            } else {
                canvas.toBlob(function (blob) {
                    self.sendBlob(blob, func);
                });
            }
        },

        sendBlob: function (blob, func) {
            var fd = new FormData();
            fd.append('auth', 'lkl123456');
            fd.append('file', blob);
            var xhr = new XMLHttpRequest();
            xhr.open('post', 'http://123.206.7.80:10082/api/parse', true);
            xhr.onload = function () {
               func ? func(JSON.parse(xhr.responseText)) : null;
            };
            xhr.send(fd);
        },

        Base64ToBlob: function (base64) {
            var code = win.atob(base64.split(',')[1]);
            var len = code.length;
            var as = new Uint8Array(len);
            for (var i = 0; i < len; i++) {
                as[i] = code.charCodeAt(i);
            }
            return new Blob([as], {type: 'image/png'});
        }
    }

    win.QRScan = QRScan;
}(window, document));