window.resize = (function () {

    'use strict';

    function Resize() {
        //
    }

    Resize.prototype = {

        init: function(outputQuality) {
            this.outputQuality = (outputQuality === 'undefined' ? 0.8 : outputQuality);
        },

        photo: function(file, maxSize, outputType, callback) {

            var _this = this;

            var reader = new FileReader();
            reader.onload = function (readerEvent) {
                _this.resize(readerEvent.target.result, maxSize, outputType, callback);
            }
            reader.readAsDataURL(file);

        },

        resize: function(dataURL, maxSize, outputType, callback) {

            var _this = this;

            var image = new Image();
            image.onload = function (imageEvent) {

                // Resize image
                var canvas = document.createElement('canvas'),
                    width = image.width,
                    height = image.height;
                if (width > height) {
                    if (width > maxSize) {
                        height *= maxSize / width;
                        width = maxSize;
                    }
                } else {
                    if (height > maxSize) {
                        width *= maxSize / height;
                        height = maxSize;
                    }
                }
                canvas.width = width;
                canvas.height = height;
                canvas.getContext('2d').drawImage(image, 0, 0, width, height);

                _this.output(canvas, outputType, callback);

            }
            image.src = dataURL;

        },

        output: function(canvas, outputType, callback) {

            switch (outputType) {

                case 'file':
                    canvas.toBlob(function (blob) {
                        callback(blob);
                    }, 'image/jpeg', 0.8);
                    break;

                case 'dataURL':
                    callback(canvas.toDataURL('image/jpeg', 0.8));
                    break;

            }

        }

    };

    return Resize;

}());