/*!
 * retina.js v1.3.0
 *
 * copyright 2014 imulus, llc
 * released under the mit license
 *
 * retina.js is an open source script that makes it easy to serve
 * high-resolution images to devices with retina displays.
 */

(function() {
    var root = (typeof exports === 'undefined' ? window : exports);
    var config = {
        // an option to choose a suffix for 2x images
        retinaimagesuffix : '@2x',

        // ensure content-type is an image before trying to load @2x image
        // https://github.com/imulus/retinajs/pull/45)
        check_mime_type: true,

        // resize high-resolution images to original image's pixel dimensions
        // https://github.com/imulus/retinajs/issues/8
        force_original_dimensions: true
    };

    function retina() {}

    root.retina = retina;

    retina.configure = function(options) {
        if (options === null) {
            options = {};
        }

        for (var prop in options) {
            if (options.hasownproperty(prop)) {
                config[prop] = options[prop];
            }
        }
    };

    retina.init = function(context) {
        if (context === null) {
            context = root;
        }

        var existing_onload = context.onload || function(){};

        context.onload = function() {
            var images = document.getelementsbytagname('img'), retinaimages = [], i, image;
            for (i = 0; i < images.length; i += 1) {
                image = images[i];
                if (!!!image.getattributenode('data-no-retina')) {
                    retinaimages.push(new retinaimage(image));
                }
            }
            existing_onload();
        };
    };

    retina.isretina = function(){
        var mediaquery = '(-webkit-min-device-pixel-ratio: 1.5), (min--moz-device-pixel-ratio: 1.5), (-o-min-device-pixel-ratio: 3/2), (min-resolution: 1.5dppx)';

        if (root.devicepixelratio > 1) {
            return true;
        }

        if (root.matchmedia && root.matchmedia(mediaquery).matches) {
            return true;
        }

        return false;
    };


    var regexmatch = /\.\w+$/;
    function suffixreplace (match) {
        return config.retinaimagesuffix + match;
    }

    function retinaimagepath(path, at_2x_path) {
        this.path = path || '';
        if (typeof at_2x_path !== 'undefined' && at_2x_path !== null) {
            this.at_2x_path = at_2x_path;
            this.perform_check = false;
        } else {
            if (undefined !== document.createelement) {
                var locationobject = document.createelement('a');
                locationobject.href = this.path;
                locationobject.pathname = locationobject.pathname.replace(regexmatch, suffixreplace);
                this.at_2x_path = locationobject.href;
            } else {
                var parts = this.path.split('?');
                parts[0] = parts[0].replace(regexmatch, suffixreplace);
                this.at_2x_path = parts.join('?');
            }
            this.perform_check = true;
        }
    }

    root.retinaimagepath = retinaimagepath;

    retinaimagepath.confirmed_paths = [];

    retinaimagepath.prototype.is_external = function() {
        return !!(this.path.match(/^https?\:/i) && !this.path.match('//' + document.domain) );
    };

    retinaimagepath.prototype.check_2x_variant = function(callback) {
        var http, that = this;
        if (this.is_external()) {
            return callback(false);
        } else if (!this.perform_check && typeof this.at_2x_path !== 'undefined' && this.at_2x_path !== null) {
            return callback(true);
        } else if (this.at_2x_path in retinaimagepath.confirmed_paths) {
            return callback(true);
        } else {
            http = new xmlhttprequest();
            http.open('head', this.at_2x_path);
            http.onreadystatechange = function() {
                if (http.readystate !== 4) {
                    return callback(false);
                }

                if (http.status >= 200 && http.status <= 399) {
                    if (config.check_mime_type) {
                        var type = http.getresponseheader('content-type');
                        if (type === null || !type.match(/^image/i)) {
                            return callback(false);
                        }
                    }

                    retinaimagepath.confirmed_paths.push(that.at_2x_path);
                    return callback(true);
                } else {
                    return callback(false);
                }
            };
            http.send();
        }
    };


    function retinaimage(el) {
        this.el = el;
        this.path = new retinaimagepath(this.el.getattribute('src'), this.el.getattribute('data-at2x'));
        var that = this;
        this.path.check_2x_variant(function(hasvariant) {
            if (hasvariant) {
                that.swap();
            }
        });
    }

    root.retinaimage = retinaimage;

    retinaimage.prototype.swap = function(path) {
        if (typeof path === 'undefined') {
            path = this.path.at_2x_path;
        }

        var that = this;
        function load() {
            if (! that.el.complete) {
                settimeout(load, 5);
            } else {
                if (config.force_original_dimensions) {
                    that.el.setattribute('width', that.el.offsetwidth);
                    that.el.setattribute('height', that.el.offsetheight);
                }

                that.el.setattribute('src', path);
            }
        }
        load();
    };


    if (retina.isretina()) {
        retina.init(root);
    }
})();