yahoo/kobold-core

// Copyright 2014, Yahoo! Inc.
// Copyrights licensed under the Mit License. See the accompanying LICENSE file for terms.

var Promise = require('promise');
var utils = require('preceptor-core').utils;

var ComparisonAdapter = require('./comparisonAdapter');

/**
 * Blink-Diff comparison adapter
 *
 * @class BlinkDiffAdapter
 * @extends ComparisonAdapter
 */
var BlinkDiffAdapter = ComparisonAdapter.extend(

    /** @lends BlinkDiffAdapter.prototype */
    {
        /**
         * Runs the comparison
         *
         * @method run
         * @return {Promise} With {boolean} for success/failure
         */
        run : function () {
            return new Promise(function (resolve, reject) {
                this._runPromise.call(this, resolve, reject);
            }.bind(this));
        },

        /**
         * Loads a blink-diff instance
         *
         * @method _loadBlinkDiff
         * @return {BlinkDiff}
         * @private
         */
        _loadBlinkDiff: function () {
            var BlinkDiff = utils.require('blink-diff'),
                options = utils.deepExtend({}, [this.getOptions()]);

            options.imageA = this.getImageA();
            options.imageB = this.getImageB();

            return new BlinkDiff(options);
        },

        /**
         * Runs the promise
         *
         * @method _runPromise
         * @param {function} resolve Resolve function to complete comparison
         * @param {function} reject Reject function to reject comparison with an error
         * @private
         */
        _runPromise: function (resolve, reject) {
            var blinkDiff = this._loadBlinkDiff();

            blinkDiff.run(function (err, result) {
                this._evaluateResult.call(this, err, result, blinkDiff, resolve, reject);
            }.bind(this));
        },

        /**
         * Evaluates the result and retrieving the result image
         *
         * @method _evaluateResult
         * @param {Error|null} err Possible error that occurred during the run
         * @param {object} result Result object detailing the comparison result
         * @param {BlinkDiff} blinkDiff Blink-Diff instance
         * @param {function} resolve Resolve function to complete comparison
         * @param {function} reject Reject function to reject comparison with an error
         * @private
         */
        _evaluateResult: function (err, result, blinkDiff, resolve, reject) {
            this.setResultImage(blinkDiff._imageOutput);

            if (err) {
                reject(err);
            } else {
                resolve(blinkDiff.hasPassed(result.code));
            }
        }
    },

    {
        /**
         * Type of class
         *
         * @property TYPE
         * @type string
         */
        TYPE: 'BlinkDiffAdapter'
    });

module.exports = BlinkDiffAdapter;