/* --------------------------------------------------------------
 debug.js 2016-09-08
 Gambio GmbH
 http://www.gambio.de
 Copyright (c) 2016 Gambio GmbH
 Released under the GNU General Public License (Version 2)
 [http://www.gnu.org/licenses/gpl-2.0.html]
 --------------------------------------------------------------
 */

jse.core.debug = jse.core.debug || {};

/**
 * JSE Debug Module
 *
 * This object provides an wrapper to the console.log function and enables easy use
 * of the different log types like "info", "warning", "error" etc.
 *
 * @module JSE/Core/debug
 */
(function (exports) {
    'use strict';

    // ------------------------------------------------------------------------
    // VARIABLES
    // ------------------------------------------------------------------------

    /**
     * @type {String}
     */
    const TYPE_DEBUG = 'DEBUG';

    /**
     * @type {String}
     */
    const TYPE_INFO = 'INFO';

    /**
     * @type {String}
     */
    const TYPE_LOG = 'LOG';

    /**
     * @type {String}
     */
    const TYPE_WARN = 'WARN';

    /**
     * @type {String}
     */
    const TYPE_ERROR = 'ERROR';

    /**
     * @type {String}
     */
    const TYPE_ALERT = 'ALERT';

    /**
     * @type {String}
     */
    const TYPE_MOBILE = 'MOBILE';

    /**
     * @type {String}
     */
    const TYPE_SILENT = 'SILENT';

    /**
     * All possible debug levels in the order of importance.
     *
     * @type {String[]}
     */
    const levels = [
        TYPE_DEBUG,
        TYPE_INFO,
        TYPE_LOG,
        TYPE_WARN,
        TYPE_ERROR,
        TYPE_ALERT,
        TYPE_MOBILE,
        TYPE_SILENT
    ];

    // ------------------------------------------------------------------------
    // FUNCTIONS
    // ------------------------------------------------------------------------

    /**
     * Set Favicon to Error State.
     *
     * This method will only work if <canvas> is supported from the browser.
     *
     * @private
     */
    function _setFaviconToErrorState() {
        const canvas = document.createElement('canvas');
        const favicon = document.querySelector('[rel="shortcut icon"]');

        if (canvas.getContext && !favicon.className.includes('error-state')) {
            const img = document.createElement('img');
            canvas.height = canvas.width = 16;
            const ctx = canvas.getContext('2d');
            img.onload = function () { // Continue once the image has been loaded. 
                ctx.drawImage(this, 0, 0);
                ctx.globalAlpha = 0.65;
                ctx.fillStyle = '#FF0000';
                ctx.rect(0, 0, 16, 16);
                ctx.fill();
                favicon.href = canvas.toDataURL('image/png');
                favicon.className += 'error-state';
            };
            img.src = favicon.href;
        }
    }

    /**
     * Error handler that fetches all exceptions thrown by the javascript.
     *
     * @private
     */
    function _globalErrorHandler() {
        if (jse.core.config.get('environment') !== 'production') {
            // Log the error in the browser's console. 
            if (jse.core.debug !== undefined) {
                jse.core.debug.error('JS Engine Error Handler', arguments);
            } else {
                console.log('JS Engine Error Handler', arguments);
            }

            // Update the page title with an error count.
            const regex = /.\ \[(.+)\]\ /;
            let title = window.document.title;
            let errorCount = 1;

            // Gets the current error count and recreates the default title of the page.
            if (title.match(regex) !== null) {
                errorCount = parseInt(title.match(/\d+/)[0], 10) + 1;
                title = title.replace(regex, '');
            }

            // Re-creates the error flag at the title with the new error count.
            title = '✖ [' + errorCount + '] ' + title;
            window.document.title = title;

            // Set Favicon to Error State.
            _setFaviconToErrorState();
        }

        return true;
    }

    /**
     * Executes the correct console/alert statement.
     *
     * @param {Object} caller (optional) Contains the caller information to be displayed.
     * @param {Object} data (optional) Contains any additional data to be included in the debug output.
     *
     * @private
     */
    function _execute(caller, data) {
        const currentLogIndex = levels.indexOf(caller);
        const allowedLogIndex = levels.indexOf(jse.core.config.get('debug'));
        let consoleMethod = null;

        if (currentLogIndex >= allowedLogIndex) {
            consoleMethod = caller.toLowerCase();

            switch (consoleMethod) {
                case 'alert':
                    alert(JSON.stringify(data));
                    break;

                case 'mobile':
                    const $mobileDebugModal = $('.mobile-debug-modal');

                    if (!$mobileDebugModal.length) {
                        $('<div />')
                            .addClass('mobile-debug-modal')
                            .css({
                                position: 'fixed',
                                top: 0,
                                left: 0,
                                maxHeight: '50%',
                                minWidth: '200px',
                                maxWidth: '300px',
                                backgroundColor: 'crimson',
                                zIndex: 100000,
                                overflow: 'scroll'
                            })
                            .appendTo($('body'));
                    }

                    $mobileDebugModal.append('<p>' + JSON.stringify(data) + '</p>');
                    break;

                default:
                    if (console === undefined) {
                        return; // There is no console support so do not proceed.
                    }

                    if (typeof console[consoleMethod].apply === 'function' || typeof console.log.apply === 'function') {
                        if (console[consoleMethod] !== undefined) {
                            console[consoleMethod].apply(console, data);
                        } else {
                            console.log.apply(console, data);
                        }
                    } else {
                        console.log(data);
                    }
            }
        }
    }

    /**
     * Bind Global Error Handler
     */
    exports.bindGlobalErrorHandler = function () {
        window.onerror = _globalErrorHandler;
    };

    /**
     * Replaces console.debug
     *
     * @params {*} arguments Any data that should be shown in the console statement.
     */
    exports.debug = function () {
        _execute(TYPE_DEBUG, arguments);
    };

    /**
     * Replaces console.info
     *
     * @params {*} arguments Any data that should be shown in the console statement.
     */
    exports.info = function () {
        _execute(TYPE_INFO, arguments);
    };

    /**
     * Replaces console.log
     *
     * @params {*} arguments Any data that should be shown in the console statement.
     */
    exports.log = function () {
        _execute(TYPE_LOG, arguments);
    };

    /**
     * Replaces console.warn
     *
     * @params {*} arguments Any data that should be shown in the console statement.
     */
    exports.warn = function () {
        _execute(TYPE_WARN, arguments);
    };

    /**
     * Replaces console.error
     *
     * @param {*} arguments Any data that should be shown in the console statement.
     */
    exports.error = function () {
        _execute(TYPE_ERROR, arguments);
    };

    /**
     * Replaces alert
     *
     * @param {*} arguments Any data that should be shown in the console statement.
     */
    exports.alert = function () {
        _execute(TYPE_ALERT, arguments);
    };

    /**
     * Debug info for mobile devices.
     *
     * @param {*} arguments Any data that should be shown in the console statement.
     */
    exports.mobile = function () {
        _execute(TYPE_MOBILE, arguments);
    };

}(jse.core.debug));