/* CodeQ: an online programming tutor.
   Copyright (C) 2015,2016 UL FRI

This program is free software: you can redistribute it and/or modify it under
the terms of the GNU Affero General Public License as published by the Free
Software Foundation, either version 3 of the License, or (at your option) any
later version.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
details.

You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */

(function () {
    "use strict";
    window.siteDefinition = {logLevel: 'debug'/*, 'logService': '/ws/clientlog'*/}; // for debug purposes

    // ================================================================================
    // JSON-ization (stringification) function
    // ================================================================================

    var jsonize = JSON && JSON.stringify || function (obj) {
            var t, buffer, i, isFirst;
            if (null === obj) return 'null';
            t = typeof obj;
            if (t === 'string') {
                return '"' + obj.replace(regexpBackslash, '\\\\').replace(regexpQuote, '\\"') + '"';
            }
            if (t === 'number') {
                if (isFinite(obj)) return obj.toString();
                throw new Error('Cannot jsonize a non-finite number: ' + obj.toString());
            }
            if (t === 'boolean') {
                if (obj) return 'true';
                return 'false';
            }
            if (t === 'object') {
                if (obj instanceof String) return jsonize(obj.valueOf());
                if (obj instanceof Number) return jsonize(obj.valueOf());
                if (obj instanceof Boolean) return jsonize(obj.valueOf());
                if (obj instanceof Array) {
                    buffer = [ '[' ];
                    isFirst = true;
                    for (i = 0; i < obj.length; i++) {
                        if (isFirst) isFirst = false;
                        else buffer.push(',');
                        buffer.push(jsonize(obj[i]));
                    }
                    buffer.push(']');
                    return buffer.join('');
                }
                buffer = [ '{' ];
                isFirst = true;
                for (i in obj) {
                    if (!obj.hasOwnProperty(i)) continue;
                    if (isFirst) isFirst = false;
                    else buffer.push(',');
                    buffer.push(jsonize(i), ':', jsonize(obj[i]));
                }
                buffer.push('}');
                return buffer.join('');
            }
            throw new Error('Cannot jsonize ' + t);
        };

    // ================================================================================
    // The log module: contains methods for logging, sending logs to the server
    // ================================================================================

    var log = (function () {
        var logServiceUrl = window.siteDefinition && (typeof siteDefinition.logService === 'string') && siteDefinition.logService,
            assembleOutput = function (stuff, e) {
                var lines = [ stuff ];
                if (e && e.stack) lines.push(e.stack);
                return lines.join('\n');
            },
            console = window.console || {},
            levelPrefix = {'debug': 'DEBUG: ', 'info': 'INFO: ', 'warn': 'WARN: ', 'error': 'ERROR: '},
            levelSeverity = {'debug': 1, 'info': 2, 'warn': 3, 'error': 4, 'off': 5},
            severityThreshold = window.siteDefinition && levelSeverity[siteDefinition.logLevel] || levelSeverity['off'],
            logToConsole = function (level) {
                var prefix = levelPrefix[level];
                if (levelSeverity[level] < severityThreshold) return function () {}; // level is below threshold, ignore
                if (typeof console[level] === 'function') return function (output) {console[level](output);};
                if (typeof console.log === 'function') return function (output) {console.log(prefix + output);};
                if (typeof dump === 'function') return function (output) {dump(prefix + output);};
                return function () {}; // no way to log in browser
            },
            consoleLogger = {
                'debug': logToConsole('debug'),
                'info': logToConsole('info'),
                'warn': logToConsole('warn'),
                'error': logToConsole('error')
            },
            logger = {},
            level;

        if (logServiceUrl) {
            // log to the service and to the console
            var logs = []; // buffered logs
            for (level in levelPrefix) {
                if (!levelPrefix.hasOwnProperty(level)) continue;
                logger[level] = (function (levelLogger, level) {
                    if (levelSeverity[level] < severityThreshold) return function () {}; // level is below threshold, ignore
                    return function (stuff, e) {
                        var output = assembleOutput(stuff, e);
                        levelLogger(output);
                        logs.push({
                            't': Date.now(),
                            'l': level,
                            'm': output
                        });
                    };
                })(consoleLogger[level], level);
            }
            setInterval(function () {
                // each second send any logs to the server
                var copyOfLogs;
                if (logs.length < 1) return;
                copyOfLogs = jsonize({'logs': logs});
                logs = [];
                $.ajax({
                    contentType: 'application/json',
                    type: 'POST',
                    url: logServiceUrl,
                    data: copyOfLogs,
                    error: function (jqXHR, textStatus, errorThrown) {
                        consoleLogger.error(assembleOutput('Posting of logs to ' + logServiceUrl + ' failed: ' + textStatus, errorThrown));
                    },
                    success: function (data, textStatus, jqXHR) {}
                });
            }, 1000);
        }
        else {
            // log only to the console
            for (level in levelPrefix) {
                if (!levelPrefix.hasOwnProperty(level)) continue;
                logger[level] = (function (levelLogger) {
                    if (levelSeverity[level] < severityThreshold) return function () {}; // level is below threshold, ignore
                    return function (stuff, e) { levelLogger(assembleOutput(stuff, e)); };
                })(consoleLogger[level]);
            }
        }

        return logger;
    })();

    // uncaught error reporting
    window.onerror = function (msg, url, lineNumber) {
        if ((msg !== null) && (msg instanceof Object)) msg = msg.toString();
        codeq.log.error('Uncaught error at line ' + lineNumber + ' in ' + url + ': ' + msg);
    };

    // ================================================================================
    // The core CodeQ module
    // ================================================================================

    var jqDisabled = $('#disabled'), // used in codeq.wait()
        waitCssEnter = {'cursor': 'wait', 'display': ''};

    // regular expressions for the templating function, etc.
    var regexpQuote = new RegExp('"', 'g'),
        regexpBackslash = new RegExp('\\\\', 'g'),
        regexpAmp = new RegExp('&', 'g'),
        regexpLt = new RegExp('<', 'g'),
        regexpGt = new RegExp('>', 'g');

    // event dispatch
    var eventListeners = {}, // keyed by event name, value is an array of listeners
        asyncTimer = null,
        queuedEvents = [],
        fireEvents = function () {
            if (asyncTimer !== null) return;
            asyncTimer = setTimeout(function () {
                var N = queuedEvents.length,
                    i, event, args, listeners, j;
                asyncTimer = null;
                for (i = 0; i < N; i++) {
                    event = queuedEvents[i];
                    listeners = eventListeners[event.name];
                    if (!listeners) continue;
                    args = event.args;
                    listeners = listeners.slice(); // make a copy of the list, so we're unaffected of any changes
                    for (j = 0; j < listeners.length; j++) {
                        try {
                            listeners[j](args);
                        }
                        catch (e) {
                            codeq.log.error('Error while invoking an event handler for ' + event.name + ': ' + e, e);
                        }
                    }
                }
                queuedEvents.splice(0, N);
                if (queuedEvents.length > 0) fireEvents();
            }, 0);
        };

    var makeActivityHandler = function (editor, problem_id) {
        var lastActivityMillis = Date.now(),
            deltaActivityMillis = function deltaActivityMillisFunc () {
                var now = Date.now(),
                    dt = now - lastActivityMillis;
                lastActivityMillis = now;
                return dt;
            },
            queue = [],
            ts = null,
            timer = function () {
                var promise;
                ts = null;
                if (queue.length === 0) return Q(true);
                promise = codeq.comms.sendActivity(queue, editor.getDoc().getValue(), problem_id);
                queue.length = 0;
                return promise;
            },
            flush = function () {
                clearTimeout(ts);
                return timer();
            };

        return {
            'queueTrace': function (trace) {
                trace['dt'] = deltaActivityMillis();
                queue.push(trace);
                if (ts === null) ts = setTimeout(timer, 10000); // flush every 10 seconds
                return this;
            },
            'flush': flush,
            'addAndPurge': function (trace) {
                var accumulatedTrace = queue;
                queue = [];
                trace['dt'] = deltaActivityMillis();
                accumulatedTrace.push(trace);
                if (ts !== null) {
                    clearTimeout(ts);
                    ts = null;
                }
                return accumulatedTrace;
            }
        };
    };

    // replace window.alert with custom message box (only used for app errors)
    var jqMessage = $('div#message');
    jqMessage.find('.close').click(function () {
        jqMessage.slideUp('fast');
    });
    window.alert = function (message, type) {
        jqMessage.find('.text').text(message);
        jqMessage.removeClass().addClass(type || 'error').slideDown('fast');
    };

    window.codeq = {
        'jsonize': jsonize,

        'log': log,

        'samlLogin' : false,//falg if we logged in via saml

        'settings': {
            'gui_lang': 'en', // boot sequence overrides this if the browser uses a supported language
            'gui_layout': 'line-layout'
        },

        'experiments': [], // experiments the user is participating in

        'availableLangs': [], // filled at boot from 'supportedLangs'
        'supportedLangs': {
            'en': 'English',
            'sl': 'Slovenščina'
        },
        'supportedLayouts':[
            'line-layout',
            'square-layout'
        ],

        'runningOnPhone': false, // default value, will be changed if detected otherwise
        'browserType': 'unknown',
        'platformType': 'unknown',
        'isWebApp': false, // this is a PhoneGap/Cordova build, will be overridden in cordova.js for webapp

        'setLayout': function(newLayout){
            codeq.settings['gui_layout'] = newLayout;
            codeq.fire('layoutchange');
        },

        'getLayout': function(){
            return codeq.settings['gui_layout'];
        },

        'setLang': function (newLang) {
            codeq.settings['gui_lang'] = newLang;
            codeq.fire('langchange', {'lang': newLang});
        },

        'getLang': function(){
          return codeq.settings['gui_lang'];
        },

        'escapeHtml': function (s) {
            return ('' + s).replace(regexpAmp, '&amp;').replace(regexpLt, '&lt;').replace(regexpGt, '&gt;');
        },

        /**
         * Returns the number of Unicode code points in the given string.
         *
         * @param s {string}
         * @returns {number}
         */
        'codePointCount': function (s) {
            var n = 0, i, code;
            if (typeof s !== 'string') {
                code = 'codePointCount(): argument not a string: type = ' + typeof s + ', is null = ' + (s === null);
                if ((typeof s === 'object') && (s !== null) && s.constructor) code += ', constructor = ' + s.constructor.name;
                codeq.log.error(code);
                return 0;
            }
            for (i = 0; i < s.length; i++) {
                try {
                    code = s.charCodeAt(i);
                }
                catch (e) {
                    codeq.log.error('Invocation of charCodeAt() failed at iteration #' + i + ': ' + e, e);
                    return 0;
                }
                if ((code >= 0xd800) && (code < 0xe000)) i++;
                n++;
            }
            return n;
        },

        'makeActivityHandler': makeActivityHandler,

        'wait': function (promise) {
            jqDisabled.css(waitCssEnter);
            return promise.fin(function () {
                jqDisabled.css('display', 'none');
            });
        },

        // resolve a promise not sooner than after [timeout] seconds
        // from https://github.com/kriskowal/q/commit/681f6d201842d4b99bab5451ebc57ef0c3c0d49a
        'throttle': function (promise, timeout) {
            if (timeout === undefined) {
                timeout = promise;
                promise = undefined;
            }

            var deferred = Q.defer();
            Q.when(promise, undefined, undefined, deferred.notify);
            setTimeout(function () {
                deferred.resolve(promise);
            }, timeout);
            return deferred.promise;
        },

        // codeq event handling
        'fire': function (eventName, args) {
            queuedEvents.push({'name': eventName, 'args': args});
            fireEvents();
        },

        'on': function (eventName, callback) {
            var listeners = eventListeners[eventName],
                i;
            if (listeners) {
                for (i = listeners.length - 1; i >= 0; i--) {
                    if (listeners[i] === callback) return; // already registered
                }
            }
            else {
                listeners = [];
                eventListeners[eventName] = listeners;
            }
            listeners.push(callback);
        },

        'off': function (eventName, callback) {
            var listeners = eventListeners[eventName],
                i;
            if (listeners) {
                for (i = listeners.length - 1; i >= 0; i--) {
                    if (listeners[i] === callback) listeners.splice(i, 1);
                }
            }
        },

        // reset the app
        'reset': function (reason) {
            codeq.log.info('App reset: ' + (reason || 'no reason given'));
            codeq.globalStateMachine.transition('login');
            codeq.wait(
                    codeq.comms.forceReset()
                )
                .fin(function () {
                    if (reason) {
                        alert(reason);
                    }
                })
                .done();
        }
    };
})();