Synnefo

;(function(root){

    // root

    var root = root;

    // setup namepsaces

    var snf = root.synnefo = root.synnefo || {};

    var sync = snf.sync = snf.sync || {};

    var api = snf.api = snf.api || {};

    var storage = snf.storage = snf.storage || {};

    // shortcuts

    var bb = Backbone;

    // logging

    var logger = new snf.logging.logger("SNF-API");

    var debug = _.bind(logger.debug, logger)

    // method map

    var methodMap = {

        'create': 'POST',

        'update': 'PUT',

        'delete': 'DELETE',

        'read'  : 'GET'

    };

    // custom getUrl function

    // handles url retrieval based on the object passed

    // on most occasions in the synnefo api this will call

    // the model/collection url method

    var getUrl = function(object, options) {

        if (!(object && object.url)) return null;

        return _.isFunction(object.url) ? object.url(options) : object.url;

    };

    // Call history (set of api paths with the dates the path last called)

    var api_history = api.requests = api.requests || {};

    var addApiCallDate = function(url, d, method) {

        if (d === undefined) { d = Date() };

        var path = snf.util.parseUri(url).path;

        var key = path + "_" + method;

        // TODO: check if d is very old date

        api_history[key] = d;

        return api_history[path]

    }

    var clearApiCallDate = function(url, method) {

        var path = snf.util.parseUri(url).path;

        var key = path + "_" + method;

        api_history[key] = false;

        return api_history[path]

    }

    var api_errors = api.errors = api.errors || [];

    var add_api_error = function(settings, data) {

        api_errors.push({url:settings.url, date:new Date, settings:settings, data:data})

    }

    var setChangesSince = function(url, method) {

        var path = snf.util.parseUri(url).path;

        var d = api_history[path + "_" + method];

        if (d) {

            url = url + "?changes-since=" + snf.util.ISODateString(d)

        }

        return url;

    }

    // custom sync method

    // appends global ajax handlers

    // handles changed-since url parameter based on api path

    api.sync = function(method, model, options) {

        var type = methodMap[method];

        if (model && (model.skipMethods || []).indexOf(method) >= 0) {

            throw "Model does not support " + method + " calls";

        }

        if (!options.url) {

            var urlobject = model;

            // fallback to collection url for item creation

            if (method == "create" && model.isNew && model.isNew()) {

                urlobject = model.collection;

            }

            options.url = getUrl(model, options) || urlError();

            if (model && model.supportIncUpdates) {

                options.url = options.refresh ? options.url : setChangesSince(options.url, type);

            }

            if (!options.refresh && options.cache === undefined) {

                options.cache = true;

            }

        }

        // default error options

        options.critical = options.critical === undefined ? true : options.critical;

        options.display = options.display === undefined ? true : options.display;

        if (api.stop_calls && !options.no_skip) {

            return;

        }

        var success = options.success || function(){};

        var error = options.error || function(){};

        var complete = options.complete || function(){};

        var before_send = options.beforeSend || function(){};

        // custom json data.

        if (options.data && model && (method == 'create' || method == 'update')) {

            options.contentType = 'application/json';

            options.data = JSON.stringify(options.data);

        }

        var api_params = {};

        var api_options = _.extend(api_params, options, {

            success: api.handlerWrapper(api.successHandler, success, "success"),

            error: api.handlerWrapper(api.errorHandler, error, "error"),

            complete: api.handlerWrapper(api.completeHandler, complete, "complete"),

            beforeSend: api.handlerWrapper(api.beforeSendHandler, before_send, "beforeSend"),

            cache: options.cache || false,

            timeout: options.timeout || snf.config.ajax_timeout || window.TIMEOUT || 5000

        });

        return bb.sync(method, model, api_options);

    }

    api.timeouts_occured = 0;

    api.handlerWrapper = function(wrap, method, type) {

        var cb_type = type;

        return function() {

            var xhr = undefined;

            var handler_type = type;

            var args = arguments;

            var ajax_options = this;

            // save the request date to use it as a changes-since value

            // for opera because we are not able to determine

            // response date header for 304 requests

            if (handler_type == "beforeSend" && $.browser.opera) {

                this.date_send = new Date;

            }

            // error with status code 0 in opera

            // act as 304 response

            if (handler_type == "error" && $.browser.opera) {

                if (arguments[0].status === 0 && arguments[1] === "error") {

                    arguments[0].status = 304;

                    arguments[1] = "notmodified";

                    response_type = "success";

                    xhr = arguments[0];

                }

            }

            // add error in api errors registry

            // api errors registry will be sent

            // if user reports an error using feedback form

            if (handler_type == "error") {

                // skip logging requested ?

                // if not log this error

                if (this.log_error !== false) {

                    add_api_error(this, arguments);

                }

            }

            // identify response status

            var status = 304;

            if (arguments[0]) {

                status = arguments[0].status;

            }

            // identify aborted request

            try {

                if (args[1] === "abort") {

                    api.trigger("abort");

                    return;

                }

            } catch(error) {

                console.error("error aborting", error);

            }

            // try to set the last request date

            // only for notmodified or succeed responses

            try {

                // identify xhr object

                xhr = xhr || args[2];

                // not modified response

                if (args[1] === "notmodified") {

                    if (xhr) {

                        // use date_send if exists (opera browser)

                        var d = this.date_send || xhr.getResponseHeader('Date');

                        if (d) { addApiCallDate(this.url, new Date(d), ajax_options.type); };

                    }

                    return;

                }

                // success response

                if (args[1] == "success" && handler_type == "success") {

                    try {

                        // use date_send if exists (opera browser)

                        var d = this.date_send || args[2].getResponseHeader('Date');

                        if (d) { addApiCallDate(this.url, new Date(d), ajax_options.type); };

                    } catch (err) {

                        console.error(err)

                    }

                }

            } catch (err) {

                console.error(err);

            }

            // dont call error callback for non modified responses

            if (arguments[1] === "notmodified") {

                return;

            }

            // prepare arguments for error callbacks

            var cb_args = _.toArray(arguments);

            if (handler_type === "error") {

                cb_args.push(_.clone(this));

            }

            // determine if we need to call our callback wrapper

            var call_api_handler = true;

            // request handles errors by itself, s

            if (handler_type == "error" && this.skip_api_error) {

                call_api_handler = false

            }

            // aborted request, don't call error handler

            if (handler_type === "error" && args[1] === "abort") {

                call_api_handler = false;

            }

            // reset api call date, next call will be sent without changes-since

            // parameter set

            if (handler_type === "error") {

                if (args[1] === "error") {

                    clearApiCallDate(this.url, this.type);

                }

            }

            // call api call back and retrieve params to

            // be passed to the callback method set for

            // this type of response

            if (call_api_handler) {

                cb_args = wrap.apply(this, cb_args);

            }

            // call requested callback

            method.apply(this, _.toArray(cb_args));

        }

    }

    api.successHandler = function(data, status, xhr) {

        //debug("ajax success", arguments)

        // on success, update the last date we called the api url

        return [data, status, xhr];

    }

    api.errorHandler = function(event, xhr, settings, error) {

        // dont trigger api error untill timeouts occured

        // exceed the skips_timeouts limit

        //

        // check only requests with skips_timeouts option set

        if (xhr === "timeout" && _.last(arguments).skips_timeouts) {

            var skip_timeouts = snf.config.skip_timeouts || 1;

            if (snf.api.timeouts_occured < skip_timeouts) {

                snf.api.timeouts_occured++;

                return;

            } else {

                // reset and continue to error trigger

                snf.api.timeouts_occured = 0;

            }

        }

        // if error occured and changes-since is set for the request

        // skip triggering the error and try again without the changes-since

        // parameter set

        var url = snf.util.parseUri(this.url);

        if (url.query.indexOf("changes-since") > -1) {

            clearApiCallDate(this.url, this.type);

            return _.toArray(arguments);

        }

        // skip aborts, notmodified (opera)

        if (xhr === "error" || xhr === "timeout") {

            var args = _.toArray(arguments);

            api.trigger("error", args);

        }

        return _.toArray(arguments);

    }

    api.completeHandler = function(xhr, status) {

        //debug("ajax complete", arguments)

        return arguments;

    }

    api.beforeSendHandler = function(xhr, settings) {

        //debug("ajax beforeSend", arguments)

        // ajax settings

        var ajax_settings = this;

        return arguments;

    }

    // api call helper

    api.call = function(url, method, data, complete, error, success, options) {

            var self = this;

            error = error || function(){};

            success = success || function(){};

            complete = complete || function(){};

            var extra = data ? data._options || {} : {};

            // really ugly way to pass sync request options.

            // it works though....

            if (data && data._options) { delete data['_options'] };

            // prepare the params

            var params = {

                url: snf.config.api_url + "/" + url,

                data: data,

                success: success,

                complete: function() { api.trigger("call"); complete(this) },

                error: error

            }

            params = _.extend(params, extra, options);

            this.sync(method, this, params);

        },

    _.extend(api, bb.Events);

    // helper for callbacks that need to get called

    // in fixed intervals

    api.updateHandler = function(options) {

        this.cb = options.callback;

        this.limit = options.limit;

        this.timeout = options.timeout;

        this.normal_timeout = options.timeout;

        this.fast_timeout = options.fast;

        this._called = 0;

        this.interval = undefined;

        this.call_on_start = options.call_on_start || true;

        this.running = false;

        this.last_call = false;

        // wrapper

        function _cb() {

            if (this.fast_timeout == this.timeout){

                this._called++;

            }

            if (this._called >= this.limit && this.fast_timeout == this.timeout) {

                this.timeout = this.normal_timeout;

                this.setInterval()

            }

            this.cb();

            this.last_call = new Date;

        };

        _cb = _.bind(_cb, this);

        this.faster = function(do_call) {

            this.timeout = this.fast_timeout;

            this._called = 0;

            this.setInterval(do_call);

        }

        this.setInterval = function(do_call) {

            this.trigger("clear");

            window.clearInterval(this.interval);

            this.interval = window.setInterval(_cb, this.timeout);

            this.running = true;

            var call = do_call || this.call_on_start;

            if (this.last_call) {

                var next_call = (this.timeout - ((new Date) - this.last_call));

                if (next_call < this.timeout/2) {

                    call = true;

                } else {

                    call = false;

                }

            }

            if (call) {

                _cb();

            }

            return this;

        }

        this.start = function (call_on_start) {

            if (this.running) { this.stop() };

            this.call_on_start = call_on_start == undefined ? this.call_on_start : call_on_start;

            this.setInterval();

            return this;

        }

        this.stop = function() {

            this.trigger("clear");

            window.clearInterval(this.interval);

            this.running = false;

            return this;

        }

    }

    // api error state

    api.stop_calls = false;

    api.STATES = { NORMAL:1, WARN:0, ERROR:-1 };

    api.error_state = api.STATES.NORMAL;

    // on api error update the api error_state

    api.bind("error", function() {

        if (snf.api.error_state == snf.api.STATES.ERROR) { return };

        var args = _.toArray(_.toArray(arguments)[0]);

        var params = _.last(args);

        if (params.critical) {

            snf.api.error_state = api.STATES.ERROR;

            snf.api.stop_calls = true;

        } else {

            snf.api.error_state = api.STATES.ERROR;

        }

        snf.api.trigger("change:error_state", snf.api.error_state);

    });

    // reset api error state

    api.bind("reset", function() {

        snf.api.error_state = api.STATES.NORMAL;

        snf.api.stop_calls = false;

        snf.api.trigger("change:error_state", snf.api.error_state);

    })

    // make it eventable

    _.extend(api.updateHandler.prototype, bb.Events);

})(this);