(function () {
    'use strict';
    var serviceId = 'evernote';
    angular.module('app').factory(serviceId, ['config', '$q', 'user', '$window', '$http', evernote]);

    //evernote related service
    function evernote(config, $q, user, $window, $http) {
        var service = {
            getAllNotebooks: getAllNotebooks,
            getAllNotesForNotebook: getAllNotesForNotebook,
            getNote: getNote,
            removeOAuth: removeOAuth,
            authenticate: authenticate
        };

        return service;

        //get all notebooks for the user
        function getAllNotebooks() {
            var request = $http({
                method: "get",
                url: config.evernoteRemoteServiceUrl + 'notebooks/'
            });

            return (request.then(function (response) {
                return response.data;
            }, handleError));
        }

        //get all notes in a notebook
        function getAllNotesForNotebook(notebookId) {
            var request = $http({
                method: "get",
                url: config.evernoteRemoteServiceUrl + 'notebook/'+notebookId+'/notes'
            });

            return (request.then(function (response) {
                return response.data;
            }, handleError));
        }

        //get the full note
        function getNote(noteId) {
            var request = $http({
                method: "get",
                url: config.evernoteRemoteServiceUrl + 'note/' + noteId 
            });

            return (request.then(function (response) {
                return response.data;
            }, handleError));
        }

        //remove Evernote OAuth from MyShowcase
        function removeOAuth() {
            return user.removeEvernoteOAuth();
        }

        function handleError(response) {
            if (!angular.isObject(response.data) ||!response.data.message) 
                return ($q.reject("An unknown error occurred."));

            // Otherwise, use expected error message.
            return ($q.reject(response.data.message));
        }

        //authenticate with OAuth to Evernote
        function authenticate() {
            //to get round the browser popup blocker we have to open the popup window first - because this event is initiated by the user (clicking on a button) and the browser doesn't invoke the blocker if the user has initiated
            //once the window is open we can set the location to the correct url once it is available from the async call
            //if you open the window in the handler from the async call the browser doesn't regard it as user initiated so blocks it by default

            var deferred = $q.defer();
            //the listener funcion will be called when the opened browser window sends this window a message (not in the case of IE)
            function listener(event) {
                var response = queryParamsFromUrl(event.data);
                if (event.data!=="verified")
                    deferred.reject(response);
                else 
                    deferred.resolve(); //resolve the promise
                
                $window.removeEventListener('message', listener, false);
            }
            //open the popup, hopefully popup blockers won't stop this as it was user initiated
            var authWindow = $window.open('evernotepreauth.html', '_evernoteOauthSigninWindow', popupSize(1000, 800));
            if (isNotIE())
                $window.addEventListener('message', listener, false);
            //get the evernote call forward url  
            return user.getEvernoteCallForwardUrl().then(function (data) {
                //now set our empty popup window location to the evernote call forward url
                authWindow.location.replace(data.url);
                if(!isNotIE())
                    deferred.resolve(); //if its IE resolve the promise here because the listener function won't be called
                return deferred.promise;
            });
        }

        //test if browser is Internet Explorer
        function isNotIE() {
            return navigator.userAgent.indexOf("Trident") === -1;
        }

        //make sure we get a correct popup window
        function popupSize(popupWidth, popupHeight) {
            var popupLeft, popupTop;

            // Metrics for the current browser window.
            var x0 = $window.screenX || $window.screenLeft;
            var y0 = $window.screenY || $window.screenTop;
            var width = $window.outerWidth || $document.documentElement.clientWidth;
            var height = $window.outerHeight || $document.documentElement.clientHeight;

            // Computed popup window metrics.
            popupLeft = Math.round(x0) + (width - popupWidth) / 2;
            popupTop = Math.round(y0) + (height - popupHeight) / 2.5;
            if (popupLeft < x0) 
                popupLeft = x0;
            if (popupTop < y0) 
                popupTop = y0;

            return 'width=' + popupWidth + ',height=' + popupHeight + ',' +
                   'left=' + popupLeft + ',top=' + popupTop + ',' +
                   'dialog=yes,dependent=yes,scrollbars=yes,location=yes';
        }

        //get data from a url query string
        function queryParamsFromUrl(url) {
            var match = /^[^?#]+(\?([^\#]*))?(\#(.*))?$/.exec(url);
            if (!match) { return {}; }

            var query = match[2] || ''
              , fragment = match[4] || ''
              , fragmentOffset = fragment.indexOf('?')
              , params = {};

            if (fragmentOffset !== -1) 
                fragment = fragment.substring(fragmentOffset + 1);
            
            var kvp = query.split('&').concat(fragment.split('&'));
            kvp.forEach(function (kv) {
                var offset = kv.indexOf('=');
                if (offset === -1) 
                     return;
                
                params[decodeURIComponent(kv.substring(0, offset))] =
                       decodeURIComponent(kv.substring(offset + 1));
            });

            return params;
        }
    }
})();