/*

 * Modelled Trace API

 *

 * This file is part of ktbs4js.

 *

 * ktbs4js is free software: you can redistribute it and/or modify it

 * under the terms of the GNU Lesser General Public License as

 * published by the Free Software Foundation, either version 3 of the

 * License, or (at your option) any later version.

 *

 * ktbs4js 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 Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with ktbs4js.  If not, see <http://www.gnu.org/licenses/>.

 *

 */

/* FIXME: properly use require.js feature. This will do for debugging in the meantime */

window.tracemanager = (function($) {

     // If there are more than MAX_FAILURE_COUNT synchronisation

     // failures, then disable synchronisation

    var MAX_FAILURE_COUNT = 20;

     // If there are more than MAX_BUFFER_SIZE obsels in the buffer,

     // then "compress" them as a single "ktbsFullBuffer"

    var  MAX_BUFFER_SIZE = 500;

    var _replacement = {

         ';': '"',

         '"': ';',

         '#': '%23',

         '&': '%26',

         '?': '%3F'

     };

     var BufferedService_prototype = {

         /*

          *  Buffered service for traces

          */

         // url: "",

         // buffer: [],

         // isReady: false,

         // timer: null,

         // failureCount: 0,

         /* Flush buffer */

         flush: function() {

             // FIXME: add mutex on this.buffer

             if (! this.isReady)

             {

                 if (window.console) window.console.log("Sync service not ready");

             } else if (this.failureCount > MAX_FAILURE_COUNT)

             {

                 // Disable synchronisation

                 this.set_sync_mode('none');

             } else if (this.buffer.length) {

                 var temp = this.buffer;

                 this.buffer = [];

                 if (this.mode == 'GET')

                 {

                     // GET mode: do some data mangline. We mark the

                     // "compressed" nature of the generated JSON by

                     // prefixing it with c

                     var data = 'c' + JSON.stringify(temp.map(function (o) { return o.toCompactJSON(); }));

                     // Swap " (very frequent, which will be

                     // serialized into %22) and ; (rather rare), this

                     // saves some bytes

                     data = data.replace(/[;"#?&]/g, function(s){ return _replacement[s]; });

                     // FIXME: check data length (< 2K is safe)

                     var request=$('<img />').error( function() { this.failureCount += 1; })

                         .load( function() { this.failureCount = 0; })

                         .attr('src', this.url + 'trace/?data=' + data);

                 }

                 else

                 {

                     $.ajax({ url: this.url + 'trace/',

                              type: 'POST',

                              contentType: 'application/json',

                              data: JSON.stringify(temp.map(function (o) { return o.toJSON(); })),

                              processData: false,

                              // Type of the returned data.

                              dataType: "html",

                              error: function(jqXHR, textStatus, errorThrown) {

                                  if (window.console) window.console.log("Error when sending buffer:", textStatus);

                                  this.failureCount += 1;

                              },

                              success: function(data, textStatus, jqXHR) {

                                  // Reset failureCount to 0 as soon as there is 1 valid answer

                                  this.failureCount = 0;

                              }

                            });

                 }

             }

         },

         /* Sync mode: delayed, sync (immediate sync), none (no

          * synchronisation with server, the trace has to be explicitly saved

          * if needed */

         set_sync_mode: function(mode, default_subject) {

             this.sync_mode = mode;

             if (! this.isReady && mode !== "none")

                 this.init(default_subject);

             if (mode == 'delayed') {

                 this.start_timer();

             } else {

                 this.stop_timer();

             }

         },

         /* Enqueue an obsel */

         enqueue: function(obsel) {

             if (this.buffer.length > MAX_BUFFER_SIZE)

             {

                 obsel = new Obsel('ktbsFullBuffer', this.buffer[0].begin,

                                   this.buffer[this.buffer.length - 1].end, this.buffer[0].subject);

                 obsel.trace = this.buffer[0].trace;

                 this.buffer = [];

             }

             this.buffer.push(obsel);

             if (this.sync_mode === 'sync') {

                 // Immediate sync of the obsel.

                 this.flush();

             }

         },

         start_timer: function() {

             var self = this;

             if (this.timer === null) {

                 this.timer = window.setInterval(function() {

                                                     self.flush();

                                                 }, this.timeOut);

             }

         },

         stop_timer: function() {

             if (this.timer !== null) {

                 window.clearInterval(this.timer);

                 this.timer = null;

             }

         },

         /*

          * Initialize the sync service

          */

         init: function(default_subject) {

             var self = this;

             if (this.isReady)

                 /* Already initialized */

                 return;

             if (typeof default_subject === 'undefined')

                 default_subject = 'anonymous';

             if (this.mode == 'GET')

             {

                 var request=$('<img/>').attr('src', this.url + 'login?userinfo={"default_subject": "' + default_subject + '"}');

                 // Do not wait for the return, assume it is

                 // initialized. This assumption will not work anymore

                 // if login returns some necessary information

                 this.isReady = true;

             }

             else

             {

                 $.ajax({ url: this.url + 'login',

                          type: 'POST',

                          data: 'userinfo={"default_subject":"' + default_subject + '"}',

                          success: function(data, textStatus, jqXHR) {

                              self.isReady = true;

                              if (self.buffer.length) {

                                  self.flush();

                              }

                          }

                        });

             }

         }

     };

     var BufferedService = function(url, mode) {

         this.url = url;

         this.buffer = [];

         this.isReady = false;

         this.timer = null;

         this.failureCount = 0;

         // sync_mode is either "none", "sync" or "buffered"

         this.sync_mode = "none";

         /* mode can be either POST or GET */

         if (mode == 'POST' || mode == 'GET')

             this.mode = mode;

         else

             this.mode = 'POST';

         /* Flush buffer every timeOut ms if the sync_mode is delayed */

         this.timeOut = 2000;

     };

     BufferedService.prototype = BufferedService_prototype;

     var Trace_prototype = {

         /* FIXME: We could/should use a sorted list such as

          http://closure-library.googlecode.com/svn/docs/class_goog_structs_AvlTree.html

          to speed up queries based on time */

         obsels: [],

         /* Trace URI */

         uri: "",

         default_subject: "",

         /* baseuri is used as the base URI to resolve relative

          * attribute-type names in obsels. Strictly speaking, this

          * should rather be expressed as a reference to model, or

          * more generically, as a qname/URI dict */

         baseuri: "",

         /* Mapping of obsel type or property name to a compact

          * representation (shorthands).

          */

         shorthands: null,

         syncservice: null,

         /* Define the trace URI */

         set_uri: function(uri) {

             this.uri = uri;

         },

         /* Sync mode: delayed, sync (immediate sync), none (no

          * synchronisation with server, the trace has to be explicitly saved

          * if needed */

         set_sync_mode: function(mode) {

             if (this.syncservice !== null) {

                 this.syncservice.set_sync_mode(mode, this.default_subject);

             }

         },

         /*

          * Return a list of the obsels of this trace matching the parameters

          */

         list_obsels: function(_begin, _end, _reverse) {

             var res;

             if (typeof _begin !== 'undefined' || typeof _end !== 'undefined') {

                 /*

                  * Not optimized yet.

                  */

                 res = [];

                 var l = this.obsels.length;

                 for (var i = 0; i < l; i++) {

                     var o = this.obsels[i];

                     if ((typeof _begin !== 'undefined' && o.begin > _begin) && (typeof _end !== 'undefined' && o.end < _end)) {

                         res.push(o);

                     }

                 }

             }

             if (typeof _reverse !== 'undefined') {

                 if (res !== undefined) {

                     /* Should reverse the whole list. Make a copy. */

                     res = this.obsels.slice(0);

                 }

                 res.sort(function(a, b) { return b.begin - a.begin; });

                 return res;

             }

             if (res === undefined) {

                 res = this.obsels;

             }

             return res;

         },

         /*

          * Return the obsel of this trace identified by the URI, or undefined

          */

         get_obsel: function(id) {

             for (var i = 0; i < this.obsels.length; i++) {

                 /* FIXME: should check against variations of id/uri, take this.baseuri into account */

                 if (this.obsels[i].uri === id) {

                     return this.obsels[i];

                 }

             }

             return undefined;

         },

         set_default_subject: function(subject) {

             // FIXME: if we call this method after the sync_service

             // init method, then the default_subject will not be

             // consistent anymore. Maybe we should then call init() again?

             this.default_subject = subject;

         },

         get_default_subject: function() {

             return this.default_subject;

         },

         /* (type:ObselType, begin:int, end:int?, subject:str?, attributes:[AttributeType=>any]?) */

         /* Create a new obsel and add it to the trace */

         create_obsel: function(type, begin, end, subject, _attributes) {

             var o = new Obsel(type, begin, end, subject);

             if (typeof _attributes !== 'undefined') {

                 o.attributes = _attributes;

             }

             o.trace = this;

             this.obsels.push(o);

             if (this.syncservice !== null)

                 this.syncservice.enqueue(o);

         },

         /* Helper methods */

         /* Create a new obsel with the given attributes */

         trace: function(type, _attributes, _begin, _end, _subject) {

             var t = (new Date()).getTime();

             if (typeof begin === 'undefined') {

                 _begin = t;

             }

             if (typeof end === 'undefined') {

                 _end = _begin;

             }

             if (typeof subject === 'undefined') {

                 _subject = this.default_subject;

             }

             if (typeof _attributes === 'undefined') {

                 _attributes = {};

             }

             return this.create_obsel(type, _begin, _end, _subject, _attributes);

         }

     };

     var Trace = function(uri, requestmode) {

         /* FIXME: We could/should use a sorted list such as

          http://closure-library.googlecode.com/svn/docs/class_goog_structs_AvlTree.html

          to speed up queries based on time */

         this.obsels = [];

         /* Trace URI */

         if (uri === undefined)

             uri = "";

         this.uri = uri;

         this.sync_mode = "none";

         this.default_subject = "";

         this.shorthands = {};

         /* baseuri is used a the base URI to resolve relative attribute names in obsels */

         this.baseuri = "";

         this.syncservice = new BufferedService(uri, requestmode);

         $(window).unload( function () {

                               if (this.syncservice && this.sync_mode !== 'none') {

                                   this.syncservice.flush();

                                   this.syncservice.stop_timer();

                               }

                           });

     };

     Trace.prototype = Trace_prototype;

     var Obsel_prototype = {

         /* The following attributes are here for documentation

          * purposes. They MUST be defined in the constructor

          * function. */

         trace: undefined,

         type: undefined,

         begin: undefined,

         end: undefined,

         subject: undefined,

         /* Dictionary indexed by ObselType URIs */

         attributes: {},

         /* Method definitions */

         get_trace: function() {

             return this.trace;

         },

         get_obsel_type: function() {

             return this.type;

         },

         get_begin: function() {

             return this.begin;

         },

         get_end: function() {

             return this.end;

         },