/**
 * @ngdoc factory
 * @name  Bastion.tasks.factory:TaskNutupane
 *
 * @requires Task
 * @requires Nutupane
 *
 * @description
 *   Defines TasksNutupane factory that uses Task.registerSearch as
 *   source of data instead of the standard `query` method. This
 *   effectively creates Nutupane table that is updated by polling.
 */
angular.module('Bastion.tasks').factory('TasksNutupane',
    ['Task', 'Nutupane', function (Task, Nutupane) {
        var TasksNutupane = function () {
            var self = this;
            var nutupaneParams = {
                'disableAutoLoad': true
            };


            Nutupane.call(self, Task, {}, undefined, nutupaneParams);
            self.table.working = true;

            self.existingTasks = {};

            self.registerSearch = function (params) {
                if (!self.searchId) {
                    self.searchId = Task.registerSearch(params, self.updateTasks);
                }
            };

            self.unregisterSearch = function () {
                if (self.searchId) {
                    Task.unregisterSearch(self.searchId);
                    self.searchId = undefined;
                }
            };

            self.load = function () {
                self.table.working = true;
            };

            self.updateTasks = function (tasks) {
                self.refreshTasks(tasks);
                self.deleteOldRows(tasks);
                self.table.working = false;
                self.table.refreshing = false;
            };

            self.table.search = function () {
                self.table.resource.offset = 0;
                self.table.rows = [];
                if (!self.table.working) {
                    self.load();
                }
            };

            // Updates values for existing tasks and adds new rows
            self.refreshTasks = function (tasks) {
                // we reverse because we add new items to the top of
                // the table
                _.each(tasks.reverse(), function (task) {
                    var existingTask = self.existingTasks[task.id];
                    if (existingTask) {
                        _.each(task, function (value, key) {
                            existingTask[key] = value;
                        });
                    } else {
                        self.table.rows.unshift(task);
                        self.existingTasks[task.id] = task;
                    }
                });
            };

            // Removes rows that are no longer valid for the table
            self.deleteOldRows = function (tasks) {
                var newTaskIds = _.map(tasks, function (task) {
                        return task.id;
                    }),
                    oldTaskIds = _.keys(self.existingTasks),
                    taskIdsToDelete = _.difference(oldTaskIds, newTaskIds),
                    rowsToDelete = [];

                _.each(taskIdsToDelete, function (id) {
                    delete self.existingTasks[id];
                });

                _.each(self.table.rows, function (row, i) {
                    if (_.includes(taskIdsToDelete, row.id)) {
                        rowsToDelete.push(i);
                    }
                });

                _.each(rowsToDelete.reverse(), function (i) {
                    self.table.rows.splice(i, 1);
                });
            };
        };
        return TasksNutupane;
    }]);