;(function (define) {
    'use strict';
    define(['jquery', 'underscore', 'backbone', 'gettext', 'js/groups/models/cohort', 
            'js/models/notification', 'js/views/notification'],
        function($, _, Backbone, gettext, CohortModel) {

            var CohortFormView = Backbone.View.extend({
                events : {
                    'change .cohort-management-details-association-course input': 'onRadioButtonChange'
                },

                initialize: function(options) {
                    this.template = _.template($('#cohort-form-tpl').text());
                    this.contentGroups = options.contentGroups;
                    this.context = options.context;
                },

                showNotification: function(options, beforeElement) {
                    var model = new NotificationModel(options);
                    this.removeNotification();
                    this.notification = new NotificationView({
                        model: model
                    });
                    beforeElement.before(this.notification.$el);
                    this.notification.render();
                },

                removeNotification: function() {
                    if (this.notification) {
                        this.notification.remove();
                    }
                },

                render: function() {
                    this.$el.html(this.template({
                        cohort: this.model,
                        isDefaultCohort: this.isDefault(this.model.get('name')),
                        contentGroups: this.contentGroups,
                        studioGroupConfigurationsUrl: this.context.studioGroupConfigurationsUrl
                    }));
                    return this;
                },

                isDefault: function(name) {
                    var cohorts = this.model.collection;
                    if (_.isUndefined(cohorts)) {
                        return false;
                    }
                    var randomModels = cohorts.where({assignment_type:'random'});
                    return (randomModels.length === 1) && (randomModels[0].get('name') === name);
                },

                onRadioButtonChange: function(event) {
                    var target = $(event.currentTarget),
                        groupsEnabled = target.val() === 'yes';
                    if (!groupsEnabled) {
                        // If the user has chosen 'no', then clear the selection by setting
                        // it to the first option which represents no selection.
                        this.$('.input-cohort-group-association').val('None');
                    }
                    // Enable the select if the user has chosen groups, else disable it
                    this.$('.input-cohort-group-association').prop('disabled', !groupsEnabled);
                },

                hasAssociatedContentGroup: function() {
                    return this.$('.radio-yes').prop('checked');
                },

                getSelectedContentGroup: function() {
                    var selectValue = this.$('.input-cohort-group-association').val(),
                        ids, groupId, userPartitionId, i, contentGroup;
                    if (!this.hasAssociatedContentGroup() || selectValue === 'None') {
                        return null;
                    }
                    ids = selectValue.split(':');
                    groupId = parseInt(ids[0]);
                    userPartitionId = parseInt(ids[1]);
                    for (i=0; i < this.contentGroups.length; i++) {
                        contentGroup = this.contentGroups[i];
                        if (contentGroup.get('id') === groupId && contentGroup.get('user_partition_id') === userPartitionId) {
                            return contentGroup;
                        }
                    }
                    return null;
                },

                getUpdatedCohortName: function() {
                    var cohortName = this.$('.cohort-name').val();
                    return cohortName ? cohortName.trim() : '';
                },

                getAssignmentType: function() {
                    return this.$('input[name="cohort-assignment-type"]:checked').val();
                },

                showMessage: function(message, type, details) {
                    this.showNotification(
                        {type: type || 'confirmation', title: message, details: details},
                        this.$('.form-fields')
                    );
                },

                validate: function(fieldData) {
                    var errorMessages;
                    errorMessages = [];
                    if (!fieldData.name) {
                        errorMessages.push(gettext('You must specify a name for the cohort'));
                    }
                    if (this.hasAssociatedContentGroup() && fieldData.group_id === null) {
                        if (this.$('.input-cohort-group-association').val() === 'None') {
                            errorMessages.push(gettext('You did not select a content group'));
                        } else {
                            // If a value was selected, then it must be for a non-existent/deleted content group
                            errorMessages.push(gettext('The selected content group does not exist'));
                        }
                    }
                    return errorMessages;
                },

                saveForm: function() {
                    var self = this,
                        cohort = this.model,
                        saveOperation = $.Deferred(),
                        isUpdate = !_.isUndefined(this.model.id),
                        fieldData, selectedContentGroup, selectedAssignmentType, errorMessages, showErrorMessage;
                    showErrorMessage = function(message, details) {
                        self.showMessage(message, 'error', details);
                    };
                    this.removeNotification();
                    selectedContentGroup = this.getSelectedContentGroup();
                    selectedAssignmentType = this.getAssignmentType();
                    fieldData = {
                        name: this.getUpdatedCohortName(),
                        group_id: selectedContentGroup ? selectedContentGroup.id : null,
                        user_partition_id: selectedContentGroup ? selectedContentGroup.get('user_partition_id') : null,
                        assignment_type: selectedAssignmentType
                    };
                    errorMessages = this.validate(fieldData);

                    if (errorMessages.length > 0) {
                        showErrorMessage(
                            isUpdate ? gettext("The cohort cannot be saved") : gettext("The cohort cannot be added"),
                            errorMessages
                        );
                        saveOperation.reject();
                    } else {
                        cohort.save(
                            fieldData, {patch: isUpdate, wait: true}
                        ).done(function(result) {
                            cohort.id = result.id;
                            self.render();    // re-render to remove any now invalid error messages
                            saveOperation.resolve();
                        }).fail(function(result) {
                            var errorMessage = null;
                            try {
                                var jsonResponse = JSON.parse(result.responseText);
                                errorMessage = jsonResponse.error;
                            } catch(e) {
                                // Ignore the exception and show the default error message instead.
                            }
                            if (!errorMessage) {
                                errorMessage = gettext("We've encountered an error. Refresh your browser and then try again.");
                            }
                            showErrorMessage(errorMessage);
                            saveOperation.reject();
                        });
                    }
                    return saveOperation.promise();
                }
            });
            return CohortFormView;
        });
}).call(this, define || RequireJS.define);
