(function () {
    "use strict"

    angular.module('shared')
        .service('resourceSelectionHelper', [
            function resourceSelectionHelperService() {
                var service = this;
                service.isActivityDisabled = isActivityDisabled;
                service.handleResourceSelection = handleResourceSelection;
                service.initResourceInfo = initResourceInfo;

                var activityTypesByName = {
                    READ      : 'read',
                    LISTEN    : 'listen',
                    QUIZ      : 'quiz',
                    WORKSHEET : 'worksheet',
                    FORMATIVE_WORKSHEET : 'formative_worksheet'
                };

                var activitySelectionMetadata;
                var activities;
                var resources;

                function initResourceInfo(activitiesToReference, resourcesToCopy) {
                    activities = activitiesToReference;
                    resources = resourcesToCopy;
                    activitySelectionMetadata = {};

                    if (!isSingleResourceAssigment()) {
                        activities.forEach(function (activityObj) {
                            initActivitySelectionMetadata(activityObj);
                        });

                        resources.forEach(function (resource) {
                            if (resource.activities) {
                                resource.activities.forEach(function (activityType) {
                                    var displayType = getActivityDisplayType(activityType);
                                    activitySelectionMetadata[displayType].selectedResourcesWithActivity++;
                                })
                            }
                        });
                    }
                }

                function isSingleResourceAssigment() {
                    return resources.length === 1;
                }

                function initActivitySelectionMetadata(activityObj) {
                    var displayType = getActivityDisplayType(activityObj.activity_name);
                    if (!activitySelectionMetadata[displayType]) {
                        activitySelectionMetadata[displayType] = {
                            selectedResourcesWithActivity: 0,
                            selectedStatusWhenDeactivated: null,
                            activity: activityObj
                        };
                    }
                }

                function isActivityDisabled(activity) {
                    if (isSingleResourceAssigment()) {
                        return false;
                    }

                    return !hasSelectedResources(activity.activity_name);
                }

                function handleResourceSelection(resource) {
                    resource.activities.forEach(function (activity) {
                        var displayType = getActivityDisplayType(activity);
                        var metadata = activitySelectionMetadata[displayType]
                        if (resource.selected) {
                            metadata.selectedResourcesWithActivity++;
                            if (hasSelectedResources(activity) && metadata.selectedStatusWhenDeactivated !== null){
                                metadata.activity.selected = metadata.selectedStatusWhenDeactivated;
                                metadata.selectedStatusWhenDeactivated = null;
                            }
                        } else {
                            metadata.selectedResourcesWithActivity--;
                            if (!hasSelectedResources(activity) && metadata.selectedStatusWhenDeactivated === null) {
                                metadata.selectedStatusWhenDeactivated = metadata.activity.selected;
                                metadata.activity.selected = false;
                            }
                        }

                    })
                }

                function hasSelectedResources(activityName) {
                    var displayType = getActivityDisplayType(activityName);
                    var metadata = activitySelectionMetadata[displayType];
                    return metadata.selectedResourcesWithActivity > 0;
                }

                function getActivityDisplayType(activity) {
                    if (activity === activityTypesByName.FORMATIVE_WORKSHEET) {
                        return activityTypesByName.QUIZ;
                    }
                    return activity;
                }
            }
        ]);
})();