newscoop/JS-Scoopwriter

'use strict';
angular.module('authoringEnvironmentApp').service('nestedSort', [
    '$log',
    function NestedSort($log) {
        var service = this;
        // exposed just for testability
        this.sortByCreated = function (arr) {
            function getDate(element) {
                var str = element.created.split(/[^0-9]/);

                return new Date(str[0], str[1]-1, str[2],
                    str[3], str[4], str[5]);
            }
            return _.sortBy(arr, getDate);
        };
        this.sort = function (arr) {
            var levels = [];
            var currentLevel = 0;
            var isOnCurrentLevel = function (element) {
                return element.thread_level === currentLevel;
            };
            var found = arr.filter(isOnCurrentLevel);
            while (found.length > 0) {
                levels.push(found);
                currentLevel++;
                found = arr.filter(isOnCurrentLevel);
            }
            /* support map for accessing the comments in the tree by id,
           * and for navigating child relations. a comment will appear
           * twice here, once on the top level of the map, and once
           * within the `childs` array of the parent comment. the
           * object is exposed for testability */
            service.map = { root: { childs: [] } };
            /* navigate the levels and populate the map. since we are
           * going by levels, all the parents should already be
           * there when a child is inserted */
            levels.forEach(function (level) {
                level.forEach(function (comment) {
                    var copy = angular.copy(comment);
                    copy.childs = [];
                    if (copy.thread_level === 0) {
                        copy.parent = 'root';
                    }
                    service.map[copy.id] = copy;
                    if ('parent' in copy) {
                        if (copy.parent in service.map) {
                            service.map[copy.parent].childs.push(copy);
                        } else {
                            $log.debug('error, comment', copy, 'has parent',
                                copy.parent, 'which is not available to us');
                        }
                    } else {
                        $log.debug('error, comment', copy,
                            'is not first level but it has no parent');
                    }
                });
            });
            /* recursively navigate the map from the root, sort the
           * childs, and assign positions */
            var position = 0;
            function assignPosition(copiedComment) {
                var sortedChilds = service.sortByCreated(copiedComment.childs);
                sortedChilds.forEach(function (child) {
                    child.nestedPosition = position;
                    position++;
                    assignPosition(child);
                });
            }
            assignPosition(service.map.root);
            /* navigate the original array and copy positions from the map */
            arr.forEach(function (comment) {
                if (comment.id in service.map) {
                    comment.nestedPosition =
                            service.map[comment.id].nestedPosition;
                } else {
                    $log.error('comment', comment,
                        'is not in the nested sorting map', service.map);
                }
            });
        };
    }
]);