Source: Models/CatalogGroup.js

'use strict';

/*global require*/

var clone = require('terriajs-cesium/Source/Core/clone');
var defaultValue = require('terriajs-cesium/Source/Core/defaultValue');
var defined = require('terriajs-cesium/Source/Core/defined');
var defineProperties = require('terriajs-cesium/Source/Core/defineProperties');
var freezeObject = require('terriajs-cesium/Source/Core/freezeObject');
var knockout = require('terriajs-cesium/Source/ThirdParty/knockout');
var RuntimeError = require('terriajs-cesium/Source/Core/RuntimeError');
var when = require('terriajs-cesium/Source/ThirdParty/when');
var DeveloperError = require('terriajs-cesium/Source/Core/DeveloperError');
var combine = require('terriajs-cesium/Source/Core/combine');

var combineFilters = require('../Core/combineFilters');
var createCatalogMemberFromType = require('./createCatalogMemberFromType');
var CatalogMember = require('./CatalogMember');
var inherit = require('../Core/inherit');
var raiseErrorOnRejectedPromise = require('./raiseErrorOnRejectedPromise');

/**
 * A group of data items and other groups in the {@link Catalog}.  A group can contain
 * {@link CatalogMember|CatalogMembers} or other
 * {@link CatalogGroup|CatalogGroups}.
 *
 * @alias CatalogGroup
 * @constructor
 * @extends CatalogMember
 *
 * @param {Terria} terria The Terria instance.
 */
var CatalogGroup = function(terria) {
    CatalogMember.call(this, terria);

    this._lastLoadInfluencingValues = undefined;

    /**
     * Gets or sets a value indicating whether the group is currently expanded and showing
     * its children.  This property is observable.
     * @type {Boolean}
     */
    this.isOpen = false;

    /**
     * Gets the collection of items in this group.  This property is observable.
     * @type {CatalogMember[]}
     */
    this.items = [];

    /**
     * Gets or sets flag to prevent items in group being sorted. Subgroups will still sort unless their own preserveOrder flag is set.  The value
     * of this property only has an effect during {@CatalogGroup#load} and {@CatalogItem#updateFromJson}.
     */
    this.preserveOrder = false;

    /**
     * Gets or sets the function to be used when sorting the group's items.
     * This function takes two {@link CatalogItem} parameters and should return a negative,
     * zero, or positive value depending on the order in which they should be sorted.
     * @type {function}
     */
    this.sortFunction = function(itemA, itemB) {
        if (itemA.isPromoted && !itemB.isPromoted) {
            return -1;
        } else if (!itemA.isPromoted && itemB.isPromoted) {
            return 1;
        } else {
            var aNameSortKey = itemA.nameSortKey;
            var bNameSortKey = itemB.nameSortKey;

            for (var i = 0; i < aNameSortKey.length && i < bNameSortKey.length; ++i) {
                if (aNameSortKey[i] < bNameSortKey[i]) {
                    return -1;
                } else if (aNameSortKey[i] > bNameSortKey[i]) {
                    return 1;
                }
            }

            if (aNameSortKey.length === bNameSortKey.length) {
                return 0;
            } else {
                return aNameSortKey.length > bNameSortKey.length ? 1 : -1;
            }
        }
    };

    knockout.track(this, ['isOpen', 'items']);

    var that = this;

    // knockout.defineProperty(this, 'isAnyEnabled', {
    //     // Defining this knockout computed property makes it easy to track changes to the isEnabled properties on the items
    //     get : function() {
    //         var isAnyEnabled = false;
    //         for (var i = that.items.length - 1; i >= 0; i--) {
    //             isAnyEnabled = that.items[i].isEnabled || isAnyEnabled;  // order is important so knockout watches every item
    //         }
    //         return isAnyEnabled;
    //     }
    // });

    knockout.getObservable(this, 'isOpen').subscribe(function(newValue) {
        // Load this group's items (if we haven't already) when it is opened.
        if (newValue) {
            raiseErrorOnRejectedPromise(that.terria, when.all([that.waitForDisclaimerIfNeeded(), that.load()]));
        }
    });

    knockout.getObservable(this, 'isLoading').subscribe(function(newValue) {
        // Call load() again immediately after finishing loading, if the group is still open.  Normally this will do nothing,
        // but if the URL has changed since we started, it will kick off loading the new URL.
        // If this spins you into a stack overflow, verify that your derived-class load method only
        // loads when it actually needs to do so!
        if (newValue === false && that.isOpen) {
            raiseErrorOnRejectedPromise(that.terria, that.load());
        }
    });

    this._setupItemListeners();
};

inherit(CatalogMember, CatalogGroup);

defineProperties(CatalogGroup.prototype, {
    /**
     * Gets the type of data member represented by this instance.
     * @memberOf CatalogGroup.prototype
     * @type {String}
     */
    type: {
        get: function() {
            return 'group';
        }
    },

    /**
     * Gets a human-readable name for this type of data source, such as 'Web Map Service (WMS)'.
     * @memberOf CatalogGroup.prototype
     * @type {String}
     */
    typeName: {
        get: function() {
            return 'Group';
        }
    },

    /**
     * Gets a value that tells the UI whether this is a group.
     * Groups, when clicked, expand to show their constituent items.
     * @memberOf CatalogGroup.prototype
     * @type {Boolean}
     */
    isGroup: {
        get: function() {
            return true;
        }
    },

    /**
     * Gets the set of functions used to update individual properties in {@link CatalogMember#updateFromJson}.
     * When a property name in the returned object literal matches the name of a property on this instance, the value
     * will be called as a function and passed a reference to this instance, a reference to the source JSON object
     * literal, and the name of the property.
     * @memberOf CatalogGroup.prototype
     * @type {Object}
     */
    updaters: {
        get: function() {
            return CatalogGroup.defaultUpdaters;
        }
    },

    /**
     * Gets the set of functions used to serialize individual properties in {@link CatalogMember#serializeToJson}.
     * When a property name on the model matches the name of a property in the serializers object literal,
     * the value will be called as a function and passed a reference to the model, a reference to the destination
     * JSON object literal, and the name of the property.
     * @memberOf CatalogGroup.prototype
     * @type {Object}
     */
    serializers: {
        get: function() {
            return CatalogGroup.defaultSerializers;
        }
    },

    /**
     * Gets the set of names of the properties to be serialized for this object for a share link.
     * @memberOf CatalogGroup.prototype
     * @type {String[]}
     */
    propertiesForSharing: {
        get: function() {
            return CatalogGroup.defaultPropertiesForSharing;
        }
    }
});

/**
 * Gets or sets the set of default updater functions to use in {@link CatalogMember#updateFromJson}.  Types derived from this type
 * should expose this instance - cloned and modified if necesary - through their {@link CatalogMember#updaters} property.
 * @type {Object}
 */
CatalogGroup.defaultUpdaters = clone(CatalogMember.defaultUpdaters);

CatalogGroup.defaultUpdaters.items = function(catalogGroup, json, propertyName, options) {
    // Let the group finish loading first.  Otherwise, these changes could get clobbered by the load.
    return when(catalogGroup.load(), function() {
        return CatalogGroup.updateItems(json.items, options, catalogGroup);
    });
};

CatalogGroup.defaultUpdaters.isLoading = function(catalogGroup, json, propertyName) {};

freezeObject(CatalogGroup.defaultUpdaters);

/**
 * Gets or sets the set of default serializer functions to use in {@link CatalogMember#serializeToJson}.  Types derived from this type
 * should expose this instance - cloned and modified if neccesary - through their {@link CatalogMember#serializers} property.
 * @type {Object}
 */
CatalogGroup.defaultSerializers = clone(CatalogMember.defaultSerializers);

CatalogGroup.defaultSerializers.items = function(catalogGroup, json, propertyName, options) {
    json.items = catalogGroup.items.filter(function(item) {
        return !defined(options.itemFilter) || options.itemFilter(item);
    }).map(function(item) {
        return item.serializeToJson(options);
    }).filter(function(serializedItem) {
        return defined(serializedItem);
    });
};

/**
 * Call {@link CatalogGroup#defaultSerializers#items}, filtering out non-shareable properties and non-enabled items.
 * This is used when serializing a number of kinds of item groups where most details can be fetched from a URL and hence
 * there's no need to serialize anything that can't be changed by the user.
 */
CatalogGroup.enabledShareableItemsSerializer = function(catalogGroup, json, propertyName, options) {
    return CatalogGroup.defaultSerializers.items(catalogGroup, json, propertyName, combine({
        propertyFilter: combineFilters([options.propertyFilter, CatalogMember.propertyFilters.sharedOnly]),
        itemFilter: combineFilters([options.itemFilter, CatalogMember.itemFilters.enabled])
    }, options));
};

CatalogGroup.defaultSerializers.isLoading = function(catalogGroup, json, propertyName, options) {};

freezeObject(CatalogGroup.defaultSerializers);

/**
 * Gets or sets the default set of properties that are serialized when serializing a {@link CatalogItem}-derived object
 * for a share link.
 * @type {String[]}
 */
CatalogGroup.defaultPropertiesForSharing = clone(CatalogMember.defaultPropertiesForSharing);
CatalogGroup.defaultPropertiesForSharing.push('items');
CatalogGroup.defaultPropertiesForSharing.push('isOpen');

freezeObject(CatalogGroup.defaultPropertiesForSharing);

CatalogGroup.prototype._setupItemListeners = function() {
    var itemsChangeListeners = {
        added: function(item) {
            item.parent = this;

            // Only index this in catalog if it's actually connected to catalog, otherwise we get situations where an
            // item is added to the index before its actually built up a correct path to use as a default id.
            if (item.connectsWithRoot()) {
                indexWithDescendants([item], this.terria.catalog.shareKeyIndex);
            }
        }.bind(this),
        deleted: function(item) {
            if (item.connectsWithRoot()) {
                deIndexWithDescendants([item], this.terria.catalog.shareKeyIndex);
            }

            item.parent = undefined;
        }.bind(this)
    };

    knockout.getObservable(this, 'items').subscribe(function(changes) {
        changes.forEach(function(change) {
            if (!defined(change.moved)) {
                itemsChangeListeners[change.status](change.value);
            }
        });
    }, null, "arrayChange");
};

var NUMBER_AT_END_OF_KEY_REGEX = /\((\d+)\)$/;

/**
 * Adds all passed items to the passed index, and all the children of those items recursively.
 * @private
 * @param {CatalogMember[]} items
 * @param {Object} index
 */
function indexWithDescendants(items, index) {
    items.forEach(function(item) {
        item.allShareKeys.forEach(function(key) {
            var insertionKey = key;

            if (index[insertionKey]) {
                insertionKey = generateUniqueKey(index, key);

                if (item.uniqueId === key) {
                    // If this duplicate was the item's main key that will be used for sharing it in general, set this
                    // to the new key. This means that sharing the item will still work most of the time.
                    item.id = insertionKey;
                }

                console.warn('Duplicate shareKey: ' + key + '. Inserting new item under ' + insertionKey);
            }

            index[insertionKey] = item;
        }, this);

        if (defined(item.items)) {
            indexWithDescendants(item.items, index);
        }
    });
}

/**
 * Generates a unique key from a non-unique one by adding a number after it. If the key already has a number added,
 * it will increment that number.
 * @private
 * @param index An index to check for uniqueness.
 * @param initialKey The key to start from.
 * @returns {String} A new, unique key.
 */
function generateUniqueKey(index, initialKey) {
    var currentCandidate = initialKey;

    var counter = 0;
    while (index[currentCandidate]) {
        var numberAtEndOfKeyMatches = currentCandidate.match(NUMBER_AT_END_OF_KEY_REGEX);
        if (numberAtEndOfKeyMatches !== null) {
            var nextNumber = parseInt(numberAtEndOfKeyMatches[1], 10) + 1;

            currentCandidate = currentCandidate.replace(NUMBER_AT_END_OF_KEY_REGEX, '(' + nextNumber + ')');
        } else {
            currentCandidate += ' (1)';
        }

        // This loop should always find something eventually, but because it's a bit dangerous looping endlessly...
        counter++;
        if (counter >= 100000) {
            throw new DeveloperError('Was not able to find a unique key for ' + initialKey + ' after 100000 iterations.' +
                ' This is probably because the regex for matching keys was somehow unable to work for that key.');
        }
    }

    return currentCandidate;
}

/**
 * Removes all passed items to the passed index, and all the children of those items recursively.
 *
 * @param {CatalogMember[]} items
 * @param {Object} index
 */
function deIndexWithDescendants(items, index) {
    items.forEach(function(item) {
        item.allShareKeys.forEach(function(key) {
            index[key] = undefined;
        }, this);

        if (defined(item.items)) {
            deIndexWithDescendants(item.items, index);
        }
    });
}

/**
 * Loads the contents of this group, if the contents are not already loaded.  It is safe to
 * call this method multiple times.  The {@link CatalogGroup#isLoading} flag will be set while the load is in progress.
 * Derived classes should implement {@link CatalogGroup#_load} to perform the actual loading for the group.
 * Derived classes may optionally implement {@link CatalogGroup#_getValuesThatInfluenceLoad} to provide an array containing
 * the current value of all properties that influence this group's load process.  Each time that {@link CatalogGroup#load}
 * is invoked, these values are checked against the list of values returned last time, and {@link CatalogGroup#_load} is
 * invoked again if they are different.  If {@link CatalogGroup#_getValuesThatInfluenceLoad} is undefined or returns an
 * empty array, {@link CatalogGroup#_load} will only be invoked once, no matter how many times
 * {@link CatalogGroup#load} is invoked.
 *
 * @returns {Promise} A promise that resolves when the load is complete, or undefined if the group is already loaded.
 *
 */
CatalogGroup.prototype.load = function() {
    var parentPromise = CatalogMember.prototype.load.call(this);

    if (parentPromise) {
        return parentPromise.then(function() {
            this.sortItems(true);
        }.bind(this)).otherwise(function(e) {
            this.isOpen = false;
            throw e; // keep throwing this so we can chain more otherwises.
        }.bind(this));
    }
};

/**
 * When implemented in a derived class, this method loads the group.  The base class implementation does nothing.
 * This method should not be called directly; call {@link CatalogGroup#load} instead.
 * @return {Promise} A promise that resolves when the load is complete.
 * @protected
 */
CatalogGroup.prototype._load = function() {
    return when();
};

var emptyArray = freezeObject([]);

/**
 * When implemented in a derived class, gets an array containing the current value of all properties that
 * influence this group's load process.  See {@link CatalogGroup#load} for more information on when and
 * how this is used.  The base class implementation returns an empty array.
 * @return {Array} The array of values that influence the load process.
 * @protected
 */
CatalogGroup.prototype._getValuesThatInfluenceLoad = function() {
    return emptyArray;
};

/**
 * Adds an item or group to this group.
 *
 * @param {CatalogMember} item The item to add.
 */
CatalogGroup.prototype.add = function(item) {
    this.items.push(item);
};

/**
 * Removes an item or group from this group.
 *
 * @param {CatalogMember} item The item to remove.
 */
CatalogGroup.prototype.remove = function(item) {
    this.items.remove(item); // available for knockout observable arrays.
};

/**
 * Toggles the {@link CatalogGroup#isOpen} property of this group.  If it is open, calling this method
 * will close it.  If it is closed, calling this method will open it.
 */
CatalogGroup.prototype.toggleOpen = function() {
    this.isOpen = !this.isOpen;
};

/**
 * Finds the first item in this group that has the given name.  The search is case-sensitive.
 *
 * Instead of using this function, consider using {@link Catalog#shareKeyIndex} to look the item up, as this works in
 * constant time and allows lookups to continue working for items that have been renamed or moved as long as they have
 * a stable shareKey set. This function is retained mainly for backwards-compatibility with existing share links that
 * used names for matching.
 *
 * @param {String} name The name of the item to find.
 * @return {CatalogMember} The first item with the given name, or undefined if no item with that name exists.
 */
CatalogGroup.prototype.findFirstItemByName = function(name) {
    for (var i = 0; i < this.items.length; ++i) {
        if (this.items[i].name === name) {
            return this.items[i];
        }
    }

    return undefined;
};

/**
 * Sorts the items in this group.
 *
 * @param {Boolean} [sortRecursively=false] true to sort the items in sub-groups as well; false to sort only the items in this group.
 */
CatalogGroup.prototype.sortItems = function(sortRecursively) {
    // Allow a group to be non-sorted, while still containing sorted groups.
    if (this.preserveOrder) {
        // Bubble promoted items to the top without changing their relative order.
        var promoted = this.items.filter(function(item) { return item.isPromoted; });
        var nonPromoted = this.items.filter(function(item) { return !item.isPromoted; });

        if (promoted.length > 0 && nonPromoted.length > 0) {
            this.items = promoted.concat(nonPromoted);
        }
    } else {
        this.items.sort(this.sortFunction);
    }

    if (defaultValue(sortRecursively, false)) {
        for (var i = 0; i < this.items.length; ++i) {
            var item = this.items[i];
            if (defined(item.sortItems)) {
                item.sortItems(sortRecursively);
            }
        }
    }
};

CatalogGroup.prototype.enableWithParents = function() {
    this.isOpen = true;

    if (this.parent) {
        this.parent.enableWithParents();
    }
};

/**
 * Reads an array of catalog members in JSON format (as objects, not strings) and transforms them into actual Terria
 * models (i.e. {@link CatalogMember} instances), and adds them to the {@link CatalogMember#items} property of the
 * supplied catalogGroup, or updates only the existing items in the catalogGroup.
 *
 * @param {Object} itemsJson The items as simple JSON data. The JSON should be in the form of an object literal, not a
 *                 string.
 * @param {Object} [options] Object with the following properties:
 * @param {Boolean} [options.onlyUpdateExistingItems] true to only update existing items and never create new ones, or false is new items
 *                                                    may be created by this update.
 * @param {Boolean} [options.isUserSupplied] If specified, sets the {@link CatalogMember#isUserSupplied} property of updated catalog members
 *                                           to the given value.  If not specified, the property is left unchanged.
 * @param {CatalogGroup} catalogGroup The catalogGroup to update.
 *
 * @returns {Promise} A promise that resolves when the update is complete.
 */
CatalogGroup.updateItems = function(itemsJson, options, catalogGroup) {
    if (!(itemsJson instanceof Array)) {
        throw new DeveloperError('JSON catalog description must be an array of groups.');
    }

    options = defaultValue(options, defaultValue.EMPTY_OBJECT);
    var onlyUpdateExistingItems = defaultValue(options.onlyUpdateExistingItems, false);

    var promises = [];

    for (var itemIndex = 0; itemIndex < itemsJson.length; ++itemIndex) {
        var itemJson = itemsJson[itemIndex];

        if (!defined(itemJson.name) && !defined(itemJson.id)) {
            throw new RuntimeError('A catalog member must have a name or a id for matching.');
        }

        var itemObject;
        if (itemJson.id) {
            itemObject = catalogGroup.terria.catalog.shareKeyIndex[itemJson.id];
        } else if (itemJson.name) {
            itemObject = catalogGroup.findFirstItemByName(itemJson.name);
        }

        var updating = defined(itemObject);

        if (!updating) {
            // Skip this item entirely if we're not allowed to create it.
            if (onlyUpdateExistingItems) {
                continue;
            }

            if (!defined(itemJson.name)) {
                throw new RuntimeError('A newly created catalog member must have a name.');
            }

            if (!defined(itemJson.type)) {
                throw new RuntimeError('A catalog member must have a type.');
            }

            itemObject = createCatalogMemberFromType(itemJson.type, catalogGroup.terria);
        }

        promises.push(itemObject.updateFromJson(itemJson, options));

        if (!updating) {
            catalogGroup.add(itemObject);
        }
    }

    catalogGroup.sortItems();

    return when.all(promises);
};

module.exports = CatalogGroup;