'use strict';

var Base = require('base');
var debug = require('debug')('base:templates:collection');
var plugin = require('./plugins');
var utils = require('./utils');

/**
 * Expose `Collection`
 */

module.exports = exports = Collection;

/**
 * Create an instance of `Collection` with the given `options`.
 *
 * ```js
 * var collection = new Collection();
 * collection.addItem('foo', {content: 'bar'});
 * ```
 * @param {Object} `options`
 * @api public
 */

function Collection(options) {
  if (!(this instanceof Collection)) {
    return new Collection(options);
  }

  Base.call(this, {}, options);
  this.is('Collection');
  this.items = {};

  this.use(utils.option());
  this.use(utils.plugin());
  this.init(options || {});
}

/**
 * Inherit `Base`
 */

Base.extend(Collection);

/**
 * Mixin static methods
 */

plugin.is(Collection);

/**
 * Initialize `Collection` defaults
 */

Collection.prototype.init = function(opts) {
  debug('initializing', __filename);

  // add constructors to the instance
  this.define('Item', opts.Item || Collection.Item);
  this.define('View', opts.View || Collection.View);

  this.use(plugin.renameKey());
  this.use(plugin.item('item', 'Item', {emit: false}));

  // if an instance of `List` or `Collection` is passed, load it now
  if (Array.isArray(opts) || opts.isList) {
    this.options = opts.options;
    this.addList(opts.items);

  } else if (opts.isCollection) {
    this.options = opts.options;
    this.addItems(opts.items);

  } else {
    this.options = opts;
  }
};

/**
 * Add an item to the collection.
 *
 * ```js
 * collection.addItem('foo', {content: 'bar'});
 * ```
 * @emits `item` With the created `item` and `collection` instance as arguments.
 * @param {String|Object} `key` Item name or object
 * @param {Object} `val` Item object, when `key` is a string.
 * @developer The `item` method is decorated onto the collection using the `item` plugin
 * @return {Object} returns the `item` instance.
 * @api public
 */

Collection.prototype.addItem = function(key, val) {
  debug('adding item "%s"');
  var item = this.item(key, val);
  if (typeof item.use === 'function') {
    this.run(item);
  }
  this.emit('item', item, this);
  this.items[item.key] = item;
  return item;
};

/**
 * Identical to `.addItem`, except the collection instance is returned instead of
 * the item, to allow chaining.
 *
 * ```js
 * collection.setItem('foo', {content: 'bar'});
 * ```
 * @emits `item` With the created `item` and `collection` instance as arguments.
 * @param {String|Object} `key` Item name or object
 * @param {Object} `val` Item object, when `key` is a string.
 * @return {Object} returns the `collection` instance.
 * @api public
 */

Collection.prototype.setItem = function(/*key, value*/) {
  this.addItem.apply(this, arguments);
  return this;
};

/**
 * Get an item from `collection.items`.
 *
 * ```js
 * collection.getItem('a.html');
 * ```
 * @param {String} `key` Key of the item to get.
 * @return {Object}
 * @api public
 */

Collection.prototype.getItem = function(key) {
  return this.items[key] || this.items[this.renameKey(key)];
};

/**
 * Remove an item from `collection.items`.
 *
 * ```js
 * items.deleteItem('abc');
 * ```
 * @param {String} `key`
 * @return {Object} Returns the instance for chaining
 * @api public
 */

Collection.prototype.deleteItem = function(item) {
  if (typeof item === 'string') {
    item = this.getItem(item);
  }
  delete this.items[item.key];
  return this;
};

/**
 * Load multiple items onto the collection.
 *
 * ```js
 * collection.addItems({
 *   'a.html': {content: '...'},
 *   'b.html': {content: '...'},
 *   'c.html': {content: '...'}
 * });
 * ```
 * @param {Object|Array} `items`
 * @return {Object} returns the instance for chaining
 * @api public
 */

Collection.prototype.addItems = function(items) {
  if (Array.isArray(items)) {
    return this.addList.apply(this, arguments);
  }
  this.visit('addItem', items);
  return this;
};

/**
 * Load an array of items onto the collection.
 *
 * ```js
 * collection.addList([
 *   {path: 'a.html', content: '...'},
 *   {path: 'b.html', content: '...'},
 *   {path: 'c.html', content: '...'}
 * ]);
 * ```
 * @param {Array} `items` or an instance of `List`
 * @param {Function} `fn` Optional sync callback function that is called on each item.
 * @return {Object} returns the Collection instance for chaining
 * @api public
 */

Collection.prototype.addList = function(list, fn) {
  if (!Array.isArray(list)) {
    throw new TypeError('expected list to be an array.');
  }

  if (typeof fn !== 'function') {
    fn = utils.identity;
  }
  var len = list.length;
  var idx = -1;

  while (++idx < len) {
    this.addItem(fn(list[idx]));
  }
  return this;
};

/**
 * Expose static properties
 */

utils.define(Collection, 'Item', require('vinyl-item'));
utils.define(Collection, 'View', require('vinyl-view'));