/*!
 * lunr.Store
 * Copyright (C) @YEAR Oliver Nightingale
 */

/**
 * lunr.Store is a simple key-value store used for storing sets of tokens for
 * documents stored in index.
 *
 * @constructor
 * @module
 */
lunr.Store = function () {
  this.store = {}
  this.length = 0
}

/**
 * Loads a previously serialised store
 *
 * @param {Object} serialisedData The serialised store to load.
 * @returns {lunr.Store}
 * @memberOf Store
 */
lunr.Store.load = function (serialisedData) {
  var store = new this

  store.length = serialisedData.length
  store.store = Object.keys(serialisedData.store).reduce(function (memo, key) {
    memo[key] = lunr.SortedSet.load(serialisedData.store[key])
    return memo
  }, {})

  return store
}

/**
 * Stores the given tokens in the store against the given id.
 *
 * @param {Object} id The key used to store the tokens against.
 * @param {Object} tokens The tokens to store against the key.
 * @memberOf Store
 */
lunr.Store.prototype.set = function (id, tokens) {
  if (!this.has(id)) this.length++
  this.store[id] = tokens
}

/**
 * Retrieves the tokens from the store for a given key.
 *
 * @param {Object} id The key to lookup and retrieve from the store.
 * @returns {Object}
 * @memberOf Store
 */
lunr.Store.prototype.get = function (id) {
  return this.store[id]
}

/**
 * Checks whether the store contains a key.
 *
 * @param {Object} id The id to look up in the store.
 * @returns {Boolean}
 * @memberOf Store
 */
lunr.Store.prototype.has = function (id) {
  return id in this.store
}

/**
 * Removes the value for a key in the store.
 *
 * @param {Object} id The id to remove from the store.
 * @memberOf Store
 */
lunr.Store.prototype.remove = function (id) {
  if (!this.has(id)) return

  delete this.store[id]
  this.length--
}

/**
 * Returns a representation of the store ready for serialisation.
 *
 * @returns {Object}
 * @memberOf Store
 */
lunr.Store.prototype.toJSON = function () {
  return {
    store: this.store,
    length: this.length
  }
}