'use strict';

function _typeof(obj) {
  if (typeof Symbol === "function" && typeof Symbol.iterator === "symbol") {
    _typeof = function (obj) {
      return typeof obj;
    };
  } else {
    _typeof = function (obj) {
      return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj;
    };
  }

  return _typeof(obj);
}

function _classCallCheck(instance, Constructor) {
  if (!(instance instanceof Constructor)) {
    throw new TypeError("Cannot call a class as a function");
  }
}

function _defineProperties(target, props) {
  for (var i = 0; i < props.length; i++) {
    var descriptor = props[i];
    descriptor.enumerable = descriptor.enumerable || false;
    descriptor.configurable = true;
    if ("value" in descriptor) descriptor.writable = true;
    Object.defineProperty(target, descriptor.key, descriptor);
  }
}

function _createClass(Constructor, protoProps, staticProps) {
  if (protoProps) _defineProperties(Constructor.prototype, protoProps);
  if (staticProps) _defineProperties(Constructor, staticProps);
  return Constructor;
}

/**
 * Given an instance of EquivalentKeyMap, returns its internal value pair tuple
 * for a key, if one exists. The tuple members consist of the last reference
 * value for the key (used in efficient subsequent lookups) and the value
 * assigned for the key at the leaf node.
 *
 * @param {EquivalentKeyMap} instance EquivalentKeyMap instance.
 * @param {*} key                     The key for which to return value pair.
 *
 * @return {?Array} Value pair, if exists.
 */
function getValuePair(instance, key) {
  var _map = instance._map,
      _arrayTreeMap = instance._arrayTreeMap,
      _objectTreeMap = instance._objectTreeMap; // Map keeps a reference to the last object-like key used to set the
  // value, which can be used to shortcut immediately to the value.

  if (_map.has(key)) {
    return _map.get(key);
  } // Sort keys to ensure stable retrieval from tree.


  var properties = Object.keys(key).sort(); // Tree by type to avoid conflicts on numeric object keys, empty value.

  var map = Array.isArray(key) ? _arrayTreeMap : _objectTreeMap;

  for (var i = 0; i < properties.length; i++) {
    var property = properties[i];
    map = map.get(property);

    if (map === undefined) {
      return;
    }

    var propertyValue = key[property];
    map = map.get(propertyValue);

    if (map === undefined) {
      return;
    }
  }

  var valuePair = map.get('_ekm_value');

  if (!valuePair) {
    return;
  } // If reached, it implies that an object-like key was set with another
  // reference, so delete the reference and replace with the current.


  _map.delete(valuePair[0]);

  valuePair[0] = key;
  map.set('_ekm_value', valuePair);

  _map.set(key, valuePair);

  return valuePair;
}
/**
 * Variant of a Map object which enables lookup by equivalent (deeply equal)
 * object and array keys.
 */


var EquivalentKeyMap =
/*#__PURE__*/
function () {
  /**
   * Constructs a new instance of EquivalentKeyMap.
   *
   * @param {Iterable.<*>} iterable Initial pair of key, value for map.
   */
  function EquivalentKeyMap(iterable) {
    _classCallCheck(this, EquivalentKeyMap);

    this.clear();

    if (iterable instanceof EquivalentKeyMap) {
      // Map#forEach is only means of iterating with support for IE11.
      var iterablePairs = [];
      iterable.forEach(function (value, key) {
        iterablePairs.push([key, value]);
      });
      iterable = iterablePairs;
    }

    if (iterable != null) {
      for (var i = 0; i < iterable.length; i++) {
        this.set(iterable[i][0], iterable[i][1]);
      }
    }
  }
  /**
   * Accessor property returning the number of elements.
   *
   * @return {number} Number of elements.
   */


  _createClass(EquivalentKeyMap, [{
    key: "set",

    /**
     * Add or update an element with a specified key and value.
     *
     * @param {*} key   The key of the element to add.
     * @param {*} value The value of the element to add.
     *
     * @return {EquivalentKeyMap} Map instance.
     */
    value: function set(key, value) {
      // Shortcut non-object-like to set on internal Map.
      if (key === null || _typeof(key) !== 'object') {
        this._map.set(key, value);

        return this;
      } // Sort keys to ensure stable assignment into tree.


      var properties = Object.keys(key).sort();
      var valuePair = [key, value]; // Tree by type to avoid conflicts on numeric object keys, empty value.

      var map = Array.isArray(key) ? this._arrayTreeMap : this._objectTreeMap;

      for (var i = 0; i < properties.length; i++) {
        var property = properties[i];

        if (!map.has(property)) {
          map.set(property, new EquivalentKeyMap());
        }

        map = map.get(property);
        var propertyValue = key[property];

        if (!map.has(propertyValue)) {
          map.set(propertyValue, new EquivalentKeyMap());
        }

        map = map.get(propertyValue);
      } // If an _ekm_value exists, there was already an equivalent key. Before
      // overriding, ensure that the old key reference is removed from map to
      // avoid memory leak of accumulating equivalent keys. This is, in a
      // sense, a poor man's WeakMap, while still enabling iterability.


      var previousValuePair = map.get('_ekm_value');

      if (previousValuePair) {
        this._map.delete(previousValuePair[0]);
      }

      map.set('_ekm_value', valuePair);

      this._map.set(key, valuePair);

      return this;
    }
    /**
     * Returns a specified element.
     *
     * @param {*} key The key of the element to return.
     *
     * @return {?*} The element associated with the specified key or undefined
     *              if the key can't be found.
     */

  }, {
    key: "get",
    value: function get(key) {
      // Shortcut non-object-like to get from internal Map.
      if (key === null || _typeof(key) !== 'object') {
        return this._map.get(key);
      }

      var valuePair = getValuePair(this, key);

      if (valuePair) {
        return valuePair[1];
      }
    }
    /**
     * Returns a boolean indicating whether an element with the specified key
     * exists or not.
     *
     * @param {*} key The key of the element to test for presence.
     *
     * @return {boolean} Whether an element with the specified key exists.
     */

  }, {
    key: "has",
    value: function has(key) {
      if (key === null || _typeof(key) !== 'object') {
        return this._map.has(key);
      } // Test on the _presence_ of the pair, not its value, as even undefined
      // can be a valid member value for a key.


      return getValuePair(this, key) !== undefined;
    }
    /**
     * Removes the specified element.
     *
     * @param {*} key The key of the element to remove.
     *
     * @return {boolean} Returns true if an element existed and has been
     *                   removed, or false if the element does not exist.
     */

  }, {
    key: "delete",
    value: function _delete(key) {
      if (!this.has(key)) {
        return false;
      } // This naive implementation will leave orphaned child trees. A better
      // implementation should traverse and remove orphans.


      this.set(key, undefined);
      return true;
    }
    /**
     * Executes a provided function once per each key/value pair, in insertion
     * order.
     *
     * @param {Function} callback Function to execute for each element.
     * @param {*}        thisArg  Value to use as `this` when executing
     *                            `callback`.
     */

  }, {
    key: "forEach",
    value: function forEach(callback) {
      var _this = this;

      var thisArg = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : this;

      this._map.forEach(function (value, key) {
        // Unwrap value from object-like value pair.
        if (key !== null && _typeof(key) === 'object') {
          value = value[1];
        }

        callback.call(thisArg, value, key, _this);
      });
    }
    /**
     * Removes all elements.
     */

  }, {
    key: "clear",
    value: function clear() {
      this._map = new Map();
      this._arrayTreeMap = new Map();
      this._objectTreeMap = new Map();
    }
  }, {
    key: "size",
    get: function get() {
      return this._map.size;
    }
  }]);

  return EquivalentKeyMap;
}();

module.exports = EquivalentKeyMap;