/**
 * Deep clone
 * https://github.com/pvorb/clone
 */

var clone = (function() {
  'use strict';

  function _instanceof(obj, type) {
    return type != null && obj instanceof type;
  }

  var nativeMap;
  try {
    nativeMap = Map;
  } catch(_) {
    // maybe a reference error because no `Map`. Give it a dummy value that no
    // value will ever be an instanceof.
    nativeMap = function() {};
  }

  var nativeSet;
  try {
    nativeSet = Set;
  } catch(_) {
    nativeSet = function() {};
  }

  var nativePromise;
  try {
    nativePromise = Promise;
  } catch(_) {
    nativePromise = function() {};
  }

  /**
   * Clones (copies) an Object using deep copying.
   *
   * This function supports circular references by default, but if you are certain
   * there are no circular references in your object, you can save some CPU time
   * by calling clone(obj, false).
   *
   * Caution: if `circular` is false and `parent` contains circular references,
   * your program may enter an infinite loop and crash.
   *
   * @param `parent` - the object to be cloned
   * @param `circular` - set to true if the object to be cloned may contain
   *    circular references. (optional - true by default)
   * @param `depth` - set to a number if the object is only to be cloned to
   *    a particular depth. (optional - defaults to Infinity)
   * @param `prototype` - sets the prototype to be used when cloning an object.
   *    (optional - defaults to parent prototype).
   * @param `includeNonEnumerable` - set to true if the non-enumerable properties
   *    should be cloned as well. Non-enumerable properties on the prototype
   *    chain will be ignored. (optional - false by default)
   */
  function clone(parent, circular, depth, prototype, includeNonEnumerable) {
    if (typeof circular === 'object') {
      depth = circular.depth;
      prototype = circular.prototype;
      includeNonEnumerable = circular.includeNonEnumerable;
      circular = circular.circular;
    }
    // maintain two arrays for circular references, where corresponding parents
    // and children have the same index
    var allParents = [];
    var allChildren = [];

    var useBuffer = typeof Buffer != 'undefined';

    if (typeof circular == 'undefined')
      circular = true;

    if (typeof depth == 'undefined')
      depth = Infinity;

    // recurse this function so we don't reset allParents and allChildren
    function _clone(parent, depth) {
      // cloning null always returns null
      if (parent === null)
        return null;

      if (depth === 0)
        return parent;

      var child;
      var proto;
      if (typeof parent != 'object') {
        return parent;
      }

      if (_instanceof(parent, nativeMap)) {
        child = new nativeMap();
      } else if (_instanceof(parent, nativeSet)) {
        child = new nativeSet();
      } else if (_instanceof(parent, nativePromise)) {
        child = new nativePromise(function (resolve, reject) {
          parent.then(function(value) {
            resolve(_clone(value, depth - 1));
          }, function(err) {
            reject(_clone(err, depth - 1));
          });
        });
      } else if (clone.__isArray(parent)) {
        child = [];
      } else if (clone.__isRegExp(parent)) {
        child = new RegExp(parent.source, __getRegExpFlags(parent));
        if (parent.lastIndex) child.lastIndex = parent.lastIndex;
      } else if (clone.__isDate(parent)) {
        child = new Date(parent.getTime());
      } else if (useBuffer && Buffer.isBuffer(parent)) {
        child = new Buffer(parent.length);
        parent.copy(child);
        return child;
      } else if (_instanceof(parent, Error)) {
        child = Object.create(parent);
      } else {
        if (typeof prototype == 'undefined') {
          proto = Object.getPrototypeOf(parent);
          child = Object.create(proto);
        }
        else {
          child = Object.create(prototype);
          proto = prototype;
        }
      }

      if (circular) {
        var index = allParents.indexOf(parent);

        if (index != -1) {
          return allChildren[index];
        }
        allParents.push(parent);
        allChildren.push(child);
      }

      if (_instanceof(parent, nativeMap)) {
        parent.forEach(function(value, key) {
          var keyChild = _clone(key, depth - 1);
          var valueChild = _clone(value, depth - 1);
          child.set(keyChild, valueChild);
        });
      }
      if (_instanceof(parent, nativeSet)) {
        parent.forEach(function(value) {
          var entryChild = _clone(value, depth - 1);
          child.add(entryChild);
        });
      }

      for (var i in parent) {
        var attrs;
        if (proto) {
          attrs = Object.getOwnPropertyDescriptor(proto, i);
        }

        if (attrs && attrs.set == null) {
          continue;
        }
        child[i] = _clone(parent[i], depth - 1);
      }

      if (Object.getOwnPropertySymbols) {
        var symbols = Object.getOwnPropertySymbols(parent);
        for (var i = 0; i < symbols.length; i++) {
          // Don't need to worry about cloning a symbol because it is a primitive,
          // like a number or string.
          var symbol = symbols[i];
          var descriptor = Object.getOwnPropertyDescriptor(parent, symbol);
          if (descriptor && !descriptor.enumerable && !includeNonEnumerable) {
            continue;
          }
          child[symbol] = _clone(parent[symbol], depth - 1);
          if (!descriptor.enumerable) {
            Object.defineProperty(child, symbol, {
              enumerable: false
            });
          }
        }
      }

      if (includeNonEnumerable) {
        var allPropertyNames = Object.getOwnPropertyNames(parent);
        for (var i = 0; i < allPropertyNames.length; i++) {
          var propertyName = allPropertyNames[i];
          var descriptor = Object.getOwnPropertyDescriptor(parent, propertyName);
          if (descriptor && descriptor.enumerable) {
            continue;
          }
          child[propertyName] = _clone(parent[propertyName], depth - 1);
          Object.defineProperty(child, propertyName, {
            enumerable: false
          });
        }
      }

      return child;
    }

    return _clone(parent, depth);
  }

  /**
   * Simple flat clone using prototype, accepts only objects, usefull for property
   * override on FLAT configuration object (no nested props).
   *
   * USE WITH CAUTION! This may not behave as you wish if you do not know how this
   * works.
   */
  clone.clonePrototype = function clonePrototype(parent) {
    if (parent === null)
      return null;

    var c = function () {};
    c.prototype = parent;
    return new c();
  };

// private utility functions

  function __objToStr(o) {
    return Object.prototype.toString.call(o);
  }
  clone.__objToStr = __objToStr;

  function __isDate(o) {
    return typeof o === 'object' && __objToStr(o) === '[object Date]';
  }
  clone.__isDate = __isDate;

  function __isArray(o) {
    return typeof o === 'object' && __objToStr(o) === '[object Array]';
  }
  clone.__isArray = __isArray;

  function __isRegExp(o) {
    return typeof o === 'object' && __objToStr(o) === '[object RegExp]';
  }
  clone.__isRegExp = __isRegExp;

  function __getRegExpFlags(re) {
    var flags = '';
    if (re.global) flags += 'g';
    if (re.ignoreCase) flags += 'i';
    if (re.multiline) flags += 'm';
    return flags;
  }
  clone.__getRegExpFlags = __getRegExpFlags;

  return clone;
})();

if (typeof module === 'object' && module.exports) {
  module.exports = clone;
}