var baseGetTag = require('./_baseGetTag'),

getPrototype = require('./_getPrototype'),
isObjectLike = require('./isObjectLike');

/** `Object#toString` result references. */ var objectTag = '[object Object]';

/** Used for built-in method references. */ var funcProto = Function.prototype,

objectProto = Object.prototype;

/** Used to resolve the decompiled source of functions. */ var funcToString = funcProto.toString;

/** Used to check objects for own properties. */ var hasOwnProperty = objectProto.hasOwnProperty;

/** Used to infer the `Object` constructor. */ var objectCtorString = funcToString.call(Object);

/**

* Checks if `value` is a plain object, that is, an object created by the
* `Object` constructor or one with a `[[Prototype]]` of `null`.
*
* @static
* @memberOf _
* @since 0.8.0
* @category Lang
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
* @example
*
* function Foo() {
*   this.a = 1;
* }
*
* _.isPlainObject(new Foo);
* // => false
*
* _.isPlainObject([1, 2, 3]);
* // => false
*
* _.isPlainObject({ 'x': 0, 'y': 0 });
* // => true
*
* _.isPlainObject(Object.create(null));
* // => true
*/

function isPlainObject(value) {

if (!isObjectLike(value) || baseGetTag(value) != objectTag) {
  return false;
}
var proto = getPrototype(value);
if (proto === null) {
  return true;
}
var Ctor = hasOwnProperty.call(proto, 'constructor') && proto.constructor;
return typeof Ctor == 'function' && Ctor instanceof Ctor &&
  funcToString.call(Ctor) == objectCtorString;

}

module.exports = isPlainObject;