/*!
    Copyright (c) 2009, 280 North Inc. http://280north.com/
    MIT License. http://github.com/280north/narwhal/blob/master/README.md
*/

// Brings an environment as close to ECMAScript 5 compliance
// as is possible with the facilities of erstwhile engines.

// ES5 Draft
// http://www.ecma-international.org/publications/files/drafts/tc39-2009-050.pdf

// NOTE: this is a draft, and as such, the URL is subject to change.  If the
// link is broken, check in the parent directory for the latest TC39 PDF.
// http://www.ecma-international.org/publications/files/drafts/

// Previous ES5 Draft
// http://www.ecma-international.org/publications/files/drafts/tc39-2009-025.pdf
// This is a broken link to the previous draft of ES5 on which most of the
// numbered specification references and quotes herein were taken.  Updating
// these references and quotes to reflect the new document would be a welcome
// volunteer project.

//
// Array
// =====
//

// ES5 15.4.3.2
if (!Array.isArray) {
    Array.isArray = function(obj) {
        return Object.prototype.toString.call(obj) == "[object Array]";
    };
}

// ES5 15.4.4.18
if (!Array.prototype.forEach) {
    Array.prototype.forEach =  function(block, thisObject) {
        var len = this.length >>> 0;
        for (var i = 0; i < len; i++) {
            if (i in this) {
                block.call(thisObject, this[i], i, this);
            }
        }
    };
}

// ES5 15.4.4.19
// https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Objects/Array/map
if (!Array.prototype.map) {
    Array.prototype.map = function(fun /*, thisp*/) {
        var len = this.length >>> 0;
        if (typeof fun != "function")
          throw new TypeError();

        var res = new Array(len);
        var thisp = arguments[1];
        for (var i = 0; i < len; i++) {
            if (i in this)
                res[i] = fun.call(thisp, this[i], i, this);
        }

        return res;
    };
}

// ES5 15.4.4.20
if (!Array.prototype.filter) {
    Array.prototype.filter = function (block /*, thisp */) {
        var values = [];
        var thisp = arguments[1];
        for (var i = 0; i < this.length; i++)
            if (block.call(thisp, this[i]))
                values.push(this[i]);
        return values;
    };
}

// ES5 15.4.4.16
if (!Array.prototype.every) {
    Array.prototype.every = function (block /*, thisp */) {
        var thisp = arguments[1];
        for (var i = 0; i < this.length; i++)
            if (!block.call(thisp, this[i]))
                return false;
        return true;
    };
}

// ES5 15.4.4.17
if (!Array.prototype.some) {
    Array.prototype.some = function (block /*, thisp */) {
        var thisp = arguments[1];
        for (var i = 0; i < this.length; i++)
            if (block.call(thisp, this[i]))
                return true;
        return false;
    };
}

// ES5 15.4.4.21
// https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Objects/Array/reduce
if (!Array.prototype.reduce) {
    Array.prototype.reduce = function(fun /*, initial*/) {
        var len = this.length >>> 0;
        if (typeof fun != "function")
            throw new TypeError();

        // no value to return if no initial value and an empty array
        if (len == 0 && arguments.length == 1)
            throw new TypeError();

        var i = 0;
        if (arguments.length >= 2) {
            var rv = arguments[1];
        } else {
            do {
                if (i in this) {
                    rv = this[i++];
                    break;
                }

                // if array contains no values, no initial value to return
                if (++i >= len)
                    throw new TypeError();
            } while (true);
        }

        for (; i < len; i++) {
            if (i in this)
                rv = fun.call(null, rv, this[i], i, this);
        }

        return rv;
    };
}

// ES5 15.4.4.22
// https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Objects/Array/reduceRight
if (!Array.prototype.reduceRight) {
    Array.prototype.reduceRight = function(fun /*, initial*/) {
        var len = this.length >>> 0;
        if (typeof fun != "function")
            throw new TypeError();

        // no value to return if no initial value, empty array
        if (len == 0 && arguments.length == 1)
            throw new TypeError();

        var i = len - 1;
        if (arguments.length >= 2) {
            var rv = arguments[1];
        } else {
            do {
                if (i in this) {
                    rv = this[i--];
                    break;
                }

                // if array contains no values, no initial value to return
                if (--i < 0)
                    throw new TypeError();
            } while (true);
        }

        for (; i >= 0; i--) {
            if (i in this)
                rv = fun.call(null, rv, this[i], i, this);
        }

        return rv;
    };
}

// ES5 15.4.4.14
if (!Array.prototype.indexOf) {
    Array.prototype.indexOf = function (value /*, fromIndex */ ) {
        var length = this.length;
        if (!length)
            return -1;
        var i = arguments[1] || 0;
        if (i >= length)
            return -1;
        if (i < 0)
            i += length;
        for (; i < length; i++) {
            if (!Object.prototype.hasOwnProperty.call(this, i))
                continue;
            if (value === this[i])
                return i;
        }
        return -1;
    };
}

// ES5 15.4.4.15
if (!Array.prototype.lastIndexOf) {
    Array.prototype.lastIndexOf = function (value /*, fromIndex */) {
        var length = this.length;
        if (!length)
            return -1;
        var i = arguments[1] || length;
        if (i < 0)
            i += length;
        i = Math.min(i, length - 1);
        for (; i >= 0; i--) {
            if (!Object.prototype.hasOwnProperty.call(this, i))
                continue;
            if (value === this[i])
                return i;
        }
        return -1;
    };
}


//
// Object
// ======
//

// ES5 15.2.3.2
if (!Object.getPrototypeOf) {
    Object.getPrototypeOf = function (object) {
        return object.__proto__;
        // or undefined if not available in this engine
    };
}

// ES5 15.2.3.3
if (!Object.getOwnPropertyDescriptor) {
    Object.getOwnPropertyDescriptor = function (object) {
        return {}; // XXX
    };
}

// ES5 15.2.3.4
if (!Object.getOwnPropertyNames) {
    Object.getOwnPropertyNames = function (object) {
        return Object.keys(object);
    };
}

// ES5 15.2.3.5
if (!Object.create) {
    Object.create = function(prototype, properties) {
        if (typeof prototype != "object" || prototype === null)
            throw new TypeError("typeof prototype["+(typeof prototype)+"] != 'object'");
        function Type() {};
        Type.prototype = prototype;
        var object = new Type();
        if (typeof properties !== "undefined")
            Object.defineProperties(object, properties);
        return object;
    };
}

// ES5 15.2.3.6
if (!Object.defineProperty) {
    Object.defineProperty = function(object, property, descriptor) {
        var has = Object.prototype.hasOwnProperty;
        if (typeof descriptor == "object" && object.__defineGetter__) {
            if (has.call(descriptor, "value")) {
                if (!object.__lookupGetter__(property) && !object.__lookupSetter__(property))
                    // data property defined and no pre-existing accessors
                    object[property] = descriptor.value;
                if (has.call(descriptor, "get") || has.call(descriptor, "set"))
                    // descriptor has a value property but accessor already exists
                    throw new TypeError("Object doesn't support this action");
            }
            // fail silently if "writable", "enumerable", or "configurable"
            // are requested but not supported
            /*
            // alternate approach:
            if ( // can't implement these features; allow false but not true
                !(has.call(descriptor, "writable") ? descriptor.writable : true) ||
                !(has.call(descriptor, "enumerable") ? descriptor.enumerable : true) ||
                !(has.call(descriptor, "configurable") ? descriptor.configurable : true)
            )
                throw new RangeError(
                    "This implementation of Object.defineProperty does not " +
                    "support configurable, enumerable, or writable."
                );
            */
            else if (typeof descriptor.get == "function")
                object.__defineGetter__(property, descriptor.get);
            if (typeof descriptor.set == "function")
                object.__defineSetter__(property, descriptor.set);
        }
        return object;
    };
}

// ES5 15.2.3.7
if (!Object.defineProperties) {
    Object.defineProperties = function(object, properties) {
        for (var property in properties) {
            if (Object.prototype.hasOwnProperty.call(properties, property))
                Object.defineProperty(object, property, properties[property]);
        }
        return object;
    };
}

// ES5 15.2.3.8
if (!Object.seal) {
    Object.seal = function (object) {
        return object;
    };
}

// ES5 15.2.3.9
if (!Object.freeze) {
    Object.freeze = function (object) {
        return object;
    };
}

// ES5 15.2.3.10
if (!Object.preventExtensions) {
    Object.preventExtensions = function (object) {
        return object;
    };
}

// ES5 15.2.3.11
if (!Object.isSealed) {
    Object.isSealed = function (object) {
        return false;
    };
}

// ES5 15.2.3.12
if (!Object.isFrozen) {
    Object.isFrozen = function (object) {
        return false;
    };
}

// ES5 15.2.3.13
if (!Object.isExtensible) {
    Object.isExtensible = function (object) {
        return true;
    };
}

// ES5 15.2.3.14
if (!Object.keys) {
    Object.keys = function (object) {
        var keys = [];
        for (var name in object) {
            if (Object.prototype.hasOwnProperty.call(object, name)) {
                keys.push(name);
            }
        }
        return keys;
    };
}

//
// Date
// ====
//

// ES5 15.9.5.43
// Format a Date object as a string according to a subset of the ISO-8601 standard.
// Useful in Atom, among other things.
if (!Date.prototype.toISOString) {
    Date.prototype.toISOString = function() {
        return (
            this.getFullYear() + "-" +
            (this.getMonth() + 1) + "-" +
            this.getDate() + "T" +
            this.getHours() + ":" +
            this.getMinutes() + ":" +
            this.getSeconds() + "Z"
        );
    }
}

// ES5 15.9.4.4
if (!Date.now) {
    Date.now = function () {
        return new Date().getTime();
    };
}

// ES5 15.9.5.44
if (!Date.prototype.toJSON) {
    Date.prototype.toJSON = function (key) {
        // This function provides a String representation of a Date object for
        // use by JSON.stringify (15.12.3). When the toJSON method is called
        // with argument key, the following steps are taken:

        // 1.  Let O be the result of calling ToObject, giving it the this
        // value as its argument.
        // 2. Let tv be ToPrimitive(O, hint Number).
        // 3. If tv is a Number and is not finite, return null.
        // XXX
        // 4. Let toISO be the result of calling the [[Get]] internal method of
        // O with argument "toISOString".
        // 5. If IsCallable(toISO) is false, throw a TypeError exception.
        if (typeof this.toISOString != "function")
            throw new TypeError();
        // 6. Return the result of calling the [[Call]] internal method of
        // toISO with O as the this value and an empty argument list.
        return this.toISOString();

        // NOTE 1 The argument is ignored.

        // NOTE 2 The toJSON function is intentionally generic; it does not
        // require that its this value be a Date object. Therefore, it can be
        // transferred to other kinds of objects for use as a method. However,
        // it does require that any such object have a toISOString method. An
        // object is free to use the argument key to filter its
        // stringification.
    };
}


//
// Function
// ========
//

// ES-5 15.3.4.5
// http://www.ecma-international.org/publications/files/drafts/tc39-2009-025.pdf
var slice = Array.prototype.slice;
if (!Function.prototype.bind) {
    Function.prototype.bind = function (that) { // .length is 1
        // 1. Let Target be the this value.
        var target = this;
        // 2. If IsCallable(Target) is false, throw a TypeError exception.
        // XXX this gets pretty close, for all intents and purposes, letting
        // some duck-types slide
        if (typeof target.apply != "function" || typeof target.call != "function")
            return new TypeError();
        // 3. Let A be a new (possibly empty) internal list of all of the
        //   argument values provided after thisArg (arg1, arg2 etc), in order.
        var args = slice.call(arguments);
        // 4. Let F be a new native ECMAScript object.
        // 9. Set the [[Prototype]] internal property of F to the standard
        //   built-in Function prototype object as specified in 15.3.3.1.
        // 10. Set the [[Call]] internal property of F as described in
        //   15.3.4.5.1.
        // 11. Set the [[Construct]] internal property of F as described in
        //   15.3.4.5.2.
        // 12. Set the [[HasInstance]] internal property of F as described in
        //   15.3.4.5.3.
        // 13. The [[Scope]] internal property of F is unused and need not
        //   exist.
        var bound = function () {

            if (this instanceof bound) {
                // 15.3.4.5.2 [[Construct]]
                // When the [[Construct]] internal method of a function object,
                // F that was created using the bind function is called with a
                // list of arguments ExtraArgs the following steps are taken:
                // 1. Let target be the value of F's [[TargetFunction]]
                //   internal property.
                // 2. If target has no [[Construct]] internal method, a
                //   TypeError exception is thrown.
                // 3. Let boundArgs be the value of F's [[BoundArgs]] internal
                //   property.
                // 4. Let args be a new list containing the same values as the
                //   list boundArgs in the same order followed by the same
                //   values as the list ExtraArgs in the same order.

                var self = Object.create(target.prototype);
                target.apply(self, args.concat(slice.call(arguments)));
                return self;

            } else {
                // 15.3.4.5.1 [[Call]]
                // When the [[Call]] internal method of a function object, F,
                // which was created using the bind function is called with a
                // this value and a list of arguments ExtraArgs the following
                // steps are taken:
                // 1. Let boundArgs be the value of F's [[BoundArgs]] internal
                //   property.
                // 2. Let boundThis be the value of F's [[BoundThis]] internal
                //   property.
                // 3. Let target be the value of F's [[TargetFunction]] internal
                //   property.
                // 4. Let args be a new list containing the same values as the list
                //   boundArgs in the same order followed by the same values as
                //   the list ExtraArgs in the same order. 5.  Return the
                //   result of calling the [[Call]] internal method of target
                //   providing boundThis as the this value and providing args
                //   as the arguments.

                // equiv: target.call(this, ...boundArgs, ...args)
                return target.call.apply(
                    target,
                    args.concat(slice.call(arguments))
                );

            }

        };
        // 5. Set the [[TargetFunction]] internal property of F to Target.
        // extra:
        bound.bound = target;
        // 6. Set the [[BoundThis]] internal property of F to the value of
        // thisArg.
        // extra:
        bound.boundTo = that;
        // 7. Set the [[BoundArgs]] internal property of F to A.
        // extra:
        bound.boundArgs = args;
        bound.length = (
            // 14. If the [[Class]] internal property of Target is "Function", then
            typeof target == "function" ?
            // a. Let L be the length property of Target minus the length of A.
            // b. Set the length own property of F to either 0 or L, whichever is larger.
            Math.max(target.length - args.length, 0) :
            // 15. Else set the length own property of F to 0.
            0
        )
        // 16. The length own property of F is given attributes as specified in
        //   15.3.5.1.
        // TODO
        // 17. Set the [[Extensible]] internal property of F to true.
        // TODO
        // 18. Call the [[DefineOwnProperty]] internal method of F with
        //   arguments "caller", PropertyDescriptor {[[Value]]: null,
        //   [[Writable]]: false, [[Enumerable]]: false, [[Configurable]]:
        //   false}, and false.
        // TODO
        // 19. Call the [[DefineOwnProperty]] internal method of F with
        //   arguments "arguments", PropertyDescriptor {[[Value]]: null,
        //   [[Writable]]: false, [[Enumerable]]: false, [[Configurable]]:
        //   false}, and false.
        // TODO
        // NOTE Function objects created using Function.prototype.bind do not
        // have a prototype property.
        // XXX can't delete it in pure-js.
        return bound;
    };
}

//
// String
// ======
//

// ES5 15.5.4.20
if (!String.prototype.trim) {
    // http://blog.stevenlevithan.com/archives/faster-trim-javascript
    var trimBeginRegexp = /^\s\s*/;
    var trimEndRegexp = /\s\s*$/;
    String.prototype.trim = function () {
        return String(this).replace(trimBeginRegexp, '').replace(trimEndRegexp, '');
    };
}