/*
Script: Hash.js
	Contains Hash Prototypes. Provides a means for overcoming the JavaScript practical impossibility of extending native Objects.

License:
	MIT-style license.
*/

Hash.implement({

	has: Object.prototype.hasOwnProperty,

	keyOf: function(value){
		for (var key in this){
			if (this.hasOwnProperty(key) && this[key] === value) return key;
		}
		return null;
	},

	hasValue: function(value){
		return (Hash.keyOf(this, value) !== null);
	},

	extend: function(properties){
		Hash.each(properties, function(value, key){
			Hash.set(this, key, value);
		}, this);
		return this;
	},

	merge: function(properties){
		Hash.each(properties, function(value, key){
			Hash.include(this, key, value);
		}, this);
		return this;
	},

	remove: function(key){
		if (this.hasOwnProperty(key)) delete this[key];
		return this;
	},

	get: function(key){
		return (this.hasOwnProperty(key)) ? this[key] : null;
	},

	set: function(key, value){
		if (!this[key] || this.hasOwnProperty(key)) this[key] = value;
		return this;
	},

	empty: function(){
		Hash.each(this, function(value, key){
			delete this[key];
		}, this);
		return this;
	},

	include: function(key, value){
		var k = this[key];
		if (!$defined(k)) this[key] = value;
		return this;
	},

	map: function(fn, bind){
		var results = new Hash;
		Hash.each(this, function(value, key){
			results.set(key, fn.call(bind, value, key, this));
		}, this);
		return results;
	},

	filter: function(fn, bind){
		var results = new Hash;
		Hash.each(this, function(value, key){
			if (fn.call(bind, value, key, this)) results.set(key, value);
		}, this);
		return results;
	},

	every: function(fn, bind){
		for (var key in this){
			if (this.hasOwnProperty(key) && !fn.call(bind, this[key], key)) return false;
		}
		return true;
	},

	some: function(fn, bind){
		for (var key in this){
			if (this.hasOwnProperty(key) && fn.call(bind, this[key], key)) return true;
		}
		return false;
	},

	getClean: function(){
		var clean = {};
		Hash.each(this, function(value, key){
			clean[key] = value;
		});
		return clean;
	},

	getKeys: function(){
		var keys = [];
		Hash.each(this, function(value, key){
			keys.push(key);
		});
		return keys;
	},

	getValues: function(){
		var values = [];
		Hash.each(this, function(value){
			values.push(value);
		});
		return values;
	},

	toQueryString: function(){
		var queryString = [];
		Hash.each(this, function(value, key){
			$splat(value).each(function(val){
				queryString.push(key + '=' + encodeURIComponent(val));
			});
		});
		return queryString.join('&');
	}

});

Hash.alias('keyOf', 'indexOf').alias('hasValue', 'contains').alias('remove', 'erase');