/*
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;
	},

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

	erase: 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 (k == undefined) 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;
	},

	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(base){
		var queryString = [];
		Hash.each(this, function(value, key){
			if (base) key = base + '[' + key + ']';
			var result;
			switch ($type(value)){
				case 'object': result = Hash.toQueryString(value, key); break;
				case 'array':
					var qs = {};
					value.each(function(val, i){
						qs[i] = val;
					});
					result = Hash.toQueryString(qs, key);
				break;
				default: result = key + '=' + encodeURIComponent(value);
			}
			if (value != undefined) queryString.push(result);
		});
		
		return queryString.join('&');
	}

});

Hash.alias({keyOf: 'indexOf', hasValue: 'contains'});