/*
 * JavaScript backwards-compatibility alternatives and other convenience functions
 */

jQuery.extend({
	trimLeft : function( str ) {
		return str === null ? '' : str.toString().replace( /^\s+/, '' );
	},
	trimRight : function( str ) {
		return str === null ?
				'' : str.toString().replace( /\s+$/, '' );
	},
	ucFirst : function( str ) {
		return str.substr( 0, 1 ).toUpperCase() + str.substr( 1 );
	},
	escapeRE : function( str ) {
		return str.replace ( /([\\{}()|.?*+\-^$\[\]])/g, "\\$1" );
	},
	isDomElement : function( el ) {
		return !!el && !!el.nodeType;
	},
	isEmpty : function( v ) {
		var key;
		if ( v === "" || v === 0 || v === "0" || v === null
			|| v === false || typeof v === 'undefined' )
		{
			return true;
		}
		// the for-loop could potentially contain prototypes
		// to avoid that we check it's length first
		if ( v.length === 0 ) {
			return true;
		}
		if ( typeof v === 'object' ) {
			for ( key in v ) {
				return false;
			}
			return true;
		}
		return false;
	},
	compareArray : function( arrThis, arrAgainst ) {
		if ( arrThis.length != arrAgainst.length ) {
			return false;
		}
		for ( var i = 0; i < arrThis.length; i++ ) {
			if ( arrThis[i] instanceof Array ) {
				if ( !$.compareArray( arrThis[i], arrAgainst[i] ) ) {
					return false;
				}
			} else if ( arrThis[i] !== arrAgainst[i] ) {
				return false;
			}
		}
		return true;
	},
	compareObject : function( objectA, objectB ) {

		// Do a simple check if the types match
		if ( typeof objectA == typeof objectB ) {

			// Only loop over the contents if it really is an object
			if ( typeof objectA == 'object' ) {
				// If they are aliases of the same object (ie. mw and mediaWiki) return now
				if ( objectA === objectB ) {
					return true;
				} else {
					var prop;
					// Iterate over each property
					for ( prop in objectA ) {
						// Check if this property is also present in the other object
						if ( prop in objectB ) {
							// Compare the types of the properties
							var type = typeof objectA[prop];
							if ( type == typeof objectB[prop] ) {
								// Recursively check objects inside this one
								switch ( type ) {
									case 'object' :
										if ( !$.compareObject( objectA[prop], objectB[prop] ) ) {
											return false;
										}
										break;
									case 'function' :
										// Functions need to be strings to compare them properly
										if ( objectA[prop].toString() !== objectB[prop].toString() ) {
											return false;
										}
										break;
									default:
										// Strings, numbers
										if ( objectA[prop] !== objectB[prop] ) {
											return false;
										}
										break;
								}
							} else {
								return false;
							}
						} else {
							return false;
						}
					}
					// Check for properties in B but not in A
					// This is about 15% faster (tested in Safari 5 and Firefox 3.6)
					// ...than incrementing a count variable in the above and below loops
					// See also: http://www.mediawiki.org/wiki/ResourceLoader/Default_modules/compareObject_test#Results
					for ( prop in objectB ) {
						if ( !( prop in objectA ) ) {
							return false;
						}
					}
				}
			}
		} else {
			return false;
		}
		return true;
	}
});