/**
 * JavaScript Call Tracer
 *
 * Copyright 2007 (C) John McKerrell - john@mckerrell.net
 * This contents of this source file are subject to
 * the GNU Public License (GPL) Version 2.0
 *
 */
var JSCT = {
	/**
	 * The private array of functions that JSCT has overridden.
	 * @type Array
	 * @private
	 */
    _functions : [],
	/**
	 * If set to true then JSCT will not call any logging functions.
	 * @type boolean
	 * @private
	 */
    _silent : false,

    /**
     * Sets up tracing for an array of named objects or functions. These must
     * be available on the window object.
     * @param {Array} objects An array of object or function names, not references to the objects or functions themselves.
	 * @param {String} (optional) The prefix you would like to use, defaults to 'window', you might prefer 'self'.
	 * @param {String} (optional) Unused argument that would allow alternative loggers to firebug to be used.
     */
    setupTrace : function( objects, prefix, logger ) {
        if( ! prefix )
            prefix = 'window';
        for( var i = 0, l = objects.length; i < l; ++i ) {
            if( window[objects[i]] ) {
                this._setupObject( objects[i], window[objects[i]], window, prefix, logger );
            }
        }
    },

    /**
     * Shuts the tracer up, in case you have a noisy interval.
     */
    silence : function() {
        this._silent = true;
    },

    /**
     * Replaces all of the functions in an object and any child objects with
     * wrapped functions that can be traced. If passed a reference to a function
     * just wraps that function.
     * @private
     */
    _setupObject : function( name, obj, parent, prefix, logger ) {
        if( ! obj )
            return;
        if( obj.JSCTtouched )
            return;
        obj.JSCTtouched = true;
        // Only use foo['bar'] if we have to, otherwise use foo.bar
        if( name.match( /[$a-zA-Z][$a-zA-Z0-9]*/ ) ) {
            prefix = prefix+'.'+name;
        } else {
            prefix = prefix+'[\''+name.replace( /\\/, "\\\\" ).replace( /'/g, "\'" )+'\']';
        }
        switch( typeof( obj ) ) {
        case 'function':
            var funcNum = this._functions.length;
            this._functions[funcNum] = obj;
            parent[name] = this._makeFunction( name, funcNum, parent, prefix, logger );
            for( var key in obj ) {
                parent[name][key] = obj[key];
                this._setupObject( key, obj[key], obj, prefix, logger );
            }
            break;
        case 'object':
            for( var key in obj ) {
                this._setupObject( key, obj[key], obj, prefix, logger );
            }
        }
    },
    
	/**
	 * Creates an anonymous function closure to replace an existing function.
	 * When called, this function will perform the logging (unless JSCT
	 * has been silenced) and then call the original function.
	 * @private
	 */
    _makeFunction : function( name, num, parent, funcName, logger ) {
        return function() {
            var eval_call = 'JSCT._functions['+num+'].call( this';
            var log_call = "console.group( funcName+'('";
            var start_time = new Date();
            for( var i = 0, l = arguments.length; i < l; ++i ) {
                eval_call += ', arguments['+i+']';
                if( i > 0 )
                    log_call += ', ","';
                log_call += ', arguments['+i+']';
            }
            eval_call += ' )';
            log_call += ', ")" )';
            if( ! JSCT._silent ) {
                eval( log_call );
            }
            var result = eval( eval_call );
            // !!! Function may return here.
            if( ! JSCT._silent ) {
                console.groupEnd();
                if( typeof( result ) == 'undefined' ) {
                    console.log( funcName+'(...) took '+((new Date()) - start_time)+'ms and returned nothing' );
                } else {
                    console.log( funcName+'(...) took '+((new Date()) - start_time)+'ms and returned: ', result );
                }
            }
            return result;
        }
    }
}