// This allows creating a new web page using the construct "new WebPage",
// which feels more natural than "phantom.createWebPage()".
window.WebPage = function() {
    var page = phantom.createWebPage(),
        handlers = {};

    function defineSetter(handlerName, signalName) {
        page.__defineSetter__(handlerName, function(f) {
            if (handlers && typeof handlers[signalName] === 'function') {
                try {
                    this[signalName].disconnect(handlers[signalName]);
                } catch (e) {}
            }
            handlers[signalName] = f;
            this[signalName].connect(handlers[signalName]);
        });
    };

    // deep copy
    page.settings = JSON.parse(JSON.stringify(phantom.defaultPageSettings));

    defineSetter("onLoadStarted", "loadStarted");

    defineSetter("onLoadFinished", "loadFinished");

    defineSetter("onResourceRequested", "resourceRequested");

    defineSetter("onResourceReceived", "resourceReceived");

    defineSetter("onAlert", "javaScriptAlertSent");

    defineSetter("onConsoleMessage", "javaScriptConsoleMessageSent");

    page.open = function () {
        if (arguments.length === 1) {
            this.openUrl(arguments[0], 'get', this.settings);
            return;
        }
        if (arguments.length === 2) {
            this.onLoadFinished = arguments[1];
            this.openUrl(arguments[0], 'get', this.settings);
            return;
        } else if (arguments.length === 3 && typeof arguments[2] === 'function') {
            this.onLoadFinished = arguments[2];
            this.openUrl(arguments[0], arguments[1], this.settings);
            return;
        } else if (arguments.length ===3) {
            this.openUrl(arguments[0], {
                operation: arguments[1],
                data: arguments[2]
                }, this.settings);
            return;            
        } else if (arguments.length === 4) {
            this.onLoadFinished = arguments[3];
            this.openUrl(arguments[0], {
                operation: arguments[1],
                data: arguments[2]
                }, this.settings);
            return;
        }
        throw "Wrong use of WebPage#open";
    };

    page.includeJs = function(scriptUrl, onScriptLoaded) {
        // Register temporary signal handler for 'alert()'
        this.javaScriptAlertSent.connect(function(msgFromAlert) {
            if ( msgFromAlert === scriptUrl ) {
                // Resource loaded, time to fire the callback
                onScriptLoaded(scriptUrl);
                // And disconnect the signal handler
                try {
                    this.javaScriptAlertSent.disconnect(arguments.callee);
                } catch (e) {}
            }
        });

        // Append the script tag to the body
        this._appendScriptElement(scriptUrl);
    };

    return page;
};

// Make "fs.open" throw an exception in case it fails
window.fs.open = function(path, mode) {
    var file = window.fs._open(path, mode);
    if (file) {
        return file;
    }
    throw "Unable to open file '"+ path +"'";
};