/**

* Handles opening of and synchronization with the reveal.js
* notes window.
*
* Handshake process:
* 1. This window posts 'connect' to notes window
*    - Includes URL of presentation to show
* 2. Notes window responds with 'connected' when it is available
* 3. This window proceeds to send the current presentation state
*    to the notes window
*/

var RevealNotes = (function() {

function openNotes( notesFilePath ) {

        if( !notesFilePath ) {
                var jsFileLocation = document.querySelector('script[src$="notes.js"]').src;  // this js file path
                jsFileLocation = jsFileLocation.replace(/notes\.js(\?.*)?$/, '');   // the js folder path
                notesFilePath = jsFileLocation + 'notes.html';
        }

        var notesPopup = window.open( notesFilePath, 'reveal.js - Notes', 'width=1100,height=700' );

        // Allow popup window access to Reveal API
        notesPopup.Reveal = this.Reveal;

        /**
         * Connect to the notes window through a postmessage handshake.
         * Using postmessage enables us to work in situations where the
         * origins differ, such as a presentation being opened from the
         * file system.
         */
        function connect() {
                // Keep trying to connect until we get a 'connected' message back
                var connectInterval = setInterval( function() {
                        notesPopup.postMessage( JSON.stringify( {
                                namespace: 'reveal-notes',
                                type: 'connect',
                                url: window.location.protocol + '//' + window.location.host + window.location.pathname + window.location.search,
                                state: Reveal.getState()
                        } ), '*' );
                }, 500 );

                window.addEventListener( 'message', function( event ) {
                        var data = JSON.parse( event.data );
                        if( data && data.namespace === 'reveal-notes' && data.type === 'connected' ) {
                                clearInterval( connectInterval );
                                onConnected();
                        }
                } );
        }

        /**
         * Posts the current slide data to the notes window
         */
        function post( event ) {

                var slideElement = Reveal.getCurrentSlide(),
                        notesElement = slideElement.querySelector( 'aside.notes' ),
                        fragmentElement = slideElement.querySelector( '.current-fragment' );

                var messageData = {
                        namespace: 'reveal-notes',
                        type: 'state',
                        notes: '',
                        markdown: false,
                        whitespace: 'normal',
                        state: Reveal.getState()
                };

                // Look for notes defined in a slide attribute
                if( slideElement.hasAttribute( 'data-notes' ) ) {
                        messageData.notes = slideElement.getAttribute( 'data-notes' );
                        messageData.whitespace = 'pre-wrap';
                }

                // Look for notes defined in a fragment
                if( fragmentElement ) {
                        var fragmentNotes = fragmentElement.querySelector( 'aside.notes' );
                        if( fragmentNotes ) {
                                notesElement = fragmentNotes;
                        }
                        else if( fragmentElement.hasAttribute( 'data-notes' ) ) {
                                messageData.notes = fragmentElement.getAttribute( 'data-notes' );
                                messageData.whitespace = 'pre-wrap';

                                // In case there are slide notes
                                notesElement = null;
                        }
                }

                // Look for notes defined in an aside element
                if( notesElement ) {
                        messageData.notes = notesElement.innerHTML;
                        messageData.markdown = typeof notesElement.getAttribute( 'data-markdown' ) === 'string';
                }

                notesPopup.postMessage( JSON.stringify( messageData ), '*' );

        }

        /**
         * Called once we have established a connection to the notes
         * window.
         */
        function onConnected() {

                // Monitor events that trigger a change in state
                Reveal.addEventListener( 'slidechanged', post );
                Reveal.addEventListener( 'fragmentshown', post );
                Reveal.addEventListener( 'fragmenthidden', post );
                Reveal.addEventListener( 'overviewhidden', post );
                Reveal.addEventListener( 'overviewshown', post );
                Reveal.addEventListener( 'paused', post );
                Reveal.addEventListener( 'resumed', post );

                // Post the initial state
                post();

        }

        connect();

}

if( !/receiver/i.test( window.location.search ) ) {

        // If the there's a 'notes' query set, open directly
        if( window.location.search.match( /(\?|\&)notes/gi ) !== null ) {
                openNotes();
        }

        // Open the notes when the 's' key is hit
        document.addEventListener( 'keydown', function( event ) {
                // Disregard the event if the target is editable or a
                // modifier is present
                if ( document.querySelector( ':focus' ) !== null || event.shiftKey || event.altKey || event.ctrlKey || event.metaKey ) return;

                // Disregard the event if keyboard is disabled
                if ( Reveal.getConfig().keyboard === false ) return;

                if( event.keyCode === 83 ) {
                        event.preventDefault();
                        openNotes();
                }
        }, false );

        // Show our keyboard shortcut in the reveal.js help overlay
        if( window.Reveal ) Reveal.registerKeyboardShortcut( 'S', 'Speaker notes view' );

}

return { open: openNotes };

})();