$(function () {

    function slideSeparatorLines(text) {
        var lines = text.split('\n');

        var separatorLineNumbers = [];

        for (i = 0; i < lines.length; i++) {
            var line = lines[i];
            if (line === '---') {
                separatorLineNumbers.push(i);
            }
        }

        return separatorLineNumbers;
    }

    function currentCursorSlide(cursorLine) {
        var text = ace.edit("editor").getValue();
        var separatorPositions = slideSeparatorLines(text);
        var slideNumber = separatorPositions.length;
        separatorPositions.every(function (pos, num) {
            if (pos >= cursorLine) {
                slideNumber = num;
                return false;
            }
            return true;
        });
        return slideNumber;
    }


    var editor = ace.edit("editor");
    editor.setTheme("ace/theme/chrome");
    editor.getSession().setMode("ace/mode/markdown");
    editor.getSession().setUseWrapMode(true);
    editor.setShowPrintMargin(true);
    $.get('/slides.md', function (data) {
        editor.setValue(data, -1);
    });
    var lastSRow = -1;
    ace.edit('editor').getSession().selection.on('changeCursor', function (e) {
        var cursorRow = ace.edit('editor').getCursorPosition().row;
        if (lastSRow === cursorRow) {
            return; // no update
        }
        lastSRow = cursorRow;
        var currentSlide = currentCursorSlide(cursorRow);
        $('#slides-frame')[0].contentWindow.postMessage(JSON.stringify({
            method: 'slide',
            args: [currentSlide]
        }), window.location.origin);
    });
});