// vim: et:ts=4:sw=4:sts=4:ft=js

/*@
Ox.SyntaxHighlighter <function> Syntax Highlighter
    (options[, self]) -> <o> Syntax Highlighter
    options <o> Options
        offset <n|1> First line number
        showLineNumbers <b|false> If true, show line numbers
        showLinebreaks <b|false> If true, show linebreaks
        showWhitespace <b|false> If true, show whitespace
        stripComments <b|false> If true, strip comments
    self <o> Shared private 
@*/

Ox.SyntaxHighlighter = function(options, self) {

 	self = self || {}; 
    var that = Ox.Element({}, self)
            .defaults({
                height: 40,
                lineLength: 80,         //@ number of characters per line
                offset: 1,              //@ first line number
                showLineNumbers: false,
                showLinebreaks: false,  //@ show linebreak symbols
                showTabs: false,        //@ show tab symbols
                showWhitespace: false,  //@ show irregular leading or trailing whitespace
                source: '',             //@ JavaScript source
                stripComments: false,   //@ strip all comments
                stripLinebreaks: false, //@ strip multiple linebreaks, NOT IMPLEMENTED
                stripWhitespace: false, //@ strip all whitespace, NOT IMPLEMENTED
                tabLength: 4,           //@ number of spaces per tab
                width: 80
            })
            .options(options || {})
            .addClass('OxSyntaxHighlighter');

    renderSource();

    function renderSource() {
        var lines, source = '', tokens,
            linebreak = (
                self.options.showLinebreaks ? 
                '<span class="OxLinebreak">\u21A9</span>' : ''
            ) + '<br/>',
            tab = (
                self.options.showTabs ?
                '<span class="OxTab">\u2192</span>' : ''
            ) + Ox.repeat('&nbsp;', self.options.tabLength - self.options.showTabs),
            whitespace = self.options.showWhitespace ? '\u00B7' : '&nbsp;';
        self.options.source = self.options.source
            .replace(/\r\n/g, '\n')
            .replace(/\r/g, '\n');
        tokens = Ox.tokenize(self.options.source);
        tokens.forEach(function(token, i) {
            var classNames,
                substr = self.options.source.substr(token.offset, token.length);
            if (
                !(self.options.stripComments && token.type == 'comment')
            ) {
                classNames = 'Ox' + Ox.toTitleCase(token.type);
                if (self.options.showWhitespace && token.type == 'whitespace') {
                    if (isAfterLinebreak() && hasIrregularSpaces()) {
                        classNames += ' OxLeading'
                    } else if (isBeforeLinebreak()) {
                        classNames += ' OxTrailing'
                    }
                }
                source += '<span class="' + classNames + '">' +
                    Ox.encodeHTML(substr)
                    .replace(/ /g, whitespace)
                    .replace(/\t/g, tab)
                    .replace(/\n/g, linebreak) + '</span>';
            }
            function isAfterLinebreak() {
                return i == 0 ||
                    tokens[i - 1].type == 'linebreak';
            }
            function isBeforeLinebreak() {
                return i == tokens.length - 1 ||
                    tokens[i + 1].type == 'linebreak';
            }
            function hasIrregularSpaces() {
                return substr.split('').reduce(function(prev, curr) {
                    return prev + (curr == ' ' ? 1 : 0);
                }, 0) % self.options.tabLength;
            }
        });
        lines = source.split('<br/>');
        that.empty();
        ///*
        var $test = new Ox.Element()
            .css({
                position: 'absolute',
                top: '-1000px'
            })
            .html(Ox.repeat('&nbsp;', self.options.lineLength))
            .appendTo(that);
        var width = $test.width() + 4; // add padding
        $test.removeElement();
        //*/
        if (self.options.showLineNumbers) {
            self.$lineNumbers = new Ox.Element()
                .addClass('OxLineNumbers')
                .html(
                    Ox.range(lines.length).map(function(line) {
                        return (line + self.options.offset);
                    }).join('<br/>')
                )
                .appendTo(that);
        }
        self.$source = new Ox.Element()
            .addClass('OxSourceCode')
            .css({
                background: '-moz-linear-gradient(left, rgb(255, 255, 255), rgb(255, 255, 255) ' +
                    width + 'px, rgb(248, 248, 248) ' + width + 'px, rgb(248, 248, 248))'
            })
            .css({
                background: '-webkit-linear-gradient(left, rgb(255, 255, 255) ' +
                    width + 'px, rgb(192, 192, 192) ' + width + 'px, rgb(255, 255, 255) ' +
                    (width + 1) + 'px)'
            })
            .html(source)
            .appendTo(that);
    }

    self.setOption = function(key, value) {
        renderSource();
    };

    return that;

};