/**
* author Remy Sharp
* url http://remysharp.com/tag/marquee
*/

(function ($) {
    $.fn.marquee = function (klass) {
        var newMarquee = [],
            last = this.length;

        // works out the left or right hand reset position, based on scroll
        // behavior, current direction and new direction
        function getReset(newDir, behavior, marqueeRedux, width, dir) {
            var r = 0;
            if (behavior == 'alternate') {
                r = newDir == 1 ? marqueeRedux.scrollWidth - (width*2) : width;
            } else if (behavior == 'slide') {
                if (newDir == -1) {
                    r = dir == -1 ? marqueeRedux.scrollWidth : width;
                } else {
                    r = dir == -1 ? marqueeRedux.scrollWidth - (width*2) : 0;
                }
            } else {
                r = newDir == -1 ? marqueeRedux.scrollWidth : 0;
            }
            return r;
        }

        // single "thread" animation
        function animateMarquee() {
            var i = newMarquee.length,
                marqueeRedux = null,
                $marqueeRedux = null,
                marqueeState = {},
                newMarqueeList = [],
                hitedge = false;
                
            while (i--) {
                marqueeRedux = newMarquee[i];
                $marqueeRedux = $(marqueeRedux);
                marqueeState = $marqueeRedux.data('marqueeState');
                
                if ($marqueeRedux.data('paused') !== true) {
                    // TODO read scrollamount, dir, behavior, loops and last from data
                    marqueeRedux.scrollLeft += (marqueeState.scrollamount * marqueeState.dir);

                    // only true if it's hit the end
                    hitedge = marqueeState.dir == -1 ? marqueeRedux.scrollLeft <= getReset(marqueeState.dir * -1, marqueeState.behavior, marqueeRedux, marqueeState.width, marqueeState.dir) : marqueeRedux.scrollLeft >= getReset(marqueeState.dir * -1, marqueeState.behavior, marqueeRedux, marqueeState.width, marqueeState.dir);

                    if ((marqueeState.behavior == 'scroll' && marqueeState.last == marqueeRedux.scrollLeft) || (marqueeState.behavior == 'alternate' && hitedge && marqueeState.last != -1) || (marqueeState.behavior == 'slide' && hitedge && marqueeState.last != -1)) {
                        if (marqueeState.behavior == 'alternate') {
                            marqueeState.dir *= -1; // flip
                        }
                        marqueeState.last = -1;

                        $marqueeRedux.trigger('stop');

                        marqueeState.loops--;
                        if (marqueeState.loops === 0) {
                            if (marqueeState.behavior != 'slide') {
                                marqueeRedux.scrollLeft = getReset(marqueeState.dir, marqueeState.behavior, marqueeRedux, marqueeState.width, marqueeState.dir);
                            } else {
                                // corrects the position
                                marqueeRedux.scrollLeft = getReset(marqueeState.dir * -1, marqueeState.behavior, marqueeRedux, marqueeState.width, marqueeState.dir);
                            }

                            $marqueeRedux.trigger('end');
                        } else {
                            // keep this marquee going
                            newMarqueeList.push(marqueeRedux);
                            $marqueeRedux.trigger('start');
                            marqueeRedux.scrollLeft = getReset(marqueeState.dir, marqueeState.behavior, marqueeRedux, marqueeState.width, marqueeState.dir);
                        }
                    } else {
                        newMarqueeList.push(marqueeRedux);
                    }
                    marqueeState.last = marqueeRedux.scrollLeft;

                    // store updated state only if we ran an animation
                    $marqueeRedux.data('marqueeState', marqueeState);
                } else {
                    // even though it's paused, keep it in the list
                    newMarqueeList.push(marqueeRedux);                    
                }
            }

            newMarquee = newMarqueeList;
            
            if (newMarquee.length) {
                setTimeout(animateMarquee, 25);
            }            
        }
        
        // TODO consider whether using .html() in the wrapping process could lead to loosing predefined events...
        this.each(function (i) {
            var $marquee = $(this),
                width = $marquee.attr('width') || $marquee.width(),
                $marqueeRedux = $marquee.after('<div ' + (klass ? 'class="' + klass + '" ' : '') + 'style="display: block-inline; width: ' + width + 'px; overflow: hidden;"><div style="padding: 0 ' + width + 'px; float: left; white-space: nowrap;">' + $marquee.html() + '</div></div>').next(),
                marqueeRedux = $marqueeRedux.get(0),
                hitedge = 0,
                marqueeState = {
                    dir : $marquee.attr('direction') == 'right' ? -1 : 1,
                    last : -1,
                    loops : $marquee.attr('loop') || -1,
                    scrollamount : $marquee.attr('scrollamount') || this.scrollAmount || 2,
                    behavior : ($marquee.attr('behavior') || 'scroll').toLowerCase(),
                    width : width
                };
            
            $marquee.remove();            
            
            // events
            $marqueeRedux.bind('stop', function () {
                $marqueeRedux.data('paused', true);
            }).bind('pause', function () {
                $marqueeRedux.data('paused', true);
            }).bind('start', function () {
                $marqueeRedux.data('paused', false);
            }).bind('unpause', function () {
                $marqueeRedux.data('paused', false);
            }).data('marqueeState', marqueeState); // finally: store the state
            
            // todo - rerender event allowing us to do an ajax hit and redraw the marquee

            newMarquee.push(marqueeRedux);

            marqueeRedux.scrollLeft = getReset(marqueeState.dir, marqueeState.behavior, marqueeRedux, marqueeState.width, marqueeState.dir);
            $marqueeRedux.trigger('start');
            
            // on the very last marquee, trigger the animation
            if (i+1 == last) {
                animateMarquee();
            }
        });            

        return $(newMarquee);
    };
}(jQuery));