/*!
 * jquery scrollbox
 * (c) 2009-2013 hunter wu <hunter.wu@gmail.com>
 * mit licensed.
 *
 * http://github.com/wmh/jquery-scrollbox
 */

(function($) {

$.fn.scrollbox = function(config) {
  //default config
  var defconfig = {
    linear: false,          // scroll method
    startdelay: 2,          // start delay (in seconds)
    delay: 3,               // delay after each scroll event (in seconds)
    step: 5,                // distance of each single step (in pixels)
    speed: 32,              // delay after each single step (in milliseconds)
    switchitems: 1,         // items to switch after each scroll event
    direction: 'vertical',
    distance: 'auto',
    autoplay: true,
    onmouseoverpause: true,
    paused: false,
    queue: null
  };
  config = $.extend(defconfig, config);
  config.scrolloffset = config.direction === 'vertical' ? 'scrolltop' : 'scrollleft';
  if (config.queue) {
    config.queue = $('#' + config.queue);
  }

  return this.each(function() {
    var container = $(this),
        containerul,
        scrollingid = null,
        nextscrollid = null,
        paused = false,
        backward,
        forward,
        resetclock,
        scrollforward,
        scrollbackward;

    if (config.onmouseoverpause) {
      container.bind('mouseover', function() { paused = true; });
      container.bind('mouseout', function() { paused = false; });
    }
    containerul = container.children('ul:first-child');

    scrollforward = function() {
      if (paused) {
        return;
      }
      var curli,
          i,
          newscrolloffset,
          scrolldistance,
          thestep;

      curli = containerul.children('li:first-child');

      scrolldistance = config.distance !== 'auto' ? config.distance :
        config.direction === 'vertical' ? curli.height() : curli.width();

      // offset
      if (!config.linear) {
        thestep = math.max(3, parseint((scrolldistance - container[0][config.scrolloffset]) * 0.3, 10));
        newscrolloffset = math.min(container[0][config.scrolloffset] + thestep, scrolldistance);
      } else {
        newscrolloffset = math.min(container[0][config.scrolloffset] + config.step, scrolldistance);
      }
      container[0][config.scrolloffset] = newscrolloffset;

      if (newscrolloffset >= scrolldistance) {
        for (i = 0; i < config.switchitems; i++) {
          if (config.queue && config.queue.haschildnodes() && config.queue.getelementsbytagname('li').length > 0) {
            containerul.append(config.queue.getelementsbytagname('li')[0]);
            containerul.remove(containerul.children('li:first-child'));
          } else {
            containerul.append(containerul.children('li:first-child'));
          }
        }
        container[0][config.scrolloffset] = 0;
        clearinterval(scrollingid);
        if (config.autoplay) {
          nextscrollid = settimeout(forward, config.delay * 1000);
        }
      }
    };

    // backward
    // 1. if forwarding, then reverse
    // 2. if stoping, then backward once
    scrollbackward = function() {
      if (paused) {
        return;
      }
      var curli,
          i,
          lilen,
          newscrolloffset,
          scrolldistance,
          thestep;

      // init
      if (container[0][config.scrolloffset] === 0) {
        lilen = containerul.children('li').length;
        for (i = 0; i < config.switchitems; i++) {
          containerul.children('li:last-child').insertbefore(containerul.children('li:first-child'));
        }

        curli = container.children('li:first-child');
        scrolldistance = config.distance !== 'auto' ?
            config.distance :
            config.direction === 'vertical' ? curli.height() : curli.width();
        container[0][config.scrolloffset] = scrolldistance;
      }

      // new offset
      if (!config.linear) {
        thestep = math.max(3, parseint(container[0][config.scrolloffset] * 0.3, 10));
        newscrolloffset = math.max(container[0][config.scrolloffset] - thestep, 0);
      } else {
        newscrolloffset = math.max(container[0][config.scrolloffset] - config.step, 0);
      }
      container[0][config.scrolloffset] = newscrolloffset;

      if (newscrolloffset === 0) {
        clearinterval(scrollingid);
        if (config.autoplay) {
          nextscrollid = settimeout(forward, config.delay * 1000);
        }
      }
    };

    forward = function() {
      clearinterval(scrollingid);
      scrollingid = setinterval(scrollforward, config.speed);
    };

    backward = function() {
      clearinterval(scrollingid);
      scrollingid = setinterval(scrollbackward, config.speed);
    };

    resetclock = function(delay) {
      config.delay = delay || config.delay;
      cleartimeout(nextscrollid);
      if (config.autoplay) {
        nextscrollid = settimeout(forward, config.delay * 1000);
      }
    };

    if (config.autoplay) {
      nextscrollid = settimeout(forward, config.startdelay * 1000);
    }

    // bind events for container
    container.bind('resetclock', function(delay) { resetclock(delay); });
    container.bind('forward', function() { cleartimeout(nextscrollid); forward(); });
    container.bind('backward', function() { cleartimeout(nextscrollid); backward(); });
    container.bind('speedup', function(speed) {
      if (typeof speed === 'undefined') {
        speed = math.max(1, parseint(config.speed / 2, 10));
      }
      config.speed = speed;
    });
    container.bind('speeddown', function(speed) {
      if (typeof speed === 'undefined') {
        speed = config.speed * 2;
      }
      config.speed = speed;
    });
  });
};

}(jquery));