/**
 *	ImageFlow 0.8
 *
 *	This code is based on Michael L. Perrys Cover flow in Javascript.
 *	For he wrote that "You can take this code and use it as your own" [1]
 *	this is my attempt to improve some things. Feel free to use it! If
 *	you have any questions on it leave me a message in my shoutbox [2].
 *
 *	The reflection is generated server-sided by a slightly hacked
 *	version of Richard Daveys easyreflections [3] written in PHP.
 *
 *	The mouse wheel support is an implementation of Adomas Paltanavicius
 *	JavaScript mouse wheel code [4].
 *
 *	Thanks to Stephan Droste ImageFlow is now compatible with Safari 1.x.
 *
 *
 *	[1] http://www.adventuresinsoftware.com/blog/?p=104#comment-1981
 *	[2] http://shoutbox.finnrudolph.de/
 *	[3] http://reflection.corephp.co.uk/v2.php
 *	[4] http://adomas.org/javascript-mouse-wheel/
 */

/* Configuration variables */
var conf_reflection_p = 0.5;         // Sets the height of the reflection in % of the source image
var conf_focus = 3;                  // Sets the numbers of images on each side of the focussed one
var conf_slider_width = 14;          // Sets the px width of the slider div
var conf_images_cursor = 'pointer';  // Sets the cursor type for all images default is 'default'
var conf_slider_cursor = 'default';  // Sets the slider cursor type: try "e-resize" default is 'default'

/* Id names used in the HTML */
var conf_imageflow = 'imageflow';    // Default is 'imageflow'
var conf_loading = 'if_loading';        // Default is 'loading'
var conf_images = 'if_images';          // Default is 'images'
var conf_captions = 'if_captions';      // Default is 'captions'
var conf_scrollbar = 'if_scrollbar';    // Default is 'scrollbar'
var conf_slider = 'if_slider';          // Default is 'slider'
var conf_ext_captions = 'if_ext_captions';      // Default is 'captions'

/* Define global variables */
var caption_id = 0;
var new_caption_id = 0;
var current = 0;
var target = 0;
var mem_target = 0;
var timer = 0;
var array_images = new Array();
var new_slider_pos = 0;
var dragging = false;
var dragobject = null;
var dragx = 0;
var posx = 0;
var new_posx = 0;
var xstep = 150;
var max;

function step() {
  switch (target < current-1 || target > current+1) {
    case true:
      moveTo(current + (target-current)/3);
      window.setTimeout(step, 50);
      timer = 1;
      break;

    default:
      timer = 0;
      break;
  }
}

function glideTo(x, new_caption_id) {
  /* Animate gliding to new x position */
  target = x;
  mem_target = x;
  if (timer == 0) {
    window.setTimeout(step, 50);
    timer = 1;
  }
  /* Display new caption */
  caption_id = new_caption_id;
  var caption;
  if (img_div) {
    caption = img_div.childNodes.item(array_images[caption_id]).getAttribute('alt');
  }
  if (caption == '') caption = '&nbsp;';
  caption_div.innerHTML = caption;
/*
  // fle
  if (img_div.childNodes.item(array_images[caption_id]).getAttribute('id'))
    ext_caption = document.getElementById('mitarbeiter_' + img_div.childNodes.item(array_images[caption_id]).getAttribute('id')).innerHTML; // fle
  else
    ext_caption = '&nbsp;';
  if (ext_caption == '') ext_caption = '&nbsp;';
  ext_caption_div.innerHTML = ext_caption;
  // fle ende
*/

  /* Set scrollbar slider to new position */
  if (dragging == false) 	{
    new_slider_pos = (scrollbar_width * (-(x*100/((max-1)*xstep))) / 100) - new_posx;
    slider_div.style.marginLeft = (new_slider_pos - conf_slider_width) + 'px';
  }
}

function moveTo(x) {
  current = x;
  var zIndex = max;

  /* Main loop */
  for (var index = 0; index < max; index++) 	{
    var image = img_div.childNodes.item(array_images[index]);
    var current_image = index * -xstep;

    if (!image.h) { image.h = image.height; }
    if (!image.w) { image.w = image.width; }

    /* Don't display images that are not conf_focussed */
    if ((current_image+max_conf_focus) < mem_target || (current_image-max_conf_focus) > mem_target) 	{
      image.style.visibility = 'hidden';
      image.style.display = 'none';
    }
    else {
      var z = Math.sqrt(10000 + x * x) + 100;
      var xs = x / z * size + size;

      /* Still hide images until they are processed, but set display style to block */
      image.style.display = 'block';

      /* Process new image height and image width */
      var new_img_h = (image.h / image.w * image.pc) / z * size;
      switch ( new_img_h > max_height ) {
        case false:
          var new_img_w = image.pc / z * size;
          break;

        default:
          new_img_h = max_height;
          var new_img_w = image.w * new_img_h / image.h;
          break;
      }
      var new_img_top = (images_width * 0.34 - new_img_h) + images_top + ((new_img_h / (conf_reflection_p + 1)) * conf_reflection_p);

      /* Set new image properties */
      image.style.left = xs - (image.pc / 2) / z * size + images_left + 'px';
      image.style.height = new_img_h + 'px';
      image.style.width = new_img_w + 'px';
      image.style.top = new_img_top + 'px';
      image.style.visibility = 'visible';

      /* Set image layer through zIndex */
      switch ( x < 0 ) {
        case true:
          zIndex++;
          break;

        default:
          zIndex = zIndex - 1;
          break;
      }

      /* Change zIndex and onclick function of the focussed image */
      switch ( image.i == caption_id ) {
        case false:
          image.onclick = function() { glideTo(this.x_pos, this.i); }
          break;

        default:
          zIndex = zIndex + 1;
          //image.onclick = function() { document.location = this.url; }
          image.onclick = function() {};
          break;
      }
      image.style.zIndex = zIndex;
    }
    x += xstep;
  }
}

/* Main function */
function refresh(onload) {
  /* Cache document objects in global variables */
  imageflow_div = document.getElementById(conf_imageflow);
  img_div = document.getElementById(conf_images);
  max = img_div.getElementsByTagName('img').length;
  scrollbar_div = document.getElementById(conf_scrollbar);
  slider_div = document.getElementById(conf_slider);
  caption_div = document.getElementById(conf_captions);

  /* Cache global variables, that only change on refresh */
  images_width = img_div.offsetWidth;
  images_top = imageflow_div.offsetTop;
  images_left = imageflow_div.offsetLeft - 50;
  max_conf_focus = conf_focus * xstep;
  size = images_width * 0.5;
  scrollbar_width = images_width * 0.6;
  conf_slider_width = conf_slider_width * 0.5;
  max_height = images_width * 0.51;

  /* Change imageflow div properties */
  imageflow_div.style.height = max_height + 'px';

  /* Change images div properties */
  img_div.style.height = images_width * 0.338 + 'px';

  /* Change captions div properties */
  caption_div.style.width = images_width + 'px';
  caption_div.style.marginTop = images_width * 0.03 + 'px';

  /* Change scrollbar div properties */
  scrollbar_div.style.marginTop = images_width * 0.02 + 'px';
  scrollbar_div.style.marginLeft = images_width * 0.2 + 'px';
  scrollbar_div.style.width = scrollbar_width + 'px';

  /* Set slider attributes */
  slider_div.onmousedown = function () { dragstart(this); };
  /*slider_div.style.cursor = conf_slider_cursor;*/

  /* Cache EVERYTHING! */
  max = img_div.childNodes.length;
  var i = 0;
  for (var index = 0; index < max; index++) {
    var image = img_div.childNodes.item(index);
    if (image.nodeType == 1) {
      array_images[i] = index;

      /* Set image onclick by adding i and x_pos as attributes! */
      image.onclick = function() { glideTo(this.x_pos, this.i); }
      image.x_pos = (-i * xstep);
      image.i = i;

      /* Add width and height as attributes ONLY once onload */
      if(onload == true) {
        image.w = image.width;
        image.h = image.height;
      }

      /* Check source image format. Get image height minus reflection height! */
      switch ((image.w + 1) > (image.h / (conf_reflection_p + 1))) {
        /* Landscape format */
        case true:
          image.pc = 118;
          break;

        /* Portrait and square format */
        default:
          image.pc = 100;
          break;
      }

      /* Set ondblclick event */
      //image.url = image.getAttribute('longdesc');
      //image.ondblclick = function() { document.location = this.url; }
      image.ondblclick = function() {};

      /* Set image cursor type */
      image.style.cursor = conf_images_cursor;

      i++;
    }
  }
  max = array_images.length;

  if(onload == true) {
    return false;
  }
  /* Display images in current order */
  moveTo(current);
  glideTo(current, caption_id);
}

/* Show/hide element functions */
function show(id) {
  var element = document.getElementById(id);
  element.style.visibility = 'visible';
}
function hide(id) {
  var element = document.getElementById(id);
  element.style.visibility = 'hidden';
  element.style.display = 'none';
}

/* Refresh ImageFlow on window resize */
window.onresize = function() {
  if(document.getElementById(conf_imageflow)) refresh();
}

/* Handle the wheel angle change (delta) of the mouse wheel */
function handle(delta) {
  var change = false;
  switch (delta > 0) {
    case true:
      if(caption_id >= 1) {
        target = target + xstep;
        new_caption_id = caption_id - 1;
        change = true;
      }
      break;

    default:
      if(caption_id < (max-1))
      {
        target = target - xstep;
        new_caption_id = caption_id + 1;
        change = true;
      }
      break;
  }

  /* Glide to next (mouse wheel down) / previous (mouse wheel up) image */
  if (change == true) {
    glideTo(target, new_caption_id);
  }
}

/* Event handler for mouse wheel event */
function wheel(event) {
  var delta = 0;
  if (!event) event = window.event;
  if (event.wheelDelta) {
    delta = event.wheelDelta / 120;
  }
  else if (event.detail) {
    delta = -event.detail / 3;
  }
  if (delta) handle(delta);
  if (event.preventDefault) event.preventDefault();
  event.returnValue = false;
}

/* Initialize mouse wheel event listener */
function initMouseWheel() {
  if(window.addEventListener) imageflow_div.addEventListener('DOMMouseScroll', wheel, false);
  imageflow_div.onmousewheel = wheel;
}

/* This function is called to drag an object (= slider div) */
function dragstart(element) {
  dragobject = element;
  dragx = posx - dragobject.offsetLeft + new_slider_pos;
}

/* This function is called to stop dragging an object */
function dragstop() {
  dragobject = null;
  dragging = false;
}

/* This function is called on mouse movement and moves an object (= slider div) on user action */
function drag(e) {
  posx = document.all ? window.event.clientX : e.pageX;
  if(dragobject != null) {
    dragging = true;
    new_posx = (posx - dragx) + conf_slider_width;

    /* Make sure, that the slider is moved in proper relation to previous movements by the glideTo function */
    if(new_posx < ( - new_slider_pos)) new_posx = - new_slider_pos;
    if(new_posx > (scrollbar_width - new_slider_pos)) new_posx = scrollbar_width - new_slider_pos;

    var slider_pos = (new_posx + new_slider_pos);
    var step_width = slider_pos / ((scrollbar_width) / (max-1));
    var image_number = Math.round(step_width);
    var new_target = (image_number) * -xstep;
    var new_caption_id = image_number;

    dragobject.style.left = new_posx + "px";
    glideTo(new_target, new_caption_id);
  }
}

/* Initialize mouse event listener */
function initMouseDrag() {
  document.onmousemove = drag;
  document.onmouseup = dragstop;
}

function getKeyCode(event) {
  event = event || window.event;
  return event.keyCode;
}

document.onkeydown = function(event) {
  var charCode  = getKeyCode(event);
  switch (charCode)
  {
    /* Right arrow key */
    case 39:
      handle(-1);
      break;

    /* Left arrow key */
    case 37:
      handle(1);
      break;
  }
}