/**
 * Copyright (c) 2008, Canterbury City Council. All rights reserved.
 * aiwg@beerdragon.co.uk
 */

var _gis_area = document.getElementById ("gis_area");
var _gis_tilesW, _gis_tilesH;
var _gis_tile, _gis_imageurl;
var _gis_mousecapture, _gis_mouse_x, _gis_mouse_y, _gis_noclick;
var _gis_easting, _gis_northing, _gis_scale;
var _gis_pushpin_x, _gis_pushpin_y;
var _gis_onclick_url = null, _gis_onclick_xenc, _gis_onclick_yenc, _gis_onclick_zenc;
var _gis_onclick_ajax = null, _gis_onclick_js;
var _gis_area_x = 0, _gis_area_y = 0;

function _gis_compatible () {
  if (!document.documentElement && !document.body) return false;
  if (!_gis_area) return false;
  _gis_area.style.position = "relative";
  if (!_gis_area.offsetWidth || !_gis_area.offsetHeight) return false;
  if (!_gis_area.offsetLeft || !_gis_area.offsetTop) return false;
  var p = _gis_area;
  while (p != null) {
    _gis_area_x += p.offsetLeft;
    _gis_area_y += p.offsetTop;
    p = p.offsetParent;
  }
  return true;
}

function _gis_idiv (i, j) {
  return Math.floor (i / j);
}

function _gis_imul (i, j) {
  return Math.floor (i * j);
}

function _gis_refresh () {
  if (_gis_easting < 500000) _gis_easting = 500000; else
  if (_gis_easting > 700000) _gis_easting = 700000;
  if (_gis_northing < 100000) _gis_northing = 100000; else
  if (_gis_northing > 200000) _gis_northing = 200000;
  if (_gis_scale < 1000) _gis_scale = 1000; else
  if (_gis_scale > 250000) _gis_scale = 250000;
  mpp = 0.00026458333333333 * _gis_scale;
  leftE = _gis_easting - _gis_imul (_gis_area.offsetWidth / 2, mpp);
  tileW = _gis_imul (256, mpp);
  leftE2 = leftE % tileW;
  leftE -= leftE2;
  leftX = -_gis_idiv (leftE2, mpp);
  topN = _gis_northing + _gis_imul (_gis_area.offsetHeight / 2, mpp);
  tileH = _gis_imul (256, mpp);
  topN2 = topN % tileH;
  topN = topN - topN2;
  topY = _gis_idiv (topN2, mpp) - 256;
  x = leftX;
  e = leftE;
  url = _gis_imageurl + "z=" + _gis_scale + "&amp;";
  urlPin = (_gis_pushpin_x && _gis_pushpin_y) ? url + "px=" + _gis_pushpin_x + "&amp;py=" + _gis_pushpin_y + "&amp;" : 0;
  for (i = 0; i < _gis_tilesW; i++) {
    y = topY;
    n = topN;
    for (j = 0; j < _gis_tilesH; j++) {
      t = _gis_tile[i][j];
      if (urlPin) {
        mapurl = ((_gis_pushpin_x >= e - 30 * mpp) && (_gis_pushpin_x < e + tileW + 30 * mpp) && (_gis_pushpin_y >= n - 40 * mpp) && (_gis_pushpin_y < n + tileH + 40 * mpp)) ? urlPin : url;
      } else {
        mapurl = url;
      }
      if ((t.easting != e) || (t.northing != n) || (t.mapurl != mapurl)) {
        t.innerHTML = "<img src='" + (t.mapurl = mapurl) + "x=" + (t.easting = e) + "&amp;y=" + (t.northing = n) + "' width='256' height='256' />";
      }
      t.style.left = x + "px";
      t.style.top = y + "px";
      y += 256;
      n -= tileH;
    }
    x += 256;
    e += tileW;
  }
}

function _gis_mousedown (e) {
  if (e == null) if ((e = window.event) == null) return;
  var popup = document.getElementById ("gis_popup");
  if (popup && (popup.style.display == "block")) popup.style.display = "none";
  _gis_mousecapture = true;
  _gis_noclick = false;
  _gis_mouse_x = e.clientX;
  _gis_mouse_y = e.clientY;
  if (_gis_area.setCapture) _gis_area.setCapture ();
  _gis_area.style.cursor = "move";
}

function _gis_mouseup (e) {
  _gis_mousecapture = false;
  if (_gis_area.releaseCapture) {
    _gis_area.releaseCapture ();
  } else if (_gis_area.setCapture) {
    _gis_area.setCapture (false);
  }
  _gis_area.style.cursor = "auto";
}

function _gis_rotl (arr) {
  tmp = arr[0];
  for (i = 0; i < arr.length - 1; i++) {
    arr[i] = arr[i + 1];
  }
  arr[i] = tmp;
}

function _gis_rotr (arr) {
  tmp = arr[i = arr.length - 1];
  for (; i > 0; i--) {
    arr[i] = arr[i - 1];
  }
  arr[0] = tmp;
}

function _gis_mousemove (e) {
  if (!_gis_mousecapture) return;
  _gis_noclick = true;
  if (e == null) if ((e = window.event) == null) return;
  mpp = 0.00026458333333333 * _gis_scale;
  dx = _gis_imul (_gis_mouse_x - e.clientX, mpp);
  dy = _gis_imul (e.clientY - _gis_mouse_y, mpp);
  if ((dx == 0) || (dy == 0)) return;
  _gis_mouse_x = e.clientX;
  _gis_mouse_y = e.clientY;
  w1 = _gis_imul (_gis_area.offsetWidth / 2, mpp);
  xx = _gis_easting - w1;
  w2 = _gis_imul (256, mpp);
  x = _gis_idiv (xx - (xx % w2), w2);
  xx = (_gis_easting += dx) - w1;
  x -= _gis_idiv (xx - (xx % w2), w2);
  h1 = _gis_imul (_gis_area.offsetHeight / 2, mpp);
  yy = _gis_northing + h1;
  h2 = _gis_imul (256, mpp);
  y = _gis_idiv (yy - (yy % h2), h2);
  yy = (_gis_northing += dy) + h1;
  y -= _gis_idiv (yy - (yy % h2), h2);
  if (x < 0) {
    if (x > -_gis_tilesW) {
      while (x < 0) {
        _gis_rotl (_gis_tile);
        x++;
      }
    }
  } else if (x > 0) {
    if (x < _gis_tilesW) {
      while (x > 0) {
        _gis_rotr (_gis_tile);
        x--;
      }
    }
  }
  if (y < 0) {
    if (y > -_gis_tilesH) {
      while (y < 0) {
        for (j = 0; j < _gis_tilesW; j++) {
          _gis_rotr (_gis_tile[j]);
        }
        y++;
      }
    }
  } else if (y > 0) {
    if (y < _gis_tilesH) {
      while (y > 0) {
        for (j = 0; j < _gis_tilesW; j++) {
          _gis_rotl (_gis_tile[j]);
        }
        y--;
      }
    }
  }
  _gis_refresh ();
}

function _gis_onclick (e) {
  if (_gis_noclick) return;
  if (e == null) if ((e = window.event) == null) return;
  mpp = 0.00026458333333333 * _gis_scale;
  x = _gis_easting + _gis_imul ((e.pageX ? e.pageX : (e.clientX + (document.documentElement ? document.documentElement : document.body).scrollLeft)) - _gis_area_x - _gis_area.offsetWidth / 2, mpp);
  y = _gis_northing + _gis_imul (_gis_area.offsetHeight / 2 - ((e.pageY ? e.pageY : (e.clientY + (document.documentElement ? document.documentElement : document.body).scrollTop)) - _gis_area_y), mpp);
  gis_getdata (x, y);
}

function gis_getdata (easting, northing) {
  url = (_gis_onclick_url != null) ? _gis_onclick_url.replace (_gis_onclick_xenc, easting).replace (_gis_onclick_yenc, northing).replace (_gis_onclick_zenc, _gis_scale) : null;
  if (_gis_onclick_ajax != null) {
    req = null;
    if (typeof XMLHttpRequest != "undefined") {
      req = new XMLHttpRequest ();
    } else if (window.ActiveXObject) {
      req = new ActiveXObject ("Microsoft.XMLHTTP");
    } else {
      _gis_onclick_ajax = null;
    }
    if (req != null) {
      req.onreadystatechange = function (_req) {
        return function () {
	  if (_req.readyState == 4) {
            //document.write (_req.responsetext);
           // _gis_onclick_js (_req.responsetext);
            _gis_onclick_js (_req.responseXML.documentElement.childNodes[0].nodeValue, url);
          }
	};
      } (req);
      req.open ("GET", _gis_onclick_ajax + "&x=" + easting + "&y=" + northing + "&z=" + _gis_scale, true);
      req.send (null);
      return;
    }
  }
  if (url != null) document.location = url;
}

function gis_zoomin () {
  if (_gis_scale > 250000) _gis_scale=250000; else
if (_gis_scale > 200000) _gis_scale=200000; else
if (_gis_scale > 150000) _gis_scale=150000; else
if (_gis_scale > 100000) _gis_scale=100000; else
if (_gis_scale > 50000) _gis_scale=50000; else
if (_gis_scale > 25000) _gis_scale=25000; else
if (_gis_scale > 10000) _gis_scale=10000; else
if (_gis_scale > 5000) _gis_scale=5000; else
if (_gis_scale > 2500) _gis_scale=2500; else
if (_gis_scale > 1000) _gis_scale=1000; else
  return;
  _gis_refresh ();
}

function gis_setzoom (scale) {
  _gis_scale = scale + 1;
  gis_zoomin ();
}

function gis_getzoom () {
  return _gis_scale;
}

function gis_zoomout () {
  if (_gis_scale < 1000) _gis_scale=1000; else
if (_gis_scale < 2500) _gis_scale=2500; else
if (_gis_scale < 5000) _gis_scale=5000; else
if (_gis_scale < 10000) _gis_scale=10000; else
if (_gis_scale < 25000) _gis_scale=25000; else
if (_gis_scale < 50000) _gis_scale=50000; else
if (_gis_scale < 100000) _gis_scale=100000; else
if (_gis_scale < 150000) _gis_scale=150000; else
if (_gis_scale < 200000) _gis_scale=200000; else
if (_gis_scale < 250000) _gis_scale=250000; else
  return;
  _gis_refresh ();
}

function _gis_init (params, easting, northing, scale, pushpin, search) {
  _gis_area.style.overflow = "hidden";
  _gis_area.style.maxHeight = _gis_area.style.height = _gis_area.offsetHeight + "px";
  _gis_imageurl = "/cgi-bin/authority/gis/planningapps?mode=map&" + params;
  _gis_easting = easting;
  _gis_northing = northing;
  _gis_scale = scale;
  _gis_pushpin_x = pushpin ? easting : 0;
  _gis_pushpin_y = pushpin ? northing : 0;
  html = "<div><a href=\"javascript:gis_zoomin()\" title=\"Zoom in\"><img src=\"/authority/gis/zoomin.gif\" alt=\"Zoom in\" /></a><br /><a href=\"javascript:gis_zoomout()\" title=\"Zoom out\"><img src=\"/authority/gis/zoomout.gif\" alt=\"Zoom out\" /></a>";
  if (search) html = html + "<br /><label for=\"gis_search\"><a href=\"javascript:_gis_search()\" title=\"Search\"><img src=\"/authority/gis/search.gif\" alt=\"Search\" /></a></label>";
  html = html + "</div>";
  if (search) html = html + "<div id=\"gis_popup\"><form method=\"POST\" action=\"\" onsubmit=\"return _gis_searchgo()\"><input type=\"text\" name=\"search\" value=\"\" id=\"gis_search\" /><input type=\"submit\" value=\"Go!\" /></form></div>";
  document.getElementById ("gis_control").innerHTML = html;
  html = "";
   _gis_area.onmousedown = _gis_mousedown;
  _gis_area.onmouseup = _gis_mouseup;
  _gis_area.onmousemove = _gis_mousemove;
  _gis_area.onclick = _gis_onclick;
  _gis_tilesW = _gis_idiv (_gis_area.offsetWidth + 255, 256) + 1;
  _gis_tilesH = _gis_idiv (_gis_area.offsetHeight + 255, 256) + 1;
  n = 0;
  _gis_tile = new Array (_gis_tilesW);
  for (i = 0; i < _gis_tilesW; i++) {
    _gis_tile[i] = new Array (_gis_tilesH);
    for (j = 0; j < _gis_tilesH; j++) {
      html = html + "<div class=\"gis_tile\" id=\"gis_div" + (++n) + "\"></div>"
    }
  }
  _gis_area.innerHTML = html;
  n = 0;
  for (i = 0; i < _gis_tilesW; i++) {
    for (j = 0; j < _gis_tilesH; j++) {
      t = document.getElementById ("gis_div" + (++n));
      t.style.width = 256 + "px";
      t.style.height = 256 + "px";
      t.innerHTML = "&nbsp;";
      _gis_tile[i][j] = t;
    }
  }
  _gis_refresh ();
}

function gis_setpushpin (easting, northing) {
  _gis_pushpin_x = easting;
  _gis_pushpin_y = northing;
  _gis_refresh ();
}

function gis_clearpushpin () {
  _gis_pushpin_x = 0;
  _gis_pushpin_y = 0;
  _gis_refresh ();
}

function _gis_search () {
  var popup = document.getElementById ("gis_popup");
  if (popup) popup.style.display = "block";
  var input = document.getElementById ("gis_search");
  input.focus ();
}

function _gis_searchgo () {
  var popup = document.getElementById ("gis_popup");
  if (popup) popup.style.display = "none";
  var input = document.getElementById ("gis_search");
  qstring = input.value;
  qstring = qstring.replace ("%", "%25").replace ("&", "%26").replace ("=", "%3D");
  document.location = _gis_onclick_url.replace (_gis_onclick_xenc, _gis_easting).replace (_gis_onclick_yenc, _gis_northing).replace (_gis_onclick_zenc, _gis_scale) + "&search=" + qstring;
  //TODO: could use the ajaxsearch= callback to handle this if available and display the results
  return false;
}