// DEPRECATED:
//   see http://code.google.com/p/earth-api-utility-library
//
//   specifically GEarthExtensions#dom.computeBounds and
//                GEarthExtensions#view.createBoundsView

/*
Copyright 2009 Google Inc.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

function getObjectCoordData(ge, kmlObject) {
  var out = {
    'coords': [],
    'altitudeMode': -1,
    'maxAltitude': -9999
  };

  function pushLatLngAlt(lat, lng, alt) {
    out.coords.push({
      lat: lat,
      lng: lng,
      alt: alt
    });

    out.maxAltitude = Math.max(out.maxAltitude, alt);
  }
  
  function pushCoord(pointOrCoord) {
    pushLatLngAlt(pointOrCoord.getLatitude(), pointOrCoord.getLongitude(),
                  pointOrCoord.getAltitude());
  }
  
  function pushChildCall(retval, altitudeMode) {
    out.coords = out.coords.concat(retval.coords);
    out.maxAltitude = Math.max(out.maxAltitude, retval.maxAltitude);
    
    // stop at first altitudeMode, so if it's already set, don't update it
    if (out.altitudeMode == -1)
      out.altitudeMode = retval.altitudeMode;
  }
  
  // extract the points from the given object
  if (kmlObject && 'getType' in kmlObject) {
    if (out.altitudeMode == -1 && 'getAltitudeMode' in kmlObject)
      out.altitudeMode = kmlObject.getAltitudeMode();
    
    switch (kmlObject.getType()) {
      // features
      case 'KmlFolder':
      case 'KmlDocument':
        var children = kmlObject.getFeatures().getChildNodes();
        var numChildren = children.getLength();
        for (var i = 0; i < numChildren; i++)
          pushChildCall(getObjectCoordData(ge, children.item(i)));
        break;
      
      case 'KmlPlacemark':
        if ('getGeometry' in kmlObject)
          return getObjectCoordData(ge, kmlObject.getGeometry());
        break;

      case 'KmlGroundOverlay':
        var latLonBox = kmlObject.getLatLonBox();
        var alt = kmlObject.getAltitude();
        pushLatLngAlt(latLonBox.getNorth(), latLonBox.getEast(), alt);
        pushLatLngAlt(latLonBox.getNorth(), latLonBox.getWest(), alt);
        pushLatLngAlt(latLonBox.getSouth(), latLonBox.getEast(), alt);
        pushLatLngAlt(latLonBox.getSouth(), latLonBox.getWest(), alt);
        break;
      
      // geometries
      case 'KmlMultiGeometry':
        var children = kmlObject.getGeometries().getChildNodes();
        var numChildren = children.getLength();
        for (var i = 0; i < numChildren; i++)
          pushChildCall(getObjectCoordData(ge, children.item(i)));
        break;

      case 'KmlModel':
        pushCoord(kmlObject.getLocation());
        break;
      
      case 'KmlPolygon':
        pushChildCall(getObjectCoordData(ge, kmlObject.getOuterBoundary()));
        break;
      
      case 'KmlLinearRing':
      case 'KmlLineString':
        var coordsObj = kmlObject.getCoordinates();
        var n = coordsObj.getLength();
        for (var i = 0; i < n; i++)
          pushCoord(coordsObj.get(i));
        break;
      
      case 'KmlCoord': // coordinates
      case 'KmlLocation': // models
      case 'KmlPoint': // points
        pushCoord(kmlObject);
        break;
    }
  }
  
  return out;
}

function computeFitLookAt(ge, obj, aspectRatio) {
  var DEGREES = Math.PI / 180;
  var EARTH_RADIUS = 6378137;
  
  var coordData = getObjectCoordData(ge, obj);

  if ('getAbstractView' in obj) {
    var la = obj.getAbstractView();
    if (la != null)
      return la;
  }
  
  if (coordData.coords.length) {
    // range calculation -- the hard part
    var center = null;
    var range = 0.0;
    if (coordData.coords.length == 1) {
      center = new google.maps.LatLng(coordData.coords[0].lat,
                                      coordData.coords[0].lng);
      range = 1000;
    } else {
      // compute bbox
      var bounds = new google.maps.LatLngBounds();
      for (var i = 0; i < coordData.coords.length; i++)
        bounds.extend(new google.maps.LatLng(coordData.coords[i].lat,
                                             coordData.coords[i].lng));
      
      // find center
      center = bounds.getCenter();
      var sw = bounds.getSouthWest();
      var ne = bounds.getNorthEast();
    
      var lngSpan = new google.maps.LatLng(center.lat(), sw.lng()).
        distanceFrom(new google.maps.LatLng(center.lat(), ne.lng()));
      var latSpan = new google.maps.LatLng(sw.lat(), center.lng()).
        distanceFrom(new google.maps.LatLng(ne.lat(), center.lng()));
    
      if (!aspectRatio)
        aspectRatio = 1.0;
    
      var PAD_FACTOR = 1.5; // add 50% to the computed range for padding
      var beta;
      
      var aspectUse = Math.max(aspectRatio, Math.min(1.0, lngSpan / latSpan));
      
       // computed experimentally;
      var alpha = (45.0 / (aspectUse + 0.4) - 2.0) * DEGREES;
      
      // create LookAt using distance formula
      if (lngSpan > latSpan) {
        // polygon is wide
        beta = Math.min(90 * DEGREES, alpha + lngSpan / 2 / EARTH_RADIUS);
      } else {
        // polygon is taller
        beta = Math.min(90 * DEGREES, alpha + latSpan / 2 / EARTH_RADIUS);
      }
    
      range = PAD_FACTOR * EARTH_RADIUS * (Math.sin(beta) *
        Math.sqrt(1 / Math.pow(Math.tan(alpha),2) + 1) - 1);
    }
    
    var la = ge.createLookAt('');
    la.set(center.lat(), center.lng(), coordData.maxAltitude,
           coordData.altitudeMode, 0, 0, range);
    return la;
  }
  
  return null;
}