<?php

/**
 * @file
 * - Provides a Google maps location picker widget for Geo cck fields.
 * - Provides a field formatter for Geo fields that displays point, line, or
 *   polygon data on a Google map.
 */

/**
 * Implementation of FAPI hook_elements().
 */
function gmap_geo_elements() {
  return array(
    'gmap_geo_picker' => array(
      '#input' => TRUE,
      '#columns' => array('lat', 'lon', 'wkt'),
      '#delta' => 0,
      '#process' => array('gmap_geo_picker_process'),
    ),
  );
}

/**
 * Implementation of hook_widget_info().
 */
function gmap_geo_widget_info() {
  return array(
    'gmap_geo_picker' => array(
      'label' => t('GMap picker'),
      'field types' => array('geo'),
    ),
  );
}

/**
 * Implementation of hook_widget().
 */
function gmap_geo_widget(&$form, &$form_state, $field, $items, $delta = 0) {
  return array(
    '#type' => $field['widget']['type'],
    '#default_value' => isset($items[$delta]) ? $items[$delta] : '',
  );
}

/**
 * Implementation of hook_widget_settings().
 * Adds a place to set a GMap macro for the initial location picker map.
 */
function gmap_geo_widget_settings($op, $widget) {
  switch ($op) {
    case 'form':
      $form = array();
      $form['gmap_geo_picker_macro'] = array(
        '#type' => 'textfield',
        '#title' => 'GMap macro',
        '#default_value' => $widget['gmap_geo_picker_macro'] ? $widget['gmap_geo_picker_macro'] : '[gmap]',
        '#description' => t("A GMap macro describing the initial location picker map. <em>[gmap]</em> displays a map with the settings from !gmap-admin.", array('!gmap-admin' => l('admin/settings/gmap', 'admin/settings/gmap'))),
      );
      return $form;
    case 'save':
      return array('gmap_geo_picker_macro');
  }
}

/**
 * See the gmap_set_location() function in gmap.module and its' companion location_latlon_form() in location.inc
 */
function gmap_geo_picker_process($element, $edit, $form_state, $form) {
  $field = $form['#field_info'][$element['#field_name']];
  
  $element['#title'] = $field['widget']['label'];
  $element['#type'] = 'fieldset';

  $element['map'] = array();  // reserve spot at top of form for map

  $element['lat'] = array(
    '#type' => 'textfield',
    '#title' => t('Latitude'),
    '#default_value' => isset($element['#value']['lat']) ? $element['#value']['lat'] : NULL,
    '#required' => $field['required'],
    '#size' => 15,
    '#prefix' => '<div class="container-inline">',
  );
  $element['lon'] = array(
    '#type' => 'textfield',
    '#title' => t('Longitude'),
    '#default_value' => isset($element['#value']['lon']) ? $element['#value']['lon'] : NULL,
    '#required' => $field['required'],
    '#size' => 15,
    '#suffix' => '</div>',
  );
  $element['wkt'] = array(
    '#type' => 'value',
    '#value' => isset($element['#value']['wkt']) ? $element['#value']['wkt'] : NULL,
  );

  $element['map']['gmap']['#value'] = gmap_set_location($field['widget']['gmap_geo_picker_macro'], $element, array('latitude' => 'lat', 'longitude' => 'lon'));
  $element['map_instructions'] = array(
    '#type' => 'markup',
    '#weight' => 2,
    '#prefix' => '<div class=\'description\'>',
    '#value' => t('You may set the location by clicking on the map, or dragging the location marker.  To clear the location, click on the marker.'), 
    '#suffix' => '</div>',
  );

  return $element;
}

/**
 * Implementation of hook_theme().
 */
function gmap_geo_theme() {
  return array(
    'gmap_geo_picker' => array(
      'arguments' => array('element' => NULL),
    ),
    'gmap_geo_formatter_gmap_geo' => array(
      'function' => 'theme_gmap_geo_formatter',
      'arguments' => array('element' => NULL),
    ),
    'gmap_geo_formatter_gmap_geo_simplify' => array(
      'function' => 'theme_gmap_geo_formatter',
      'arguments' => array('element' => NULL),
    ),
  );
}

/**
 * Theme the gmap_picker widget.
 */
function theme_gmap_geo_picker($element) {
  return $element['#children'];
}

/**
 * Implementation of hook_field_formatter_info().
 * Note that the formatters don't actually work for geo_data fields yet, because
 * that field type doesn't (yet) provide its data in WKT.
 */
function gmap_geo_field_formatter_info() {
  return array(
    'gmap_geo' => array(
      'label' => t('GMap'),
      'field types' => array('geo', 'geo_data'),
      'multiple values' => CONTENT_HANDLE_MODULE,
    ),
    'gmap_geo_simplify' => array(
      'label' => t('Simplified Polygon on a GMap'),
      'field types' => array('geo', 'geo_data'),
      'multiple values' => CONTENT_HANDLE_MODULE,
    ),
  );
}

/**
 * Themes a geo field as a gmap.
 * 
 * Wasn't sure what to use as the base map settings. GMap default settings? GMap
 * picker macro settings? Bdragon and I (Bec) have talked about a "gmap profile"
 * setup, in which case we could provide a field formatter for each gmap profile 
 * ("GMap: profile_name"). This would be ideal.
 *
 * - Right now this map's settings are based on the gmap_picker widget settings,
 * if present.
 *
 * - Should this be checking to make sure that the WKT is well-formed?
 * Possibly with geo_wkt_validate()?
 *
 * - This field formatter is not useful with geodata  from most shapefiles, 
 * because these shapes often have more points than JavaScript-based can handle
 * (generally 1,000 points/vertices is a reasonable maximum).
 *
 * - Autozoom doesn't yet zoom for polygons and lines; this field formatter 
 * doesn't provide any autozoom stuff either.
 *
 * - Polygons don't get drawn at all by gmap unless at least one of their
 * vertices is within the visible area. If not all of a polygon's vertices are
 * within the visible area, they may be rendered incorrectly.
 */
function theme_gmap_geo_formatter($element) {
  $i = 0;
  $total_points = 0;
  while (isset($element[$i])) {
    $item = $element[$i]['#item'];
    $i++;
  
    if ($total_points > 1000) {
      $i = -1;
      drupal_set_message(t('Some data is not displayed on the map because there are too many items.'), 'warning');
      break;
    }

    // get the feature's coordinates
    $geodata = _gmap_geo_from_wkt($item['wkt']);
  
    switch ($geodata['type']) {
      case 'POINT':
        foreach($geodata['data'] as $point) {
          $coords = explode(' ', $point);
          $map['markers'][] = array('longitude' => $coords[0], 'latitude' => $coords[1]);
          $total_points++;
        }
        break;
      case 'POLYGON':
      case 'LINESTRING':
        if (isset($item['centroid'])) {
          $centroid_raw = _gmap_geo_from_wkt($item['centroid']);
          $centroid = explode(' ', reset($centroid_raw['data']));
          // autozoom for polygons is coming in GMap 1.1 (2008-12-30)
          $map['latitude'] = $centroid[0];
          $map['longitude'] = $centroid[1];
        }

        // get feature coordinates
        $shape_coords = array();
        foreach($geodata['data'] as $point) {
          $shape_coords[] = explode(' ', $point);
        }
        
        // polygon simplification is resource intensive.
        // I am not sure how well this handles line data -- quite possibly it
        // would be fine, if you provide a centroid.
        if ($element['#formatter'] == 'gmap_geo_simplify' && isset($centroid)) {
          module_load_include('inc', 'gmap_geo', 'simplify');
          $shape_coords = gmap_geo_simplify($shape_coords, $centroid);
        }

        // if the poly/line is too complex, let's not crash the browser...
        if (count($shape_coords) < 200) {
          $map['shapes'][] = array(
            'type' => ($geodata['type'] == 'POLYGON' ? 'polygon' : 'line'),
            'points' => $shape_coords,
          );
          $total_points += count($shape_coords);
        }
        else {
          $map['markers'][] = array(
            'longitude' => $centroid[0],
            'latitude' => $centroid[1],
            'text' => t('This shape has too many points to display on a Google Map')
          );
          $total_points++;
        }
        break;
    }
  }
  
  if ($map) {
    // Load field instance info. If the field uses the gmap_picker widget, use
    // the widget's gmap macro to build the map array.
    module_load_include('inc', 'content', 'includes/content.crud');
    $field = content_field_instance_read(array('type_name' => $element['#type_name'], 'field_name' => $element['#field_name']));
    if ($field[0]['widget']['type'] == 'gmap_picker') {
      $field_map = gmap_parse_macro($field[0]['widget']['gmap_picker_macro']);
      $map = array_merge($field_map, $map);
    }
  
    $map['behavior'] = array('autozoom');
    if (isset($field_map['zoom'])) {
      $map['maxzoom'] = $field_map['zoom'];
    }
    return theme('gmap', $map);
  }
}

/**
 * Split WKT into an array.
 */
function _gmap_geo_from_wkt($wkt) {
  $geodata = preg_split('/ *\(|,|\)/', $wkt, -1, PREG_SPLIT_NO_EMPTY);
  $geodata_type = array_shift($geodata);
  return array('type' => $geodata_type, 'data' => $geodata);
}