<?php

/**
 * Parses a given file as a zipped shapefile.
 */
class GeoShapefileParser extends FeedsParser {

  /**
   * Parses a raw string and returns a Feed object from it.
   */
  public function parse(FeedsFetcherResult $fetcherResult, FeedsSource $source) {
    
    if ($fetcherResult->type != 'text/filepath') {
      throw new Exception(t('You must use Shapefile Parser with File Fetcher.'));
    }
    
    $options = $source->getConfigFor($this);
    
    $filepath = ($fetcherResult->value);
    
    $shapefile_data = geo_process_shapefile($fetcherResult->value, $options['spatial_field_name']);
    
    // Apply titles in lower case.
    foreach ($shapefile_data['columns'] as $i => $title) {
      $shapefile_data['columns'][$i] = strtolower($title); // Use lower case only.
    }
    $result_rows = array();
    foreach ($shapefile_data['data'] as $i => $row) {
      $result_row = array();
      foreach ($row as $j => $col) {
        $result_row[$shapefile_data['columns'][$j]] = $col;
      }
      $result_rows[] = $result_row;
    }
    
    // Return result.
    return new FeedsParserResult(array('items' => $result_rows));
  }

  /**
   * Override parent::getSourceElement to use only lower keys.
   */
  public function getSourceElement($item, $element_key) {
    $element_key = strtolower($element_key);
    return isset($item[$element_key]) ? $item[$element_key] : '';
  }

  /**
   * Define defaults.
   */
  public function sourceDefaults() {
    return array(
      'spatial_field_name' => $this->config['spatial_field_name'],
      'srid' => $this->config['srid'],
    );
  }

  /**
   * Source form.
   *
   * Show mapping configuration as a guidance for import form users.
   */
  public function sourceForm($source_config) {
    $form = array();
    $form['#weight'] = -10;

    $mappings = feeds_importer($this->id)->processor->config['mappings'];
    $sources = $uniques = array();
    foreach ($mappings as $mapping) {
      $sources[] = $mapping['source'];
      if ($mapping['unique']) {
        $uniques[] = $mapping['source'];
      }
    }

    $items = array(
      t('Import zipped !shapefile with one or more of these columns: !columns.', array('!shapefile' => l(t('Shapefiles'), 'http://en.wikipedia.org/wiki/Shapefile'), '!columns' => implode(', ', $sources))),
      format_plural(count($uniques), t('Column <strong>!column</strong> is mandatory and considered unique: only one item per !column value will be created.', array('!column' => implode(', ', $uniques))), t('Columns <strong>!columns</strong> are mandatory and values in these columns are considered unique: only one entry per value in one of these column will be created.', array('!columns' => implode(', ', $uniques)))),
    );
    $form['help']['#value'] = '<div class="help">'. theme('item_list', $items) .'</div>';
    
    $form['spatial_field_name'] = array(
      '#type' => 'textfield',
      '#title' => t('Spatial Data Column'),
      '#default_value' => $source_config['spatial_field_name'],
      '#size' => 24,
      '#maxlength' => 24,
      '#description' => t('The database column name that the spatial data should be stored in.')
    );
    $form['srid'] = array(
      '#type' => 'textfield',
      '#title' => t('SRID (Spatial projection)'),
      '#default_value' => $source_config['srid'],
      '#size' => 24,
      '#maxlength' => 24,
      '#description' => t('Integer represeting the SRID of the uploaded shapefile. If you are unsure, use \'4326\' (lat/lon).')
    );
    
    return $form;
  }

  /**
   * Define default configuration.
   */
  public function configDefaults() {
    return array(
      'spatial_field_name' => 'geom',
      'srid' => '4326',
    );
  }

}


/**
 * Process Shapefile
 *
 * This is where the action happens. Given a path, get all the data out of a
 * zipped shapefile.
 */
function geo_process_shapefile($filepath, $spatial_field = 'geom') {
	include_once(drupal_get_path('module', 'geo') .'/includes/shp2sql.inc');
	
  if (!is_readable($filepath) || (!is_resource($zip = zip_open($filepath)))) {
    drupal_set_message(t('zip file nonexistant or unreadable.'), 'error');
    return;
  }

  // Catalog the contents of the zip file.
  $files = array();
  while ($res = zip_read($zip)) {
    $ext = strtolower(substr(strrchr(zip_entry_name($res), '.'), 1));
    $files[$ext] = $res;
  }

  // The zip file must minimally contain a shp, dbf and shx file.
  if (!isset($files['shp']) || !isset($files['dbf']) || !isset($files['shx'])) {
    drupal_set_message(t('This does not appear to be an archive that contains valid shp data.'), 'error');
    return;
  }

  // See if we can get the projection information from the prj file.
  if (isset($files['prj'])) {
    // TODO Parse srid from prj file, for conversion if necessary.
  }

  if (isset($files['dbt'])) {
    drupal_set_message(t('This database contains longtext/memo fields, which are unsupported.  Proceeding to enter other data anyway.'), 'warning');
  }

  // Get headers and table definition from the dbf file.
  $schema = array('description' => t('Imported shapefile'), 'fields' => array());
  $headers = _dbf_headers($files['dbf'], $schema);

  // Shape file headers are stored in the first 100 bytes of the shp/shx files.
  $headers += _shp_headers(zip_entry_read($files['shp'], 100));
  
  // Get column names
  $columns = array_keys($headers['field_lengths']);

   // Add 'spatial_field' to the list of columns
  $columns[] = $spatial_field;
  
  // Add spatial_field to schema
  $schema['fields'][$spatial_field] = array (
    'type' => 'blob',
    'mysql_type' => 'geometry',
    'pgsql_type' => 'geometry',
    'gis type' => $headers['geo_type'],
    'description' => 'Geomtry Field'
  );
  
  $data = array();
  
  $row_count = 0;
  while ($shp = _shp_get_record($files['shp'])) {
    $values = array();
    $dbf_data = zip_entry_read($files['dbf'], $headers['record_size']);
    $dbf_data = substr($dbf_data, 1); // Remove "record deleted" flag.
    foreach($headers['field_lengths'] as $name => $length) {
      $value = substr($dbf_data, 0, $length);
      $dbf_data = substr($dbf_data, $length);

      // Use a predefined function to filter and process each value.
      $process = $headers['field_filters'][$name];
      $values[] = $value;
    }

    // Add the geometry text.
    $values[] = $shp['data']['wkt'];
    $data[] = $values;
    
    $row_count++;
  }
  
  return array(
    'schema' => $schema,
    'headers' => $headers,
    'columns' => $columns, 
    'shapecolumn' => $spatial_field,
    'data' => $data,
    'srid' => NULL,
  );
}

?>