<?php

class JqGridHelper extends AppHelper {

  var $jqGrid_options;
  var $included;
  var $columns;

  function __construct() {
    $this->reset();
  }

  function reset() {
    $this->jqGrid_options
      = array('limit' => 20);

    $this->columns  = array();
    $this->included = array();
    return $this;
  }

  // Add to the set of columns for this grid
  function columns($columns) {
    if (isset($columns)) {
      if (is_array($columns))
	$this->columns += $columns;
      else
	array_push($this->columns, $columns);
    }
    return $this;
  }

  // Included fields will be included unless excluded.
  function included($fields) {
    if (isset($fields)) {
      if (is_array($fields))
	$this->included = array_merge($this->included, $fields);
      else
	array_push($this->included, $fields);
    }
    return $this;
  }

  function limit() {
    $this->jqGrid_options['limit'] = 20;
    return $this;
  }

  function id_list($items) {
    $this->jqGrid_options
      += array('custom_ids' =>
	       array_map(create_function('$data',
					 'return $data["id"];'),
			 $items));
    return $this;
  }

  function render($included = array(), $excluded = array()) {
    pr("<H2>jqGrid</H2>");

    $columns  = $this->columns;
    $we_want  = $this->included;
    $they_want = $included;
    $we_dont_want = array_diff(array_keys($this->columns), $this->included);
    $they_dont_want = $excluded;

    if (is_bool($included) && $included)
      $included = array_keys($columns);
    elseif (is_bool($included) && !$included)
      $included = array();

    if (is_bool($excluded) && $excluded)
      $excluded = array_keys($columns);
    elseif (is_bool($excluded) && !$excluded)
      $excluded = array();

    $hopefully_wanted = array_merge($this->included, $included);
    $hopefully_get = array_diff(array_merge($this->included, $included), $excluded);

    $actually_get = array_intersect(array_keys($this->columns), $hopefully_get);
    $actually_dont_get = array_diff(array_keys($this->columns), $hopefully_get);

    pr(compact('we_want', 'they_want', 'we_dont_want', 'they_dont_want',
	       'hopefully_wanted', 'hopefully_get',
	       'actually_get', 'actually_dont_get'));

    // Since we only have one instance of this class
    // as a helper, we must assume it could be used
    // again later to render an entirely different grid.
    // Reset the variables to prevent contamination.
    $this->reset();
    return $this;
  }
  
}