<?php
// $Id: flag_weights.module,v 1.2 2010-12-15 08:52:44 lyricnz Exp $

/**
 * @file
 * Add flag-weights to the Flag module.
 */

define('MIN_DEFAULT_WEIGHT', -128);
define('MAX_DEFAULT_WEIGHT', 127);

/**
 * Implements hook_schema_alter(). We alter $schema by reference().
 *
 * @param $schema
 *   The system-wide schema collected by drupal_get_schema().
 */
function flag_weights_schema_alter(&$schema) {
  // Add fields to existing schema.
  $schema['flag_content']['fields']['weight'] = array(
    'type' => 'int',
    'not null' => TRUE,
    'default' => 0,
    'size' => 'tiny',
    // 'description' => t('Flag weight within region.'),
  );

  $schema['flags']['fields']['default_weight'] = array(
     'type' => 'int',
     'not null' => TRUE,
     'default' => 0,
     'size' => 'tiny',
     'description' => t('Default weight applied to new items.'),
   );
}

/**
 * Implements hook_views_data().
 *
 * Provide a field that can be used to sort a view.
 */
function flag_weights_views_data() {
  $data = array();

  $data['flag_content']['weight'] = array(
    'title' => t('Weight'),
    'help' => t('Used for sorting the list of flagged items.'),
    'real field' => 'weight',
    'field' => array(
      'handler' => 'views_handler_field_numeric',
      'click sortable' => TRUE,
    ),
    'sort' => array(
      'handler' => 'views_handler_sort',
    ),
  );

  return $data;
}

/**
 * Flag an item using the given Flag name.
 *
 * @param $flag_name
 *   The content-type for the flag, eg: node.
 * @see _flag_weights_flag()
 */
function flag_weights_set_flag($content_type, $content_id, $account = NULL, $weight = 0) {
  $handler = flag_create_handler($content_type);
  return _flag_weights_flag($handler, $content_id, $account, $weight);
}

/**
 * Flag an item using the given Flag name.
 *
 * @param $flag_name
 *   The machine-name for the flag to use, eg: bookmarks.
 * @see _flag_weights_flag()
 */
function flag_weights_set_flag_with_flag($flag_name, $content_id, $account = NULL, $weight = 0) {
  $handler = flag_get_flag($flag_name);
  return _flag_weights_flag($handler, $content_id, $account, $weight);
}

/**
 * Flags an item, and set it's weight.
 *
 * @param $handler
 *   The Flag to use
 * @param $content_id
 *   The ID of the item to flag or unflag.
 * @param $account
 *   The user on whose behalf to flag. Leave empty for the current user.
 * @param $weight
 *   A weight used for ordering the item within the flagged-items list.
 * @return
 *   FALSE if some error occured (e.g., user has no permission, flag isn't
 *   applicable to the item, etc.), TRUE otherwise.
 */
function _flag_weights_flag($handler, $content_id, $account = NULL, $weight = 0) {
  $ok = $handler->flag('flag', $content_id, $account);
  if ($ok && $weight != 0) {
    if (!isset($account)) {
      $account = $GLOBALS['user'];
    }
    flag_weights_set_weight($handler->fid, $handler->content_type, $content_id, $account->uid, $weight);
  }
  return $ok;
}

/**
 * Update the weight of an existing flagged item.
 */
function flag_weights_set_weight($fid, $content_type, $content_id, $uid, $weight) {

  db_update('flag_content')
  ->fields(array(
    'weight' => $weight,
  ))
  ->condition('fid', $fid)
  ->condition('content_type', $content_type)
  ->condition('content_id', $content_id)
  ->condition('uid', $uid)
  ->execute();
}

/**
 * Implements hook_draggableviews_handlers().
 *
 * Integrate with Draggable Views module.
 */
function flag_weights_draggableviews_handlers() {
  return array(
    'flag_weights' => array(
      'file' => 'draggableviews_handler_flag_weights.inc',
      'title' => t('Flag Weights'),
      'description' => t('Default implementation with Flag Weights'),
      'handler' => 'draggableviews_handler_flag_weights',
    ),
  );
}

/**
 * Implements hook_form_FORMID_alter().
 *
 * Add the default-weight setting to the Flags edit page.
 */
function flag_weights_form_flag_form_alter(&$form, &$form_state) {
  $default_weight = _flag_weights_get_default_weight($form['#flag']->fid);
  if ($default_weight == MIN_DEFAULT_WEIGHT) {
    $default_weight = 'MIN';
  }
  elseif ($default_weight == MAX_DEFAULT_WEIGHT) {
    $default_weight = 'MAX';
  }

  $form['default_weight'] = array(
    '#type' => 'textfield',
    '#title' => t('Default weight'),
    '#default_value' => $default_weight,
    '#description' => t('Enter the default weight for this Flag (or MIN/MAX to set the weight lower/higher than existing content respectively.'),
    '#required' => TRUE,
    '#weight' => 15,
    '#length' => 3,
    // '#access' => empty($flag->locked['unflag_short']),
  );

  $form['#submit'][] = 'flag_weights_flag_form_submit';

}

/**
 * Custom submit handler for flag_form form.
 */
function flag_weights_flag_form_submit($form, &$form_state) {
  // Parse the textfield to determine the value to apply to the DB
  $default_weight = $form_state['values']['default_weight'];
  if (strcasecmp($default_weight, 'MIN') == 0) {
    $default_weight = MIN_DEFAULT_WEIGHT;
  }
  elseif (strcasecmp($default_weight, 'MAX') == 0) {
    $default_weight = MAX_DEFAULT_WEIGHT;
  }

  // By the time this executed, the Flag will already have been inserted/updated
  // so $flag->fid is set
  _flag_weights_set_default_weight($form['#flag']->fid, $default_weight);
}

function _flag_weights_get_default_weight($fid) {
  return (int) db_query("SELECT default_weight FROM {flags} WHERE fid = :fid", array(':fid' => $fid))->fetchField();
}

function _flag_weights_set_default_weight($fid, $default_weight) {
  db_update('flags')
  ->fields(array(
    'default_weight' => $default_weight,
  ))
  ->condition('fid', $fid)
  ->execute();
}

/**
 * Implements hook_flag().
 *
 * When content has been flagged, update the flag to use the default weight.
 */
function flag_weights_flag($action, $flag, $content_id, $account) {
  if ($action == 'flag') {
    $default_weight = _flag_weights_get_default_weight($flag->fid);

    // If the configured default weight is MIN/MAX then set it to the right int.
    if ($default_weight == MIN_DEFAULT_WEIGHT) {
      $found_min = db_query("SELECT min(weight) FROM {flag_content} WHERE fid = :fid AND uid = :uid", array(':fid' => $flag->fid, ':uid' => $account->uid))->fetchField();
      if ($found_min !== FALSE && $found_min > MIN_DEFAULT_WEIGHT) {
        $default_weight = $found_min - 1;
      }
    }
    elseif ($default_weight == MAX_DEFAULT_WEIGHT) {
      $found_max = db_query("SELECT max(weight) FROM {flag_content} WHERE fid = :fid AND uid = :uid", array(':fid' => $flag->fid, ':uid' => $account->uid))->fetchField();
      if ($found_max !== FALSE && $found_max < MAX_DEFAULT_WEIGHT) {
        $default_weight = $found_max + 1;
      }
    }

    // Don't bother applying a weight of 0 - this is the default.
    if ($default_weight != 0) {
      db_update('flag_content')
  ->fields(array(
        'weight' => $default_weight,
      ))
  ->condition('fid', $flag->fid)
  ->condition('content_id', $content_id)
  ->execute();
    }
  }
}