<?php

define('TITLE_LENGTH_CHARS', 8000);

/**
 * Implements hook_schema_alter().
 */
function title_length_schema_alter(&$schema) {
  if (isset($schema['node'])) {
    $schema['node']['fields']['title']['length'] = TITLE_LENGTH_CHARS;
    $schema['node']['indexes']['node_title_type'] = array(array('title', 250), array('type', 4));

  }

  if (isset($schema['node_revision'])) {
    $schema['node_revision']['fields']['title']['length'] = TITLE_LENGTH_CHARS;
  }
}

/**
 * Implements hook_install().
 */
function title_length_install() {
  $schema = drupal_get_schema();
  if (empty($schema['node']['fields']['title'])) {
    // Is it possible?
    throw new Exception('Node module is not installed.');
  }

  $node_title_field_definition = $schema['node']['fields']['title'];
  $revision_title_field_definition = $schema['node_revision']['fields']['title'];

  $revision_title_field_definition['length'] = TITLE_LENGTH_CHARS;
  $node_title_field_definition['length'] = TITLE_LENGTH_CHARS;
  $index_definition = array('indexes' => array('node_title_type' => array(array('title', 250), array('type', 4))));

  db_drop_index('node', 'node_title_type');
  db_change_field('node', 'title', 'title', $node_title_field_definition, $index_definition);
  db_change_field('node_revision', 'title', 'title', $revision_title_field_definition);
}

/**
 * Implements hook_uninstall().
 */
function title_length_uninstall() {
  $schema = drupal_get_schema();
  if (empty($schema['node']['fields']['title'])) {
    // Is it possible?
    return;
  }

  $length_function = 'char_length';

  switch (Database::getConnection()->databaseType()) {
    case 'sqlite':
      $length_function = 'length';
      break;

    case 'sqlsrv':
      $length_function = 'len';
      break;
  }

  $long_title_count = db_query("SELECT COUNT(*) FROM {node} WHERE {$length_function}(title) > 255")->fetchField();
  $long_revision_title_count = db_query("SELECT COUNT(*) FROM {node_revision} WHERE {$length_function}(title) > 255")->fetchField();

  if ($long_title_count + $long_revision_title_count > 0) {
    throw new Exception('Nodes or node revisions exist with long titles. Module cannot be deleted.');
  }

  $node_title_field_definition = $schema['node']['fields']['title'];
  $revision_title_field_definition = $schema['node_revision']['fields']['title'];

  $node_title_field_definition['length'] = 255;
  $revision_title_field_definition['length'] = 255;
  $index_definition = array('indexes' => array('node_title_type' => array('title', array('type', 4))));

  db_drop_index('node', 'node_title_type');
  db_change_field('node', 'title', 'title', $node_title_field_definition, $index_definition);
  db_change_field('node_revision', 'title', 'title', $revision_title_field_definition);
}