<?php

/**
 * @file
 * The Schema module provides functionality built on the Schema API.
 */

/**
 * Implements hooK_help().
 */
function schema_help($path, $arg) {
  switch ($path) {
    case 'admin/structure/schema':
      return '<p>' . t('This page compares the live database as it currently exists against the combination of all schema information provided by all enabled modules.') . '<p>';

    case 'admin/structure/schema/describe':
      return '<p>' . t("This page describes the Drupal database schema. Click on a table name to see that table's description and fields. Table names within a table or field description are hyperlinks to that table's description.") . '</p>';

    case 'admin/structure/schema/inspect':
      $output = '<p>' . t("This page shows the live database schema as it currently exists on this system. Known tables are grouped by the module that defines them; unknown tables are all grouped together.") . '</p>';
      $output .= '<p>' . t("To implement hook_schema() for a module that has existing tables, copy the schema structure for those tables directly into the module's hook_schema() and return \$schema.") . '</p>';
      return $output;

    case 'admin/structure/schema/sql':
      return '<p>' . t('This page shows the CREATE TABLE statements that the Schema API generates for the selected database engine for each table defined by a module. It is for debugging purposes.') . '</p>';

    case 'admin/structure/schema/show':
      return '<p>' . t('This page displays the Drupal database schema data structure. It is for debugging purposes.') . '</p>';
  }

}

/**
 * Implements hook_permission().
 */
function schema_permission() {
  return array(
    'administer schema' => array(
      'title' => t('Administer schema module'),
    ),
  );
}

/**
 * Implements hook_menu().
 */
function schema_menu() {
  $items['admin/structure/schema'] = array(
    'title' => 'Schema',
    'description' => 'Manage the database schema for this system.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('schema_compare'),
    'access arguments' => array('administer schema'),
    'file' => 'schema.pages.inc',
  );
  $items['admin/structure/schema/compare'] = array(
    'title' => 'Compare',
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => -10,
  );
  $items['admin/structure/schema/describe'] = array(
    'title' => 'Describe',
    'type' => MENU_LOCAL_TASK,
    'page callback' => 'drupal_get_form',
    'page arguments' => array('schema_describe'),
    'weight' => -8,
    'access arguments' => array('administer schema'),
    'file' => 'schema.pages.inc',
  );
  $items['admin/structure/schema/inspect'] = array(
    'title' => 'Inspect',
    'type' => MENU_LOCAL_TASK,
    'page callback' => 'drupal_get_form',
    'page arguments' => array('schema_inspect'),
    'weight' => -6,
    'access arguments' => array('administer schema'),
    'file' => 'schema.pages.inc',
  );
  $items['admin/structure/schema/sql'] = array(
    'title' => 'SQL',
    'type' => MENU_LOCAL_TASK,
    'page callback' => 'schema_sql',
    'weight' => -4,
    'access arguments' => array('administer schema'),
    'file' => 'schema.pages.inc',
  );

  // This can't work unless we rename the functions in database.*.inc.
  // global $_schema_engines;
  // if (FALSE && isset($_schema_engines) && is_array($_schema_engines)) {
  //   foreach ($_schema_engines as $engine) {
  //     $items['admin/structure/schema/sql/' . $engine] = array(
  //       'title' => $engine,
  //       'type' => ($engine == db_driver() ? MENU_DEFAULT_LOCAL_TASK :
  //         MENU_LOCAL_TASK),
  //       'page callback' => 'schema_sql',
  //       'callback arguments' => $engine,
  //       'access arguments' => array('administer schema'),
  //       );
  //   }
  // }

  $items['admin/structure/schema/show'] = array(
    'title' => 'Show',
    'type' => MENU_LOCAL_TASK,
    'page callback' => 'schema_show',
    'weight' => -2,
    'access arguments' => array('administer schema'),
    'file' => 'schema.pages.inc',
  );
  $items['admin/structure/schema/settings'] = array(
    'title' => 'Settings',
    'type' => MENU_LOCAL_TASK,
    'page callback' => 'drupal_get_form',
    'page arguments' => array('schema_settings_form'),
    'weight' => 50,
    'access arguments' => array('administer schema'),
    'file' => 'schema.admin.inc',
  );

  return $items;
}

/**
 * Fetch the schema engine class name for a given database connection.
 *
 * @param string $connection
 *   A database connection key, defaults to 'default'.
 *
 * @return
 *   The schema engine class name if available, otherwise FALSE.
 */
function schema_get_connection_engine_class($connection = 'default') {
  if ($info = Database::getConnectionInfo($connection)) {
    $driver = $info['default']['driver'];
    $class_name = 'SchemaDatabaseSchema_' . $driver;
    if (class_exists($class_name)) {
      return $class_name;
    }
  }

  return FALSE;
}

/**
 * Fetch a schema engine class instance for a given database connection.
 *
 * @param string $connection
 *   A database connection key, defaults to the schema_database_connection
 *   variable, which itself defaults to 'default'.
 *
 * @return object
 *   A schema engine class set to the given connection.
 */
function schema_dbobject($connection = NULL) {
  if (!isset($connection)) {
    $connection = variable_get('schema_database_connection', 'default');
  }

  if ($class = schema_get_connection_engine_class($connection)) {
    return new $class(Database::getConnection('default', $connection));
  }
}

/**
 * Get an array of connection options that are supported by schema inspection.
 */
function schema_get_connection_options() {
  $options = &drupal_static(__FUNCTION__);

  if (!isset($options)) {
    foreach ($GLOBALS['databases'] as $connection => $targets) {
      // Only support connections that can be inspected by schema module.
      if (!schema_get_connection_engine_class($connection)) {
        continue;
      }

      $options[$connection] = $connection;
    }
  }

  return $options;
}

//////////////////////////////////////////////////////////////////////
// Schema print functions
//////////////////////////////////////////////////////////////////////

/**
 * Builds a pretty ASCII-formatted version of a $schema array.
 *
 * This is nothing more than a specialized variation of var_dump and
 * similar functions and is used only as a convenience to generate the
 * PHP for existing database tables (to bootstrap support for modules
 * that previously used CREATE TABLE explicitly) and for debugging.
 */
function schema_phpprint($schema) {
  $out = '';
  foreach ($schema as $name => $table) {
    $out .= schema_phpprint_table($name, $table);
  }
  return $out;
}

function schema_phpprint_table($name, $table) {
  $cols = array();
  if (isset($table['fields'])) {
    foreach ($table['fields'] as $colname => $col) {
      $cols[] = "'$colname' => " . schema_phpprint_column($col, TRUE);
    }
  }
  $unique = $index = array();
  if (isset($table['unique keys'])) {
    foreach ($table['unique keys'] as $keyname => $key) {
      $unique[] = "'$keyname' => " . schema_phpprint_key($key);
    }
  }
  if (isset($table['indexes'])) {
    foreach ($table['indexes'] as $keyname => $key) {
      $index[] = "'$keyname' => " . schema_phpprint_key($key);
    }
  }
  if ($table['description']) {
    $description = $table['description'];
  }
  else {
    $description = t('TODO: please describe this table!');
  }
  $out = '';
  $out .= "\$schema['" . $name . "'] = array(\n";
  $out .= "  'description' => '$description',\n";
  $out .= "  'fields' => array(\n    ";
  $out .= implode(",\n    ", $cols);
  $out .= ",\n  ),\n";
  if (isset($table['primary key'])) {
    $out .= "  'primary key' => array('" . implode("', '", $table['primary key']) . "'),\n";
  }
  if (count($unique) > 0) {
    $out .= "  'unique keys' => array(\n    ";
    $out .= implode(",\n    ", $unique);
    $out .= "\n  ),\n";
  }
  if (count($index) > 0) {
    $out .= "  'indexes' => array(\n    ";
    $out .= implode(",\n    ", $index);
    $out .= ",\n  ),\n";
  }
  $out .= ");\n";
  return $out;
}

function schema_phpprint_column($col, $multiline=FALSE) {
  $attrs = array();
  if (isset($col['description']) && $col['description']) {
    $description = $col['description'];
  }
  else {
    $description = t('TODO: please describe this field!');
  }
  unset($col['description']);
  $attrs[] = "'description' => '$description'";
  if ($col['type'] == 'varchar' || $col['size'] == 'normal') {
    unset($col['size']);
  }
  foreach (array('type', 'unsigned', 'size', 'length', 'not null', 'default') as $attr) {
    if (isset($col[$attr])) {
      if (is_string($col[$attr])) {
        $attrs[] = "'$attr' => '$col[$attr]'";
      }
      elseif (is_bool($col[$attr])) {
        $attrs[] = "'$attr' => " . ($col[$attr] ? 'TRUE' : 'FALSE');
      }
      else {
        $attrs[] = "'$attr' => $col[$attr]";
      }
      unset($col[$attr]);
    }
  }
  foreach (array_keys($col) as $attr) {
    if (is_string($col[$attr])) {
      $attrs[] = "'$attr' => '$col[$attr]'";
    }
    else {
      $attrs[] = "'$attr' => $col[$attr]";
    }
  }
  if ($multiline) {
    return "array(\n      " . implode(",\n      ", $attrs) . ",\n    )";
  }
  return "array(" . implode(', ', $attrs) . ")";
}

function schema_phpprint_key($keys) {
  $ret = array();
  foreach ($keys as $key) {
    if (is_array($key)) {
      $ret[] = "array('$key[0]', $key[1])";
    }
    else {
      $ret[] = "'$key'";
    }
  }
  return "array(" . implode(", ", $ret) . ")";
}

//////////////////////////////////////////////////////////////////////
// Schema comparison functions
//////////////////////////////////////////////////////////////////////

function schema_unprefix_table($name) {
  // TODO: Deal with D7 prefixing
  global $db_prefix;
  static $_db_prefix;

  if (is_array($db_prefix)) {
    if (!isset($_db_prefix)) {
      foreach ($db_prefix as $key => $val) {
        $_db_prefix[$val . $key] = $key;
      }
    }
    if (isset($_db_prefix[$name])) {
      return $_db_prefix[$name];
    }
    elseif (!empty($db_prefix['default']) && preg_match('@^' . $db_prefix['default'] . '(.*)@', $name, $m)) {
      return $m[1];
    }
    else {
      // On pgsql, key and index names are also prefixed
      // (e.g. 'prefix_blocks_roles_rid_idx').
      foreach ($db_prefix as $key => $val) {
        if (($key != 'default' && preg_match('@^' . $val . '(' . $key . '.*)@', $name, $m)) ||
          ($key == 'default' && preg_match('@^' . $val . '(.*)@', $name, $m))) {
          return $m[1];
        }
      }
      return $name;
    }
  }
  elseif (!empty($db_prefix) && preg_match('@^' . $db_prefix . '(.*)@', $name, $m)) {
      return $m[1];
  }
  elseif (empty($_db_prefix)) {
    $info = Database::getConnectionInfo($connection = 'default'); // FIXME: obtain the correct connection
    $_db_prefix = empty($info['default']['prefix'])
      ? ''
      : reset($info['default']['prefix']);
    $db_prefix = $_db_prefix;
    $name = drupal_substr($name, drupal_strlen($_db_prefix));
  }
  return $name;
}

/**
 * Converts a column's Schema type into an engine-specific data type.
 */
function schema_engine_type($col, $table, $field, $engine = NULL) {
  $map = schema_dbobject()->getFieldTypeMap();
  $size = (isset($col['size']) ? $col['size'] : 'normal');
  $type = $col['type'] . ':' . $size;
  if (isset($map[$type])) {
    return $map[$type];
  }
  else {
    drupal_set_message(t('%table.%field: no %engine type for Schema type %type.',
                         array('%engine' => $engine, '%type' => $type, '%table' => $table, '%field' => $field)),
      'warning');
    return $col['type'];
  }
}

/**
 * Convert an engine-specific data type into a Schema type.
 */
function schema_schema_type($type, $table, $field, $engine = NULL) {
  $map = schema_dbobject()->schema_type_map();
  $type = strtolower($type);
  if (isset($map[$type])) {
    return explode(':', $map[$type]);
  }
  else {
    if (!variable_get('schema_suppress_type_warnings', FALSE)) {
      drupal_set_message(t('Field @table.@field: no Schema type for @engine type @type.', array('@engine' => $engine, '@type' => $type, '@table' => $table, '@field' => $field)), 'warning');
    }
    return array($type, 'normal');
  }
}

/**
 * Compares two complete schemas.
 * @param $ref is considered the reference copy
 * @param $inspect is compared against it.  If $inspect is NULL, a
 *         schema for the active database is generated and used.
 */
function schema_compare_schemas($ref, $inspect = NULL) {
  if (!isset($inspect)) {
    $inspect = schema_dbobject()->inspect();
  }

  $info = array();

  // Error checks to consider adding:
  // All type serial columns must be in an index or key.
  // All columns in a primary or unique key must be NOT NULL.

  // Error check: column type and default type must match
  foreach ($ref as $t_name => $table) {
    if (!isset($table['fields']) || !is_array($table['fields'])) {
      drupal_set_message(t('Table %table: Missing or invalid \'fields\' array.', array('%table' => $t_name)), 'warning');
      continue;
    }

    foreach ($table['fields'] as $c_name => $col) {
      switch ($col['type']) {
        case 'int':
        case 'float':
        case 'numeric':
          if (isset($col['default']) &&
            (! is_numeric($col['default']) || is_string($col['default']))) {
            $info['warn'][] = t('%table.%column is type %type but its default %default is PHP type %phptype', array('%table' => $t_name, '%column' => $c_name, '%type' => $col['type'], '%default' => $col['default'], '%phptype' => gettype($col['default'])));
          }
          break;

        default:
          if (isset($col['default']) && !is_string($col['default'])) {
            $info['warn'][] = t('%table.%column is type %type but its default %default is PHP type %phptype', array('%table' => $t_name, '%column' => $c_name, '%type' => $col['type'], '%default' => $col['default'], '%phptype' => gettype($col['default'])));
          }
          break;
      }
    }
  }

  // Error check: 'text' and 'blob' columns cannot have a default value
  foreach ($ref as $t_name => $table) {
    if (!isset($table['fields'])) {
      continue;
    }

    foreach ($table['fields'] as $c_name => $col) {
      switch ($col['type']) {
        case 'text':
        case 'blob':
          if (isset($col['default'])) {
            $info['warn'][] = t('%table.%column is type %type and may not have a default value', array('%table' => $t_name, '%column' => $c_name, '%type' => $col['type']));
          }
          break;
      }
    }
  }

  // Error check: primary keys must be 'not null'
  foreach ($ref as $t_name => $table) {
    if (isset($table['primary key'])) {
      $keys = db_field_names($table['primary key']);
      foreach ($keys as $key) {
        if (!isset($table['fields'][$key]['not null']) || $table['fields'][$key]['not null'] != TRUE) {
          $info['warn'][] = t('%table.%column is part of the primary key but is not specified to be \'not null\'.', array('%table' => $t_name, '%column' => $key));
        }
      }
    }
  }

  foreach ($ref as $name => $table) {
    if (isset($table['module'])) {
      $module = $table['module'];
    }
    else {
      $module = '';
    }
    if (!isset($inspect[$name])) {
      $info['missing'][$module][$name] = array('status' => 'missing');
    }
    else {
      $status = schema_compare_table($table, $inspect[$name]);
      $info[$status['status']][$module][$name] = $status;
      unset($inspect[$name]);
    }
  }

  foreach ($inspect as $name => $table) {
    $info['extra'][] = $name;
  }
  return $info;
}

/**
 * Compares a reference specification (such as one returned by a
 * module's hook_schema) to an inspected specification from the
 * database.
 * @param $inspect if not provided, the database is inspected.
 */
function schema_compare_table($ref, $inspect = NULL) {
  $_db_type = db_driver();

  if (!isset($inspect)) {
    // TODO: Handle prefixing the D7 way
//    $ref_name = db_prefix_tables('{' . $ref['name'] . '}');
    $ref_name = $ref['name'];
    $inspect = schema_dbobject()->inspect(NULL, $ref_name);
    $inspect = $inspect[$ref['name']];
  }
  if (!isset($inspect)) {
    return array('status' => 'missing');
  }

  $reasons = $notes = array();
  $col_keys = array_flip(
    array('type', 'size', 'not null', 'length', 'unsigned', 'default', 'scale', 'precision'));
  foreach ($ref['fields'] as $colname => $col) {

    // Many Schema types can map to the same engine type (e.g. in
    // PostgresSQL, text:{small,medium,big} are all just text).  When
    // we inspect the database, we see the common type, but the
    // reference we are comparing against can have a specific type.
    // We therefore run the reference's specific type through the
    // type conversion cycle to get its common type for comparison.
    //
    // Sadly, we need a special-case hack for 'serial'.
    $serial = ($col['type'] == 'serial' ? TRUE : FALSE);
    $name = isset($ref['name']) ? $ref['name'] : '';
    $dbtype = schema_engine_type($col, $name, $colname);
    list($col['type'], $col['size']) = schema_schema_type($dbtype, $name, $colname);
    if ($serial) {
      $col['type'] = 'serial';
    }

    // If an engine-specific type is specified, use it.  XXX $inspect
    // will contain the schema type for the engine type, if one
    // exists, whereas dbtype_type contains the engine type.
    if (isset($col[$_db_type . '_type'])) {
      $col['type'] = $col[$_db_type . '_type'];
    }

    $col = array_intersect_key($col, $col_keys);
    if (!isset($inspect['fields'][$colname])) {
      $reasons[] = "$colname: not in database";
      continue;
    }

    // Account for schemas that contain unnecessary 'default' => NULL
    if (!isset($col['default']) ||
        (is_null($col['default']) && !isset($inspect['fields'][$colname]['default']))) {
      unset($col['default']);
    }

    $kdiffs = array();
    foreach ($col_keys as $key => $val) {

      if (!(
          // First part tests that item exists for both and has same value in both places
           (isset($col[$key]) && !is_null($col[$key]) && $col[$key] !== FALSE
          && isset($inspect['fields'][$colname][$key]) && $inspect['fields'][$colname][$key] !== FALSE
          && $col[$key] == $inspect['fields'][$colname][$key] )
          // Second test is that it does not exist or exists but is null in both places
       || ((!isset($col[$key]) || is_null($col[$key]) || $col[$key] === FALSE)
             && (!isset($inspect['fields'][$colname][$key]) || $inspect['fields'][$colname][$key] === FALSE) ) ) ) {
        // One way or another, difference between the two so note it to explicitly identify it later.
        $kdiffs[] = $key;
      }
    }
    if (count($kdiffs) != 0) {
      $reasons[] = "column $colname - difference" .
          ( count($kdiffs) > 1 ? 's' : '') . " on: " .
          implode(', ', $kdiffs) . "<br/>declared: " .
          schema_phpprint_column($col) . '<br/>actual: ' .
          schema_phpprint_column($inspect['fields'][$colname]);
    }
    unset($inspect['fields'][$colname]);
  }
  foreach ($inspect['fields'] as $colname => $col) {
    $reasons[] = "$colname: unexpected column in database";
  }

  if (isset($ref['primary key'])) {
    if (!isset($inspect['primary key'])) {
      $reasons[] = "primary key: missing in database";
    }
    elseif ($ref['primary key'] !== $inspect['primary key']) {
      $reasons[] = ("primary key:<br />declared: " .
        schema_phpprint_key($ref['primary key']) . '<br />actual: ' .
        schema_phpprint_key($inspect['primary key']));
    }
  }
  elseif (isset($inspect['primary key'])) {
    $reasons[] = "primary key: missing in schema";
  }

  foreach (array('unique keys', 'indexes') as $type) {
    if (isset($ref[$type])) {
      foreach ($ref[$type] as $keyname => $key) {
        if (!isset($inspect[$type][$keyname])) {
          $reasons[] = "$type $keyname: missing in database";
          continue;
        }
        // $key is column list
        if ($key !== $inspect[$type][$keyname]) {
          $reasons[] = ("$type $keyname:<br />declared: " .
            schema_phpprint_key($key) . '<br />actual: ' .
            schema_phpprint_key($inspect[$type][$keyname]));
        }
        unset($inspect[$type][$keyname]);
      }
    }
    if (isset($inspect[$type])) {
      foreach ($inspect[$type] as $keyname => $col) {
        // this is not an error, the dba might have added it on purpose
        $notes[] = "$type $keyname: unexpected (not an error)";
      }
    }
  }

  $status = (count($reasons) ? 'different' : 'same');
  return array('status' => $status, 'reasons' => $reasons, 'notes' => $notes);
}
