<?php

/**
 * @file
 * Functions shared between mysql and mysqli database engines.
 */

/**
 * Runs a basic query in the active database.
 *
 * User-supplied arguments to the query should be passed in as separate
 * parameters so that they can be properly escaped to avoid SQL injection
 * attacks.
 *
 * @param $query
 *   A string containing an SQL query.
 * @param ...
 *   A variable number of arguments which are substituted into the query
 *   using printf() syntax. Instead of a variable number of query arguments,
 *   you may also pass a single array containing the query arguments.
 *
 *   Valid %-modifiers are: %s, %d, %f, %b (binary data, do not enclose
 *   in '') and %%.
 *
 *   NOTE: using this syntax will cast NULL and FALSE values to decimal 0,
 *   and TRUE values to decimal 1.
 *
 * @return
 *   A database query result resource, or FALSE if the query was not
 *   executed correctly.
 */
function db_query($query) {
  $args = func_get_args();
  array_shift($args);
  $query = db_prefix_tables($query);
  if (isset($args[0]) and is_array($args[0])) { // 'All arguments in one array' syntax
    $args = $args[0];
  }
  _db_query_callback($args, TRUE);
  $query = preg_replace_callback(DB_QUERY_REGEXP, '_db_query_callback', $query);
  return _db_query($query);
}

/**
 * @ingroup schemaapi
 * @{
 */

/**
 * Generate SQL to create a new table from a Drupal schema definition.
 *
 * @param $name
 *   The name of the table to create.
 * @param $table
 *   A Schema API table definition array.
 * @return
 *   An array of SQL statements to create the table.
 */
function db_create_table_sql($name, $table) {

  if (empty($table['mysql_suffix'])) {
    $table['mysql_suffix'] = '/*!40100 DEFAULT CHARACTER SET utf8';
    // By default, MySQL uses the default collation for new tables, which is
    // 'utf8_general_ci' for utf8. If an alternate collation has been set, it
    // needs to be explicitly specified.
    // @see db_connect()
    $collation = (!empty($table['collation']) ? $table['collation'] : (!empty($GLOBALS['db_collation']) ? $GLOBALS['db_collation'] : ''));
    if ($collation) {
      $table['mysql_suffix'] .= ' COLLATE ' . $collation;
    }
    $table['mysql_suffix'] .= ' */';
  }

  $sql = "CREATE TABLE {". $name ."} (\n";

  // Add the SQL statement for each field.
  foreach ($table['fields'] as $field_name => $field) {
    $sql .= _db_create_field_sql($field_name, _db_process_field($field)) .", \n";
  }

  // Process keys & indexes.
  $keys = _db_create_keys_sql($table);
  if (count($keys)) {
    $sql .= implode(", \n", $keys) .", \n";
  }

  // Remove the last comma and space.
  $sql = substr($sql, 0, -3) ."\n) ";

  $sql .= $table['mysql_suffix'];

  return array($sql);
}

function _db_create_keys_sql($spec) {
  $keys = array();

  if (!empty($spec['primary key'])) {
    $keys[] = 'PRIMARY KEY ('. _db_create_key_sql($spec['primary key']) .')';
  }
  if (!empty($spec['unique keys'])) {
    foreach ($spec['unique keys'] as $key => $fields) {
      $keys[] = 'UNIQUE KEY '. $key .' ('. _db_create_key_sql($fields) .')';
    }
  }
  if (!empty($spec['indexes'])) {
    foreach ($spec['indexes'] as $index => $fields) {
      $keys[] = 'INDEX '. $index .' ('. _db_create_key_sql($fields) .')';
    }
  }

  return $keys;
}

function _db_create_key_sql($fields) {
  $ret = array();
  foreach ($fields as $field) {
    if (is_array($field)) {
      $ret[] = $field[0] .'('. $field[1] .')';
    }
    else {
      $ret[] = $field;
    }
  }
  return implode(', ', $ret);
}

/**
 * Set database-engine specific properties for a field.
 *
 * @param $field
 *   A field description array, as specified in the schema documentation.
 */
function _db_process_field($field) {

  if (!isset($field['size'])) {
    $field['size'] = 'normal';
  }

  // Set the correct database-engine specific datatype.
  if (!isset($field['mysql_type'])) {
    $map = db_type_map();
    $field['mysql_type'] = $map[$field['type'] .':'. $field['size']];
  }

  if ($field['type'] == 'serial') {
    $field['auto_increment'] = TRUE;
  }

  return $field;
}

/**
 * Create an SQL string for a field to be used in table creation or alteration.
 *
 * Before passing a field out of a schema definition into this function it has
 * to be processed by _db_process_field().
 *
 * @param $name
 *    Name of the field.
 * @param $spec
 *    The field specification, as per the schema data structure format.
 */
function _db_create_field_sql($name, $spec) {
  $sql = "`". $name ."` ". $spec['mysql_type'];

  if (in_array($spec['type'], array('varchar', 'char', 'text')) && isset($spec['length'])) {
    $sql .= '('. $spec['length'] .')';
  }
  elseif (isset($spec['precision']) && isset($spec['scale'])) {
    $sql .= '('. $spec['precision'] .', '. $spec['scale'] .')';
  }

  if (!empty($spec['unsigned'])) {
    $sql .= ' unsigned';
  }

  if (!empty($spec['not null'])) {
    $sql .= ' NOT NULL';
  }

  if (!empty($spec['auto_increment'])) {
    $sql .= ' auto_increment';
  }

  if (isset($spec['default'])) {
    if (is_string($spec['default'])) {
      $spec['default'] = "'". $spec['default'] ."'";
    }
    $sql .= ' DEFAULT '. $spec['default'];
  }

  if (empty($spec['not null']) && !isset($spec['default'])) {
    $sql .= ' DEFAULT NULL';
  }

  return $sql;
}

/**
 * This maps a generic data type in combination with its data size
 * to the engine-specific data type.
 */
function db_type_map() {
  // Put :normal last so it gets preserved by array_flip.  This makes
  // it much easier for modules (such as schema.module) to map
  // database types back into schema types.
  $map = array(
    'varchar:normal'  => 'VARCHAR',
    'char:normal'     => 'CHAR',

    'text:tiny'       => 'TINYTEXT',
    'text:small'      => 'TINYTEXT',
    'text:medium'     => 'MEDIUMTEXT',
    'text:big'        => 'LONGTEXT',
    'text:normal'     => 'TEXT',

    'serial:tiny'     => 'TINYINT',
    'serial:small'    => 'SMALLINT',
    'serial:medium'   => 'MEDIUMINT',
    'serial:big'      => 'BIGINT',
    'serial:normal'   => 'INT',

    'int:tiny'        => 'TINYINT',
    'int:small'       => 'SMALLINT',
    'int:medium'      => 'MEDIUMINT',
    'int:big'         => 'BIGINT',
    'int:normal'      => 'INT',

    'float:tiny'      => 'FLOAT',
    'float:small'     => 'FLOAT',
    'float:medium'    => 'FLOAT',
    'float:big'       => 'DOUBLE',
    'float:normal'    => 'FLOAT',

    'numeric:normal'  => 'DECIMAL',

    'blob:big'        => 'LONGBLOB',
    'blob:normal'     => 'BLOB',

    'datetime:normal' => 'DATETIME',
  );
  return $map;
}

/**
 * Rename a table.
 *
 * @param $ret
 *   Array to which query results will be added.
 * @param $table
 *   The table to be renamed.
 * @param $new_name
 *   The new name for the table.
 */
function db_rename_table(&$ret, $table, $new_name) {
  $ret[] = update_sql('ALTER TABLE {'. $table .'} RENAME TO {'. $new_name .'}');
}

/**
 * Drop a table.
 *
 * @param $ret
 *   Array to which query results will be added.
 * @param $table
 *   The table to be dropped.
 */
function db_drop_table(&$ret, $table) {
  $ret[] = update_sql('DROP TABLE {'. $table .'}');
}

/**
 * Add a new field to a table.
 *
 * @param $ret
 *   Array to which query results will be added.
 * @param $table
 *   Name of the table to be altered.
 * @param $field
 *   Name of the field to be added.
 * @param $spec
 *   The field specification array, as taken from a schema definition.
 *   The specification may also contain the key 'initial', the newly
 *   created field will be set to the value of the key in all rows.
 *   This is most useful for creating NOT NULL columns with no default
 *   value in existing tables.
 * @param $keys_new
 *   Optional keys and indexes specification to be created on the
 *   table along with adding the field. The format is the same as a
 *   table specification but without the 'fields' element.  If you are
 *   adding a type 'serial' field, you MUST specify at least one key
 *   or index including it in this array. See db_change_field() for more
 *   explanation why.
 */
function db_add_field(&$ret, $table, $field, $spec, $keys_new = array()) {
  $fixnull = FALSE;
  if (!empty($spec['not null']) && !isset($spec['default'])) {
    $fixnull = TRUE;
    $spec['not null'] = FALSE;
  }
  $query = 'ALTER TABLE {'. $table .'} ADD ';
  $query .= _db_create_field_sql($field, _db_process_field($spec));
  if (count($keys_new)) {
    $query .= ', ADD '. implode(', ADD ', _db_create_keys_sql($keys_new));
  }
  $ret[] = update_sql($query);
  if (isset($spec['initial'])) {
    // All this because update_sql does not support %-placeholders.
    $sql = 'UPDATE {'. $table .'} SET '. $field .' = '. db_type_placeholder($spec['type']);
    $result = db_query($sql, $spec['initial']);
    $ret[] = array('success' => $result !== FALSE, 'query' => check_plain($sql .' ('. $spec['initial'] .')'));
  }
  if ($fixnull) {
    $spec['not null'] = TRUE;
    db_change_field($ret, $table, $field, $field, $spec);
  }
}

/**
 * Drop a field.
 *
 * @param $ret
 *   Array to which query results will be added.
 * @param $table
 *   The table to be altered.
 * @param $field
 *   The field to be dropped.
 */
function db_drop_field(&$ret, $table, $field) {
  $ret[] = update_sql('ALTER TABLE {'. $table .'} DROP '. $field);
}

/**
 * Set the default value for a field.
 *
 * @param $ret
 *   Array to which query results will be added.
 * @param $table
 *   The table to be altered.
 * @param $field
 *   The field to be altered.
 * @param $default
 *   Default value to be set. NULL for 'default NULL'.
 */
function db_field_set_default(&$ret, $table, $field, $default) {
  if ($default === NULL) {
    $default = 'NULL';
  }
  else {
    $default = is_string($default) ? "'$default'" : $default;
  }

  $ret[] = update_sql('ALTER TABLE {'. $table .'} ALTER COLUMN '. $field .' SET DEFAULT '. $default);
}

/**
 * Set a field to have no default value.
 *
 * @param $ret
 *   Array to which query results will be added.
 * @param $table
 *   The table to be altered.
 * @param $field
 *   The field to be altered.
 */
function db_field_set_no_default(&$ret, $table, $field) {
  $ret[] = update_sql('ALTER TABLE {'. $table .'} ALTER COLUMN '. $field .' DROP DEFAULT');
}

/**
 * Add a primary key.
 *
 * @param $ret
 *   Array to which query results will be added.
 * @param $table
 *   The table to be altered.
 * @param $fields
 *   Fields for the primary key.
 */
function db_add_primary_key(&$ret, $table, $fields) {
  $ret[] = update_sql('ALTER TABLE {'. $table .'} ADD PRIMARY KEY ('.
    _db_create_key_sql($fields) .')');
}

/**
 * Drop the primary key.
 *
 * @param $ret
 *   Array to which query results will be added.
 * @param $table
 *   The table to be altered.
 */
function db_drop_primary_key(&$ret, $table) {
  $ret[] = update_sql('ALTER TABLE {'. $table .'} DROP PRIMARY KEY');
}

/**
 * Add a unique key.
 *
 * @param $ret
 *   Array to which query results will be added.
 * @param $table
 *   The table to be altered.
 * @param $name
 *   The name of the key.
 * @param $fields
 *   An array of field names.
 */
function db_add_unique_key(&$ret, $table, $name, $fields) {
  $ret[] = update_sql('ALTER TABLE {'. $table .'} ADD UNIQUE KEY '.
    $name .' ('. _db_create_key_sql($fields) .')');
}

/**
 * Drop a unique key.
 *
 * @param $ret
 *   Array to which query results will be added.
 * @param $table
 *   The table to be altered.
 * @param $name
 *   The name of the key.
 */
function db_drop_unique_key(&$ret, $table, $name) {
  $ret[] = update_sql('ALTER TABLE {'. $table .'} DROP KEY '. $name);
}

/**
 * Add an index.
 *
 * @param $ret
 *   Array to which query results will be added.
 * @param $table
 *   The table to be altered.
 * @param $name
 *   The name of the index.
 * @param $fields
 *   An array of field names.
 */
function db_add_index(&$ret, $table, $name, $fields) {
  $query = 'ALTER TABLE {'. $table .'} ADD INDEX '. $name .' ('. _db_create_key_sql($fields) .')';
  $ret[] = update_sql($query);
}

/**
 * Drop an index.
 *
 * @param $ret
 *   Array to which query results will be added.
 * @param $table
 *   The table to be altered.
 * @param $name
 *   The name of the index.
 */
function db_drop_index(&$ret, $table, $name) {
  $ret[] = update_sql('ALTER TABLE {'. $table .'} DROP INDEX '. $name);
}

/**
 * Change a field definition.
 *
 * IMPORTANT NOTE: To maintain database portability, you have to explicitly
 * recreate all indices and primary keys that are using the changed field.
 *
 * That means that you have to drop all affected keys and indexes with
 * db_drop_{primary_key,unique_key,index}() before calling db_change_field().
 * To recreate the keys and indices, pass the key definitions as the
 * optional $keys_new argument directly to db_change_field().
 *
 * For example, suppose you have:
 * @code
 * $schema['foo'] = array(
 *   'fields' => array(
 *     'bar' => array('type' => 'int', 'not null' => TRUE)
 *   ),
 *   'primary key' => array('bar')
 * );
 * @endcode
 * and you want to change foo.bar to be type serial, leaving it as the
 * primary key.  The correct sequence is:
 * @code
 * db_drop_primary_key($ret, 'foo');
 * db_change_field($ret, 'foo', 'bar', 'bar',
 *   array('type' => 'serial', 'not null' => TRUE),
 *   array('primary key' => array('bar')));
 * @endcode
 *
 * The reasons for this are due to the different database engines:
 *
 * On PostgreSQL, changing a field definition involves adding a new field
 * and dropping an old one which* causes any indices, primary keys and
 * sequences (from serial-type fields) that use the changed field to be dropped.
 *
 * On MySQL, all type 'serial' fields must be part of at least one key
 * or index as soon as they are created.  You cannot use
 * db_add_{primary_key,unique_key,index}() for this purpose because
 * the ALTER TABLE command will fail to add the column without a key
 * or index specification.  The solution is to use the optional
 * $keys_new argument to create the key or index at the same time as
 * field.
 *
 * You could use db_add_{primary_key,unique_key,index}() in all cases
 * unless you are converting a field to be type serial. You can use
 * the $keys_new argument in all cases.
 *
 * @param $ret
 *   Array to which query results will be added.
 * @param $table
 *   Name of the table.
 * @param $field
 *   Name of the field to change.
 * @param $field_new
 *   New name for the field (set to the same as $field if you don't want to change the name).
 * @param $spec
 *   The field specification for the new field.
 * @param $keys_new
 *   Optional keys and indexes specification to be created on the
 *   table along with changing the field. The format is the same as a
 *   table specification but without the 'fields' element.
 */

function db_change_field(&$ret, $table, $field, $field_new, $spec, $keys_new = array()) {
  $sql = 'ALTER TABLE {'. $table .'} CHANGE `'. $field .'` '.
    _db_create_field_sql($field_new, _db_process_field($spec));
  if (count($keys_new)) {
    $sql .= ', ADD '. implode(', ADD ', _db_create_keys_sql($keys_new));
  }
  $ret[] = update_sql($sql);
}

/**
 * Returns the last insert id.
 *
 * @param $table
 *   The name of the table you inserted into.
 * @param $field
 *   The name of the autoincrement field.
 */
function db_last_insert_id($table, $field) {
  return db_result(db_query('SELECT LAST_INSERT_ID()'));
}
