<?php
/*
 +--------------------------------------------------------------------+
 | CiviCRM version 4.3                                                |
 +--------------------------------------------------------------------+
 | Copyright CiviCRM LLC (c) 2004-2013                                |
 +--------------------------------------------------------------------+
 | This file is a part of CiviCRM.                                    |
 |                                                                    |
 | CiviCRM is free software; you can copy, modify, and distribute it  |
 | under the terms of the GNU Affero General Public License           |
 | Version 3, 19 November 2007 and the CiviCRM Licensing Exception.   |
 |                                                                    |
 | CiviCRM is distributed in the hope that it will be useful, but     |
 | WITHOUT ANY WARRANTY; without even the implied warranty of         |
 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.               |
 | See the GNU Affero General Public License for more details.        |
 |                                                                    |
 | You should have received a copy of the GNU Affero General Public   |
 | License and the CiviCRM Licensing Exception along                  |
 | with this program; if not, contact CiviCRM LLC                     |
 | at info[AT]civicrm[DOT]org. If you have questions about the        |
 | GNU Affero General Public License or the licensing of CiviCRM,     |
 | see the CiviCRM license FAQ at http://civicrm.org/licensing        |
 +--------------------------------------------------------------------+
*/

/**
 *
 * @package CRM
 * @copyright CiviCRM LLC (c) 2004-2013
 * $Id$
 *
 */
class CRM_Logging_Schema {
  private $logs = array();
  private $tables = array();

  private $db;
  private $useDBPrefix = TRUE;

  private $reports = array(
    'logging/contact/detail',
    'logging/contact/summary',
    'logging/contribute/detail',
    'logging/contribute/summary',
  );

  /**
   * Populate $this->tables and $this->logs with current db state.
   */
  function __construct() {
    $dao = new CRM_Contact_DAO_Contact();
    $civiDBName = $dao->_database;

    $dao = CRM_Core_DAO::executeQuery("
SELECT TABLE_NAME
FROM   INFORMATION_SCHEMA.TABLES
WHERE  TABLE_SCHEMA = '{$civiDBName}'
AND    TABLE_TYPE = 'BASE TABLE'
AND    TABLE_NAME LIKE 'civicrm_%'
");
    while ($dao->fetch()) {
      $this->tables[] = $dao->TABLE_NAME;
    }

    // do not log temp import, cache and log tables
    $this->tables = preg_grep('/^civicrm_import_job_/', $this->tables, PREG_GREP_INVERT);
    $this->tables = preg_grep('/_cache$/', $this->tables, PREG_GREP_INVERT);
    $this->tables = preg_grep('/_log/', $this->tables, PREG_GREP_INVERT);
    $this->tables = preg_grep('/^civicrm_task_action_temp_/', $this->tables, PREG_GREP_INVERT);
    $this->tables = preg_grep('/^civicrm_export_temp_/', $this->tables, PREG_GREP_INVERT);
    $this->tables = preg_grep('/^civicrm_queue_/', $this->tables, PREG_GREP_INVERT);

    // do not log civicrm_mailing_event* tables, CRM-12300
    $this->tables = preg_grep('/^civicrm_mailing_event_/', $this->tables, PREG_GREP_INVERT);

    if (defined('CIVICRM_LOGGING_DSN')) {
      $dsn = DB::parseDSN(CIVICRM_LOGGING_DSN);
      $this->useDBPrefix = (CIVICRM_LOGGING_DSN != CIVICRM_DSN);
    }
    else {
      $dsn = DB::parseDSN(CIVICRM_DSN);
      $this->useDBPrefix = FALSE;
    }
    $this->db = $dsn['database'];

    $dao = CRM_Core_DAO::executeQuery("
SELECT TABLE_NAME
FROM   INFORMATION_SCHEMA.TABLES
WHERE  TABLE_SCHEMA = '{$this->db}'
AND    TABLE_TYPE = 'BASE TABLE'
AND    TABLE_NAME LIKE 'log_civicrm_%'
");
    while ($dao->fetch()) {
      $log = $dao->TABLE_NAME;
      $this->logs[substr($log, 4)] = $log;
    }
  }

  /**
   * Return logging custom data tables.
   */
  function customDataLogTables() {
    return preg_grep('/^log_civicrm_value_/', $this->logs);
  }

  /**
   * Disable logging by dropping the triggers (but keep the log tables intact).
   */
  function disableLogging() {
    $config = CRM_Core_Config::singleton();
    $config->logging = FALSE;

    $this->dropTriggers();

    // invoke the meta trigger creation call
    CRM_Core_DAO::triggerRebuild();

    $this->deleteReports();
  }

  /**
   * Drop triggers for all logged tables.
   */
  function dropTriggers($tableName = NULL) {
    $dao = new CRM_Core_DAO;

    if ($tableName) {
      $tableNames = array($tableName);
    }
    else {
      $tableNames = $this->tables;
    }

    foreach ($tableNames as $table) {
      // before triggers
      $dao->executeQuery("DROP TRIGGER IF EXISTS {$table}_before_insert");
      $dao->executeQuery("DROP TRIGGER IF EXISTS {$table}_before_update");
      $dao->executeQuery("DROP TRIGGER IF EXISTS {$table}_before_delete");

     // after triggers
      $dao->executeQuery("DROP TRIGGER IF EXISTS {$table}_after_insert");
      $dao->executeQuery("DROP TRIGGER IF EXISTS {$table}_after_update");
      $dao->executeQuery("DROP TRIGGER IF EXISTS {$table}_after_delete");
    }
  }

  /**
   * Enable sitewide logging.
   *
   * @return void
   */
  function enableLogging() {
    $this->fixSchemaDifferences(TRUE);
    $this->addReports();
  }

  /**
   * Sync log tables and rebuild triggers.
   *
   * @param bool $enableLogging: Ensure logging is enabled
   *
   * @return void
   */
  function fixSchemaDifferences($enableLogging = FALSE) {
    $config = CRM_Core_Config::singleton();
    if ($enableLogging) {
      $config->logging = TRUE;
    }
    if ($config->logging) {
      foreach ($this->schemaDifferences() as $table => $cols) {
        $this->fixSchemaDifferencesFor($table, $cols, FALSE);
      }
    }
    // invoke the meta trigger creation call
    CRM_Core_DAO::triggerRebuild();
  }

  /**
   * Add missing (potentially specified) log table columns for the given table.
   *
   * @param $table string  name of the relevant table
   * @param $cols mixed    array of columns to add or null (to check for the missing columns)
   * @param $rebuildTrigger boolean should we rebuild the triggers
   *
   * @return void
   */
  function fixSchemaDifferencesFor($table, $cols = NULL, $rebuildTrigger = TRUE) {
    if (empty($this->logs[$table])) {
      $this->createLogTableFor($table);
      return;
    }

    if (is_null($cols)) {
      $cols = array_diff($this->columnsOf($table), $this->columnsOf("log_$table"));
    }
    if (empty($cols)) {
      return;
    }

    // use the relevant lines from CREATE TABLE to add colums to the log table
    $dao = CRM_Core_DAO::executeQuery("SHOW CREATE TABLE $table");
    $dao->fetch();
    $create = explode("\n", $dao->Create_Table);
    foreach ($cols as $col) {
      $line = preg_grep("/^  `$col` /", $create);
      $line = substr(array_pop($line), 0, -1);
      // CRM-11179
      $line = self::fixTimeStampAndNotNullSQL($line);

      CRM_Core_DAO::executeQuery("ALTER TABLE `{$this->db}`.log_$table ADD $line");
    }

    if ($rebuildTrigger) {
      // invoke the meta trigger creation call
      CRM_Core_DAO::triggerRebuild($table);
    }
  }

  function fixTimeStampAndNotNullSQL($query) {
    $query = str_ireplace("TIMESTAMP NOT NULL", "TIMESTAMP NULL", $query);
    $query = str_ireplace("DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP", '', $query);
    $query = str_ireplace("DEFAULT CURRENT_TIMESTAMP", '', $query);
    $query = str_ireplace("NOT NULL", '', $query);
    return $query;
  }

  /**
   * Find missing log table columns by comparing columns of the relevant tables.
   * Returns table-name-keyed array of arrays of missing columns, e.g. array('civicrm_value_foo_1' => array('bar_1', 'baz_2'))
   */
  function schemaDifferences() {
    $diffs = array();
    foreach ($this->tables as $table) {
      $diffs[$table] = array_diff($this->columnsOf($table), $this->columnsOf("log_$table"));
    }
    return array_filter($diffs);
  }

  private function addReports() {
    $titles = array(
      'logging/contact/detail' => ts('Logging Details'),
      'logging/contact/summary' => ts('Contact Logging Report (Summary)'),
      'logging/contribute/detail' => ts('Contribution Logging Report (Detail)'),
      'logging/contribute/summary' => ts('Contribution Logging Report (Summary)'),
    );
    // enable logging templates
    CRM_Core_DAO::executeQuery("
            UPDATE civicrm_option_value
            SET is_active = 1
            WHERE value IN ('" . implode("', '", $this->reports) . "')
        ");

    // add report instances
    $domain_id = CRM_Core_Config::domainID();
    foreach ($this->reports as $report) {
      $dao             = new CRM_Report_DAO_ReportInstance;
      $dao->domain_id  = $domain_id;
      $dao->report_id  = $report;
      $dao->title      = $titles[$report];
      $dao->permission = 'administer CiviCRM';
      if ($report == 'logging/contact/summary')
        $dao->is_reserved = 1;
      $dao->insert();
    }
  }

  /**
   * Get an array of column names of the given table.
   */
  private function columnsOf($table) {
    static $columnsOf = array();

    $from = (substr($table, 0, 4) == 'log_') ? "`{$this->db}`.$table" : $table;

    if (!isset($columnsOf[$table])) {
      CRM_Core_Error::ignoreException();
      $dao = CRM_Core_DAO::executeQuery("SHOW COLUMNS FROM $from");
      CRM_Core_Error::setCallback();
      if (is_a($dao, 'DB_Error')) {
        return array();
      }
      $columnsOf[$table] = array();
      while ($dao->fetch()) {
        $columnsOf[$table][] = $dao->Field;
      }
    }

    return $columnsOf[$table];
  }

  /**
   * Create a log table with schema mirroring the given table’s structure and seeding it with the given table’s contents.
   */
  private function createLogTableFor($table) {
    $dao = CRM_Core_DAO::executeQuery("SHOW CREATE TABLE $table");
    $dao->fetch();
    $query = $dao->Create_Table;

    // rewrite the queries into CREATE TABLE queries for log tables:
    $cols = <<<COLS
            log_date    TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
            log_conn_id INTEGER,
            log_user_id INTEGER,
            log_action  ENUM('Initialization', 'Insert', 'Update', 'Delete')
COLS;

    // - prepend the name with log_
    // - drop AUTO_INCREMENT columns
    // - drop non-column rows of the query (keys, constraints, etc.)
    // - set the ENGINE to ARCHIVE
    // - add log-specific columns (at the end of the table)
    $query = preg_replace("/^CREATE TABLE `$table`/i", "CREATE TABLE `{$this->db}`.log_$table", $query);
    $query = preg_replace("/ AUTO_INCREMENT/i", '', $query);
    $query = preg_replace("/^  [^`].*$/m", '', $query);
    $query = preg_replace("/^\) ENGINE=[^ ]+ /im", ') ENGINE=ARCHIVE ', $query);

    // log_civicrm_contact.modified_date for example would always be copied from civicrm_contact.modified_date,
    // so there's no need for a default timestamp and therefore we remove such default timestamps
    // also eliminate the NOT NULL constraint, since we always copy and schema can change down the road)
    $query = self::fixTimeStampAndNotNullSQL($query);
    $query = preg_replace("/^\) /m", "$cols\n) ", $query);

    CRM_Core_DAO::executeQuery($query);

    $columns = implode(', ', $this->columnsOf($table));
    CRM_Core_DAO::executeQuery("INSERT INTO `{$this->db}`.log_$table ($columns, log_conn_id, log_user_id, log_action) SELECT $columns, CONNECTION_ID(), @civicrm_user_id, 'Initialization' FROM {$table}");

    $this->tables[] = $table;
    $this->logs[$table] = "log_$table";
  }

  private function deleteReports() {
    // disable logging templates
    CRM_Core_DAO::executeQuery("
            UPDATE civicrm_option_value
            SET is_active = 0
            WHERE value IN ('" . implode("', '", $this->reports) . "')
        ");

    // delete report instances
    $domain_id = CRM_Core_Config::domainID();
    foreach ($this->reports as $report) {
      $dao            = new CRM_Report_DAO_ReportInstance;
      $dao->domain_id = $domain_id;
      $dao->report_id = $report;
      $dao->delete();
    }
  }

  /**
   * Predicate whether logging is enabled.
   */
  public function isEnabled() {
    $config = CRM_Core_Config::singleton();

    if ($config->logging) {
      return $this->tablesExist() and $this->triggersExist();
    }
    return FALSE;
  }

  /**
   * Predicate whether any log tables exist.
   */
  private function tablesExist() {
    return !empty($this->logs);
  }

  /**
   * Predicate whether the logging triggers are in place.
   */
  private function triggersExist() {
    // FIXME: probably should be a bit more thorough…
    // note that the LIKE parameter is TABLE NAME
    return (bool) CRM_Core_DAO::singleValueQuery("SHOW TRIGGERS LIKE 'civicrm_contact'");
  }

  function triggerInfo(&$info, $tableName = NULL) {
    // check if we have logging enabled
    $config =& CRM_Core_Config::singleton();
    if (!$config->logging) {
      return;
    }

    $insert = array('INSERT');
    $update = array('UPDATE');
    $delete = array('DELETE');

    if ($tableName) {
      $tableNames = array($tableName);
    }
    else {
      $tableNames = $this->tables;
    }

    // logging is enabled, so now lets create the trigger info tables
    foreach ($tableNames as $table) {
      $columns = $this->columnsOf($table);

      // only do the change if any data has changed
      $cond = array( );
      foreach ($columns as $column) {
        // ignore modified_date changes
        if ($column != 'modified_date') {
          $cond[] = "IFNULL(OLD.$column,'') <> IFNULL(NEW.$column,'')";
        }
      }
      $suppressLoggingCond = "@civicrm_disable_logging IS NULL OR @civicrm_disable_logging = 0";
      $updateSQL = "IF ( (" . implode( ' OR ', $cond ) . ") AND ( $suppressLoggingCond ) ) THEN ";

      if ($this->useDBPrefix) {
        $sqlStmt = "INSERT INTO `{$this->db}`.log_{tableName} (";
      }
      else {
        $sqlStmt = "INSERT INTO log_{tableName} (";
      }
      foreach ($columns as $column) {
        $sqlStmt .= "$column, ";
      }
      $sqlStmt .= "log_conn_id, log_user_id, log_action) VALUES (";

      $insertSQL = $deleteSQL = "IF ( $suppressLoggingCond ) THEN $sqlStmt ";
      $updateSQL .= $sqlStmt;

      $sqlStmt = '';
      foreach ($columns as $column) {
        $sqlStmt   .= "NEW.$column, ";
        $deleteSQL .= "OLD.$column, ";
      }
      $sqlStmt   .= "CONNECTION_ID(), @civicrm_user_id, '{eventName}');";
      $deleteSQL .= "CONNECTION_ID(), @civicrm_user_id, '{eventName}');";

      $sqlStmt   .= "END IF;";
      $deleteSQL .= "END IF;";

      $insertSQL .= $sqlStmt;
      $updateSQL .= $sqlStmt;

      $info[] = array(
        'table' => array($table),
        'when' => 'AFTER',
        'event' => $insert,
        'sql' => $insertSQL,
      );

      $info[] = array(
        'table' => array($table),
        'when' => 'AFTER',
        'event' => $update,
        'sql' => $updateSQL,
      );

      $info[] = array(
        'table' => array($table),
        'when' => 'AFTER',
        'event' => $delete,
        'sql' => $deleteSQL,
      );
    }
  }

  /**
   * This allow logging to be temporarily disabled for certain cases
   * where we want to do a mass cleanup but dont want to bother with
   * an audit trail
   *
   * @static
   * @public
   */
  static function disableLoggingForThisConnection( ) {
    // do this only if logging is enabled
    $config = CRM_Core_Config::singleton( );
    if ( $config->logging ) {
      CRM_Core_DAO::executeQuery( 'SET @civicrm_disable_logging = 1' );
    }
  }

}