<?php
/**
 * Oracle-specific installer.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 * @ingroup Deployment
 */

use Wikimedia\Rdbms\DBConnectionError;

/**
 * Class for setting up the MediaWiki database using Oracle.
 *
 * @ingroup Deployment
 * @since 1.17
 */
class OracleInstaller extends DatabaseInstaller {

	protected $globalNames = [
		'wgDBserver',
		'wgDBname',
		'wgDBuser',
		'wgDBpassword',
		'wgDBprefix',
	];

	protected $internalDefaults = [
		'_OracleDefTS' => 'USERS',
		'_OracleTempTS' => 'TEMP',
		'_InstallUser' => 'SYSTEM',
	];

	public $minimumVersion = '9.0.1'; // 9iR1

	protected $connError = null;

	public function getName() {
		return 'oracle';
	}

	public function isCompiled() {
		return self::checkExtension( 'oci8' );
	}

	public function getConnectForm() {
		if ( $this->getVar( 'wgDBserver' ) == 'localhost' ) {
			$this->parent->setVar( 'wgDBserver', '' );
		}

		return $this->getTextBox(
			'wgDBserver',
			'config-db-host-oracle',
			[],
			$this->parent->getHelpBox( 'config-db-host-oracle-help' )
		) .
			Html::openElement( 'fieldset' ) .
			Html::element( 'legend', [], wfMessage( 'config-db-wiki-settings' )->text() ) .
			$this->getTextBox( 'wgDBprefix', 'config-db-prefix' ) .
			$this->getTextBox( '_OracleDefTS', 'config-oracle-def-ts' ) .
			$this->getTextBox(
				'_OracleTempTS',
				'config-oracle-temp-ts',
				[],
				$this->parent->getHelpBox( 'config-db-oracle-help' )
			) .
			Html::closeElement( 'fieldset' ) .
			$this->parent->getWarningBox( wfMessage( 'config-db-account-oracle-warn' )->text() ) .
			$this->getInstallUserBox() .
			$this->getWebUserBox();
	}

	public function submitInstallUserBox() {
		parent::submitInstallUserBox();
		$this->parent->setVar( '_InstallDBname', $this->getVar( '_InstallUser' ) );

		return Status::newGood();
	}

	public function submitConnectForm() {
		// Get variables from the request
		$newValues = $this->setVarsFromRequest( [
			'wgDBserver',
			'wgDBprefix',
			'wgDBuser',
			'wgDBpassword'
		] );
		$this->parent->setVar( 'wgDBname', $this->getVar( 'wgDBuser' ) );

		// Validate them
		$status = Status::newGood();
		if ( !strlen( $newValues['wgDBserver'] ) ) {
			$status->fatal( 'config-missing-db-server-oracle' );
		} elseif ( !self::checkConnectStringFormat( $newValues['wgDBserver'] ) ) {
			$status->fatal( 'config-invalid-db-server-oracle', $newValues['wgDBserver'] );
		}
		if ( !preg_match( '/^[a-zA-Z0-9_]*$/', $newValues['wgDBprefix'] ) ) {
			$status->fatal( 'config-invalid-schema', $newValues['wgDBprefix'] );
		}
		if ( !$status->isOK() ) {
			return $status;
		}

		// Submit user box
		$status = $this->submitInstallUserBox();
		if ( !$status->isOK() ) {
			return $status;
		}

		// Try to connect trough multiple scenarios
		// Scenario 1: Install with a manually created account
		$status = $this->getConnection();
		if ( !$status->isOK() ) {
			if ( $this->connError == 28009 ) {
				// _InstallUser seems to be a SYSDBA
				// Scenario 2: Create user with SYSDBA and install with new user
				$status = $this->submitWebUserBox();
				if ( !$status->isOK() ) {
					return $status;
				}
				$status = $this->openSYSDBAConnection();
				if ( !$status->isOK() ) {
					return $status;
				}
				if ( !$this->getVar( '_CreateDBAccount' ) ) {
					$status->fatal( 'config-db-sys-create-oracle' );
				}
			} else {
				return $status;
			}
		} else {
			// check for web user credentials
			// Scenario 3: Install with a priviliged user but use a restricted user
			$statusIS3 = $this->submitWebUserBox();
			if ( !$statusIS3->isOK() ) {
				return $statusIS3;
			}
		}

		/**
		 * @var $conn Database
		 */
		$conn = $status->value;

		// Check version
		$version = $conn->getServerVersion();
		if ( version_compare( $version, $this->minimumVersion ) < 0 ) {
			return Status::newFatal( 'config-oracle-old', $this->minimumVersion, $version );
		}

		return $status;
	}

	public function openConnection() {
		$status = Status::newGood();
		try {
			$db = new DatabaseOracle(
				$this->getVar( 'wgDBserver' ),
				$this->getVar( '_InstallUser' ),
				$this->getVar( '_InstallPassword' ),
				$this->getVar( '_InstallDBname' ),
				0,
				$this->getVar( 'wgDBprefix' )
			);
			$status->value = $db;
		} catch ( DBConnectionError $e ) {
			$this->connError = $e->db->lastErrno();
			$status->fatal( 'config-connection-error', $e->getMessage() );
		}

		return $status;
	}

	public function openSYSDBAConnection() {
		$status = Status::newGood();
		try {
			$db = new DatabaseOracle(
				$this->getVar( 'wgDBserver' ),
				$this->getVar( '_InstallUser' ),
				$this->getVar( '_InstallPassword' ),
				$this->getVar( '_InstallDBname' ),
				DBO_SYSDBA,
				$this->getVar( 'wgDBprefix' )
			);
			$status->value = $db;
		} catch ( DBConnectionError $e ) {
			$this->connError = $e->db->lastErrno();
			$status->fatal( 'config-connection-error', $e->getMessage() );
		}

		return $status;
	}

	public function needsUpgrade() {
		$tempDBname = $this->getVar( 'wgDBname' );
		$this->parent->setVar( 'wgDBname', $this->getVar( 'wgDBuser' ) );
		$retVal = parent::needsUpgrade();
		$this->parent->setVar( 'wgDBname', $tempDBname );

		return $retVal;
	}

	public function preInstall() {
		# Add our user callback to installSteps, right before the tables are created.
		$callback = [
			'name' => 'user',
			'callback' => [ $this, 'setupUser' ]
		];
		$this->parent->addInstallStep( $callback, 'database' );
	}

	public function setupDatabase() {
		$status = Status::newGood();

		return $status;
	}

	public function setupUser() {
		global $IP;

		if ( !$this->getVar( '_CreateDBAccount' ) ) {
			return Status::newGood();
		}

		// normaly only SYSDBA users can create accounts
		$status = $this->openSYSDBAConnection();
		if ( !$status->isOK() ) {
			if ( $this->connError == 1031 ) {
				// insufficient  privileges (looks like a normal user)
				$status = $this->openConnection();
				if ( !$status->isOK() ) {
					return $status;
				}
			} else {
				return $status;
			}
		}

		$this->db = $status->value;
		$this->setupSchemaVars();

		if ( !$this->db->selectDB( $this->getVar( 'wgDBuser' ) ) ) {
			$this->db->setFlag( DBO_DDLMODE );
			$error = $this->db->sourceFile( "$IP/maintenance/oracle/user.sql" );
			if ( $error !== true || !$this->db->selectDB( $this->getVar( 'wgDBuser' ) ) ) {
				$status->fatal( 'config-install-user-failed', $this->getVar( 'wgDBuser' ), $error );
			}
		} elseif ( $this->db->getFlag( DBO_SYSDBA ) ) {
			$status->fatal( 'config-db-sys-user-exists-oracle', $this->getVar( 'wgDBuser' ) );
		}

		if ( $status->isOK() ) {
			// user created or already existing, switching back to a normal connection
			// as the new user has all needed privileges to setup the rest of the schema
			// i will be using that user as _InstallUser from this point on
			$this->db->close();
			$this->db = false;
			$this->parent->setVar( '_InstallUser', $this->getVar( 'wgDBuser' ) );
			$this->parent->setVar( '_InstallPassword', $this->getVar( 'wgDBpassword' ) );
			$this->parent->setVar( '_InstallDBname', $this->getVar( 'wgDBuser' ) );
			$status = $this->getConnection();
		}

		return $status;
	}

	/**
	 * Overload: after this action field info table has to be rebuilt
	 * @return Status
	 */
	public function createTables() {
		$this->setupSchemaVars();
		$this->db->setFlag( DBO_DDLMODE );
		$this->parent->setVar( 'wgDBname', $this->getVar( 'wgDBuser' ) );
		$status = parent::createTables();
		$this->db->clearFlag( DBO_DDLMODE );

		$this->db->query( 'BEGIN fill_wiki_info; END;' );

		return $status;
	}

	public function getSchemaVars() {
		$varNames = [
			# These variables are used by maintenance/oracle/user.sql
			'_OracleDefTS',
			'_OracleTempTS',
			'wgDBuser',
			'wgDBpassword',

			# These are used by tables.sql
			'wgDBprefix',
		];
		$vars = [];
		foreach ( $varNames as $name ) {
			$vars[$name] = $this->getVar( $name );
		}

		return $vars;
	}

	public function getLocalSettings() {
		$prefix = $this->getVar( 'wgDBprefix' );

		return "# Oracle specific settings
\$wgDBprefix = \"{$prefix}\";
";
	}

	/**
	 * Function checks the format of Oracle connect string
	 * The actual validity of the string is checked by attempting to connect
	 *
	 * Regex should be able to validate all connect string formats
	 * [//](host|tns_name)[:port][/service_name][:POOLED]
	 * http://www.orafaq.com/wiki/EZCONNECT
	 *
	 * @since 1.22
	 *
	 * @param string $connect_string
	 *
	 * @return bool Whether the connection string is valid.
	 */
	public static function checkConnectStringFormat( $connect_string ) {
		// @@codingStandardsIgnoreStart Long lines with regular expressions.
		// @todo Very long regular expression. Make more readable?
		$isValid = preg_match( '/^[[:alpha:]][\w\-]*(?:\.[[:alpha:]][\w\-]*){0,2}$/', $connect_string ); // TNS name
		$isValid |= preg_match( '/^(?:\/\/)?[\w\-\.]+(?::[\d]+)?(?:\/(?:[\w\-\.]+(?::(pooled|dedicated|shared))?)?(?:\/[\w\-\.]+)?)?$/', $connect_string ); // EZConnect
		// @@codingStandardsIgnoreEnd
		return (bool)$isValid;
	}
}