<?php
/**
 * This is a helper class for the SS installer.
 * 
 * It does all the specific checking for SQLiteDatabase
 * to ensure that the configuration is setup correctly.
 * 
 * @package sqlite3
 */
class SQLiteDatabaseConfigurationHelper implements DatabaseConfigurationHelper {

	/**
	 * Ensure that one of the database classes
	 * is available. If it is, we assume the PHP module for this
	 * database has been setup correctly.
	 * 
	 * @param array $databaseConfig Associative array of database configuration, e.g. "type", "path" etc
	 * @return boolean
	 */
	public function requireDatabaseFunctions($databaseConfig) {
		if($databaseConfig['type'] == 'SQLitePDODatabase' || version_compare(phpversion(), '5.3.0', '<')) return class_exists('PDO') ? true : false;
		return class_exists('SQLite3');
	}

	/**
	 * Ensure that the database server exists.
	 * @param array $databaseConfig Associative array of db configuration, e.g. "type", "path" etc
	 * @return array Result - e.g. array('success' => true, 'error' => 'details of error')
	 */
	public function requireDatabaseServer($databaseConfig) {
		$path = $databaseConfig['path'];
		
		if(!$path) {
			$success = false;
			$error = 'No database path provided';
		} 
		// check if parent folder is writeable
		elseif(is_writable(dirname($path))) {
			$success = true;
		} else {
			$success = false;
			$error = 'Webserver can\'t write database file to path "' . $path . '"';
		}

		return array(
			'success' => $success,
			'error' => $error
		);
	}

	/**
	 * Ensure a database connection is possible using credentials provided.
	 * 
	 * @todo Validate path
	 * 
	 * @param array $databaseConfig Associative array of db configuration, e.g. "type", "path" etc
	 * @return array Result - e.g. array('success' => true, 'error' => 'details of error')
	 */
	public function requireDatabaseConnection($databaseConfig) {
		$success = false;
		$error = '';

		$path = $databaseConfig['path'];
		if($path && $databaseConfig['database']) {
			// create and secure db directory
			if(!file_exists($path)) {
				self::create_db_dir($path);
			}
			self::secure_db_dir($path);

			$file = $path . '/' . $databaseConfig['database'];
			$file = preg_replace('/\/$/', '', $file);

			if($databaseConfig['type'] == 'SQLitePDODatabase' || version_compare(phpversion(), '5.3.0', '<')) {
				$conn = @(new PDO("sqlite:$file"));
			} else {
				$conn = @(new SQLite3($file, SQLITE3_OPEN_READWRITE | SQLITE3_OPEN_CREATE));
			}

			if($conn) {
				$success = true;
			} else {
				$success = false;
				$error = '';
			}
		} else {
			$success = false;
		}
		
		
		return array(
			'success' => $success,
			'connection' => $conn,
			'error' => $error
		);
	}

	/**
	 * Ensure that the database connection is able to use an existing database,
	 * or be able to create one if it doesn't exist.
	 *
	 * Unfortunately, PostgreSQLDatabase doesn't support automatically creating databases
	 * at the moment, so we can only check that the chosen database exists.
	 * 
	 * @param array $databaseConfig Associative array of db configuration, e.g. "server", "username" etc
	 * @return array Result - e.g. array('success' => true, 'alreadyExists' => 'true')
	 */
	public function requireDatabaseOrCreatePermissions($databaseConfig) {
		$success = false;
		$alreadyExists = false;
		$canCreate = false;
		
		$check = $this->requireDatabaseConnection($databaseConfig);
		$conn = $check['connection'];
		
		if($conn) {
			$success = true;
			$alreadyExists = true;
		} else {
			$success = false;
			$alreadyExists = false;
		}

		return array(
			'success' => $success,
			'alreadyExists' => $alreadyExists,
		);
	}
	
	/**
	 * Creates the provided directory and prepares it for
	 * storing SQLlite. Use {@link secure_db_dir()} to
	 * secure it against unauthorized access.
	 * 
	 * @param String $path Absolute path, usually with a hidden folder.
	 * @return boolean
	 */
	public static function create_db_dir($path) {
		return (!file_exists($path)) ? mkdir($path) : true;
	}
	
	/**
	 * Secure the provided directory via web-access
	 * by placing a .htaccess file in it. 
	 * This is just required if the database directory
	 * is placed within a publically accessible webroot (the
	 * default path is in a hidden folder within assets/).
	 * 
	 * @param String $path Absolute path, containing a SQLite datatbase
	 * @return boolean
	 */
	public static function secure_db_dir($path) {
		file_put_contents($path . '/.htaccess', 'deny from all');
	}
}