<?php
/**
 * Part of the Joomla Framework Database Package
 *
 * @copyright  Copyright (C) 2005 - 2021 Open Source Matters, Inc. All rights reserved.
 * @license    GNU General Public License version 2 or later; see LICENSE
 */

namespace Joomla\Database\Sqlite;

use Joomla\Database\Pdo\PdoDriver;

/**
 * SQLite database driver supporting PDO based connections
 *
 * @link   https://www.php.net/manual/en/ref.pdo-sqlite.php
 * @since  1.0
 */
class SqliteDriver extends PdoDriver
{
	/**
	 * The name of the database driver.
	 *
	 * @var    string
	 * @since  1.0
	 */
	public $name = 'sqlite';

	/**
	 * The character(s) used to quote SQL statement names such as table names or field names, etc.
	 *
	 * If a single character string the same character is used for both sides of the quoted name, else the first character will be used for the
	 * opening quote and the second for the closing quote.
	 *
	 * @var    string
	 * @since  1.0
	 */
	protected $nameQuote = '`';

	/**
	 * Destructor.
	 *
	 * @since   1.0
	 */
	public function __destruct()
	{
		$this->disconnect();
	}

	/**
	 * Alter database's character set.
	 *
	 * @param   string  $dbName  The database name that will be altered
	 *
	 * @return  boolean|resource
	 *
	 * @since   2.0.0
	 * @throws  \RuntimeException
	 */
	public function alterDbCharacterSet($dbName)
	{
		return false;
	}

	/**
	 * Connects to the database if needed.
	 *
	 * @return  void  Returns void if the database connected successfully.
	 *
	 * @since   2.0.0
	 * @throws  RuntimeException
	 */
	public function connect()
	{
		if ($this->connection)
		{
			return;
		}

		parent::connect();

		$this->connection->sqliteCreateFunction(
			'ROW_NUMBER',
			function ($init = null)
			{
				static $rownum, $partition;

				if ($init !== null)
				{
					$rownum = $init;
					$partition = null;

					return $rownum;
				}

				$args = \func_get_args();
				array_shift($args);

				$partitionBy = $args ? implode(',', $args) : null;

				if ($partitionBy === null || $partitionBy === $partition)
				{
					$rownum++;
				}
				else
				{
					$rownum    = 1;
					$partition = $partitionBy;
				}

				return $rownum;
			}
		);
	}

	/**
	 * Create a new database using information from $options object.
	 *
	 * @param   \stdClass  $options  Object used to pass user and database name to database driver. This object must have "db_name" and "db_user" set.
	 * @param   boolean    $utf      True if the database supports the UTF-8 character set.
	 *
	 * @return  boolean|resource
	 *
	 * @since   2.0.0
	 * @throws  \RuntimeException
	 */
	public function createDatabase($options, $utf = true)
	{
		// SQLite doesn't have a query for this
		return true;
	}

	/**
	 * Method to escape a string for usage in an SQLite statement.
	 *
	 * Note: Using query objects with bound variables is preferable to the below.
	 *
	 * @param   string   $text   The string to be escaped.
	 * @param   boolean  $extra  Unused optional parameter to provide extra escaping.
	 *
	 * @return  string  The escaped string.
	 *
	 * @since   1.0
	 */
	public function escape($text, $extra = false)
	{
		if (\is_int($text))
		{
			return $text;
		}

		if (\is_float($text))
		{
			// Force the dot as a decimal point.
			return str_replace(',', '.', $text);
		}

		return \SQLite3::escapeString($text);
	}

	/**
	 * Method to get the database collation in use by sampling a text field of a table in the database.
	 *
	 * @return  string|boolean  The collation in use by the database or boolean false if not supported.
	 *
	 * @since   1.0
	 */
	public function getCollation()
	{
		return false;
	}

	/**
	 * Method to get the database connection collation in use by sampling a text field of a table in the database.
	 *
	 * @return  string|boolean  The collation in use by the database connection (string) or boolean false if not supported.
	 *
	 * @since   1.6.0
	 * @throws  \RuntimeException
	 */
	public function getConnectionCollation()
	{
		return false;
	}

	/**
	 * Method to get the database encryption details (cipher and protocol) in use.
	 *
	 * @return  string  The database encryption details.
	 *
	 * @since   2.0.0
	 * @throws  \RuntimeException
	 */
	public function getConnectionEncryption(): string
	{
		// TODO: Not fake this
		return '';
	}

	/**
	 * Method to test if the database TLS connections encryption are supported.
	 *
	 * @return  boolean  Whether the database supports TLS connections encryption.
	 *
	 * @since   2.0.0
	 */
	public function isConnectionEncryptionSupported(): bool
	{
		// TODO: Not fake this
		return false;
	}

	/**
	 * Shows the table CREATE statement that creates the given tables.
	 *
	 * Note: Doesn't appear to have support in SQLite
	 *
	 * @param   mixed  $tables  A table name or a list of table names.
	 *
	 * @return  array  A list of the create SQL for the tables.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function getTableCreate($tables)
	{
		$this->connect();

		// Sanitize input to an array and iterate over the list.
		$tables = (array) $tables;

		return $tables;
	}

	/**
	 * Retrieves field information about a given table.
	 *
	 * @param   string   $table     The name of the database table.
	 * @param   boolean  $typeOnly  True to only return field types.
	 *
	 * @return  array  An array of fields for the database table.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function getTableColumns($table, $typeOnly = true)
	{
		$this->connect();

		$columns = [];

		$fieldCasing = $this->getOption(\PDO::ATTR_CASE);

		$this->setOption(\PDO::ATTR_CASE, \PDO::CASE_UPPER);

		$table = strtoupper($table);

		$fields = $this->setQuery('pragma table_info(' . $table . ')')->loadObjectList();

		if ($typeOnly)
		{
			foreach ($fields as $field)
			{
				$columns[$field->NAME] = $field->TYPE;
			}
		}
		else
		{
			foreach ($fields as $field)
			{
				// Do some dirty translation to MySQL output.
				// TODO: Come up with and implement a standard across databases.
				$columns[$field->NAME] = (object) [
					'Field'   => $field->NAME,
					'Type'    => $field->TYPE,
					'Null'    => $field->NOTNULL == '1' ? 'NO' : 'YES',
					'Default' => $field->DFLT_VALUE,
					'Key'     => $field->PK != '0' ? 'PRI' : '',
				];
			}
		}

		$this->setOption(\PDO::ATTR_CASE, $fieldCasing);

		return $columns;
	}

	/**
	 * Get the details list of keys for a table.
	 *
	 * @param   string  $table  The name of the table.
	 *
	 * @return  array  An array of the column specification for the table.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function getTableKeys($table)
	{
		$this->connect();

		$keys = [];

		$fieldCasing = $this->getOption(\PDO::ATTR_CASE);

		$this->setOption(\PDO::ATTR_CASE, \PDO::CASE_UPPER);

		$table = strtoupper($table);

		$rows = $this->setQuery('pragma table_info( ' . $table . ')')->loadObjectList();

		foreach ($rows as $column)
		{
			if ($column->PK == 1)
			{
				$keys[$column->NAME] = $column;
			}
		}

		$this->setOption(\PDO::ATTR_CASE, $fieldCasing);

		return $keys;
	}

	/**
	 * Method to get an array of all tables in the database (schema).
	 *
	 * @return  array   An array of all the tables in the database.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function getTableList()
	{
		$this->connect();

		$type = 'table';

		$query = $this->getQuery(true)
			->select('name')
			->from('sqlite_master')
			->where('type = :type')
			->bind(':type', $type)
			->order('name');

		return $this->setQuery($query)->loadColumn();
	}

	/**
	 * Get the version of the database connector.
	 *
	 * @return  string  The database connector version.
	 *
	 * @since   1.0
	 */
	public function getVersion()
	{
		$this->connect();

		return $this->setQuery('SELECT sqlite_version()')->loadResult();
	}

	/**
	 * Select a database for use.
	 *
	 * @param   string  $database  The name of the database to select for use.
	 *
	 * @return  boolean  True if the database was successfully selected.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function select($database)
	{
		$this->connect();

		return true;
	}

	/**
	 * Set the connection to use UTF-8 character encoding.
	 *
	 * Returns false automatically for the Oracle driver since
	 * you can only set the character set when the connection
	 * is created.
	 *
	 * @return  boolean  True on success.
	 *
	 * @since   1.0
	 */
	public function setUtf()
	{
		$this->connect();

		return false;
	}

	/**
	 * Locks a table in the database.
	 *
	 * @param   string  $table  The name of the table to unlock.
	 *
	 * @return  $this
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function lockTable($table)
	{
		return $this;
	}

	/**
	 * Renames a table in the database.
	 *
	 * @param   string  $oldTable  The name of the table to be renamed
	 * @param   string  $newTable  The new name for the table.
	 * @param   string  $backup    Not used by Sqlite.
	 * @param   string  $prefix    Not used by Sqlite.
	 *
	 * @return  $this
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function renameTable($oldTable, $newTable, $backup = null, $prefix = null)
	{
		$this->setQuery('ALTER TABLE ' . $oldTable . ' RENAME TO ' . $newTable)->execute();

		return $this;
	}

	/**
	 * Method to truncate a table.
	 *
	 * @param   string  $table  The table to truncate
	 *
	 * @return  void
	 *
	 * @since   1.2.1
	 * @throws  \RuntimeException
	 */
	public function truncateTable($table)
	{
		$this->setQuery('DELETE FROM ' . $this->quoteName($table))
			->execute();
	}

	/**
	 * Unlocks tables in the database.
	 *
	 * @return  $this
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function unlockTables()
	{
		return $this;
	}

	/**
	 * Test to see if the PDO ODBC connector is available.
	 *
	 * @return  boolean  True on success, false otherwise.
	 *
	 * @since   1.0
	 */
	public static function isSupported()
	{
		return class_exists('\\PDO') && class_exists('\\SQLite3') && \in_array('sqlite', \PDO::getAvailableDrivers(), true);
	}

	/**
	 * Method to commit a transaction.
	 *
	 * @param   boolean  $toSavepoint  If true, commit to the last savepoint.
	 *
	 * @return  void
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function transactionCommit($toSavepoint = false)
	{
		$this->connect();

		if (!$toSavepoint || $this->transactionDepth <= 1)
		{
			parent::transactionCommit($toSavepoint);
		}
		else
		{
			$this->transactionDepth--;
		}
	}

	/**
	 * Method to roll back a transaction.
	 *
	 * @param   boolean  $toSavepoint  If true, rollback to the last savepoint.
	 *
	 * @return  void
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function transactionRollback($toSavepoint = false)
	{
		$this->connect();

		if (!$toSavepoint || $this->transactionDepth <= 1)
		{
			parent::transactionRollback($toSavepoint);
		}
		else
		{
			$savepoint = 'SP_' . ($this->transactionDepth - 1);
			$this->setQuery('ROLLBACK TO ' . $this->quoteName($savepoint))->execute();

			$this->transactionDepth--;
		}
	}

	/**
	 * Method to initialize a transaction.
	 *
	 * @param   boolean  $asSavepoint  If true and a transaction is already active, a savepoint will be created.
	 *
	 * @return  void
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function transactionStart($asSavepoint = false)
	{
		$this->connect();

		if (!$asSavepoint || !$this->transactionDepth)
		{
			parent::transactionStart($asSavepoint);
		}
		else
		{
			$savepoint = 'SP_' . $this->transactionDepth;
			$this->setQuery('SAVEPOINT ' . $this->quoteName($savepoint))->execute();

			$this->transactionDepth++;
		}
	}
}