<?php
/**
 * @package     Awf
 * @copyright   2014 Nicholas K. Dionysopoulos / Akeeba Ltd
 * @license     GNU GPL version 3 or later
 */

namespace Awf\Database\Restore;

use Awf\Container\Container;
use Awf\Database;

class Postgresql extends Database\Restore
{
	/**
	 * Overloaded constructor, allows us to set up error codes and connect to
	 * the database.
	 *
	 * @param   Container $container Configuration array
	 */
	public function __construct(Container $container)
	{
		parent::__construct($container);

		// Set up allowed error codes
		$this->allowedErrorCodes = array();

		// Set up allowed comment delimiters
		$this->comment = array(
			'#',
			'\'-- ',
			'---',
			'/*!',
		);

		// Connect to the database
		$this->getDatabase();

		// Suppress foreign key checks
		if ($this->getParam('foreignkey', 1))
		{
			// Nothing. PostgreSQL does not support that
		}
	}

	/**
	 * Overloaded method which will create the database (if it doesn't exist).
	 *
	 * @return  Database\Driver
	 */
	protected function getDatabase()
	{
		if (!is_object($this->db))
		{
			$db = parent::getDatabase();
			try
			{
				$db->select($this->container['dbname']);
			}
			catch (\Exception $exc)
			{
				// We couldn't connect to the database. Maybe we have to create
				// it first. Let's see...
				$options = (object)array(
					'db_name' => $this->container['dbname'],
					'db_user' => $this->container['dbuser'],
				);
				$db->createDatabase($options, true);
				$db->select($this->container['dbname']);
			}
		}

		return $this->db;
	}

	/**
	 * Processes and runs the query
	 *
	 * @param   string $query The query to process
	 *
	 * @return  boolean  True on success
	 */
	protected function processQueryLine($query)
	{
		$db = $this->getDatabase();

		$prefix = $this->getParam('prefix', 'awf_');
		$existing = $this->getParam('existing', 'drop');
		$forceutf8 = $this->getParam('utf8tables', 0);
		$replacesql = $this->getParam('replace', 0);

		$changeEncoding = false;
		$identityTable = null;

		// CREATE TABLE query pre-processing
		// If the table has a prefix, back it up (if requested). In any case, drop
		// the table. before attempting to create it.
		if (substr($query, 0, 12) == 'CREATE TABLE')
		{
			// Yes, try to get the table name
			$restOfQuery = trim(substr($query, 12, strlen($query) - 12)); // Rest of query, after CREATE TABLE
			// Is there a bracket?
			if (substr($restOfQuery, 0, 1) == '"')
			{
				// There is... Good, we'll just find the matching bracket
				$pos = strpos($restOfQuery, '"', 1);
				$tableName = substr($restOfQuery, 1, $pos - 1);
			}
			else
			{
				// Nope, let's assume the table name ends in the next blank character
				$pos = strpos($restOfQuery, ' ', 1);
				$tableName = substr($restOfQuery, 1, $pos - 1);
			}
			unset($restOfQuery);

			// Should I back the table up?
			if (($prefix != '') && ($existing == 'backup') && (strpos($tableName, '#__') == 0))
			{
				// It's a table with a prefix, a prefix IS specified and we are asked to back it up.
				// Start by dropping any existing backup tables
				$backupTable = str_replace('#__', 'bak_', $tableName);
				try
				{
					$db->dropTable($backupTable);
					$db->renameTable($tableName, $backupTable);
				}
				catch (\Exception $exc)
				{
					// We can't rename the table. Try deleting it.
					$db->dropTable($tableName);
				}
			}
			else
			{
				// Try to drop the table anyway
				$db->dropTable($tableName);
			}

			$changeEncoding = $forceutf8;
		}
		// CREATE VIEW query pre-processing
		// In any case, drop the view before attempting to create it. (Views can't be renamed)
		elseif ((substr($query, 0, 7) == 'CREATE ') && (strpos($query, ' VIEW ') !== false))
		{
			// Yes, try to get the view name
			$view_pos = strpos($query, ' VIEW ');
			$restOfQuery = trim(substr($query, $view_pos + 6)); // Rest of query, after VIEW string
			// Is there a bracket?
			if (substr($restOfQuery, 0, 1) == '"')
			{
				// There is... Good, we'll just find the matching bracket
				$pos = strpos($restOfQuery, '"', 1);
				$tableName = substr($restOfQuery, 1, $pos - 1);
			}
			else
			{
				// Nope, let's assume the table name ends in the next blank character
				$pos = strpos($restOfQuery, ' ', 1);
				$tableName = substr($restOfQuery, 1, $pos - 1);
			}
			unset($restOfQuery);

			// Try to drop the view anyway
			$dropQuery = 'DROP VIEW "' . $tableName . '";';
			$db->setQuery(trim($dropQuery));
			try
			{
				$db->execute();
			}
			catch (\Exception $exc)
			{
				// Do nothing
			}
		}
		/**
		 * // CREATE PROCEDURE pre-processing
		 * elseif ((substr($query, 0, 7) == 'CREATE ') && (strpos($query, 'PROCEDURE ') !== false))
		 * {
		 * // Try to get the procedure name
		 * $entity_keyword = ' PROCEDURE ';
		 * $entity_pos = strpos($query, $entity_keyword);
		 * $restOfQuery = trim( substr($query, $entity_pos + strlen($entity_keyword)) ); // Rest of query, after entity key string
		 * // Is there a backtick?
		 * if (substr($restOfQuery,0,1) == '`')
		 * {
		 * // There is... Good, we'll just find the matching backtick
		 * $pos = strpos($restOfQuery, '`', 1);
		 * $entity_name = substr($restOfQuery,1,$pos - 1);
		 * }
		 * else
		 * {
		 * // Nope, let's assume the entity name ends in the next blank character
		 * $pos = strpos($restOfQuery, ' ', 1);
		 * $entity_name = substr($restOfQuery,1,$pos - 1);
		 * }
		 * unset($restOfQuery);
		 *
		 * // Try to drop the entity anyway
		 * $dropQuery = 'DROP' . $entity_keyword . 'IF EXISTS `'.$entity_name.'`;';
		 * $db->setQuery(trim($dropQuery));
		 * $db->execute();
		 *
		 * $replaceAll = true; // When processing entities, we might have to replace SEVERAL metaprefixes.
		 * $useDelimiter = true; // Instruct the engine to change the delimiter for this query to //
		 * }
		 * // CREATE FUNCTION pre-processing
		 * elseif ((substr($query, 0, 7) == 'CREATE ') && (strpos($query, 'FUNCTION ') !== false))
		 * {
		 * // Try to get the procedure name
		 * $entity_keyword = ' FUNCTION ';
		 * $entity_pos = strpos($query, $entity_keyword);
		 * $restOfQuery = trim( substr($query, $entity_pos + strlen($entity_keyword)) ); // Rest of query, after entity key string
		 * // Is there a backtick?
		 * if (substr($restOfQuery,0,1) == '`')
		 * {
		 * // There is... Good, we'll just find the matching backtick
		 * $pos = strpos($restOfQuery, '`', 1);
		 * $entity_name = substr($restOfQuery,1,$pos - 1);
		 * }
		 * else
		 * {
		 * // Nope, let's assume the entity name ends in the next blank character
		 * $pos = strpos($restOfQuery, ' ', 1);
		 * $entity_name = substr($restOfQuery,1,$pos - 1);
		 * }
		 * unset($restOfQuery);
		 *
		 * // Try to drop the entity anyway
		 * $dropQuery = 'DROP'.$entity_keyword.'IF EXISTS `'.$entity_name.'`;';
		 * $db->setQuery(trim($dropQuery));
		 * $db->execute();
		 *
		 * $replaceAll = true; // When processing entities, we might have to replace SEVERAL metaprefixes.
		 * $useDelimiter = true; // Instruct the engine to change the delimiter for this query to //
		 * }
		 * // CREATE TRIGGER pre-processing
		 * elseif ((substr($query, 0, 7) == 'CREATE ') && (strpos($query, 'TRIGGER ') !== false))
		 * {
		 * // Try to get the procedure name
		 * $entity_keyword = ' TRIGGER ';
		 * $entity_pos = strpos($query, $entity_keyword);
		 * $restOfQuery = trim( substr($query, $entity_pos + strlen($entity_keyword)) ); // Rest of query, after entity key string
		 * // Is there a backtick?
		 * if(substr($restOfQuery,0,1) == '`')
		 * {
		 * // There is... Good, we'll just find the matching backtick
		 * $pos = strpos($restOfQuery, '`', 1);
		 * $entity_name = substr($restOfQuery,1,$pos - 1);
		 * }
		 * else
		 * {
		 * // Nope, let's assume the entity name ends in the next blank character
		 * $pos = strpos($restOfQuery, ' ', 1);
		 * $entity_name = substr($restOfQuery,1,$pos - 1);
		 * }
		 * unset($restOfQuery);
		 *
		 * // Try to drop the entity anyway
		 * $dropQuery = 'DROP'.$entity_keyword.'IF EXISTS `'.$entity_name.'`;';
		 * $db->setQuery(trim($dropQuery));
		 * $db->execute();
		 *
		 * $replaceAll = true; // When processing entities, we might have to replace SEVERAL metaprefixes.
		 * $useDelimiter = true; // Instruct the engine to change the delimiter for this query to //
		 * }
		 **/
		elseif (substr($query, 0, 6) == 'INSERT')
		{
			if ($replacesql)
			{
				// Nope, SQL Server doesn't support this. You lose.
			}

			// Yes, try to get the table name
			$restOfQuery = trim(substr($query, 11, strlen($query) - 12)); // Rest of query, after INSERT INTO
			// Is there a bracket?
			if (substr($restOfQuery, 0, 1) == '"')
			{
				// There is... Good, we'll just find the matching bracket
				$pos = strpos($restOfQuery, '"', 1);
				$tableName = substr($restOfQuery, 1, $pos - 1);
			}
			else
			{
				// Nope, let's assume the table name ends in the next blank character
				$pos = strpos($restOfQuery, ' ', 1);
				$tableName = substr($restOfQuery, 1, $pos - 1);
			}
			unset($restOfQuery);

			// Get the concrete table name
			$tableName = $db->replacePrefix($tableName);

			// Do we have identity columns?

			$q = $db->getQuery(true)
					->select('*')
					->from('information_schema.columns')
					->where($db->qn('table_name') . ' = ' . $db->q($tableName))
					->where($db->qn('table_catalog') . ' = ' . $db->q($this->container['dbname']))
					->where($db->qn('column_default') . ' LIKE ' . $db->q('nextval(%::regclass)'));
			$db->setQuery($q);
			$idColumns = $db->loadAssocList();

			if (count($idColumns) >= 1)
			{
				$identityTable = $tableName;

				$identityColumns = array();
				$newIdentityColumns = array();

				foreach ($idColumns as $col)
				{
					$identityColumns[] = $db->qn($col['column_name']);
					$newIdentityColumns[] = 'NEW.' . $db->qn($col['column_name']);
				}

				$identityColumns = implode(',', $identityColumns);
				$newIdentityColumns = implode(',', $newIdentityColumns);
			}
		}

		if (!empty($query))
		{
			if (!is_null($identityTable) && isset($identityColumns) && isset($newIdentityColumns))
			{
				$sql = 'CREATE RULE "' . $identityTable . '_on_duplicate_ignore" AS ON INSERT TO "' . $identityTable . '" '
					. 'WHERE EXISTS(SELECT 1 FROM "' . $identityTable . '" WHERE (' . $identityColumns . ') '
					. ' = (' . $newIdentityColumns . ')) DO INSTEAD NOTHING;';

				$this->execute($sql);
			}

			$this->execute($query);

			if (!is_null($identityTable))
			{
				$sql = 'DROP RULE "' . $identityTable . '_on_duplicate_ignore" ON "' . $identityTable . '";';

				$this->execute($sql);
			}

			// Do we have to force UTF8 encoding?
			if ($changeEncoding)
			{
				// ROFL! Not on SQL Server, amigo!
			}
		}

		return true;
	}
}