<?php
/* $Id$ */
namespace Mammut\DB\Sql\Dialect;

(defined('MAMMUT') && (basename(__FILE__) != basename($_SERVER['PHP_SELF']))) or die('ACCESS DENIED');

use Mammut\DB\DB;
use Mammut\DB\Sql\Select;
use Mammut\DB\Sql\Types;
use Mammut\Exception\IllegalStateException;
use Mammut\Exception\ImplementationException;
use Mammut\DB\Sql\Expression\iExprValue;
use Mammut\DB\Sql\Expression\SQLFunction;
use Mammut\DB\Sql\Expression\Literal;
use Mammut\DB\Sql\Expression\iExprBool;
use Mammut\DB\Sql\Expression\iExprCalc;
use Mammut\DB\Sql\Query;
use Mammut\StrictObject;

/**
 * Postgresql dialect implementation
 *
 * @author Stefan Daurer <s.daurer@q-spot.org>
 * @package Mammut\DB\Dialect
 */
class Postgresql extends Sql92 implements iDialect {
	/**
	 *
	 * @var resource \PDO
	 */
	protected $con = null;

	public function __construct($connection = null) {
		$this->con = $connection;
	}

	public function getName() {
		return DB::DIALECT_PGSQL;
	}
	
	public function isOffsetSupported() {
		return true;
	}
	
	public function isConstraintNameGlobal() {
		return true;
	}
	
	protected static function genNumSequence($table, $column) {
		$seqName = strtolower($table) . '_' . strtolower($column) . '_seq';
		$preSQL = 'CREATE SEQUENCE "' . $seqName . '"';
		$postSQL = 'ALTER SEQUENCE "' . $seqName . '" OWNED BY "' . $table . '"."' . $column . '"';
	
		$result = array('name' => $seqName,'pre' => $preSQL,'post' => $postSQL);
	
		return $result;
	}
	
	public function getDdl() {
		if(!is_null($this->ddlInstance))
			return $this->ddlInstance;
		$this->ddlInstance = new \Mammut\DB\Sql\Dialect\Ddl\PostgresqlDdl($this->con);
		return $this->ddlInstance;
	}
	
	public function quoteValue($value) {
		if(is_int($value))
			return $value;
		if(is_null($value))
			return 'NULL';
		
		if(is_resource($this->con))
			return '\'' . pg_escape_string($this->con, $value) . '\'';
		if($this->con instanceof \PDO)
			return $this->con->quote($value);
		return '\'' . addcslashes($value, "\x00\n\r\\'\"\x1a") . '\'';
	}
	
	public function quoteIdentInFragment($identifier, array $safeWords = array()) {
		$parts = preg_split('#([^0-9,a-z,A-Z$_])#', $identifier, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
		if ($safeWords) {
			$safeWords = array_flip($safeWords);
			$safeWords = array_change_key_case($safeWords, CASE_LOWER);
		}
		foreach ($parts as $i => $part) {
			if ($safeWords && isset($safeWords[strtolower($part)])) {
				continue;
			}
			switch ($part) {
				case ' ':
				case '.':
				case '*':
				case 'AS':
				case 'As':
				case 'aS':
				case 'as':
					break;
				default:
					$parts[$i] = '"' . str_replace('"', '""', $part) . '"';
			}
		}
		return implode('', $parts);
	}
	
	public function escapeString($string) {
		if(is_int($value))
			return $value;
		if(is_null($value))
			return 'NULL';
		
		if(is_resource($this->con))
			return pg_escape_string($this->con, $value);
		if($this->con instanceof \PDO) {
			$st = $this->con->quote($string);
			return substr($st, 1, -1);
		}
		return addcslashes($value, "\x00\n\r\\'\"\x1a");
	}

	public function getSymbol($type) {
		switch($type) {
			case self::SYMB_QUOTE_VALUE:
				return '\'';
			case self::SYMB_QUOTE_IDENT:
				return '"';
			case self::SYMB_IDENT_SEP:
				return '.';
		}
		return false;
	}
	
	public function getExpressionSQL($param, $hint = NULL) {
		if (is_bool($param))
			return $param ? 'TRUE' : 'FALSE';
		return parent::getExpressionSQL($param, $hint);
	}
	
	public function getTruncateSQL($table) {
		$table = $this->quoteIdent($table);
		return "TRUNCATE TABLE {$table}";
	}
	
	public function getNativeType($type) {
		switch($type) {
			case Types::TYPE_BOOLEAN:
				return 'BOOLEAN';
			
			case Types::TYPE_TINY:
				return 'SMALLINT'; // pgsql has no tinyint type
			
			case Types::TYPE_SHORT:
				return 'SMALLINT';
			
			case Types::TYPE_INT:
				return 'INTEGER';
			
			case Types::TYPE_LONG:
				return 'BIGINT';
			
			case Types::TYPE_FLOAT:
				return 'REAL';
			
			case Types::TYPE_DOUBLE:
				return 'DOUBLE PRECISION';
			
			case Types::TYPE_DECIMAL:
				return 'DECIMAL';
			
			case Types::TYPE_CHAR:
				return 'CHAR';
			
			case Types::TYPE_VCHAR:
				return 'VARCHAR';
			
			case Types::TYPE_TEXT:
				return 'TEXT';
			
			case Types::TYPE_BINARY:
				return 'BYTEA';
			
			case Types::TYPE_BLOB:
				return 'BYTEA';
			
			case Types::TYPE_DATE:
				return 'DATE';
			
			case Types::TYPE_DATETIME:
				return 'TIMESTAMP';
			
			case Types::TYPE_UTS:
				return 'INT';
			
			case Types::TYPE_ENUM:
				throw new ImplementationException('ENUM not implemented');
		}
		return $type;
	}
}