<?php
/***********************************************************************

  Copyright (C) 2002-2008  PunBB.org

  This file is part of PunBB.

  PunBB 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.

  PunBB 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., 59 Temple Place, Suite 330, Boston,
  MA  02111-1307  USA

************************************************************************/


// Make sure we have built in support for PostgreSQL
if (!function_exists('pg_connect'))
	exit('This PHP environment doesn\'t have PostgreSQL support built in. PostgreSQL support is required if you want to use a PostgreSQL database to run this forum. Consult the PHP documentation for further assistance.');


class DBLayer
{
	var $prefix;
	var $link_id;
	var $query_result;
	var $last_query_text = array();
	var $in_transaction = 0;

	var $saved_queries = array();
	var $num_queries = 0;

	var $error_no = false;
	var $error_msg = 'Unknown';


	function DBLayer($db_host, $db_username, $db_password, $db_name, $db_prefix, $p_connect)
	{
		$this->prefix = $db_prefix;

		if ($db_host != '')
		{
			if (strpos($db_host, ':') !== false)
			{
				list($db_host, $dbport) = explode(':', $db_host);
				$connect_str[] = 'host='.$db_host.' port='.$dbport;
			}
			else
			{
				if ($db_host != 'localhost')
					$connect_str[] = 'host='.$db_host;
			}
		}

		if ($db_name)
			$connect_str[] = 'dbname='.$db_name;

		if ($db_username != '')
			$connect_str[] = 'user='.$db_username;

		if ($db_password != '')
			$connect_str[] = 'password='.$db_password;

		if ($p_connect)
			$this->link_id = @pg_pconnect(implode(' ', $connect_str));
		else
			$this->link_id = @pg_connect(implode(' ', $connect_str));

		if (!$this->link_id)
			error('Unable to connect to PostgreSQL server.', __FILE__, __LINE__);
		else
			return $this->link_id;
	}


	function start_transaction()
	{
		++$this->in_transaction;

		return (@pg_query($this->link_id, 'BEGIN')) ? true : false;
	}


	function end_transaction()
	{
		--$this->in_transaction;

		if (@pg_query($this->link_id, 'COMMIT'))
			return true;
		else
		{
			@pg_query($this->link_id, 'ROLLBACK');
			return false;
		}
	}


	function query($sql, $unbuffered = false)	// $unbuffered is ignored since there is no pgsql_unbuffered_query()
	{
		if (strlen($sql) > 140000)
			exit('Insane query. Aborting.');

		if (strrpos($sql, 'LIMIT') !== false)
			$sql = preg_replace('#LIMIT ([0-9]+),([ 0-9]+)#', 'LIMIT \\2 OFFSET \\1', $sql);

		if (defined('PUN_SHOW_QUERIES'))
			$q_start = get_microtime();

		@pg_send_query($this->link_id, $sql);
		$this->query_result = @pg_get_result($this->link_id);

		if (pg_result_status($this->query_result) != PGSQL_FATAL_ERROR)
		{
			if (defined('PUN_SHOW_QUERIES'))
				$this->saved_queries[] = array($sql, sprintf('%.5f', get_microtime() - $q_start));

			++$this->num_queries;

			$this->last_query_text[$this->query_result] = $sql;

			return $this->query_result;
		}
		else
		{
			if (defined('PUN_SHOW_QUERIES'))
				$this->saved_queries[] = array($sql, 0);

			$this->error_msg = @pg_result_error($this->query_result);

			if ($this->in_transaction)
				@pg_query($this->link_id, 'ROLLBACK');

			--$this->in_transaction;

			return false;
		}
	}


	function query_build($query, $unbuffered = false)
	{
		$sql = '';

		if (isset($query['SELECT']))
		{
			$sql = 'SELECT '.$query['SELECT'].' FROM '.(isset($query['PARAMS']['NO_PREFIX']) ? '' : $this->prefix).$query['FROM'];

			if (isset($query['JOINS']))
			{
				foreach ($query['JOINS'] as $cur_join)
					$sql .= ' '.key($cur_join).' '.(isset($query['PARAMS']['NO_PREFIX']) ? '' : $this->prefix).current($cur_join).' ON '.$cur_join['ON'];
			}

			if (!empty($query['WHERE']))
				$sql .= ' WHERE '.$query['WHERE'];
			if (!empty($query['GROUP BY']))
				$sql .= ' GROUP BY '.$query['GROUP BY'];
			if (!empty($query['HAVING']))
				$sql .= ' HAVING '.$query['HAVING'];
			if (!empty($query['ORDER BY']))
				$sql .= ' ORDER BY '.$query['ORDER BY'];
			if (!empty($query['LIMIT']))
				$sql .= ' LIMIT '.$query['LIMIT'];
		}
		else if (isset($query['INSERT']))
		{
			$sql = 'INSERT INTO '.(isset($query['PARAMS']['NO_PREFIX']) ? '' : $this->prefix).$query['INTO'];

			if (!empty($query['INSERT']))
				$sql .= ' ('.$query['INSERT'].')';

			$sql .= ' VALUES('.$query['VALUES'].')';
		}
		else if (isset($query['UPDATE']))
		{
			$query['UPDATE'] = (isset($query['PARAMS']['NO_PREFIX']) ? '' : $this->prefix).$query['UPDATE'];

			$sql = 'UPDATE '.$query['UPDATE'].' SET '.$query['SET'];

			if (!empty($query['WHERE']))
				$sql .= ' WHERE '.$query['WHERE'];
		}
		else if (isset($query['DELETE']))
		{
			$sql = 'DELETE FROM '.(isset($query['PARAMS']['NO_PREFIX']) ? '' : $this->prefix).$query['DELETE'];

			if (!empty($query['WHERE']))
				$sql .= ' WHERE '.$query['WHERE'];
		}

		return $this->query($sql, $unbuffered);
	}


	function result($query_id = 0, $row = 0)
	{
		return ($query_id) ? @pg_fetch_result($query_id, $row, 0) : false;
	}


	function fetch_assoc($query_id = 0)
	{
		return ($query_id) ? @pg_fetch_assoc($query_id) : false;
	}


	function fetch_row($query_id = 0)
	{
		return ($query_id) ? @pg_fetch_row($query_id) : false;
	}


	function num_rows($query_id = 0)
	{
		return ($query_id) ? @pg_num_rows($query_id) : false;
	}


	function affected_rows()
	{
		return ($this->query_result) ? @pg_affected_rows($this->query_result) : false;
	}


	function insert_id()
	{
		$query_id = $this->query_result;

		if ($query_id && $this->last_query_text[$query_id] != '')
		{
			if (preg_match('/^INSERT INTO ([a-z0-9\_\-]+)/is', $this->last_query_text[$query_id], $table_name))
			{
				// Hack (don't ask)
				if (substr($table_name[1], -6) == 'groups')
					$table_name[1] .= '_g';

				$temp_q_id = @pg_query($this->link_id, 'SELECT currval(\''.$table_name[1].'_id_seq\')');
				return ($temp_q_id) ? intval(@pg_fetch_result($temp_q_id, 0)) : false;
			}
		}

		return false;
	}


	function get_num_queries()
	{
		return $this->num_queries;
	}


	function get_saved_queries()
	{
		return $this->saved_queries;
	}


	function free_result($query_id = false)
	{
		if (!$query_id)
			$query_id = $this->query_result;

		return ($query_id) ? @pg_free_result($query_id) : false;
	}


	function escape($str)
	{
		return is_array($str) ? '' : pg_escape_string($str);
	}


	function error()
	{
		$result['error_sql'] = @current(@end($this->saved_queries));
		$result['error_no'] = false;
/*
		if (!empty($this->query_result))
		{
			$result['error_msg'] = trim(@pg_result_error($this->query_result));
			if ($result['error_msg'] != '')
				return $result;
		}

		$result['error_msg'] = (!empty($this->link_id)) ? trim(@pg_last_error($this->link_id)) : trim(@pg_last_error());
*/
		$result['error_msg'] = $this->error_msg;

		return $result;
	}


	function close()
	{
		if ($this->link_id)
		{
			if ($this->in_transaction)
			{
				if (defined('PUN_SHOW_QUERIES'))
					$this->saved_queries[] = array('COMMIT', 0);

				@pg_query($this->link_id, 'COMMIT');
			}

			if ($this->query_result)
				@pg_free_result($this->query_result);

			return @pg_close($this->link_id);
		}
		else
			return false;
	}


	function table_exists($table_name)
	{
		$result = $this->query('SELECT 1 FROM pg_class WHERE relname = \''.$this->escape($table_name).'\'');
		return $this->num_rows($result) > 0;
	}


	function field_exists($table_name, $field_name)
	{
		$result = $this->query('SELECT 1 FROM pg_class c INNER JOIN pg_attribute a ON a.attrelid = c.oid WHERE c.relname = \''.$this->escape($table_name).'\' AND a.attname = \''.$this->escape($field_name).'\'');
		return $this->num_rows($result) > 0;
	}


	function index_exists($table_name, $index_name)
	{
		$result = $this->query('SELECT 1 FROM pg_index i INNER JOIN pg_class c1 ON c1.oid = i.indrelid INNER JOIN pg_class c2 ON c2.oid = i.indexrelid WHERE c1.relname = \''.$this->escape($table_name).'\' AND c2.relname = \''.$this->escape($index_name).'\'');
		return $this->num_rows($result) > 0;
	}


	function add_field($table_name, $field_name, $field_type, $allow_null, $default_value = null, $after_field = null)
	{
		if ($this->field_exists($table_name, $field_name))
			return;

		$field_type = str_replace(array('TINY', 'FLOAT'), array('SMALL', 'REAL'), strtoupper($field_type));
		$field_type = preg_replace('/(.*?INT)(\([0-9]+)\)/', '$1', $field_type);

		$this->query('ALTER TABLE '.$table_name.' ADD '.$field_name.' '.$field_type) or error(__FILE__, __LINE__);

		if ($default_value !== null)
		{
			if (!is_int($default_value) && !is_float($default_value))
				$default_value = '\''.$this->escape($default_value).'\'';

			$this->query('ALTER TABLE '.$table_name.' ALTER '.$field_name.' SET DEFAULT '.$default_value) or error(__FILE__, __LINE__);
			$this->query('UPDATE '.$table_name.' SET '.$field_name.'='.$default_value) or error(__FILE__, __LINE__);
		}

		if (!$allow_null)
			$this->query('ALTER TABLE '.$table_name.' ALTER '.$field_name.' SET NOT NULL') or error(__FILE__, __LINE__);
	}


	function drop_field($table_name, $field_name)
	{
		if (!$this->field_exists($table_name, $field_name))
			return;

		$this->query('ALTER TABLE '.$table_name.' DROP '.$field_name) or error(__FILE__, __LINE__);
	}
}