<?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 SQLite
if (!function_exists('sqlite_open'))
	exit('This PHP environment doesn\'t have SQLite support built in. SQLite support is required if you want to use a SQLite database to run this forum. Consult the PHP documentation for further assistance.');


class DBLayer
{
	var $prefix;
	var $link_id;
	var $query_result;
	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)
	{
		// Prepend $db_name with the path to the forum root directory
		$db_name = PUN_ROOT.$db_name;

		$this->prefix = $db_prefix;

		if (!file_exists($db_name))
		{
			@touch($db_name);
			@chmod($db_name, 0666);
			if (!file_exists($db_name))
				error('Unable to create new database \''.$db_name.'\'. Permission denied.', __FILE__, __LINE__);
		}

		if (!is_readable($db_name))
			error('Unable to open database \''.$db_name.'\' for reading. Permission denied.', __FILE__, __LINE__);

		if (!is_writable($db_name))
			error('Unable to open database \''.$db_name.'\' for writing. Permission denied.', __FILE__, __LINE__);

		if ($p_connect)
			$this->link_id = @sqlite_popen($db_name, 0666, $sqlite_error);
		else
			$this->link_id = @sqlite_open($db_name, 0666, $sqlite_error);

		if (!$this->link_id)
			error('Unable to open database \''.$db_name.'\'. SQLite reported: '.$sqlite_error, __FILE__, __LINE__);
		else
			return $this->link_id;
	}


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

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


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

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


	function query($sql, $unbuffered = false)
	{
		if (strlen($sql) > 140000)
			exit('Insane query. Aborting.');

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

		if ($unbuffered)
			$this->query_result = @sqlite_unbuffered_query($this->link_id, $sql);
		else
			$this->query_result = @sqlite_query($this->link_id, $sql);

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

			++$this->num_queries;

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

			$this->error_no = @sqlite_last_error($this->link_id);
			$this->error_msg = @sqlite_error_string($this->error_no);

			if ($this->in_transaction)
				@sqlite_query($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'];
		}
		else if (isset($query['REPLACE']))
		{
			$sql = 'REPLACE INTO '.(isset($query['PARAMS']['NO_PREFIX']) ? '' : $this->prefix).$query['INTO'];

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

			$sql .= ' VALUES('.$query['VALUES'].')';
		}

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


	function result($query_id = 0, $row = 0)
	{
		if ($query_id)
		{
			if ($row != 0)
				@sqlite_seek($query_id, $row);

			return @current(@sqlite_current($query_id));
		}
		else
			return false;
	}


	function fetch_assoc($query_id = 0)
	{
		if ($query_id)
		{
			$cur_row = @sqlite_fetch_array($query_id, SQLITE_ASSOC);
			if ($cur_row)
			{
				// Horrible hack to get rid of table names and table aliases from the array keys
				while (list($key, $value) = @each($cur_row))
				{
					$dot_spot = strpos($key, '.');
					if ($dot_spot !== false)
					{
						unset($cur_row[$key]);
						$key = substr($key, $dot_spot+1);
						$cur_row[$key] = $value;
					}
				}
			}

			return $cur_row;
		}
		else
			return false;
	}


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


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


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


	function insert_id()
	{
		return ($this->link_id) ? @sqlite_last_insert_rowid($this->link_id) : false;
	}


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


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


	function free_result($query_id = false)
	{
		return true;
	}


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


	function error()
	{
		$result['error_sql'] = @current(@end($this->saved_queries));
		$result['error_no'] = $this->error_no;
		$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);

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

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


	function table_exists($table_name)
	{
		$result = $this->query('SELECT 1 FROM sqlite_master WHERE name = \''.$this->escape($table_name).'\' AND type=\'table\'');
		return $this->num_rows($result) > 0;
	}


	function field_exists($table_name, $field_name)
	{
		$result = $this->query('SELECT sql FROM sqlite_master WHERE name = \''.$this->escape($table_name).'\' AND type=\'table\'');
		if (!$this->num_rows($result))
			return false;

		return preg_match('/[\r\n]'.preg_quote($field_name).' /', $this->result($result));
	}


	function index_exists($table_name, $index_name)
	{
		$result = $this->query('SELECT 1 FROM sqlite_master WHERE tbl_name = \''.$this->escape($table_name).'\' AND name = \''.$this->escape($index_name).'\' AND type=\'index\'');
		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;

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

		$this->query('ALTER TABLE '.$table_name.' ADD '.$field_name.' '.$field_type.($allow_null ? ' ' : ' NOT NULL').($default_value !== null ? ' DEFAULT '.$default_value : ' ')) or error(__FILE__, __LINE__);
	}


	function drop_field($table_name, $field_name)
	{
		// No DROP column in SQLite
		return;
	}
}