<?php
/*
**	Copyright (C) 1995-2021 by the ITools Authors.
**	This file is part of ITools - the Internet Tools Library
**
**	ITools 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 3 of the License, or
**	(at your option) any later version.
**
**	ITools 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, see <http://www.gnu.org/licenses/>.
**
**	dbi.class - UltraFlexible Database Interface 3000
*/

class it_dbi_postgres extends it_dbi
{

static $_global_key = 'it_dbi_postgres'; # Override base class to get our own singleton

function _where($params)
{
	if ($params['LIMIT'] && ($m = it::match('^\s*(\d+)\s*,\s*(\d+)\s*$', $params['LIMIT'])))
	{
		unset($params['LIMIT']);
		$params[] = " OFFSET $m[0] LIMIT $m[1]";
	}

	return parent::_where($params);
}

function replace($tags = [])
{
	foreach (array_keys($this->_fields) as $k)
	{
		$escaped = $this->escape_name($k);
		$strings[] = $escaped . '= EXCLUDED.' . $escaped;
	}

	$this->insert(array_merge($tags, [' ON CONFLICT (' . $this->escape_name($this->_p['keyfield']) . ') DO UPDATE SET ' . implode(', ', $strings)]));
}

function _tables($p = array())
{
	for ($qr = $this->query('SELECT table_name FROM information_schema.tables ' . $this->_where(['table_catalog' => $this->_p['db'], 'table_schema' => 'public'], $p), $p); $row = $this->_fetch_assoc($qr);)
		$result[] = $row['table_name'];

	return (array)$result;
}

function _get_field_defs()
{
	list($table_name, $table_schema) = array_reverse(explode('.', $this->_p['table'], 2));
	$where = $this->_where(['t.table_name' => $table_name, 't.table_schema' => $table_schema ?: 'public', 't.table_catalog' => $this->_p['db']]);

	# Recreate Key column of mysql show columns
	$res = $this->query('SELECT column_name,constraint_type,ordinal_position FROM information_schema.table_constraints AS t JOIN information_schema.key_column_usage USING (constraint_name, constraint_schema, constraint_catalog) ' . $where);
	while ($res && ($row = $this->_fetch_assoc($res)))
	{
		if ($row['constraint_type'] == 'PRIMARY KEY')
			$keys[$row['column_name']] = 'PRI';
		else if ($row['ordinal_position'] == 1)
			$keys[$row['column_name']] = $row['constraint_type'] == 'UNIQUE' ? 'UNI' : 'MUL';
	}

	$res = $this->query('SELECT * FROM information_schema.columns AS t ' . $where);
	while ($res && ($field = $this->_fetch_assoc($res)))
		$result[$field['column_name']] = ['Field' => $field['column_name'], 'Type' => $field['data_type'], 'Extra' => it::match('^nextval\(', $field['column_default']) ? 'auto_increment' : '', 'Key' => $keys[$field['column_name']]];

	return $result;
}

function _escape_string($str)
{
	return pg_escape_literal($this->_link, $str);
}

function _escape_name($str)
{
	return pg_escape_identifier($this->_link, $str);
}

function _connect_db($p) {
	$result = @pg_connect("host=$p[server] user=$p[user] dbname=$p[db] password=$p[pw]");

	if ($result)
	{
		# set charset used for this connection
		if ($p['charset'])
			if (!pg_set_client_encoding($result, $p['charset']))
				$this->_fatal("_connect(): can't set charset \"{$p['charset']}\"");
	}

	return [$result, $result ? '' : 'Could not connect'];
}

function _query($query, $p)
{
	if ($this->_p['keyfield'] && it::match('^INSERT ', $query))
	{
		$isinsert = true;
		$query .= ' RETURNING ' . $this->_escape_name($this->_p['keyfield']);
	}

	if (!($result = pg_query($this->_link, $query)) && $p['safety'])
	{
		/* TODO
		$errno = mysqli_errno($this->_link);
		if (($p['safety'] < 2) && ($errno == 1062)) # Duplicate entry
			return false;

		if ($errno == 2006) # mysql server has gone away: retry
		{
			it::log('sqllog', "it_dbi(): reconnecting mysqli_connect {$p['server']}, {$p['db']}");
			$this->_connect(array('reconnect' => true));
			$result = mysqli_query($this->_link, $query, $p['unbuffered'] ? MYSQLI_USE_RESULT : MYSQLI_STORE_RESULT);
		}
		*/
	}

	$this->_affectedrows = pg_affected_rows($result);
	$this->_insertid = $isinsert ? $this->_fetch_assoc($result)[$this->_p['keyfield']] : 0;
	/* TODO probably PGSQl_NOTICE_ALL
	if (($warning = $this->_link->get_warnings()))
	{
		do {
			if (!it::match(trim($this->_p['ignored_warnings'] . "|1364|1261|1051|1062", "|"), $warning->errno))
				$messages[] = $warning->message . " [error $warning->errno]";
		} while ($warning->next() && ++$checked < 20);

		if ($messages)
			it::error(['title' => "Mysql warning: " . $messages[0], 'body' => "$query\n\n" . implode("\n", $messages) . "\n"]);
	}
	*/

	return $result;
}

function _json_extract($col, $field)
{
	return "$col->>" . $this->escape_string($field);
}

function _json_object($tags)
{
	foreach ((array)$tags as $f => $v)
		$strings[] = $this->escape_string($f) . ', ' . $v;
	return "JSONB_BUILD_OBJECT(" . implode(', ', $strings) . ")";
}

function _json_set($source, $tags)
{
	return "$source || " . $this->_json_object($tags);
}

function _json_remove($source, $fields)
{
	foreach ((array)$fields as $f)
		$strings[] = $this->escape_string($f);
	return "($source - " . implode(" - ", $strings) . ")";
}

function _fetch_assoc($res)
{
	return pg_fetch_assoc($res);
}

function _num_rows($res)
{
	return pg_num_rows($res);
}


function _seek($res, $offset)
{
	pg_result_seek($res, $offset);
}

function _error($text)
{
	$text = get_class($this).'::'.$text;

	if ($this->_link && ($errstr = pg_last_error($this->_link)))
		$text = "\"$errstr\" in $text";

	return $text;
}

}