<?php
/**
 * @class pgsqlConnection
 * @brief PostgreSQL Database Driver
 *
 * See the {@link dbLayer} documentation for common methods.
 *
 * This class adds a method for PostgreSQL only: {@link callFunction()}.
 *
 * @package Clearbricks
 * @subpackage DBLayer
 *
 * @copyright Olivier Meunier & Association Dotclear
 * @copyright GPL-2.0-only
 */

/* @cond ONCE */
if (class_exists('dbLayer')) {
    /** @endcond */
    class pgsqlConnection extends dbLayer implements i_dbLayer
    {
        protected $__driver        = 'pgsql';
        protected $__syntax        = 'postgresql';
        protected $utf8_unicode_ci = null;

        private function get_connection_string($host, $user, $password, $database)
        {
            $str  = '';
            $port = false;

            if ($host) {
                if (strpos($host, ':') !== false) {
                    $bits = explode(':', $host);
                    $host = array_shift($bits);
                    $port = abs((integer) array_shift($bits));
                }
                $str .= "host = '" . addslashes($host) . "' ";

                if ($port) {
                    $str .= 'port = ' . $port . ' ';
                }
            }
            if ($user) {
                $str .= "user = '" . addslashes($user) . "' ";
            }
            if ($password) {
                $str .= "password = '" . addslashes($password) . "' ";
            }
            if ($database) {
                $str .= "dbname = '" . addslashes($database) . "' ";
            }

            return $str;
        }

        public function db_connect($host, $user, $password, $database)
        {
            if (!function_exists('pg_connect')) {
                throw new Exception('PHP PostgreSQL functions are not available');
            }

            $str = $this->get_connection_string($host, $user, $password, $database);

            if (($link = @pg_connect($str)) === false) {
                throw new Exception('Unable to connect to database');
            }

            $this->db_post_connect($link, $database);

            return $link;
        }

        public function db_pconnect($host, $user, $password, $database)
        {
            if (!function_exists('pg_pconnect')) {
                throw new Exception('PHP PostgreSQL functions are not available');
            }

            $str = $this->get_connection_string($host, $user, $password, $database);

            if (($link = @pg_pconnect($str)) === false) {
                throw new Exception('Unable to connect to database');
            }

            $this->db_post_connect($link, $database);

            return $link;
        }

        private function db_post_connect($handle, $database)
        {
            if (version_compare($this->db_version($handle), '9.1') >= 0) {
                // Only for PostgreSQL 9.1+
                $result = $this->db_query($handle, "SELECT * FROM pg_collation WHERE (collcollate LIKE '%.utf8')");
                if ($this->db_num_rows($result) > 0) {
                    $this->db_result_seek($result, 0);
                    $row                   = $this->db_fetch_assoc($result);
                    $this->utf8_unicode_ci = '"' . $row['collname'] . '"';
                }
            }
        }

        public function db_close($handle)
        {
            if (is_resource($handle)) {
                pg_close($handle);
            }
        }

        public function db_version($handle)
        {
            if (is_resource($handle)) {
                return pg_parameter_status($handle, 'server_version');
            }

            return '';
        }

        public function db_query($handle, $query)
        {
            if (is_resource($handle)) {
                $res = @pg_query($handle, $query);
                if ($res === false) {
                    $e = new Exception($this->db_last_error($handle));

                    throw $e;
                }

                return $res;
            }
        }

        public function db_exec($handle, $query)
        {
            return $this->db_query($handle, $query);
        }

        public function db_num_fields($res)
        {
            if (is_resource($res)) {
                return pg_num_fields($res);
            }

            return 0;
        }

        public function db_num_rows($res)
        {
            if (is_resource($res)) {
                return pg_num_rows($res);
            }

            return 0;
        }

        public function db_field_name($res, $position)
        {
            if (is_resource($res)) {
                return pg_field_name($res, $position);
            }

            return '';
        }

        public function db_field_type($res, $position)
        {
            if (is_resource($res)) {
                return pg_field_type($res, $position);
            }

            return '';
        }

        public function db_fetch_assoc($res)
        {
            if (is_resource($res)) {
                return pg_fetch_assoc($res);
            }

            return false;
        }

        public function db_result_seek($res, $row)
        {
            if (is_resource($res)) {
                return pg_result_seek($res, (int) $row);
            }

            return false;
        }

        public function db_changes($handle, $res)
        {
            if (is_resource($handle) && is_resource($res)) {
                return pg_affected_rows($res);
            }

            return 0;
        }

        public function db_last_error($handle)
        {
            if (is_resource($handle)) {
                return pg_last_error($handle);
            }

            return false;
        }

        public function db_escape_string($str, $handle = null)
        {
            return pg_escape_string($str);
        }

        public function db_write_lock($table)
        {
            $this->execute('BEGIN');
            $this->execute('LOCK TABLE ' . $this->escapeSystem($table) . ' IN EXCLUSIVE MODE');
        }

        public function db_unlock()
        {
            $this->execute('END');
        }

        public function vacuum($table)
        {
            $this->execute('VACUUM FULL ' . $this->escapeSystem($table));
        }

        public function dateFormat($field, $pattern)
        {
            $rep = [
                '%d' => 'DD',
                '%H' => 'HH24',
                '%M' => 'MI',
                '%m' => 'MM',
                '%S' => 'SS',
                '%Y' => 'YYYY'
            ];

            $pattern = str_replace(array_keys($rep), array_values($rep), $pattern);

            return 'TO_CHAR(' . $field . ',' . "'" . $this->escape($pattern) . "') ";
        }

        public function orderBy()
        {
            $default = [
                'order'   => '',
                'collate' => false
            ];
            foreach (func_get_args() as $v) {
                if (is_string($v)) {
                    $res[] = $v;
                } elseif (is_array($v) && !empty($v['field'])) {
                    $v          = array_merge($default, $v);
                    $v['order'] = (strtoupper($v['order']) == 'DESC' ? 'DESC' : '');
                    if ($v['collate']) {
                        if ($this->utf8_unicode_ci) {
                            $res[] = $v['field'] . ' COLLATE ' . $this->utf8_unicode_ci . ' ' . $v['order'];
                        } else {
                            $res[] = 'LOWER(' . $v['field'] . ') ' . $v['order'];
                        }
                    } else {
                        $res[] = $v['field'] . ' ' . $v['order'];
                    }
                }
            }

            return empty($res) ? '' : ' ORDER BY ' . implode(',', $res) . ' ';
        }

        public function lexFields()
        {
            $fmt = $this->utf8_unicode_ci ? '%s COLLATE ' . $this->utf8_unicode_ci : 'LOWER(%s)';
            foreach (func_get_args() as $v) {
                if (is_string($v)) {
                    $res[] = sprintf($fmt, $v);
                } elseif (is_array($v)) {
                    $res = array_map(function ($i) use ($fmt) {return sprintf($fmt, $i);}, $v);
                }
            }

            return empty($res) ? '' : implode(',', $res);
        }

        /**
         * Function call
         *
         * Calls a PostgreSQL function an returns the result as a {@link record}.
         * After <var>$name</var>, you can add any parameters you want to append
         * them to the PostgreSQL function. You don't need to escape string in
         * arguments.
         *
         * @param string    $name    Function name
         * @return    record
         */
        public function callFunction($name)
        {
            $data = func_get_args();
            array_shift($data);

            foreach ($data as $k => $v) {
                if (is_null($v)) {
                    $data[$k] = 'NULL';
                } elseif (is_string($v)) {
                    $data[$k] = "'" . $this->escape($v) . "'";
                } elseif (is_array($v)) {
                    $data[$k] = $v[0];
                } else {
                    $data[$k] = $v;
                }
            }

            $req = 'SELECT ' . $name . "(\n" .
            implode(",\n", array_values($data)) .
                "\n) ";

            return $this->select($req);
        }
    }

    /* @cond ONCE */
}
/* @endcond */
