<?php

/*
    This file is a part of myTinyTodo.
    (C) Copyright 2020-2022 Max Pozdeev <maxpozdeev@gmail.com>
    Licensed under the GNU GPL version 2 or any later. See file COPYRIGHT for details.
*/

// ---------------------------------------------------------------------------- //
class DatabaseResult_Mysql extends DatabaseResult_Abstract
{
    /** @var PDOStatement */
    protected $q;
    protected $affected;

    function __construct($dbh, $query, $resultless = 0)
    {
        // use with DELETE, INSERT, UPDATE
        if ($resultless)
        {
            $this->affected = $dbh->exec($query); //throws PDOException
        }
        // SELECT
        else
        {
            $this->q = $dbh->query($query); //throws PDOException
            $this->affected = $this->q->rowCount();
        }
    }

    function fetchRow()
    {
        return $this->q->fetch(PDO::FETCH_NUM);
    }

    function fetchAssoc()
    {
        return $this->q->fetch(PDO::FETCH_ASSOC);
    }

    function rowsAffected()
    {
        return $this->affected;
    }
}

// ---------------------------------------------------------------------------- //
class Database_Mysql extends Database_Abstract
{
    /** @var PDO */
    protected $dbh;
    protected $affected = null;
    protected $dbname;

    function __construct()
    {
    }

    function connect($params)
    {
        $host = $params['host'];
        $user = $params['user'];
        $pass = $params['password'];
        $db = $params['db'];
        $options = array(
            PDO::MYSQL_ATTR_FOUND_ROWS => true,
            PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
        );
        $this->dbname = $db;

        $this->dbh = new PDO("mysql:host=$host;dbname=$db", $user, $pass, $options);
        return true;
    }


    /*
        Returns single row of SELECT query as indexed array (FETCH_NUM).
        Returns single field value if resulting array has only one field.
    */
    function sq($query, $p = NULL)
    {
        $q = $this->_dq($query, $p);

        $res = $q->fetchRow();
        if ($res === false) return NULL;

        if (sizeof($res) > 1) return $res;
        else return $res[0];
    }

    /*
        Returns single row of SELECT query as dictionary array (FETCH_ASSOC).
        Returns single field value if resulting array has only one field.
    */
    function sqa($query, $p = NULL)
    {
        $q = $this->_dq($query, $p);

        $res = $q->fetchAssoc();
        if ($res === false) return NULL;

        if (sizeof($res) > 1) return $res;
        else return $res[0];
    }

    function dq($query, $p = NULL) : DatabaseResult_Abstract
    {
        return $this->_dq($query, $p);
    }

    /*
        for resultless queries like INSERT,UPDATE,DELETE
    */
    function ex($query, $p = NULL)
    {
        $dbr = $this->_dq($query, $p, true);
        return $this->affected();
    }

    private function _dq($query, $p = NULL, $resultless = 0) : DatabaseResult_Abstract
    {
        if (!isset($p)) $p = array();
        elseif (!is_array($p)) $p = array($p);

        $m = explode('?', $query);

        if (sizeof($p) > 0)
        {
            if (sizeof($m) < sizeof($p)+1) {
                throw new Exception("params to set MORE than query params");
            }
            if (sizeof($m) > sizeof($p)+1) {
                throw new Exception("params to set LESS than query params");
            }
            $query = "";
            for ($i=0; $i<sizeof($m)-1; $i++) {
                $query .= $m[$i]. (is_null($p[$i]) ? 'NULL' : $this->quote($p[$i]));
            }
            $query .= $m[$i];
        }
        $this->lastQuery = $query;
        $dbr = new DatabaseResult_Mysql($this->dbh, $query, $resultless);
        $this->affected = $dbr->rowsAffected();
        return $dbr;
    }

    function affected()
    {
        return $this->affected;
    }

    function quote($s)
    {
        return '\''. addslashes($s). '\'';
    }

    function quoteForLike($format, $s)
    {
        $s = str_replace(array('%','_'), array('\%','\_'), addslashes($s));
        return '\''. sprintf($format, $s). '\'';
    }

    function lastInsertId($name = null)
    {
        return $this->dbh->lastInsertId();
    }

    function tableExists($table)
    {
        $r = $this->sq("SELECT 1 FROM information_schema.tables WHERE TABLE_SCHEMA = ? AND TABLE_NAME = ?",
                        array($this->dbname, $table) );
        if ($r === false || $r === null) return false;
        return true;
    }

    function tableFieldExists($table, $field): bool
    {
        $table = str_replace('`', '\\`', addslashes($table));
        $q = $this->dq("DESCRIBE `$table`");
        while ($r = $q->fetchRow()) {
            if ($r[0] == $field) return true;
        }
        return false;
    }
}