<?php

class FronkDB {
    public $link;
    private $result;
    private $lastError;
    private $log;
    public $insert_id;
    private static $instances = [];
    public $host;
    public $user;
    public $pass;
    public $db;

    public function __construct($host = false, $user = false, $pass = false, $db = false) {
        $this->host = $host;
        $this->user = $user;
        $this->pass = $pass;
        $this->db = $db;

        if(!$host) $this->host = FRONKDB_DBHOST;
        if(!$user) $this->user = FRONKDB_DBUSER;
        if(!$pass) $this->pass = FRONKDB_DBPASS;
        if(!$db) $this->db = FRONKDB_DBNAME;

        $this->connect();
        $this->log = mfLoghandler::singleton();
    }

    public static function singleton($host = false, $user = false, $pass = false, $db = false) {
        $instance_name = $host . $user . $db;
        if(!$instance_name) {
            $instance_name = "default";
        }

        if(!isset(self::$instances[$instance_name])) {
            //echo "new FronkDB instance $instance_name\n";
            $c = __CLASS__;
            self::$instances[$instance_name] = new $c($host, $user, $pass, $db);
        }
        return self::$instances[$instance_name];
    }

    private function connect() {
        //echo "FronkDB connection to ".$this->host." (".$this->user.", ".$this->db.")\n";
        if(!$this->link) {
            $this->link = mysqli_connect($this->host, $this->user, $this->pass, $this->db) or die("Error connecting to database..." . mysqli_error($this->link));
        }
        mysqli_select_db($this->link, $this->db) or die("Error connecting to database..." . mysqli_error($this->link));
        if(function_exists("mysqli_set_charset")) {
            mysqli_set_charset($this->link, 'utf8mb4');
        } else {
            $this->query("SET NAMES utf8mb4");
        }
    }

    public function reconnect() {
        $this->instances = [];
        $this->link = false;
        $this->connect();
    }

    public function disconnect() {
        if($this->link) {
            mysqli_close($this->link);
            $this->link = false;
        }
    }

    public function escape($string) {
        return mysqli_real_escape_string($this->link, $string);
    }

    public function query($sql, $print_error = false) {
        // unset last insert id on qvery new query
        $this->insert_id = null;

        if(!$this->link) {
            $this->connect();
        }

        if(FRONKDB_SQLDEBUG == true) {
            /*$this->log->debug("[FronkDB] ================");
            $this->log->debug("[FronkDB] START SQL QUERY");
            $bt = debug_backtrace();
            foreach($bt as $n => $b) {
              $this->log->debug($n.") ".$b["file"]."(".$b['line']."): ".$b['class']."->".$b['function']."()" );
            }*/
            $this->log->debug("[FronkDB] $sql");
            //$this->log->debug("[FronkDB] END SQL QUERY");
            //echo "$sql\n";
        }

        try {
            $this->result = mysqli_query($this->link, $sql);
            $return = $this->result;
            $log_query = false;

            // check for errors
            if(!$this->result) {
                $return = false;
                $log_query = true;
                $this->lastError = mysqli_error($this->link);
                if($print_error) {
                    echo "Error in SQL-query:<br />\n" . $sql . "<br />\n" . $this->lastError . "<br />\n";
                }
                $this->log->warn("SQL Last Error: ".$this->lastError);
            }

            $this->insert_id = mysqli_insert_id($this->link);

            // check for warnings
            if(mysqli_warning_count($this->link) > 0) {
                $log_query = true;
                $warning = mysqli_get_warnings($this->link);
                if($warning !== false) {
                    do {
                        $this->log->warn("SQL Warning: ".$warning->errno." - ".$warning->message);
                    } while ($warning->next());
                }
            }

            if($log_query) {
                $this->log->warn("SQL Query was: $sql");
            }

            return $return;

        } catch(Exception $e) {
            $this->log->warn("SQL Query Exception " . $e->getCode() . ": " . $e->getMessage() . "\nQuery was:\n$sql\n".$e->getTraceAsString());
            throw $e;
        }
    }

    public function getLastError() {
        return $this->lastError;
    }

    public function num_rows($_res = false) {
        $rows = false;
        $res = $this->result;

        if($_res)
            $res = $_res;

        if(!$res)
            return 0;

        if($rows = mysqli_num_rows($res))
            return $rows;

        return 0;
    }

    public function fetch_array($_res = false) {
        $array = false;
        $res = $this->result;

        if($_res)
            $res = $_res;

        if(!$res)
            return false;

        if($array = mysqli_fetch_assoc($res))
            return $array;

        return false;
    }

    public function fetch_object($_res = false) {
        $obj = false;
        $res = $this->result;

        if($_res)
            $res = $_res;

        if(!$res)
            return false;

        if($obj = mysqli_fetch_object($res))
            return $obj;

        return false;
    }

    public function fetch_all_assoc($_res = false) {
        $array = array();
        $res = $this->result;

        if($_res)
            $res = $_res;

        if(!$res)
            return false;

        while($row = mysqli_fetch_assoc($res)) {
            $array[] = $row;
        }

        return $array;
    }

    public function insert($_table, $_data, $_forcestr = array(), $_forcebinary = array()) {
        if(empty($_table)) {
            $this->lastError = "Error constructing INSERT: tablename ommited";
            return false;
        }

        $table = $_table;

        $fields = "";
        $values = "";
        $STRINGS = $_forcestr;

        // Build INSERT

        foreach($_data as $f => $v) {
            $_Q = "'";
            if(is_string($v)) {
                $v = $this->escape($v);
            }
            if(is_numeric($v)) {
                if(!in_array($f, $STRINGS)) {
                    $_Q = "";
                }
            }

            $fields .= ",`$f`";

            if($v === null) {
                $values .= ", NULL";
            } else {
                if(in_array($f, $_forcebinary)) {
                    $values .= ", _binary" . $_Q . $v . $_Q;
                } else {
                    $values .= "," . $_Q . $v . $_Q;
                }
            }

        }

        $fields = preg_replace('/^,/', '', $fields);
        $values = preg_replace('/^,/', '', $values);

        $SQLstr = "INSERT INTO `$table` ($fields) VALUES($values)";

        if(!$this->query($SQLstr)) {
            return false;
        }

        return true;
    }

    public function update($_table, $_data, $_where, $_forcestr = array(), $_forcebinary = array()) {
        if(empty($_table)) {
            $this->lastError = "Error constructing UPDATE: tablename ommited";
            return false;
        }

        if(empty($_where)) {
            $this->lastError = "Security breach on all decks! UPDATE without WHERE clause.";
            return false;
        }

        $table = $_table;

        $Pairs = "";
        $where = "WHERE $_where";
        $STRINGS = $_forcestr;


        // Build field/value pairs string

        foreach($_data as $f => $v) {
            $_Q = "'";
            if(is_string($v)) {
                $v = $this->escape($v);
            }
            if(is_numeric($v)) {
                if(!in_array($f, $STRINGS)) {
                    $_Q = '';
                }
            }

            if($v === null) {
                $Pairs .= ", `$f`=NULL";
            } else {
                if(in_array($f, $_forcebinary)) {
                    $Pairs .= ", `$f`= _binary " . $_Q . $v . $_Q;
                } else {
                    $Pairs .= ", `$f`=" . $_Q . $v . $_Q;
                }
            }
        }

        $Pairs = preg_replace('/^,/', '', $Pairs);

        $SQLstr = "UPDATE `$table` SET $Pairs $where";

        if(!$this->query($SQLstr)) {
            return false;
        }

        return true;

    }

    public function select($_table, $_fields = "*", $_where = "") {
        $table = $_table;
        $fields = $_fields;
        $where = "";

        if(!empty($_where)) {
            $where = "WHERE $_where";
        }

        if(empty($_table)) {
            $this->lastError = "No table specified";
            return false;
        }

        if(empty($_fields))
            $fields = "*";

        if(!is_array($fields)) {
            $fields = preg_split('/ ?, ?/', $fields);
        }

        $fstr = "";

        foreach($fields as $f) {
            $fstr .= ",`$f`";
            if($f == "*") $fstr = "*";
        }

        $fstr = preg_replace('/^,/', '', $fstr);
        $SQLstr = "SELECT $fstr FROM `$table` $where";

        if($res = $this->query($SQLstr)) {
            return $res;
        }

        return false;

    }

    public function delete($_table, $_where, $_limit = false) {
        if(empty($_where)) {
            $this->lastError = "Security breach on all decks! DELETE without WHERE clause!";
            return false;
        }

        if(empty($_table)) {
            $this->lastError = "Keine Tabelle angegeben!";
            return false;
        }

        $table = $_table;
        $where = $_where;
        $limit = "";
        if($_limit) {
            $limit = "LIMIT $_limit";
        }

        $sql = "DELETE FROM `$table` WHERE $where $limit";
        //echo $sql;
        if($this->query($sql)) {
            return true;
        } else {
            return false;
        }
    }

    public function startTransaction() {
        $this->query("START TRANSACTION");
    }

    public function commitTransaction() {
        $this->query("COMMIT");
    }

    public function rollbackTransaction() {
        $this->query("ROLLBACK");
    }
}