<?php

class DB
{
    private static $_instance = null;
    private $_pdo,
        $_query,
        $_error = false,
        $_results,
        $_count = 0;

    private function __construct()
    {
        try {
            $this->_pdo = new PDO('mysql:host=' . Config::get('mysql/host') . ';dbname=' . Config::get('mysql/db'), Config::get('mysql/username'), Config::get('mysql/password'));
        } catch (PDOException $e) {
            die ($e->getMessage());
        }
    }

    public static function getInstance()
    {
        if (!isset(self::$_instance)) {
            self::$_instance = new DB();
        }
        return self::$_instance;
    }

    public function query($sql, $params = array())
    {
        $this->_error = false;
        if ($this->_query = $this->_pdo->prepare($sql)) {
            $x = 1;
            if (count($params)) {
                foreach ($params as $param) {
                    $this->_query->bindValue($x, $param);
                    $x++;
                }
            }
            if ($this->_query->execute()) {
                $this->_results = $this->_query->fetchAll(PDO::FETCH_OBJ);
                $this->_count = $this->_query->rowCount();
                print_r($this->results());
                die();
            } else {
                $this->_error = true;
            }
        }
        return $this;
    }

    public function action($action, $table, $where = array())
    {
        if (count($where) === 3) {
            $operators = array('=','<','>','<=','>=',"!=");
            $field=        $where[0];
            $operator=     $where[1];
            $value=        $where[2];
            if (in_array($operator,$operators)){
                $sql = "{$action} FROM {$table} WHERE {$field} {$operator} ?";
                if (!$this->query($sql,array($value))->error()){
                    return $this ;
                }
            }
        }
        return false ;
    }
    public function get($table,$where){
        return $this->action("SELECT *" ,$table,$where);
    }public function delete($table,$where){
        return $this->action("DELETE" ,$table,$where);
    }
    public function insert($table,$fields = array()){
        if (count($fields)){
            $keys=array_keys($fields);
            $values='';
            $x=1;
            $sql= "INSERT INTO {$table} (`".implode("`,`",$keys)."`)";
            foreach ($fields as $field){
                $values .= "?" ;
                if ($x<count($fields)){
                    $values .=',';
                }
                $x++;
            }
            $sql .= "VALUES (".$values.")";
            if (!$this->query($sql,$fields)->error())
            {die("done !");
                return true ;
            }
        }
        return false ;
    }
    public function update($table,$id,$fields){
        $set='';
        $x=1;
        foreach ($fields as $name=>$value ){
            $set .= "{$name}=?";
                if ($x<count($fields)){
                    $set .=',';
                }
                $x++;
        }

        $sql  = "UPDATE {$table} SET {$set} WHERE id = {$id}";
        if(!$this->query($sql,$fields)->error()){
            return true ;
        }
        return false ;
    }
    public function error()
    {
        return $this->_error;
    }
    public function results(){
        return $this->_results ;
    }
    public function first(){
        return $this->results()[0];
    }
    public function count(){
        return $this->_count ;
    }
}