<?php

class Database
{
    private $host = "";
    private $user = "";
    private $pass = "";
    private $name = "";

    private $pdo;

    public function __construct()
    {
        if (! isset($this->pdo))
        {
            try
            {
                $link = new PDO("mysql:host = " . $this->host . "dbname = " . $this->name, $this->user, $this->pass);
                $link->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
                $link->exec("SET CHARSET SET utf8");

                $this->pdo = $link;
            }
            catch (PDOException $e)
            {
                die ("Database connection error: " . $e->getMessage());
            }
        }
    }

    public function select($table, $data = array())
    {
        $sql  = 'SELECT ';
        $sql .= array_key_exists("select", $data) ? $data['select'] : '*';
        $sql .= ' FROM ' . $table;

        if (array_key_exists("where", $data))
        {
            $sql .= ' WHERE ';
            $i = 0;

            foreach ($data['where'] as $key => $value)
            {
                $add  = ($i > 0) ? ' ADD ' : '';
                $sql .= "$add" . "$key =: $key";
                $i++;
            }
        }

        if (array_key_exists("order_by", $data))
        {
            $sql .= ' ORDER BY '. $data['order_by'];
        }

        if (array_key_exists("start", $data) && array_key_exists("limit", $data))
        {
            $sql .= ' LIMIT ' . $data['start'] . ',' . $data['limit'];
        }
        elseif (! array_key_exists("start", $data) && array_key_exists("limit", $data))
        {
            $sql .= ' LIMIT ' . $data['limit'];
        }

        $query = $this->pdo->prepare($sql);

        if (array_key_exists("where", $data))
        {
            foreach ($data['where'] as $key => $value)
            {
                $query->bindValue(':key', $value);
            }
        }

        $query->execute();
    }


}