<?php

namespace App\Database;


use PDO;

class DB
{

	/** @var  DB */
	protected static $instance;

	/** @var string */
	private static $password;

	/** @var string */
	private static $username;

	/** @var PDO */
	protected $pdo;

	/** @var string */
	protected static $dsn = 'sqlite:database.db';

	/** @var string */
	protected $currentDriver;

	public function __construct(string $dsn, string $username = null, string $password = null)
	{
		self::setDsn($dsn, $username, $password);

		$this->pdo = new PDO($dsn, $username, $password);
		$this->pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
		$this->pdo->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_OBJ);

		$this->currentDriver = $this->pdo->getAttribute(PDO::ATTR_DRIVER_NAME);
		if ($this->currentDriver === 'sqlite') {
			$this->pdo->exec('PRAGMA foreign_keys = ON');
		}
	}

	public function query(string $query, $parameters = [])
	{
		if (!is_array($parameters)) {
			$parameters = [$parameters];
		}
		$query = $this->pdo->prepare($query);

		foreach ($parameters as $index => $parameter) {
			$query->bindValue($index + 1, $parameter, is_int($parameter) ? PDO::PARAM_INT : PDO::PARAM_STR);
		}

		$query->execute();
		return $query;
	}

	/**
	 * Get the PDO instance
	 * @return PDO
	 */
	public function getPdo(): PDO
	{
		return $this->pdo;
	}

	/**
	 * Get the current PDO driver
	 * @return string
	 */
	public function getCurrentDriver(): string
	{
		return $this->currentDriver;
	}

	public static function getInstance(): DB
	{
		if (self::$instance === null) {
			self::$instance = new self(self::$dsn, self::$username, self::$password);
		}

		return self::$instance;
	}

	/**
	 * Perform a query
	 * @param string $query
	 * @param array $parameters
	 * @return bool|\PDOStatement|string
	 */
	public static function doQuery(string $query, $parameters = [])
	{
		return self::getInstance()->query($query, $parameters);
	}

	/**
	 * Static method to get the current driver name
	 * @return string
	 */
	public static function driver(): string
	{

		return self::getInstance()->getCurrentDriver();
	}

	/**
	 * Get directly the PDO instance
	 * @return PDO
	 */
	public static function raw(): PDO
	{

		return self::getInstance()->getPdo();
	}

	/**
	 * Set the PDO connection string
	 * @param string $dsn
	 * @param string|null $username
	 * @param string|null $password
	 */
	public static function setDsn(string $dsn, string $username = null, string $password = null)
	{
		self::$dsn = $dsn;
		self::$username = $username;
		self::$password = $password;
	}

}