<?php

/*
 *
 *  ____            _        _   __  __ _                  __  __ ____
 * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
 * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
 * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
 * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * @author PocketMine Team
 * @link http://www.pocketmine.net/
 *
 *
*/

declare(strict_types=1);

namespace pocketmine\network\mcpe\protocol;

#include <rules/DataPacket.h>

use Error;
use OutOfBoundsException;
use pocketmine\network\mcpe\CachedEncapsulatedPacket;
use pocketmine\network\mcpe\NetworkBinaryStream;
use pocketmine\network\mcpe\NetworkSession;
use pocketmine\utils\Utils;
use ReflectionClass;
use UnexpectedValueException;
use function bin2hex;
use function get_class;
use function is_object;
use function is_string;
use function method_exists;

abstract class DataPacket extends NetworkBinaryStream{

	public const NETWORK_ID = 0;

	public const PID_MASK = 0x3ff; //10 bits

	private const SUBCLIENT_ID_MASK = 0x03; //2 bits
	private const SENDER_SUBCLIENT_ID_SHIFT = 10;
	private const RECIPIENT_SUBCLIENT_ID_SHIFT = 12;

	/** @var bool */
	public $isEncoded = false;
	/** @var CachedEncapsulatedPacket|null */
	public $__encapsulatedPacket = null;

	/** @var int */
	public $senderSubId = 0;
	/** @var int */
	public $recipientSubId = 0;

	/**
	 * @return int
	 */
	public function pid(){
		return $this::NETWORK_ID;
	}

	public function getName() : string{
		return (new ReflectionClass($this))->getShortName();
	}

	public function canBeBatched() : bool{
		return true;
	}

	public function canBeSentBeforeLogin() : bool{
		return false;
	}

	/**
	 * Returns whether the packet may legally have unread bytes left in the buffer.
	 */
	public function mayHaveUnreadBytes() : bool{
		return false;
	}

	/**
	 * @return void
	 * @throws OutOfBoundsException
	 * @throws UnexpectedValueException
	 */
	public function decode(){
		$this->offset = 0;
		$this->decodeHeader();
		$this->decodePayload();
	}

	/**
	 * @return void
	 * @throws OutOfBoundsException
	 * @throws UnexpectedValueException
	 */
	protected function decodeHeader(){
		$header = $this->getUnsignedVarInt();
		$pid = $header & self::PID_MASK;
		if($pid !== static::NETWORK_ID){
			throw new UnexpectedValueException("Expected " . static::NETWORK_ID . " for packet ID, got $pid");
		}
		$this->senderSubId = ($header >> self::SENDER_SUBCLIENT_ID_SHIFT) & self::SUBCLIENT_ID_MASK;
		$this->recipientSubId = ($header >> self::RECIPIENT_SUBCLIENT_ID_SHIFT) & self::SUBCLIENT_ID_MASK;
	}

	/**
	 * Note for plugin developers: If you're adding your own packets, you should perform decoding in here.
	 *
	 * @return void
	 * @throws OutOfBoundsException
	 * @throws UnexpectedValueException
	 */
	protected function decodePayload(){

	}

	/**
	 * @return void
	 */
	public function encode(){
		$this->reset();
		$this->encodeHeader();
		$this->encodePayload();
		$this->isEncoded = true;
	}

	/**
	 * @return void
	 */
	protected function encodeHeader(){
		$this->putUnsignedVarInt(
			static::NETWORK_ID |
			($this->senderSubId << self::SENDER_SUBCLIENT_ID_SHIFT) |
			($this->recipientSubId << self::RECIPIENT_SUBCLIENT_ID_SHIFT)
		);
	}

	/**
	 * Note for plugin developers: If you're adding your own packets, you should perform encoding in here.
	 *
	 * @return void
	 */
	protected function encodePayload(){

	}

	/**
	 * Performs handling for this packet. Usually you'll want an appropriately named method in the NetworkSession for this.
	 *
	 * This method returns a bool to indicate whether the packet was handled or not. If the packet was unhandled, a debug message will be logged with a hexdump of the packet.
	 * Typically this method returns the return value of the handler in the supplied NetworkSession. See other packets for examples how to implement this.
	 *
	 * @return bool true if the packet was handled successfully, false if not.
	 */
	abstract public function handle(NetworkSession $session) : bool;

	/**
	 * @return $this
	 */
	public function clean(){
		$this->buffer = "";
		$this->isEncoded = false;
		$this->offset = 0;
		return $this;
	}

	/**
	 * @return mixed[]
	 */
	public function __debugInfo(){
		$data = [];
		foreach((array) $this as $k => $v){
			if($k === "buffer"){
				$data[$k] = bin2hex($v);
			}elseif(is_string($v) or (is_object($v) and method_exists($v, "__toString"))){
				$data[$k] = Utils::printable((string) $v);
			}else{
				$data[$k] = $v;
			}
		}

		return $data;
	}

	/**
	 * @param string $name
	 *
	 * @return mixed
	 */
	public function __get($name){
		throw new Error("Undefined property: " . get_class($this) . "::\$" . $name);
	}

	/**
	 * @param string $name
	 * @param mixed  $value
	 *
	 * @return void
	 */
	public function __set($name, $value){
		throw new Error("Undefined property: " . get_class($this) . "::\$" . $name);
	}
}
