<?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/
 * 
 *
*/

class NBT{
	public $tree = array();
	public $binary = b"";
	private $offset = 0;

	const TAG_END = 0;
	const TAG_BYTE = 1;
	const TAG_SHORT = 2;
	const TAG_INT = 3;
	const TAG_LONG = 4;
	const TAG_FLOAT = 5;
	const TAG_DOUBLE = 6;
	const TAG_BYTE_ARRAY = 7;
	const TAG_STRING = 8;
	const TAG_LIST = 9;
	const TAG_COMPOUND = 10;
	
	public function read($n){
		if($n <= 0){
			return "";		
		}
		$this->offset += $n;
		return substr($this->binary, $this->offset - $n, $n);
	}
	
	public function write($bin){
		$this->binary .= $bin;
	}
	
	public function load($str){
		$this->offset = 0;
		$this->binary = (string) $str;
		$this->parseTree($this->tree);
	}
	
	public function readTAG_BYTE(){
		return Utils::readByte($this->read(1));
	}
	
	public function readTAG_SHORT(){
		return Utils::readLShort($this->read(2));
	}
	
	public function readTAG_INT(){
		return Utils::readLInt($this->read(4));
	}
	
	public function readTAG_LONG(){
		return Utils::readLLong($this->read(8));
	}
	
	public function readTAG_FLOAT(){
		return Utils::readLFloat($this->read(4));
	}
	
	public function readTAG_DOUBLE(){
		return Utils::readLDouble($this->read(8));
	}
	
	public function readTAG_BYTE_ARRAY(){
		return $this->read($this->readTAG_INT());
	}
	
	public function readTAG_STRING(){
		return $this->read(Utils::readLShort($this->read(2), false));
	}
	
	public function writeTAG_BYTE($v){
		$this->binary .= chr($v);
	}
	
	public function writeTAG_SHORT($v){
		$this->binary .= Utils::writeLShort($v);
	}
	
	public function writeTAG_INT($v){
		$this->binary .= Utils::writeLInt($v);
	}
	
	public function writeTAG_LONG($v){
		$this->binary .= Utils::writeLLong($v);
	}
	
	public function writeTAG_FLOAT($v){
		$this->binary .= Utils::writeLFloar($v);
	}
	
	public function writeTAG_DOUBLE($v){
		$this->binary .= Utils::writeLDouble($v);
	}
	
	public function writeTAG_BYTE_ARRAY($v){
		$this->binary .= $this->writeTAG_INT(strlen($v)).$v;
	}
	
	public function writeTAG_STRING($v){
		$this->binary .= $this->writeTAG_SHORT(strlen($v)).$v;
	}

	private function parseList(&$node, $tag, $cnt){
		for($i = 0; $i < $cnt; ++$i){
			switch($tag){
				case self::TAG_BYTE:				
					$value = $this->readTAG_BYTE();
					break;
				case self::TAG_SHORT:
					$value = $this->readTAG_SHORT();
					break;
				case self::TAG_INT:
					$value = $this->readTAG_INT();
					break;
				case self::TAG_LONG:
					$value = $this->readTAG_LONG();
					break;
				case self::TAG_FLOAT:
					$value = $this->readTAG_FLOAT();
					break;
				case self::TAG_DOUBLE:
					$value = $this->readTAG_DOUBLE();
					break;
				case self::TAG_BYTE_ARRAY:
					$value = $this->readTAG_BYTE_ARRAY();
					break;
				case self::TAG_STRING:
					$value = $this->readTAG_STRING();
					break;
				case self::TAG_LIST:
					$value = array();
					$this->parseList($value, ord($this->read(1)), Utils::readLInt($this->read(4)));
					break;
				case self::TAG_COMPOUND:
					$value = array();
					$this->parseTree($value);
					break;
				default:
					die("Invalid NBT Tag $tag");
					break;
			}
			$node[] = $value;
		}
	}
	
	private function parseTree(&$node){
		while(($tag = ord($this->read(1))) !== self::TAG_END){
			$name = $this->readTAG_STRING();
			switch($tag){
				case self::TAG_BYTE:				
					$value = $this->readTAG_BYTE();
					break;
				case self::TAG_SHORT:
					$value = $this->readTAG_SHORT();
					break;
				case self::TAG_INT:
					$value = $this->readTAG_INT();
					break;
				case self::TAG_LONG:
					$value = $this->readTAG_LONG();
					break;
				case self::TAG_FLOAT:
					$value = $this->readTAG_FLOAT();
					break;
				case self::TAG_DOUBLE:
					$value = $this->readTAG_DOUBLE();
					break;
				case self::TAG_BYTE_ARRAY:
					$value = $this->readTAG_BYTE_ARRAY();
					break;
				case self::TAG_STRING:
					$value = $this->readTAG_STRING();
					break;
				case self::TAG_LIST:
					$value = array();
					$this->parseList($value, ord($this->read(1)), Utils::readLInt($this->read(4)));
					break;
				case self::TAG_COMPOUND:
					$value = array();
					$this->parseTree($value);
					break;
				default:
					die("Invalid NBT Tag $tag");
					break;
			}
			$node[$name] = $value;
		}
	}
}