<?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\data\bedrock\item\upgrade;

use pocketmine\utils\AssumptionFailedError;
use pocketmine\utils\SingletonTrait;
use pocketmine\utils\Utils;
use Symfony\Component\Filesystem\Path;
use function file_get_contents;
use function is_array;
use function is_string;
use function json_decode;
use function mb_strtolower;
use const pocketmine\BEDROCK_ITEM_UPGRADE_SCHEMA_PATH;

/**
 * Maps all known 1.12 and lower item IDs to their respective block IDs, where appropriate.
 * If an item ID does not have a corresponding 1.12 block ID, assume the item is not a blockitem.
 *
 * This is only needed for deserializing blockitems from 1.8 and lower (or 1.12 and lower in the case of PM). In 1.9 and
 * above, the blockstate NBT is stored in the itemstack NBT, and the item ID is not used.
 */
final class R12ItemIdToBlockIdMap{
	use SingletonTrait;

	private static function make() : self{
		$map = json_decode(
			Utils::assumeNotFalse(file_get_contents(Path::join(BEDROCK_ITEM_UPGRADE_SCHEMA_PATH, '1.12.0_item_id_to_block_id_map.json')), "Missing required resource file"),
			associative: true,
			flags: JSON_THROW_ON_ERROR
		);
		if(!is_array($map)){
			throw new AssumptionFailedError("Invalid blockitem ID mapping table, expected array as root type");
		}

		$builtMap = [];
		foreach($map as $itemId => $blockId){
			if(!is_string($itemId)){
				throw new AssumptionFailedError("Invalid blockitem ID mapping table, expected string as key");
			}
			if(!is_string($blockId)){
				throw new AssumptionFailedError("Invalid blockitem ID mapping table, expected string as value");
			}
			$builtMap[$itemId] = $blockId;
		}

		return new self($builtMap);
	}

	/**
	 * @var string[]
	 * @phpstan-var array<string, string>
	 */
	private array $itemToBlock = [];
	/**
	 * @var string[]
	 * @phpstan-var array<string, string>
	 */
	private array $blockToItem = [];

	/**
	 * @param string[] $itemToBlock
	 * @phpstan-param array<string, string> $itemToBlock
	 */
	public function __construct(array $itemToBlock){
		foreach(Utils::stringifyKeys($itemToBlock) as $itemId => $blockId){
			$this->itemToBlock[mb_strtolower($itemId, 'US-ASCII')] = $blockId;
			$this->blockToItem[mb_strtolower($blockId, 'US-ASCII')] = $itemId;
		}
	}

	public function itemIdToBlockId(string $itemId) : ?string{
		return $this->itemToBlock[mb_strtolower($itemId, 'US-ASCII')] ?? null;
	}

	public function blockIdToItemId(string $blockId) : ?string{
		//we don't need this for any functionality, but it might be nice to have for debugging
		return $this->blockToItem[mb_strtolower($blockId, 'US-ASCII')] ?? null;
	}
}