import os
import os.path

CHUNK_SIZE = 16
FILE_VERSION = 0

def _get_chunk_path(x: int, z: int) -> str:
	return f"world/{x}.{z}.fwc"

def get_chunk_data(x: int, z: int) -> bytes or None:
	if os.path.exists(loc := _get_chunk_path(x, z)):
		with open(loc, "rb") as fp:
			if fp.read(3) != b"FWC":
				raise RuntimeError(f"{loc} is not a FWC file!")
			if (version := int.from_bytes(fp.read(2))) != FILE_VERSION:
				raise RuntimeError(f"{loc} is wrong FWC version! Found {version}, expected {FILE_VERSION}.")
			return fp.read()

def save_chunk_data(x: int, z: int, data: bytes) -> None:
	if not os.path.isdir("world"): os.mkdir("world")
	with open(_get_chunk_path(x, z), "wb") as fp:
		fp.write(b"FWC" + FILE_VERSION.to_bytes(2))
		fp.write(data)

def chunk_exists(x: int, z: int) -> bool:
	return os.path.exists(_get_chunk_path(x, z))