import json
import os
from dusk.event import Event

class Chunk:
  def __init__(self, map, x, y, z):
    self.map = map
    self.x = x
    self.y = y
    self.z = z
    self.current = {}
    self.original = {}
    self.onChunkData = Event()

  def load(self):
    fname = self.getFilename()
    if not fname or not os.path.exists(fname):
      self.new()
      return
    try:
      with open(fname, 'r') as f:
        self.current = json.load(f)
      self.original = json.loads(json.dumps(self.current))  # Deep copy
      self.onChunkData.invoke(self.current)
    except Exception as e:
      raise RuntimeError(f"Failed to load chunk file: {e}")

  def save(self):
    fname = self.getFilename()
    if not fname:
      raise ValueError("No filename specified for saving chunk.")
    try:
      with open(fname, 'w') as f:
        json.dump(self.current, f, indent=2)
      self.original = json.loads(json.dumps(self.current))  # Deep copy
    except Exception as e:
      raise RuntimeError(f"Failed to save chunk file: {e}")

  def new(self):
    self.current = {}
    self.original = {}
    self.onChunkData.invoke(self.current)

  def isDirty(self):
    return json.dumps(self.current, sort_keys=True) != json.dumps(self.original, sort_keys=True)

  def getFilename(self):
    if not self.map or not hasattr(self.map, 'getMapDirectory'):
      return None
    dir_path = self.map.getMapDirectory()
    if dir_path is None:
      return None
    return f"{dir_path}/{self.x}_{self.y}_{self.z}.json"