import sys, os
import xml.etree.ElementTree as ET
from assethelpers import getAssetRelativePath
from args import args
from constants import ASSET_FILE_NAME_MAX_LENGTH
from processimage import processPalette, processImage

def processTileset(assetPath):
  # Process the tileset file
  print(f"Processing tileset: {assetPath}")

  # Load the tileset XML
  tree = ET.parse(assetPath)
  root = tree.getroot()

  # Needs tilewidth, tileheight, tilecount and columns attributes
  if not all(attr in root.attrib for attr in ['tilewidth', 'tileheight', 'tilecount', 'columns']):
    print(f"Error: Tileset {assetPath} is missing required attributes.")
    return
  
  tilewidth = int(root.attrib.get('tilewidth', 0))
  tileheight = int(root.attrib.get('tileheight', 0))
  tilecount = int(root.attrib.get('tilecount', 0))
  columns = int(root.attrib.get('columns', 0))
  
  if tilewidth <= 0 or tileheight <= 0 or tilecount <= 0 or columns <= 0:
    print(f"Error: Tileset {assetPath} has invalid attribute values.")
    return

  # Exactly one image element is required
  imagesNode = root.findall('image')
  if len(imagesNode) != 1:
    print(f"Error: Tileset {assetPath} must have exactly one image element.")
    return

  imageNode = imagesNode[0]
  if 'source' not in imageNode.attrib:
    print(f"Error: Tileset {assetPath} is missing image source.")
    return

  imageSource = imageNode.attrib['source']

  directory = os.path.dirname(assetPath)
  image = processImage(os.path.join(directory, imageSource))

  # Build 
  relativeFile = getAssetRelativePath(assetPath)
  relativeDir = os.path.dirname(relativeFile)

  data = "DTF"  # Header for Dusk Tileset Format
  # Write width (int32_t)
  data += tilewidth.to_bytes(4, byteorder='little').decode('latin1')
  # Write height (int32_t)
  data += tileheight.to_bytes(4, byteorder='little').decode('latin1')
  # Write tilecount (int32_t)
  data += tilecount.to_bytes(4, byteorder='little').decode('latin1')
  # Write column count (int32_t)
  data += columns.to_bytes(4, byteorder='little').decode('latin1')
  # Write row count (int32_t)
  rows = (tilecount + columns - 1) // columns
  data += rows.to_bytes(4, byteorder='little').decode('latin1')

  # Write image source file name, padd to ASSET_FILE_NAME_MAX_LENGTH
  imageSourceBytes = image["outputFile"].encode('utf-8')
  data += len(imageSourceBytes).to_bytes(4, byteorder='little').decode('latin1')
  data += imageSourceBytes.decode('latin1')
  paddingLength = max(0, ASSET_FILE_NAME_MAX_LENGTH - len(imageSourceBytes))
  data += '\x00' * paddingLength

  # Write to output file
  fileNameWithoutExt = os.path.splitext(os.path.basename(assetPath))[0]
  outputFilePath = os.path.join(args.output_assets, relativeDir, f"{fileNameWithoutExt}.dtf")
  os.makedirs(os.path.dirname(outputFilePath), exist_ok=True)
  with open(outputFilePath, 'wb') as f:
    f.write(data.encode('latin1'))

  return {
    "outputFile": os.path.relpath(outputFilePath, args.output_assets),
    "tileWidth": tilewidth,
    "tileHeight": tileheight,
    "tileCount": tilecount,
    "columns": columns,
    "rows": rows,
    "image": image
  }