import sys
import os
from args import args
from xml.etree import ElementTree as ET
from processtileset import processTileset
from assetcache import assetCache, assetGetCache
from assethelpers import getAssetRelativePath

def processMap(asset):
  cache = assetGetCache(asset['path'])
  if cache is not None:
    return cache

  # Load the TMX file
  tree = ET.parse(asset['path'])
  root = tree.getroot()

  # Root needs to be "map" element.
  if root.tag != 'map':
    print(f"Error: TMX file {asset['path']} does not have a <map> root element")
    sys.exit(1)

  # Root needs to be orientation="orthogonal"
  if 'orientation' not in root.attrib or root.attrib['orientation'] != 'orthogonal':
    print(f"Error: TMX file {asset['path']} does not have orientation='orthogonal'")
    sys.exit(1)
  
  # Extract width, height, tilewidth, tileheight attributes
  if 'width' not in root.attrib or 'height' not in root.attrib or 'tilewidth' not in root.attrib or 'tileheight' not in root.attrib:
    print(f"Error: TMX file {asset['path']} is missing required attributes (width, height, tilewidth, tileheight)")
    sys.exit(1)

  mapWidth = int(root.attrib['width'])
  mapHeight = int(root.attrib['height'])
  tileWidth = int(root.attrib['tilewidth'])
  tileHeight = int(root.attrib['tileheight'])

  # Find all tileset elements
  tilesets = []
  for tilesetElement in root.findall('tileset'):
    # Tileset must have a source attribute
    if 'source' not in tilesetElement.attrib:
      print(f"Error: <tileset> element in {asset['path']} is missing a source attribute")
      sys.exit(1)
    # Must have a firstgid attribute
    if 'firstgid' not in tilesetElement.attrib:
      print(f"Error: <tileset> element in {asset['path']} is missing a firstgid attribute")
      sys.exit(1)

    firstGid = int(tilesetElement.attrib['firstgid'])
    source = tilesetElement.attrib['source']

    # Get source path relative to the tmx file's working directory.
    # Needs normalizing also since ".." is often used.
    source = os.path.normpath(os.path.join(os.path.dirname(asset['path']), source))
    tileset = processTileset({ 'path': source, 'type': 'tileset', 'options': {} })

    tilesets.append({
      'firstGid': firstGid,
      'source': source,
      'tileset': tileset
    })

  # Sort tilesets by firstGid, highest first
  tilesets.sort(key=lambda x: x['firstGid'], reverse=True)

  # Layer types
  # objectLayers = [] # Not implemented
  tileLayers = []
  for layerElement in root.findall('layer'):
    # Assume tile layer for now
    # Must have id, name, width, height attributes
    if 'id' not in layerElement.attrib or 'name' not in layerElement.attrib or 'width' not in layerElement.attrib or 'height' not in layerElement.attrib:
      print(f"Error: <layer> element in {asset['path']} is missing required attributes (id, name, width, height)")
      sys.exit(1)

    id = int(layerElement.attrib['id'])
    name = layerElement.attrib['name']
    width = int(layerElement.attrib['width'])
    height = int(layerElement.attrib['height'])

    # Need exactly one data element
    dataElements = layerElement.findall('data')
    if len(dataElements) != 1:
      print(f"Error: <layer> element in {asset['path']} must have exactly one <data> child element")
      sys.exit(1)

    # Get text, remove whitespace, split by comman and convert to int
    dataElement = dataElements[0]
    if dataElement.attrib.get('encoding', '') != 'csv':
      print(f"Error: <data> element in {asset['path']} must have encoding='csv'")
      sys.exit(1)

    dataText = dataElement.text.strip()
    data = [int(gid) for gid in dataText.split(',') if gid.strip().isdigit()]

    # Should be exactly width * height entries
    if len(data) != width * height:
      print(f"Error: <data> element in {asset['path']} has {len(data)} entries but expected {width * height} (width * height)")
      sys.exit(1)

    tileLayers.append({
      'id': id,
      'name': name,
      'width': width,
      'height': height,
      'data': data,
    })

  # Now we have our layers all parsed out.
  data = bytearray()
  data += b'drm'  # Dusk RPG Map
  data += mapWidth.to_bytes(4, 'little')   # Map width in tiles
  data += mapHeight.to_bytes(4, 'little')  # Map height in tiles
  data += len(tilesets).to_bytes(4, 'little')  # Number of tilesets
  data += len(tileLayers).to_bytes(4, 'little')  # Number of layers

  # For each tileset
  for tileset in tilesets:
    data += tileset['firstGid'].to_bytes(4, 'little') # First GID
  
  # For each layer...
  for layer in tileLayers:
    for gid in layer['data']:
      # Get tileset for this gid, since the tilesets are already sorted we can
      # simply find the first one that has firstGid <= gid
      if gid == 0:
        # Empty tile
        localIndex = 0xFF
        tilesetIndex = 0xFFFFFFFF
      else:
        for tileset in tilesets:
          if gid >= tileset['firstGid']:
            tilesetIndex = tilesets.index(tileset)
            localIndex = gid - tileset['firstGid']
            break
        else:
          # If no tileset was found, this is an invalid gid
          print(f"Error: Invalid tile GID {gid} in {asset['path']}")
          sys.exit(1)

      if localIndex > 255:
        print(f"Error: Local tile index {localIndex} exceeds 255 in {asset['path']}")
        sys.exit(1)
      
      data += tilesetIndex.to_bytes(4, 'little')  # Tileset index
      data += localIndex.to_bytes(1, 'little')  # Local tile index

  relative = getAssetRelativePath(asset['path'])
  fileNameWithoutExt = os.path.splitext(os.path.basename(asset['path']))[0]
  outputFileRelative = os.path.join(os.path.dirname(relative), f"{fileNameWithoutExt}.drm")
  outputFilePath = os.path.join(args.output_assets, outputFileRelative)
  os.makedirs(os.path.dirname(outputFilePath), exist_ok=True)
  with open(outputFilePath, "wb") as f:
    f.write(data)

  outMap = {
    'mapPath': outputFileRelative,
    'files': [ outputFilePath ],
    'width': mapWidth,
    'height': mapHeight,
  }

  return assetCache(asset['path'], outMap)