from __future__ import annotations

from quart import current_app

DEFAULT_BROWSER_MAX_AGE = 86400
DEFAULT_EDGE_MAX_AGE = 1800

def file_cache():
  """The app's FileCache, or None when caching is not configured."""
  return getattr(current_app, 'file_cache', None)

def browser_max_age() -> int:
  cache = file_cache()
  return DEFAULT_BROWSER_MAX_AGE if cache is None else cache.blob_max_age

def edge_max_age() -> int:
  cache = file_cache()
  return DEFAULT_EDGE_MAX_AGE if cache is None else cache.edge_max_age

async def load_file(file_id: str):
  async def loader():
    return await current_app.convex.get_file(file_id=file_id)

  cache = file_cache()
  if cache is None:
    return await loader()
  return await cache.get_metadata(file_id, loader)

async def load_blob(storage_key: str) -> bytes:
  async def loader() -> bytes:
    payload = await current_app.convex.get_from_storage(storage_key)
    return payload.getvalue() if hasattr(payload, 'getvalue') else bytes(payload)

  cache = file_cache()
  if cache is None:
    return await loader()
  return await cache.get_blob(storage_key, loader)

async def drop_file_cache(file_id: str) -> None:
  """Invalidate metadata after a mutation; blobs are immutable and expire on TTL."""
  cache = file_cache()
  if cache is not None:
    await cache.invalidate(file_id)