"""Download or locate attachment files for a task."""
from __future__ import annotations

import os
from pathlib import Path
from typing import Optional

import requests

DEFAULT_API_URL = "https://agents-course-unit4-scoring.hf.space"
# Bundled copies ship with the Space as a fallback when /files/{id} 404s.
LOCAL_FILES_DIR = Path(__file__).resolve().parent.parent / "files"


def download_task_file(
    task_id: str,
    file_name: str = "",
    api_url: str = DEFAULT_API_URL,
    dest_dir: Optional[Path] = None,
) -> Optional[Path]:
    """Fetch attachment from scoring API; fall back to bundled files/."""
    dest_dir = Path(dest_dir or LOCAL_FILES_DIR)
    dest_dir.mkdir(parents=True, exist_ok=True)

    candidates = []
    if file_name:
        candidates.append(dest_dir / file_name)
    candidates.append(dest_dir / task_id)
    for ext in (".png", ".mp3", ".py", ".xlsx", ".txt", ".pdf"):
        candidates.append(dest_dir / f"{task_id}{ext}")

    for path in candidates:
        if path.is_file() and path.stat().st_size > 200:
            return path

    if not file_name:
        return None

    out = dest_dir / file_name
    url = f"{api_url.rstrip('/')}/files/{task_id}"
    try:
        resp = requests.get(url, timeout=60)
        if resp.status_code == 200 and len(resp.content) > 200:
            out.write_bytes(resp.content)
            return out
    except requests.RequestException:
        pass

    # Optional: GAIA hub download when HF_TOKEN is present
    token = os.environ.get("HF_TOKEN") or os.environ.get("HUGGINGFACEHUB_API_TOKEN")
    if token and file_name:
        try:
            from huggingface_hub import hf_hub_download

            remote = f"2023/validation/{file_name}"
            cached = hf_hub_download(
                repo_id="gaia-benchmark/GAIA",
                filename=remote,
                repo_type="dataset",
                token=token,
            )
            out.write_bytes(Path(cached).read_bytes())
            return out
        except Exception:
            pass
    return out if out.is_file() else None