import os
import runpy
import shutil
import sys
import traceback
from pathlib import Path
from typing import Optional

CODE_FILES = ["app.py", "engine.py", "engine_hedge.py", "mtm.py"]
CODE_DIR = Path("_code")
CODE_PREFIX = "code" 


def _secret_or_env(key: str, default=None):
    try:
        import streamlit as st
        try:
            val = st.secrets.get(key)
        except Exception:
            val = None
    except Exception:
        val = None
    if val is None:
        val = os.environ.get(key)
    return val if val is not None else default


def _place(src: Path, dst: Path) -> None:
    tmp = dst.with_suffix(dst.suffix + ".tmp")
    shutil.copyfile(src, tmp)
    os.replace(tmp, dst)


def _ensure_code() -> Optional[str]:
    """把程式檔備妥於 _code/。成功回傳 None，失敗回傳錯誤訊息。"""
    CODE_DIR.mkdir(exist_ok=True)
    if all((CODE_DIR / f).exists() for f in CODE_FILES):
        return None

    local_src = os.environ.get("CODE_LOCAL_DIR")
    if local_src:
        for f in CODE_FILES:
            _place(Path(local_src) / f, CODE_DIR / f)
        return None

    repo = _secret_or_env("HF_DATASET_REPO")
    token = _secret_or_env("HF_TOKEN")
    branch = _secret_or_env("HF_BRANCH", "main")
    if not (repo and token):
        return "尚未設定 HF_DATASET_REPO / HF_TOKEN（Streamlit Secrets 或環境變數）。"
    try:
        from huggingface_hub import hf_hub_download
        for f in CODE_FILES:
            cached = hf_hub_download(
                repo_id=repo,
                filename=f"{CODE_PREFIX}/{f}",
                repo_type="dataset",
                revision=branch,
                token=token,
            )
            _place(Path(cached), CODE_DIR / f)
        return None
    except Exception:
        traceback.print_exc() 
        return "程式碼載入失敗，請確認私有 dataset 的 code/ 資料夾與 Secrets 設定後重試。"


_err = _ensure_code()
if _err is not None:
    import streamlit as st
    st.error(_err)
    st.stop()

_code_path = str(CODE_DIR.resolve())
if _code_path not in sys.path:
    sys.path.insert(0, _code_path) 

runpy.run_path(str(CODE_DIR / "app.py"), run_name="__main__")