"""Manage Model — password-gated page for teammates to update the live model.

Upload an exported model (a .zip of the folder produced by the training
notebooks, i.e. config.json + model.safetensors + tokenizer files). It is
validated against the project's 7-label scheme and pushed to the Hugging Face
Hub repo the app loads from (config.PRIMARY_MODEL_ID). The Hub repo is the
durable store — a Space's own disk is wiped on restart, so we never rely on it.

Secrets (set in the Space settings, never in git):
  HF_TOKEN         a Hugging Face *write* token
  MANAGE_PASSWORD  password protecting this page
"""
import io
import json
import os
import tempfile
import zipfile
from pathlib import Path

import streamlit as st

import config

st.set_page_config(page_title="Manage Model", page_icon="🔐", layout="centered")
st.title("🔐 Manage Model")
st.caption("Update the live NER model. Restricted to the team.")


def _secret(name, default=""):
    # st.secrets raises if no secrets file exists; fall back to env.
    try:
        if name in st.secrets:
            return st.secrets[name]
    except Exception:  # noqa: BLE001
        pass
    return os.environ.get(name, default)


# ---- Password gate ----------------------------------------------------------
PASSWORD = _secret("MANAGE_PASSWORD")
if not PASSWORD:
    st.error("This page is disabled: no `MANAGE_PASSWORD` secret is configured.")
    st.stop()

if not st.session_state.get("manage_authed"):
    pw = st.text_input("Password", type="password")
    if st.button("Unlock"):
        if pw == PASSWORD:
            st.session_state["manage_authed"] = True
            st.rerun()
        else:
            st.error("Wrong password.")
    st.stop()

# ---- Authed --------------------------------------------------------------
TARGET_REPO = st.text_input("Target Hub model repo", value=config.PRIMARY_MODEL_ID,
                            help="The repo the app loads. Overwriting it updates the live model.")
private = st.checkbox("Keep repo private", value=True)

st.markdown(
    "Upload a **.zip of your exported model folder** "
    "(`config.json`, `model.safetensors`, tokenizer files, ideally `label_config.json`). "
    "This is the folder the training notebooks write to `exported_models/…`."
)
up = st.file_uploader("Model .zip", type=["zip"])

REQUIRED = ["config.json"]
WEIGHTS = ["model.safetensors", "pytorch_model.bin"]


def _find_model_dir(root: Path):
    """Locate the directory holding config.json (zip may have a wrapper folder)."""
    for cfg in root.rglob("config.json"):
        return cfg.parent
    return None


def _validate(model_dir: Path):
    files = {p.name for p in model_dir.iterdir()}
    if not any(w in files for w in WEIGHTS):
        return f"No weights file found ({' or '.join(WEIGHTS)})."
    # Label-scheme check: prefer label_config.json, else config.json id2label.
    labels = None
    if (model_dir / "label_config.json").exists():
        labels = set(json.loads((model_dir / "label_config.json").read_text())
                     .get("id2label", {}).values())
    else:
        cfg = json.loads((model_dir / "config.json").read_text())
        labels = set(cfg.get("id2label", {}).values())
    if "B-SKILL" not in labels:
        return ("Label scheme mismatch — model does not use the project's BIO tags "
                f"(expected B-SKILL/JOB_TITLE/EDUCATION, got: {sorted(labels) or 'none'}).")
    return None


if up is not None and st.button("Validate & publish", type="primary"):
    token = _secret("HF_TOKEN")
    if not token:
        st.error("No `HF_TOKEN` secret configured — cannot push to the Hub.")
        st.stop()
    try:
        from huggingface_hub import HfApi, create_repo
    except ModuleNotFoundError:
        st.error("`huggingface_hub` is not installed (add it to requirements.txt).")
        st.stop()

    with tempfile.TemporaryDirectory() as td:
        tdp = Path(td)
        try:
            with zipfile.ZipFile(io.BytesIO(up.getvalue())) as zf:
                zf.extractall(tdp)
        except zipfile.BadZipFile:
            st.error("That file is not a valid .zip.")
            st.stop()

        model_dir = _find_model_dir(tdp)
        if model_dir is None:
            st.error("No `config.json` found anywhere in the zip.")
            st.stop()

        err = _validate(model_dir)
        if err:
            st.error(err)
            st.stop()

        st.success(f"Validated: {sorted(p.name for p in model_dir.iterdir())}")
        with st.spinner(f"Publishing to {TARGET_REPO}…"):
            create_repo(TARGET_REPO, repo_type="model", private=private,
                        exist_ok=True, token=token)
            HfApi(token=token).upload_folder(
                folder_path=str(model_dir), repo_id=TARGET_REPO, repo_type="model",
                commit_message="Update model via Manage Model page",
            )
        st.success(f"✅ Published to https://huggingface.co/{TARGET_REPO}")
        st.info("Go to any page and click **🔄 Reload model** in the sidebar to use it.")