from __future__ import annotations

import csv
import json
import os
from datetime import datetime, timezone
from pathlib import Path
from uuid import uuid4

from huggingface_hub import HfApi, hf_hub_download


VOTE_FIELDS = [
    "timestamp",
    "vote_id",
    "voter_id",
    "sample_id",
    "left_clip_id",
    "right_clip_id",
    "left_model_id",
    "right_model_id",
    "winner",
    "winner_model_id",
    "notes",
]


def new_vote_id(now: datetime | None = None) -> str:
    now = now or datetime.now(timezone.utc)
    return f"{now.strftime('%Y%m%dT%H%M%SZ')}_{uuid4().hex[:12]}"


def remote_vote_path(row: dict) -> str:
    return f"votes/{row['sample_id']}/{row['vote_id']}.json"


def remote_config() -> tuple[str, str | None]:
    repo_id = os.getenv("ARENA_VOTES_REPO", "fdaudens/sonic-caucus-votes").strip()
    token = os.getenv("ARENA_HF_TOKEN") or os.getenv("HF_TOKEN")
    return repo_id, token


def append_local_vote(votes_path: Path, row: dict) -> None:
    exists = votes_path.exists()
    with votes_path.open("a", newline="") as handle:
        writer = csv.DictWriter(handle, fieldnames=VOTE_FIELDS)
        if not exists:
            writer.writeheader()
        writer.writerow(row)


def append_remote_vote(row: dict) -> str | None:
    repo_id, token = remote_config()
    if not repo_id:
        return "repo not configured"
    if not token:
        return "token not configured"

    payload = json.dumps(row, indent=2, sort_keys=True).encode("utf-8")
    try:
        HfApi().upload_file(
            path_or_fileobj=payload,
            path_in_repo=remote_vote_path(row),
            repo_id=repo_id,
            repo_type="dataset",
            token=token,
            commit_message=f"Add Sonic Caucus vote {row['vote_id']}",
        )
    except Exception as exc:
        return type(exc).__name__
    return None


def append_vote(votes_path: Path, row: dict) -> str | None:
    append_local_vote(votes_path, row)
    return append_remote_vote(row)


def read_local_votes(votes_path: Path) -> list[dict]:
    if not votes_path.exists():
        return []
    with votes_path.open() as handle:
        return list(csv.DictReader(handle))


def read_remote_votes() -> tuple[list[dict], str | None]:
    repo_id, token = remote_config()
    if not repo_id:
        return [], "repo not configured"
    if not token:
        return [], "token not configured"

    api = HfApi()
    try:
        files = api.list_repo_files(repo_id=repo_id, repo_type="dataset", token=token)
        vote_files = [name for name in files if name.startswith("votes/") and name.endswith(".json")]
        rows = []
        for filename in vote_files:
            cached = hf_hub_download(repo_id=repo_id, filename=filename, repo_type="dataset", token=token)
            rows.append(json.loads(Path(cached).read_text()))
    except Exception as exc:
        return [], type(exc).__name__
    return rows, None


def load_vote_rows(votes_path: Path) -> tuple[list[dict], str]:
    remote_rows, remote_error = read_remote_votes()
    if remote_rows:
        return remote_rows, "persistent Hugging Face dataset"

    local_rows = read_local_votes(votes_path)
    if local_rows:
        if remote_error:
            return local_rows, f"local CSV; remote unavailable ({remote_error})"
        return local_rows, "local CSV"

    if remote_error:
        return [], f"no votes; remote unavailable ({remote_error})"
    return [], "no votes"