from __future__ import annotations

import json
from pathlib import Path
import threading
from typing import Iterable

from app.models import IpEntry


class EntryStorage:
    def __init__(self, file_path: str):
        self._path = Path(file_path)
        self._lock = threading.Lock()

    def list_entries(self) -> list[IpEntry]:
        with self._lock:
            return self._read_entries_unlocked()

    def save_entries(self, entries: Iterable[IpEntry]) -> None:
        serializable = [entry.to_dict() for entry in entries]
        with self._lock:
            self._path.parent.mkdir(parents=True, exist_ok=True)
            tmp_path = self._path.with_suffix(self._path.suffix + ".tmp")
            tmp_path.write_text(json.dumps(serializable, indent=2, sort_keys=True), encoding="utf-8")
            tmp_path.replace(self._path)

    def _read_entries_unlocked(self) -> list[IpEntry]:
        if not self._path.exists():
            return []

        raw = self._path.read_text(encoding="utf-8").strip()
        if not raw:
            return []

        parsed = json.loads(raw)
        if not isinstance(parsed, list):
            raise ValueError(f"State file must be a list: {self._path}")

        return [IpEntry.from_dict(item) for item in parsed]