"""Protected inventory and restoration of automatic recovery snapshots."""
from __future__ import annotations

import json
from pathlib import Path

from fastapi import APIRouter, HTTPException, Request

from core.config import CONFIG_DIR
from core.database import char_put, reh_put
from core.validation import _safe_child_path

router = APIRouter()
_BACKUP_ROOT = CONFIG_DIR / "backups"
_BACKUP_KINDS = {"characters", "rehearsals"}


def _backup_path(kind: str, filename: str) -> Path:
    if kind not in _BACKUP_KINDS or not filename or Path(filename).name != filename or not filename.endswith(".json"):
        raise HTTPException(400, "Invalid backup reference")
    directory = _BACKUP_ROOT / kind
    path = _safe_child_path(directory, directory / filename)
    if not path.is_file():
        raise HTTPException(404, "Backup not found")
    return path


def _read_backup(path: Path) -> dict:
    try:
        data = json.loads(path.read_text(encoding="utf-8"))
    except (OSError, ValueError) as exc:
        raise HTTPException(422, f"Backup cannot be read: {exc}")
    if not isinstance(data, dict) or not isinstance(data.get("record"), dict):
        raise HTTPException(422, "Invalid backup format")
    return data


@router.get("/api/backups")
async def list_backups():
    items: list[dict] = []
    for kind in sorted(_BACKUP_KINDS):
        directory = _BACKUP_ROOT / kind
        if not directory.is_dir():
            continue
        for path in sorted(directory.glob("*.json"), key=lambda p: p.stat().st_mtime, reverse=True):
            try:
                data = _read_backup(path)
                record = data["record"]
            except HTTPException:
                continue
            items.append({
                "kind": kind,
                "file": path.name,
                "saved_at": data.get("saved_at", ""),
                "reason": data.get("reason", ""),
                "id": record.get("id"),
                "name": record.get("name") or record.get("title", ""),
            })
    return {"backups": items[:500]}


@router.post("/api/backups/restore")
async def restore_backup(request: Request):
    try:
        data = await request.json()
    except Exception:
        raise HTTPException(400, "Invalid JSON")
    kind = str(data.get("kind") or "").strip().lower()
    path = _backup_path(kind, str(data.get("file") or "").strip())
    payload = _read_backup(path)
    record = payload["record"]
    if kind == "characters":
        restored = char_put(record)
        return {"ok": True, "kind": kind, "id": restored.get("id"), "restored_from": path.name}
    restored = reh_put(record)
    return {"ok": True, "kind": kind, "id": restored.get("id"), "restored_from": path.name}