from __future__ import annotations

import json
import os
import secrets
from datetime import datetime, timezone
from pathlib import Path
from typing import Any


PROJECT_DIR = Path(__file__).resolve().parent.parent
configured_data_dir = os.environ.get("DATA_DIR", "").strip()
if configured_data_dir:
    configured_path = Path(configured_data_dir).expanduser()
    if not configured_path.is_absolute():
        configured_path = PROJECT_DIR / configured_path
    DATA_DIR = configured_path.resolve()
else:
    DATA_DIR = (PROJECT_DIR / "data").resolve()

RUNS_DIR = DATA_DIR / "runs"
RUNS_DIR.mkdir(parents=True, exist_ok=True)


def create_run_id() -> str:
    stamp = datetime.now(timezone.utc).strftime("%Y%m%dT%H%M%SZ")
    return f"{stamp}-{secrets.token_hex(4)}"


def run_dir(run_id: str) -> Path:
    if not run_id or any(
        ch not in "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_"
        for ch in run_id
    ):
        raise ValueError("Ungültige Run-ID.")
    path = RUNS_DIR / run_id
    path.mkdir(parents=True, exist_ok=True)
    return path


def write_json(run_id: str, filename: str, payload: Any) -> Path:
    path = run_dir(run_id) / filename
    temporary = path.with_suffix(path.suffix + ".tmp")
    temporary.write_text(
        json.dumps(payload, ensure_ascii=False, indent=2) + "\n",
        encoding="utf-8",
    )
    temporary.replace(path)
    return path


def read_json(run_id: str, filename: str) -> Any:
    return json.loads((run_dir(run_id) / filename).read_text(encoding="utf-8"))