#!/usr/bin/env python3
from __future__ import annotations

import argparse
from pathlib import Path
import subprocess
import sys
from tempfile import NamedTemporaryFile


PROJECT_ROOT = Path(__file__).resolve().parents[1]
if str(PROJECT_ROOT) not in sys.path:
    sys.path.insert(0, str(PROJECT_ROOT))

from common.nn_profile_schedule import (  # noqa: E402
    DEFAULT_PROFILE,
    format_active_profile_env,
    get_requested_active_profile,
    load_simple_env_file,
    normalize_profile_name,
    resolve_active_profile,
)


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(description="Switch DroneDetector NN model profile by schedule")
    parser.add_argument(
        "--project-root",
        default=str(PROJECT_ROOT),
        help="Path to repository root (default: script parent project)",
    )
    parser.add_argument(
        "--no-restart",
        action="store_true",
        help="Update runtime profile file without restarting dronedetector-nn-server",
    )
    return parser.parse_args()


def main() -> int:
    args = parse_args()
    project_root = Path(args.project_root).resolve()
    env_path = project_root / ".env"
    runtime_path = project_root / "runtime" / "nn_active_profile.env"
    compose_file = project_root / "deploy" / "docker" / "docker-compose.yml"

    if not env_path.exists():
        raise SystemExit(f"Missing root .env: {env_path}")
    if not compose_file.exists():
        raise SystemExit(f"Missing docker-compose file: {compose_file}")

    config = load_simple_env_file(env_path)
    requested_profile = get_requested_active_profile(config)
    desired_profile = resolve_active_profile(config)
    runtime_exists = runtime_path.exists()
    current_profile = read_current_profile(runtime_path)

    if requested_profile != desired_profile:
        print(
            f"[nn_profile_switcher] requested profile {requested_profile} is not configured, "
            f"falling back to {desired_profile}"
        )

    if current_profile == desired_profile and runtime_exists:
        print(f"[nn_profile_switcher] profile already active: {desired_profile}")
        return 0

    previous_contents = runtime_path.read_text(encoding="utf-8") if runtime_path.exists() else None
    write_runtime_profile(runtime_path, desired_profile)
    if runtime_exists:
        print(
            f"[nn_profile_switcher] updated runtime profile {current_profile or DEFAULT_PROFILE} -> {desired_profile}"
        )
    else:
        print(f"[nn_profile_switcher] initialized runtime profile: {desired_profile}")

    if current_profile == desired_profile:
        return 0

    if args.no_restart:
        print("[nn_profile_switcher] --no-restart set, skipping container restart")
        return 0

    try:
        restart_nn_server(project_root, compose_file)
    except Exception:
        restore_runtime_profile(runtime_path, previous_contents)
        raise

    print("[nn_profile_switcher] restarted dronedetector-nn-server")
    return 0


def read_current_profile(runtime_path: Path) -> str:
    runtime_values = load_simple_env_file(runtime_path)
    return normalize_profile_name(runtime_values.get("NN_ACTIVE_PROFILE"))


def write_runtime_profile(runtime_path: Path, profile: str) -> None:
    runtime_path.parent.mkdir(parents=True, exist_ok=True)
    contents = format_active_profile_env(profile)
    with NamedTemporaryFile("w", encoding="utf-8", dir=runtime_path.parent, delete=False) as handle:
        handle.write(contents)
        temp_path = Path(handle.name)
    temp_path.replace(runtime_path)


def restore_runtime_profile(runtime_path: Path, previous_contents: str | None) -> None:
    if previous_contents is None:
        runtime_path.unlink(missing_ok=True)
        return

    with NamedTemporaryFile("w", encoding="utf-8", dir=runtime_path.parent, delete=False) as handle:
        handle.write(previous_contents)
        temp_path = Path(handle.name)
    temp_path.replace(runtime_path)


def restart_nn_server(project_root: Path, compose_file: Path) -> None:
    subprocess.run(
        [
            "docker",
            "compose",
            "-f",
            str(compose_file),
            "restart",
            "dronedetector-nn-server",
        ],
        cwd=project_root,
        check=True,
    )


if __name__ == "__main__":
    raise SystemExit(main())