"""Runtime configuration, resolved once from the environment."""

from __future__ import annotations

import os
import socket
import time
import uuid
from dataclasses import dataclass, field


def _default_drone_id() -> str:
    """Stable per-container id: works with `docker compose up --scale`."""
    return os.environ.get("DRONE_ID") or f"dr-{socket.gethostname()[-4:]}"


def _default_flight_id() -> str:
    """Short time-sortable partition alias; canonical UUIDv7 kept separately."""
    return os.environ.get("FLIGHT_ID") or time.strftime(
        "%Y%m%dT%H%MZ", time.gmtime()
    ) + "-" + uuid.uuid4().hex[:4]


@dataclass(frozen=True)
class Config:
    drone_id: str = field(default_factory=_default_drone_id)
    flight_id: str = field(default_factory=_default_flight_id)
    flight_uuid: str = field(default_factory=lambda: str(uuid.uuid4()))

    data_dir: str = field(default_factory=lambda: os.environ.get("DATA_DIR", "./data"))
    seed: int = field(default_factory=lambda: int(os.environ.get("SEED", "42")))

    # Simulation pacing
    duration_s: float = field(
        default_factory=lambda: float(os.environ.get("DURATION_S", "120"))
    )
    speedup: float = field(
        default_factory=lambda: float(os.environ.get("SPEEDUP", "1.0"))
    )

    # Sensor rates (Hz, simulated time)
    imu_hz: float = field(default_factory=lambda: float(os.environ.get("IMU_HZ", "50")))
    baro_hz: float = 1.0
    temp_hz: float = 0.2
    battery_hz: float = 0.5
    detection_rate_hz: float = field(
        default_factory=lambda: float(os.environ.get("DETECTION_HZ", "0.05"))
    )

    # State broadcast
    state_hz: float = field(
        default_factory=lambda: float(os.environ.get("STATE_HZ", "5"))
    )
    udp_port: int = field(default_factory=lambda: int(os.environ.get("UDP_PORT", "47000")))
    broadcast_addr: str = field(
        default_factory=lambda: os.environ.get("BROADCAST_ADDR", "255.255.255.255")
    )

    # Patrol area (meters, local mission frame)
    area_size_m: float = field(
        default_factory=lambda: float(os.environ.get("AREA_SIZE_M", "400"))
    )
    cruise_alt_m: float = field(
        default_factory=lambda: float(os.environ.get("CRUISE_ALT_M", "60"))
    )
    cruise_speed_ms: float = field(
        default_factory=lambda: float(os.environ.get("CRUISE_SPEED_MS", "12"))
    )