"""Konfigurations-Loader für das Moon/Apollo-Projekt.

Lädt Werte aus .env in Umgebungsvariablen und stellt sie typisiert bereit.
Verwendet python-dotenv. Enthält Validierung & sinnvolle Defaults.
"""

from __future__ import annotations

import os
import re
from dataclasses import dataclass
from typing import Tuple

from dotenv import load_dotenv

# .env → os.environ laden
load_dotenv(override=False)


def _get_env(name: str, default: str) -> str:
    val = os.getenv(name)
    return val if val is not None and val != "" else default


def _parse_int(name: str, default: int, min_val: int | None = None) -> int:
    raw = _get_env(name, str(default))
    try:
        v = int(raw)
        if min_val is not None and v < min_val:
            raise ValueError
        return v
    except Exception as _:
        return default


def _parse_float(name: str, default: float, min_val: float | None = None) -> float:
    raw = _get_env(name, str(default))
    try:
        v = float(raw)
        if min_val is not None and v < min_val:
            raise ValueError
        return v
    except Exception as _:
        return default


_HEX = re.compile(r"^#?([0-9a-fA-F]{6})$")


def _parse_rgb(name: str, default_hex: str) -> Tuple[int, int, int]:
    """Erlaubt '#rrggbb' oder 'rrggbb'. Fällt auf default zurück, wenn ungültig."""
    raw = _get_env(name, default_hex)
    m = _HEX.match(raw)
    hx = m.group(1) if m else default_hex.lstrip("#")
    r = int(hx[0:2], 16)
    g = int(hx[2:4], 16)
    b = int(hx[4:6], 16)
    return (r, g, b)


@dataclass(frozen=True)
class Settings:
    # Anzeige
    width: int
    height: int
    fps: int
    bg_color: Tuple[int, int, int]

    # Erde
    earth_color: Tuple[int, int, int]
    earth_radius: int

    # Mond
    moon_color: Tuple[int, int, int]
    moon_radius: int
    moon_orbit_radius: int
    moon_angular_speed_deg: float  # Grad/Sekunde

    # Apollo (optional)
    apollo_color: Tuple[int, int, int]
    apollo_radius: int
    apollo_orbit_radius: int


def get_settings() -> Settings:
    """Erzeugt Settings aus Umgebungsvariablen oder Defaults."""
    return Settings(
        # Anzeige
        width=_parse_int("WIDTH", 800, min_val=100),
        height=_parse_int("HEIGHT", 600, min_val=100),
        fps=_parse_int("FPS", 60, min_val=1),
        bg_color=_parse_rgb("BG_COLOR", "#0a0a14"),
        # Erde
        earth_color=_parse_rgb("EARTH_COLOR", "#2878ff"),
        earth_radius=_parse_int("EARTH_RADIUS", 30, min_val=1),
        # Mond
        moon_color=_parse_rgb("MOON_COLOR", "#f0f0f0"),
        moon_radius=_parse_int("MOON_RADIUS", 10, min_val=1),
        moon_orbit_radius=_parse_int("MOON_ORBIT_RADIUS", 160, min_val=10),
        moon_angular_speed_deg=_parse_float("MOON_ANGULAR_SPEED_DEG", 45.0, min_val=0.1),
        # Apollo
        apollo_color=_parse_rgb("APOLLO_COLOR", "#dc3232"),
        apollo_radius=_parse_int("APOLLO_RADIUS", 7, min_val=1),
        apollo_orbit_radius=_parse_int("APOLLO_ORBIT_RADIUS", 40, min_val=5),
    )