# =============================
# app/simulation/modules/gearbox.py
# =============================

from __future__ import annotations
from app.simulation.simulator import Module, Vehicle

class GearboxModule(Module):
    PRIO = 30
    NAME = "gearbox"
    """Koppelt Engine-RPM ↔ Wheel-Speed; registriert speed_kmh/gear fürs Dashboard."""
    def __init__(self):
        self.speed_tau = 0.3
        self.rpm_couple = 0.2

    def apply(self, v: Vehicle, dt: float) -> None:
        # Dashboard registration
        v.register_metric("speed_kmh", label="Geschwindigkeit", unit="km/h", fmt=".1f", source="gearbox", priority=30)
        v.register_metric("gear",      label="Gang", source="gearbox", priority=25)

        g = int(v.ensure("gear", 0))
        rpm = float(v.ensure("rpm", 1200))
        speed = float(v.ensure("speed_kmh", 0.0))
        ratios = v.config.get("gearbox", {}).get("kmh_per_krpm", [0.0])

        if g <= 0 or g >= len(ratios):
            speed = max(0.0, speed - 6.0*dt)
            v.set("speed_kmh", speed)
            return

        kmh_per_krpm = float(ratios[g])
        target_speed = (rpm/1000.0) * kmh_per_krpm
        alpha = min(1.0, dt / max(0.05, self.speed_tau))
        speed = (1-alpha) * speed + alpha * target_speed
        v.set("speed_kmh", speed)

        wheel_rpm = (speed / max(0.1, kmh_per_krpm)) * 1000.0
        rpm = (1-self.rpm_couple) * rpm + self.rpm_couple * wheel_rpm
        v.set("rpm", int(rpm))