"""Hilfsfunktionen für die Physik-Tests (Szenen aufbauen, simulieren, Erhaltungsgrößen)."""

from __future__ import annotations

from dataclasses import replace

from sandbox.config import PHYSICS, TIME_STEP
from sandbox.physics import Body, Material, Vector2, World

WORLD_WIDTH = 1000.0
WORLD_HEIGHT = 700.0


def make_world(
    width: float = WORLD_WIDTH, height: float = WORLD_HEIGHT, **overrides: object
) -> World:
    """Welt mit Standardkonfiguration; einzelne Parameter lassen sich überschreiben."""
    return World(width, height, replace(PHYSICS, **overrides))


def material(density: float = 1.0, restitution: float = 0.5, friction: float = 0.5) -> Material:
    """Material mit gut lesbaren Standardwerten."""
    return Material(density=density, restitution=restitution, friction=friction)


def add_circle(
    world: World,
    x: float,
    y: float,
    radius: float,
    *,
    velocity: tuple[float, float] = (0.0, 0.0),
    angular_velocity: float = 0.0,
    **material_values: float,
) -> Body:
    """Fügt einen Kreis hinzu."""
    body = Body.circle(
        Vector2(x, y), radius, material(**material_values), velocity=Vector2(*velocity)
    )
    body.angular_velocity = angular_velocity
    return world.add_body(body)


def add_box(
    world: World,
    x: float,
    y: float,
    half_width: float,
    half_height: float,
    *,
    velocity: tuple[float, float] = (0.0, 0.0),
    **material_values: float,
) -> Body:
    """Fügt ein achsenparalleles Rechteck hinzu."""
    body = Body.box(
        Vector2(x, y),
        half_width,
        half_height,
        material(**material_values),
        velocity=Vector2(*velocity),
    )
    return world.add_body(body)


def simulate(world: World, seconds: float, dt: float = TIME_STEP) -> None:
    """Führt so viele feste Schritte aus, wie in ``seconds`` passen."""
    for _ in range(round(seconds / dt)):
        world.step(dt)


def total_momentum(bodies: list[Body]) -> Vector2:
    """Summe der Impulse m·v."""
    total = Vector2()
    for body in bodies:
        total = total + body.momentum()
    return total


def total_kinetic_energy(bodies: list[Body]) -> float:
    """Summe der Bewegungsenergien (translatorisch + rotatorisch)."""
    return sum(body.kinetic_energy() for body in bodies)