import type { KinematicCharacterController } from "@dimforge/rapier3d-compat";
import { PLAYER_GROUND_MIN_NORMAL_Y } from "./playerJump";

export const PLAYER_GRAVITY = -18;
export const PLAYER_CHARACTER_CONTROLLER_OFFSET = 0.02;
export const PLAYER_STEP_HEIGHT = 0.55;
export const PLAYER_STEP_MIN_WIDTH = 0.15;
export const PLAYER_GROUND_SNAP_DISTANCE = PLAYER_STEP_HEIGHT;
export const PLAYER_GROUND_STICK_VELOCITY = -0.5;
export const PLAYER_MAX_FRAME_DELTA_SECONDS = 0.05;
export const PLAYER_TERMINAL_FALL_VELOCITY = -32;

/**
 * Configures Rapier's kinematic controller for MMO-style traversal. Ordinary
 * stairs and curb-sized seams are walkable, while taller obstacles remain
 * blocking geometry and still require a real jump or another route.
 */
export function configurePlayerCharacterController(
  controller: KinematicCharacterController,
): KinematicCharacterController {
  controller.setUp({ x: 0, y: 1, z: 0 });
  controller.setSlideEnabled(true);
  controller.enableAutostep(PLAYER_STEP_HEIGHT, PLAYER_STEP_MIN_WIDTH, false);
  controller.enableSnapToGround(PLAYER_GROUND_SNAP_DISTANCE);
  controller.setMaxSlopeClimbAngle(Math.acos(PLAYER_GROUND_MIN_NORMAL_Y));
  return controller;
}

export function playerFrameDeltaSeconds(deltaSeconds: number): number {
  if (!Number.isFinite(deltaSeconds) || deltaSeconds <= 0) return 0;
  return Math.min(deltaSeconds, PLAYER_MAX_FRAME_DELTA_SECONDS);
}

export function airbornePlayerVerticalVelocity(
  currentVelocity: number,
  deltaSeconds: number,
): number {
  const velocity = Number.isFinite(currentVelocity) ? currentVelocity : 0;
  const delta = playerFrameDeltaSeconds(deltaSeconds);
  return Math.max(
    PLAYER_TERMINAL_FALL_VELOCITY,
    velocity + PLAYER_GRAVITY * delta,
  );
}