export const ATTACK_PRESENTATION_DURATION_SECONDS = 0.52;

const WINDUP_END_SECONDS = 0.12;
const STRIKE_END_SECONDS = 0.25;

function smoothstep(progress: number): number {
  const clamped = Math.max(0, Math.min(1, progress));
  return clamped * clamped * (3 - 2 * clamped);
}

/**
 * A one-shot presentation curve driven by an actual combat hit revision.
 * Negative values are the windup, positive values are the strike, and zero is
 * the locomotion pose. Keeping this pure lets the render rig layer the motion
 * over Stand/Run without putting animation timing into combat simulation.
 */
export function attackSwingAt(elapsedSeconds: number): number {
  if (!Number.isFinite(elapsedSeconds) || elapsedSeconds <= 0) return 0;
  if (elapsedSeconds >= ATTACK_PRESENTATION_DURATION_SECONDS) return 0;

  if (elapsedSeconds < WINDUP_END_SECONDS) {
    return -0.58 * smoothstep(elapsedSeconds / WINDUP_END_SECONDS);
  }

  if (elapsedSeconds < STRIKE_END_SECONDS) {
    const progress = smoothstep(
      (elapsedSeconds - WINDUP_END_SECONDS) / (STRIKE_END_SECONDS - WINDUP_END_SECONDS),
    );
    return -0.58 + (1.05 + 0.58) * progress;
  }

  const progress = smoothstep(
    (elapsedSeconds - STRIKE_END_SECONDS)
      / (ATTACK_PRESENTATION_DURATION_SECONDS - STRIKE_END_SECONDS),
  );
  return 1.05 * (1 - progress);
}