export type DevPlanTaskStatus = 'TODO' | 'DEVELOPED' | 'RELEASED';
export type DevPlanVersionStatus = 'PENDING' | 'IN_PROGRESS' | 'TESTING' | 'RELEASED';

export function computeDurationMinutes(
  devStartedAt: Date | null | undefined,
  devCompletedAt: Date | null | undefined,
): number | null {
  if (!devStartedAt || !devCompletedAt) return null;
  const ms = devCompletedAt.getTime() - devStartedAt.getTime();
  if (ms < 0) return null;
  return Math.round(ms / 60000);
}

export function versionStatusTimestamps(
  prev: DevPlanVersionStatus,
  next: DevPlanVersionStatus,
  current: {
    devStartedAt?: Date | null;
    devCompletedAt?: Date | null;
    releasedAt?: Date | null;
  },
): {
  devStartedAt?: Date | null;
  devCompletedAt?: Date | null;
  releasedAt?: Date | null;
  durationMinutes?: number | null;
} {
  const patch: {
    devStartedAt?: Date | null;
    devCompletedAt?: Date | null;
    releasedAt?: Date | null;
    durationMinutes?: number | null;
  } = {};
  const now = new Date();

  if (next === 'IN_PROGRESS' && !current.devStartedAt) {
    patch.devStartedAt = now;
  }
  if (next === 'TESTING' && !current.devCompletedAt) {
    patch.devCompletedAt = now;
  }
  if (next === 'RELEASED' && !current.releasedAt) {
    patch.releasedAt = now;
  }

  const started = patch.devStartedAt ?? current.devStartedAt ?? null;
  const completed = patch.devCompletedAt ?? current.devCompletedAt ?? null;
  const duration = computeDurationMinutes(started, completed);
  if (duration != null) patch.durationMinutes = duration;

  void prev;
  return patch;
}

export function taskCompletedAtOnStatus(
  prev: DevPlanTaskStatus,
  next: DevPlanTaskStatus,
  currentCompletedAt?: Date | null,
): Date | null | undefined {
  if (next === 'RELEASED' && !currentCompletedAt) return new Date();
  void prev;
  return undefined;
}