function resolveEffectiveDate(rawValue) {
  return rawValue ? new Date(`${rawValue}T00:00:00.000Z`) : new Date();
}

function buildDefaultChecklist(scene, employeeId) {
  const common = { employee_id: employeeId };

  if (scene === "onboarding") {
    return [
      { ...common, scene, task_type: "account_setup", title: "完成账号与权限初始化", status: "pending" },
      { ...common, scene, task_type: "asset_issue", title: "确认办公资产发放", status: "pending" },
      { ...common, scene, task_type: "policy_ack", title: "确认制度与入职须知", status: "pending" },
    ];
  }

  if (scene === "transfer") {
    return [{ ...common, scene, task_type: "handover_note", title: "确认调岗交接说明", status: "pending" }];
  }

  return [
    { ...common, scene, task_type: "asset_return", title: "确认资产归还/转交", status: "pending" },
    { ...common, scene, task_type: "access_revoke", title: "确认账号和权限回收", status: "pending" },
    { ...common, scene, task_type: "expense_clearance", title: "确认费用与审批待办已清理", status: "pending" },
    { ...common, scene, task_type: "handover_note", title: "确认离职交接说明", status: "pending" },
  ];
}

async function applyEmployeeTransfer(tx, options) {
  await tx.employee.update({
    where: { id: options.employeeId },
    data: {
      ...(options.departmentId !== undefined ? { department_id: options.departmentId } : {}),
      ...(options.directManagerId !== undefined ? { direct_manager_id: options.directManagerId } : {}),
      ...(options.title !== undefined ? { title: options.title } : {}),
      updated_by: options.actorId,
    },
  });

  await tx.employeeLifecycleEvent.create({
    data: {
      employee_id: options.employeeId,
      event_type: "transfer",
      effective_date: resolveEffectiveDate(options.effectiveDate),
      payload_json: {
        departmentId: options.departmentId ?? null,
        directManagerId: options.directManagerId ?? null,
        title: options.title ?? null,
        notes: options.notes ?? null,
      },
      created_by: options.actorId,
    },
  });

  await tx.employeeChecklistTask.createMany({
    data: buildDefaultChecklist("transfer", options.employeeId),
  });
}

module.exports = {
  applyEmployeeTransfer,
  buildDefaultChecklist,
  resolveEffectiveDate,
};