/**
 * A4 系统配置查询与写操作。
 *
 * R-26：阈值 / 上限只存系统配置一处。`useEffectiveConfigsQuery` 供业务页读取前端上限，
 * 读取失败或未登录时由调用方回退到 shared 常量（仅作展示兜底，后端仍做最终校验）。
 */
import {
  CUSTOMER_BASE_FIELD_LIMIT,
  CUSTOMER_GEN_FIELD_LIMIT,
  type SystemConfig,
  type SystemConfigChange,
  type SystemConfigHistoryQuery,
  type SystemConfigValue,
  type UpdateSystemConfigsInput,
} from '@lingxi/shared';
import {
  useMutation,
  type UseMutationResult,
  useQuery,
  useQueryClient,
  type UseQueryResult,
} from '@tanstack/react-query';

import {
  fetchEffectiveSystemConfigs,
  fetchSystemConfigHistory,
  fetchSystemConfigs,
  updateSystemConfigs,
} from '@/api/configs';
import { queryKeys } from '@/api/query-keys';

export function useSystemConfigsQuery(): UseQueryResult<{ items: SystemConfig[] }> {
  return useQuery({
    queryKey: queryKeys.systemConfigs,
    queryFn: fetchSystemConfigs,
    staleTime: 10_000,
  });
}

/** 生效配置：key → value（仅登录可读，失败不阻塞业务页） */
export function useEffectiveConfigsQuery(): UseQueryResult<Record<string, SystemConfigValue>> {
  return useQuery({
    queryKey: queryKeys.systemConfigsEffective,
    queryFn: fetchEffectiveSystemConfigs,
    select: (data) => {
      const values: Record<string, SystemConfigValue> = {};
      for (const item of data.items) {
        values[item.key] = item.value;
      }
      return values;
    },
    staleTime: 60_000,
    retry: 1,
  });
}

/** 读取单个数值型生效配置；缺失 / 非数字时回退 shared 常量 */
export function useEffectiveNumberConfig(key: string, fallback: number): number {
  const effective = useEffectiveConfigsQuery();
  const value = effective.data?.[key];
  return typeof value === 'number' ? value : fallback;
}

export interface CustomerFieldLimits {
  baseFieldLimit: number;
  genFieldLimit: number;
}

/** 客户基础字段 / 进入生成字段上限（A3 客户页与表单校验共用，R-26） */
export function useCustomerFieldLimits(): CustomerFieldLimits {
  const effective = useEffectiveConfigsQuery();
  const base = effective.data?.['limit.customer.base_field'];
  const gen = effective.data?.['limit.customer.gen_field'];
  return {
    baseFieldLimit: typeof base === 'number' ? base : CUSTOMER_BASE_FIELD_LIMIT,
    genFieldLimit: typeof gen === 'number' ? gen : CUSTOMER_GEN_FIELD_LIMIT,
  };
}

export function useSystemConfigHistoryQuery(
  query: Partial<SystemConfigHistoryQuery> = {},
  options: { enabled?: boolean } = {},
): UseQueryResult<{ items: SystemConfigChange[]; next_cursor: string | null }> {
  return useQuery({
    queryKey: queryKeys.systemConfigHistory(query),
    queryFn: () => fetchSystemConfigHistory(query),
    enabled: options.enabled ?? true,
    staleTime: 5_000,
  });
}

export function useUpdateSystemConfigsMutation(): UseMutationResult<
  { items: SystemConfig[] },
  Error,
  UpdateSystemConfigsInput
> {
  const queryClient = useQueryClient();
  return useMutation({
    mutationFn: updateSystemConfigs,
    onSuccess: async () => {
      await Promise.all([
        queryClient.invalidateQueries({ queryKey: queryKeys.systemConfigs }),
        queryClient.invalidateQueries({ queryKey: queryKeys.systemConfigsEffective }),
        queryClient.invalidateQueries({ queryKey: ['system-configs', 'history'] }),
      ]);
    },
  });
}