import { onMounted, onUnmounted } from "vue";
import { emitter } from "@/utils/mitt";

//Session 读取（与顶栏站点切换器写入格式一致：sessionStorage + JSON）
const getCurrentStationId = () => {
  const value = sessionStorage.getItem("currentStationId");
  if (!value) return null;
  try {
    return JSON.parse(value);
  } catch {
    return null;
  }
};

/**
 * 站点范围组合式函数：页面站点筛选与全局"当前站点"联动
 * 1. 页面初始化时，若站点筛选为空则默认选中全局当前站点（onMounted 中先于页面自身加载执行）
 * 2. 全局站点切换时（顶栏站点选择器），联动更新页面筛选并刷新列表
 *
 * @param formQuery 页面查询条件对象（需包含 stationId 字段）
 * @param loadData 页面数据加载方法，切换站点时以 refresh=true 重新加载
 * @param options.follow 是否响应全局站点切换，默认 true
 */
export const useStationScope = (
  formQuery: any,
  loadData?: (refresh?: boolean) => void,
  options?: { follow?: boolean }
) => {
  const follow = options?.follow !== false;

  const onStationChange = (stationId: any) => {
    if (!follow || !stationId) return;
    //站点未变化时不重复加载
    if (formQuery.stationId === stationId) return;
    formQuery.stationId = stationId;
    if (loadData) loadData(true);
  };

  onMounted(() => {
    //初始化：站点筛选为空时默认选中全局当前站点
    if (!formQuery.stationId) {
      const currentStationId = getCurrentStationId();
      if (currentStationId) {
        formQuery.stationId = currentStationId;
      }
    }
    emitter.on("stationChangeRefresh", onStationChange);
  });

  onUnmounted(() => {
    emitter.off("stationChangeRefresh", onStationChange);
  });
};