import { useCallback, useEffect, useRef } from 'react';
import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
import { apiClient } from './apiClient';
import { migrateScheduleItem, quarterDateBounds } from './hubSchedule';
import { ROUTINE_CATEGORIES } from './routineCategories';

const STORAGE_KEY = 'eene-quarter-hub-config-v1';
const QUERY_KEY = ['hub-config'] as const;

export interface HubScheduleItem {
  id: string;
  /** YYYY-MM-DD */
  date: string;
  text: string;
}

export interface HubConfig {
  sloganTitle: string;
  sloganLines: string[];
  scheduleTitle: string;
  scheduleItems: HubScheduleItem[];
  routineLabels: string[];
}

export const DEFAULT_HUB_CONFIG: HubConfig = {
  sloganTitle: '분기 중점 과제',
  sloganLines: ['인사 · 육성 · 문화 · 총무', '개선과제', '정상 추진'],
  scheduleTitle: '분기 주요 일정',
  scheduleItems: [
    { id: '1', date: '2026-04-01', text: '상반기 채용·온보딩' },
    { id: '2', date: '2026-05-15', text: '조직문화 진단·리더십 교육' },
    { id: '3', date: '2026-06-20', text: '분기 성과 점검·평가' },
  ],
  routineLabels: ['채용 운영', '학습 지원', '직원 소통', '자산·시설', '문서·행정'],
};

function migrateRoutineLabels(raw: unknown): string[] {
  if (!Array.isArray(raw)) return [...ROUTINE_CATEGORIES];
  const labels = raw.map(String);
  if (labels.length === ROUTINE_CATEGORIES.length && labels.every((label, i) => label === ROUTINE_CATEGORIES[i])) {
    return [...ROUTINE_CATEGORIES];
  }
  const legacyFull = ['채용 운영', '교육 운영', '직원 소통', '자산·시설', '문서·행정'];
  if (labels.length === legacyFull.length && labels.every((label, i) => label === legacyFull[i])) {
    return [...ROUTINE_CATEGORIES];
  }
  const legacyShort = ['채용', '교육', '소통', '시설', '자산', '행정'];
  if (labels.length === legacyShort.length && labels.every((label, i) => label === legacyShort[i])) {
    return [...ROUTINE_CATEGORIES];
  }
  if (labels.some((label) => label === '교육 운영')) {
    return labels.map((label) => (label === '교육 운영' ? '학습 지원' : label));
  }
  return labels.length > 0 ? labels : [...ROUTINE_CATEGORIES];
}

function migrateConfig(raw: Record<string, unknown>): HubConfig {
  const { year } = quarterDateBounds('2026-Q2');
  const scheduleItems = Array.isArray(raw.scheduleItems)
    ? (raw.scheduleItems as (HubScheduleItem & { month?: string })[]).map((item) =>
        migrateScheduleItem(item, year),
      )
    : DEFAULT_HUB_CONFIG.scheduleItems;

  return {
    sloganTitle: (() => {
      const t = (raw.sloganTitle as string) ?? DEFAULT_HUB_CONFIG.sloganTitle;
      return t === '분기 슬로건' ? '분기 중점 과제' : t;
    })(),
    sloganLines: (raw.sloganLines as string[]) ?? DEFAULT_HUB_CONFIG.sloganLines,
    scheduleTitle: (raw.scheduleTitle as string) ?? DEFAULT_HUB_CONFIG.scheduleTitle,
    scheduleItems,
    routineLabels: migrateRoutineLabels(raw.routineLabels),
  };
}

async function fetchHubConfig(): Promise<HubConfig> {
  const raw = await apiClient.get<Record<string, unknown>>('/hub-config').then((r) => r.data);
  return migrateConfig({ ...DEFAULT_HUB_CONFIG, ...raw });
}

async function saveHubConfig(config: HubConfig): Promise<HubConfig> {
  const raw = await apiClient.patch<Record<string, unknown>>('/hub-config', config).then((r) => r.data);
  return migrateConfig({ ...DEFAULT_HUB_CONFIG, ...raw });
}

function readLegacyLocalConfig(): HubConfig | null {
  if (typeof window === 'undefined') return null;
  try {
    const raw = localStorage.getItem(STORAGE_KEY);
    if (!raw) return null;
    return migrateConfig({ ...DEFAULT_HUB_CONFIG, ...JSON.parse(raw) });
  } catch {
    return null;
  }
}

export function useHubConfig() {
  const queryClient = useQueryClient();
  const legacyMigrated = useRef(false);

  const { data: config = DEFAULT_HUB_CONFIG, isLoading } = useQuery({
    queryKey: QUERY_KEY,
    queryFn: fetchHubConfig,
    staleTime: 30_000,
  });

  const saveMutation = useMutation({
    mutationFn: saveHubConfig,
    onSuccess: (saved) => {
      queryClient.setQueryData(QUERY_KEY, saved);
    },
  });

  useEffect(() => {
    if (isLoading || legacyMigrated.current) return;
    const legacy = readLegacyLocalConfig();
    if (!legacy) return;
    legacyMigrated.current = true;
    localStorage.removeItem(STORAGE_KEY);
    saveHubConfig(legacy)
      .then((saved) => {
        queryClient.setQueryData(QUERY_KEY, saved);
      })
      .catch(() => {
        /* API 미준비 등 — 기본값 유지 */
      });
  }, [isLoading, queryClient]);

  const setConfig = useCallback(
    (patch: Partial<HubConfig> | ((prev: HubConfig) => HubConfig)) => {
      const prev = queryClient.getQueryData<HubConfig>(QUERY_KEY) ?? DEFAULT_HUB_CONFIG;
      const next = typeof patch === 'function' ? patch(prev) : { ...prev, ...patch };
      queryClient.setQueryData(QUERY_KEY, next);
      saveMutation.mutate(next);
    },
    [queryClient, saveMutation],
  );

  const resetConfig = useCallback(() => {
    queryClient.setQueryData(QUERY_KEY, DEFAULT_HUB_CONFIG);
    saveMutation.mutate(DEFAULT_HUB_CONFIG);
  }, [queryClient, saveMutation]);

  return { config, setConfig, resetConfig, isLoading };
}