'use client';

import { useState, useEffect, useCallback, useRef } from 'react';
import { useItemMaster } from '@/contexts/ItemMasterContext';
import { useItemMasterStore } from '@/stores/item-master/useItemMasterStore';
import { itemMasterApi } from '@/lib/api/item-master';
import { getErrorMessage, ApiError } from '@/lib/api/error-handler';
import {
  transformPagesResponse,
  transformSectionsResponse,
  transformSectionTemplatesResponse,
  transformFieldsResponse,
  transformCustomTabsResponse,
  transformUnitOptionsResponse,
  transformSectionTemplateFromSection,
} from '@/lib/api/transformers';
import { toast } from 'sonner';
import type { CustomTab } from './useTabManagement';
import type { MasterOption } from '../types';

// 타입 alias
type UnitOption = MasterOption;

export interface UseInitialDataLoadingReturn {
  isInitialLoading: boolean;
  error: string | null;
  reload: () => Promise<void>;
}

interface UseInitialDataLoadingProps {
  setCustomTabs: React.Dispatch<React.SetStateAction<CustomTab[]>>;
  setUnitOptions: React.Dispatch<React.SetStateAction<UnitOption[]>>;
}

export function useInitialDataLoading({
  setCustomTabs,
  setUnitOptions,
}: UseInitialDataLoadingProps): UseInitialDataLoadingReturn {
  const {
    loadItemPages,
    loadSectionTemplates,
    loadItemMasterFields,
    loadIndependentSections,
    loadIndependentFields,
  } = useItemMaster();

  // ✅ 2025-12-24: Zustand store 연동
  const initFromApi = useItemMasterStore((state) => state.initFromApi);

  const [isInitialLoading, setIsInitialLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);

  // 초기 로딩이 이미 실행되었는지 추적하는 ref
  const hasInitialLoadRun = useRef(false);

  const loadInitialData = useCallback(async () => {
    try {
      setIsInitialLoading(true);
      setError(null);

      // ✅ Zustand store 초기화 (정규화된 상태로 저장)
      // Context와 병행 운영 - 점진적 마이그레이션
      try {
        await initFromApi();
        console.log('✅ [Zustand] Store initialized');
      } catch (zustandError) {
        // Zustand 초기화 실패해도 Context로 fallback
        console.warn('⚠️ [Zustand] Init failed, falling back to Context:', zustandError);
      }

      const data = await itemMasterApi.init();

      // 1. 페이지 데이터 로드 (섹션이 이미 포함되어 있음)
      const transformedPages = transformPagesResponse(data.pages);
      loadItemPages(transformedPages);

      // 2. 독립 섹션 로드 (모든 재사용 가능 섹션)
      if (data.sections && data.sections.length > 0) {
        const transformedSections = transformSectionsResponse(data.sections);
        loadIndependentSections(transformedSections);
        console.log('✅ 독립 섹션 로드:', transformedSections.length);
      }

      // 3. 섹션 템플릿 로드
      if (data.sectionTemplates && data.sectionTemplates.length > 0) {
        const transformedTemplates = transformSectionTemplatesResponse(data.sectionTemplates);
        loadSectionTemplates(transformedTemplates);
      } else if (data.sections && data.sections.length > 0) {
        const templates = data.sections
          .filter((s: { is_template?: boolean }) => s.is_template)
          .map(transformSectionTemplateFromSection);
        if (templates.length > 0) {
          loadSectionTemplates(templates);
        }
      }

      // 4. 필드 로드
      if (data.fields && data.fields.length > 0) {
        const transformedFields = transformFieldsResponse(data.fields);

        const independentOnlyFields = transformedFields.filter(
          f => f.section_id === null || f.section_id === undefined
        );

        // eslint-disable-next-line @typescript-eslint/no-explicit-any
        loadItemMasterFields(transformedFields as any);
        loadIndependentFields(independentOnlyFields);

        console.log('✅ 필드 로드:', {
          total: transformedFields.length,
          independent: independentOnlyFields.length,
        });
      }

      // 5. 커스텀 탭 로드
      if (data.customTabs && data.customTabs.length > 0) {
        const transformedTabs = transformCustomTabsResponse(data.customTabs);
        setCustomTabs(transformedTabs);
      }

      // 6. 단위 옵션 로드
      if (data.unitOptions && data.unitOptions.length > 0) {
        const transformedUnits = transformUnitOptionsResponse(data.unitOptions);
        setUnitOptions(transformedUnits);
      }

      console.log('✅ Initial data loaded:', {
        pages: data.pages?.length || 0,
        sections: data.sections?.length || 0,
        fields: data.fields?.length || 0,
        customTabs: data.customTabs?.length || 0,
        unitOptions: data.unitOptions?.length || 0,
      });

    } catch (err) {
      if (err instanceof ApiError && err.errors) {
        const errorMessages = Object.entries(err.errors)
          .map(([field, messages]) => `${field}: ${messages.join(', ')}`)
          .join('\n');
        toast.error(errorMessages);
        setError('입력값을 확인해주세요.');
      } else {
        const errorMessage = getErrorMessage(err);
        setError(errorMessage);
        toast.error(errorMessage);
      }
      console.error('❌ Failed to load initial data:', err);
    } finally {
      setIsInitialLoading(false);
    }
  }, [
    loadItemPages,
    loadSectionTemplates,
    loadItemMasterFields,
    loadIndependentSections,
    loadIndependentFields,
    setCustomTabs,
    setUnitOptions,
  ]);

  // 초기 로딩은 한 번만 실행 (의존성 배열의 함수들이 불안정해도 무한 루프 방지)
  useEffect(() => {
    if (hasInitialLoadRun.current) {
      return;
    }
    hasInitialLoadRun.current = true;
    loadInitialData();
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  return {
    isInitialLoading,
    error,
    reload: loadInitialData,
  };
}