/**
 * useFormStructure Hook
 *
 * API에서 품목 유형별 폼 구조를 로드하는 훅
 * - 캐싱 지원 (5분 TTL)
 * - 에러 처리 및 재시도
 * - Mock 데이터 폴백 (API 미구현 시)
 */

'use client';

import { useState, useEffect, useCallback, useRef } from 'react';
import type { ItemType, PartType } from '@/types/item';
import type {
  FormStructure,
  FormStructureResponse,
  UseFormStructureReturn,
  DynamicSection,
  DynamicField,
  ConditionalSection,
} from '../types';

// ===== 캐시 설정 =====
const CACHE_TTL = 5 * 60 * 1000; // 5분
const formStructureCache = new Map<string, { data: FormStructure; timestamp: number }>();

/**
 * 캐시 키 생성
 */
function getCacheKey(itemType: ItemType, partType?: PartType): string {
  return partType ? `${itemType}_${partType}` : itemType;
}

/**
 * 캐시에서 데이터 가져오기
 */
function getFromCache(key: string): FormStructure | null {
  const cached = formStructureCache.get(key);
  if (!cached) return null;

  const isExpired = Date.now() - cached.timestamp > CACHE_TTL;
  if (isExpired) {
    formStructureCache.delete(key);
    return null;
  }

  return cached.data;
}

/**
 * 캐시에 데이터 저장
 */
function setToCache(key: string, data: FormStructure): void {
  formStructureCache.set(key, { data, timestamp: Date.now() });
}

// ===== Mock 데이터 (API 미구현 시 사용) =====

/**
 * 제품(FG) Mock 폼 구조
 */
function getMockFGFormStructure(): FormStructure {
  return {
    page: {
      id: 1,
      page_name: '제품 등록',
      item_type: 'FG',
      is_active: true,
    },
    sections: [
      {
        id: 101,
        title: '기본 정보',
        section_type: 'BASIC',
        order_no: 1,
        is_collapsible: false,
        is_default_open: true,
        fields: [
          {
            id: 1001,
            field_name: '품목코드',
            field_key: 'item_code',
            field_type: 'textbox',
            order_no: 1,
            is_required: true,
            is_readonly: true,
            placeholder: '자동 생성',
            grid_row: 1,
            grid_col: 1,
            grid_span: 1,
          },
          {
            id: 1002,
            field_name: '품목명',
            field_key: 'item_name',
            field_type: 'textbox',
            order_no: 2,
            is_required: true,
            placeholder: '품목명을 입력하세요',
            validation_rules: { maxLength: 100 },
            grid_row: 1,
            grid_col: 2,
            grid_span: 2,
          },
          {
            id: 1003,
            field_name: '제품 카테고리',
            field_key: 'product_category',
            field_type: 'dropdown',
            order_no: 3,
            is_required: true,
            dropdown_config: {
              options: [
                { value: 'SCREEN', label: '스크린' },
                { value: 'STEEL', label: '철재' },
              ],
              placeholder: '카테고리 선택',
            },
            grid_row: 1,
            grid_col: 4,
            grid_span: 1,
          },
          {
            id: 1004,
            field_name: '단위',
            field_key: 'unit',
            field_type: 'dropdown',
            order_no: 4,
            is_required: true,
            dropdown_config: {
              options: [
                { value: 'EA', label: 'EA (개)' },
                { value: 'SET', label: 'SET (세트)' },
              ],
              placeholder: '단위 선택',
            },
            grid_row: 2,
            grid_col: 1,
            grid_span: 1,
          },
          {
            id: 1005,
            field_name: '규격',
            field_key: 'specification',
            field_type: 'textbox',
            order_no: 5,
            is_required: false,
            placeholder: '규격을 입력하세요',
            grid_row: 2,
            grid_col: 2,
            grid_span: 2,
          },
          {
            id: 1006,
            field_name: '활성 상태',
            field_key: 'is_active',
            field_type: 'switch',
            order_no: 6,
            is_required: false,
            default_value: true,
            grid_row: 2,
            grid_col: 4,
            grid_span: 1,
          },
        ],
      },
      {
        id: 102,
        title: '가격 정보',
        section_type: 'DETAIL',
        order_no: 2,
        is_collapsible: true,
        is_default_open: true,
        fields: [
          {
            id: 1010,
            field_name: '판매 단가',
            field_key: 'sales_price',
            field_type: 'currency',
            order_no: 1,
            is_required: false,
            placeholder: '0',
            grid_row: 1,
            grid_col: 1,
            grid_span: 1,
          },
          {
            id: 1011,
            field_name: '구매 단가',
            field_key: 'purchase_price',
            field_type: 'currency',
            order_no: 2,
            is_required: false,
            placeholder: '0',
            grid_row: 1,
            grid_col: 2,
            grid_span: 1,
          },
          {
            id: 1012,
            field_name: '마진율 (%)',
            field_key: 'margin_rate',
            field_type: 'number',
            order_no: 3,
            is_required: false,
            placeholder: '0',
            validation_rules: { min: 0, max: 100 },
            grid_row: 1,
            grid_col: 3,
            grid_span: 1,
          },
        ],
      },
      {
        id: 103,
        title: '부품 구성 (BOM)',
        section_type: 'BOM',
        order_no: 3,
        is_collapsible: true,
        is_default_open: true,
        fields: [],
        bom_config: {
          columns: [
            { key: 'child_item_code', label: '품목코드', width: 150 },
            { key: 'child_item_name', label: '품목명', width: 200 },
            { key: 'specification', label: '규격', width: 150 },
            { key: 'quantity', label: '수량', width: 80, type: 'number', editable: true },
            { key: 'unit', label: '단위', width: 80 },
            { key: 'note', label: '비고', width: 150, type: 'text', editable: true },
          ],
          allow_search: true,
          search_endpoint: '/api/proxy/items/search',
          allow_add: true,
          allow_delete: true,
          allow_reorder: true,
        },
      },
      {
        id: 104,
        title: '인정 정보',
        section_type: 'CERTIFICATION',
        order_no: 4,
        is_collapsible: true,
        is_default_open: false,
        fields: [
          {
            id: 1020,
            field_name: '인정번호',
            field_key: 'certification_number',
            field_type: 'textbox',
            order_no: 1,
            is_required: false,
            placeholder: '인정번호를 입력하세요',
            grid_row: 1,
            grid_col: 1,
            grid_span: 2,
          },
          {
            id: 1021,
            field_name: '인정 시작일',
            field_key: 'certification_start_date',
            field_type: 'date',
            order_no: 2,
            is_required: false,
            grid_row: 1,
            grid_col: 3,
            grid_span: 1,
          },
          {
            id: 1022,
            field_name: '인정 종료일',
            field_key: 'certification_end_date',
            field_type: 'date',
            order_no: 3,
            is_required: false,
            grid_row: 1,
            grid_col: 4,
            grid_span: 1,
          },
          {
            id: 1023,
            field_name: '시방서',
            field_key: 'specification_file',
            field_type: 'file',
            order_no: 4,
            is_required: false,
            file_config: {
              accept: '.pdf,.doc,.docx',
              max_size: 10 * 1024 * 1024, // 10MB
            },
            grid_row: 2,
            grid_col: 1,
            grid_span: 2,
          },
          {
            id: 1024,
            field_name: '인정서',
            field_key: 'certification_file',
            field_type: 'file',
            order_no: 5,
            is_required: false,
            file_config: {
              accept: '.pdf,.doc,.docx',
              max_size: 10 * 1024 * 1024,
            },
            grid_row: 2,
            grid_col: 3,
            grid_span: 2,
          },
        ],
      },
    ],
    conditionalSections: [],
    conditionalFields: [],
  };
}

/**
 * 부품(PT) Mock 폼 구조
 */
function getMockPTFormStructure(partType?: PartType): FormStructure {
  const baseFields: DynamicField[] = [
    {
      id: 2001,
      field_name: '품목코드',
      field_key: 'item_code',
      field_type: 'textbox',
      order_no: 1,
      is_required: true,
      is_readonly: true,
      placeholder: '자동 생성',
      grid_row: 1,
      grid_col: 1,
      grid_span: 1,
    },
    {
      id: 2002,
      field_name: '품목명',
      field_key: 'item_name',
      field_type: 'textbox',
      order_no: 2,
      is_required: true,
      placeholder: '품목명을 입력하세요',
      grid_row: 1,
      grid_col: 2,
      grid_span: 2,
    },
    {
      id: 2003,
      field_name: '부품 유형',
      field_key: 'part_type',
      field_type: 'dropdown',
      order_no: 3,
      is_required: true,
      dropdown_config: {
        options: [
          { value: 'ASSEMBLY', label: '조립 부품' },
          { value: 'BENDING', label: '절곡 부품' },
          { value: 'PURCHASED', label: '구매 부품' },
        ],
        placeholder: '부품 유형 선택',
      },
      grid_row: 1,
      grid_col: 4,
      grid_span: 1,
    },
    {
      id: 2004,
      field_name: '단위',
      field_key: 'unit',
      field_type: 'dropdown',
      order_no: 4,
      is_required: true,
      dropdown_config: {
        options: [
          { value: 'EA', label: 'EA (개)' },
          { value: 'SET', label: 'SET (세트)' },
          { value: 'M', label: 'M (미터)' },
        ],
      },
      grid_row: 2,
      grid_col: 1,
      grid_span: 1,
    },
  ];

  const sections: DynamicSection[] = [
    {
      id: 201,
      title: '기본 정보',
      section_type: 'BASIC',
      order_no: 1,
      is_collapsible: false,
      is_default_open: true,
      fields: baseFields,
    },
  ];

  // 조립 부품 전용 섹션
  const assemblySection: DynamicSection = {
    id: 202,
    title: '조립 부품 상세',
    section_type: 'DETAIL',
    order_no: 2,
    is_collapsible: true,
    is_default_open: true,
    display_condition: {
      field_key: 'part_type',
      operator: 'equals',
      value: 'ASSEMBLY',
    },
    fields: [
      {
        id: 2010,
        field_name: '설치 유형',
        field_key: 'installation_type',
        field_type: 'dropdown',
        order_no: 1,
        is_required: false,
        dropdown_config: {
          options: [
            { value: 'WALL', label: '벽면형' },
            { value: 'SIDE', label: '측면형' },
          ],
        },
        grid_row: 1,
        grid_col: 1,
        grid_span: 1,
      },
      {
        id: 2011,
        field_name: '조립 종류',
        field_key: 'assembly_type',
        field_type: 'dropdown',
        order_no: 2,
        is_required: false,
        dropdown_config: {
          options: [
            { value: 'M', label: 'M형' },
            { value: 'T', label: 'T형' },
            { value: 'C', label: 'C형' },
            { value: 'D', label: 'D형' },
            { value: 'S', label: 'S형' },
            { value: 'U', label: 'U형' },
          ],
        },
        grid_row: 1,
        grid_col: 2,
        grid_span: 1,
      },
      {
        id: 2012,
        field_name: '길이 (mm)',
        field_key: 'assembly_length',
        field_type: 'dropdown',
        order_no: 3,
        is_required: false,
        dropdown_config: {
          options: [
            { value: '2438', label: '2438' },
            { value: '3000', label: '3000' },
            { value: '3500', label: '3500' },
            { value: '4000', label: '4000' },
            { value: '4300', label: '4300' },
          ],
        },
        grid_row: 1,
        grid_col: 3,
        grid_span: 1,
      },
    ],
  };

  // 절곡 부품 전용 섹션
  const bendingSection: DynamicSection = {
    id: 203,
    title: '절곡 정보',
    section_type: 'BENDING',
    order_no: 2,
    is_collapsible: true,
    is_default_open: true,
    display_condition: {
      field_key: 'part_type',
      operator: 'equals',
      value: 'BENDING',
    },
    fields: [
      {
        id: 2020,
        field_name: '재질',
        field_key: 'material',
        field_type: 'dropdown',
        order_no: 1,
        is_required: true,
        dropdown_config: {
          options: [
            { value: 'EGI_1.55T', label: 'EGI 1.55T' },
            { value: 'SUS_1.2T', label: 'SUS 1.2T' },
            { value: 'SUS_1.5T', label: 'SUS 1.5T' },
          ],
        },
        grid_row: 1,
        grid_col: 1,
        grid_span: 1,
      },
      {
        id: 2021,
        field_name: '길이/목함 (mm)',
        field_key: 'bending_length',
        field_type: 'number',
        order_no: 2,
        is_required: false,
        placeholder: '길이 입력',
        grid_row: 1,
        grid_col: 2,
        grid_span: 1,
      },
      {
        id: 2022,
        field_name: '전개도',
        field_key: 'bending_diagram',
        field_type: 'custom:drawing-canvas',
        order_no: 3,
        is_required: false,
        grid_row: 2,
        grid_col: 1,
        grid_span: 4,
      },
      {
        id: 2023,
        field_name: '전개도 상세',
        field_key: 'bending_details',
        field_type: 'custom:bending-detail-table',
        order_no: 4,
        is_required: false,
        grid_row: 3,
        grid_col: 1,
        grid_span: 4,
      },
    ],
  };

  // 구매 부품 전용 섹션
  const purchasedSection: DynamicSection = {
    id: 204,
    title: '구매 부품 상세',
    section_type: 'DETAIL',
    order_no: 2,
    is_collapsible: true,
    is_default_open: true,
    display_condition: {
      field_key: 'part_type',
      operator: 'equals',
      value: 'PURCHASED',
    },
    fields: [
      {
        id: 2030,
        field_name: '구매처',
        field_key: 'supplier',
        field_type: 'textbox',
        order_no: 1,
        is_required: false,
        placeholder: '구매처를 입력하세요',
        grid_row: 1,
        grid_col: 1,
        grid_span: 2,
      },
      {
        id: 2031,
        field_name: '구매 단가',
        field_key: 'purchase_price',
        field_type: 'currency',
        order_no: 2,
        is_required: false,
        grid_row: 1,
        grid_col: 3,
        grid_span: 1,
      },
      {
        id: 2032,
        field_name: '리드타임 (일)',
        field_key: 'lead_time',
        field_type: 'number',
        order_no: 3,
        is_required: false,
        placeholder: '0',
        grid_row: 1,
        grid_col: 4,
        grid_span: 1,
      },
    ],
  };

  sections.push(assemblySection, bendingSection, purchasedSection);

  // BOM 섹션 (조립/절곡 부품만)
  const bomSection: DynamicSection = {
    id: 205,
    title: '부품 구성 (BOM)',
    section_type: 'BOM',
    order_no: 3,
    is_collapsible: true,
    is_default_open: true,
    display_condition: {
      field_key: 'part_type',
      operator: 'in',
      value: ['ASSEMBLY', 'BENDING'],
    },
    fields: [],
    bom_config: {
      columns: [
        { key: 'child_item_code', label: '품목코드', width: 150 },
        { key: 'child_item_name', label: '품목명', width: 200 },
        { key: 'quantity', label: '수량', width: 80, type: 'number', editable: true },
        { key: 'unit', label: '단위', width: 80 },
      ],
      allow_search: true,
      search_endpoint: '/api/proxy/items/search',
      allow_add: true,
      allow_delete: true,
    },
  };

  sections.push(bomSection);

  return {
    page: {
      id: 2,
      page_name: '부품 등록',
      item_type: 'PT',
      part_type: partType,
      is_active: true,
    },
    sections,
    conditionalSections: [],
    conditionalFields: [],
  };
}

/**
 * 자재(RM/SM/CS) Mock 폼 구조
 */
function getMockMaterialFormStructure(itemType: ItemType): FormStructure {
  const typeLabels: Record<string, string> = {
    RM: '원자재',
    SM: '부자재',
    CS: '소모품',
  };

  return {
    page: {
      id: itemType === 'RM' ? 3 : itemType === 'SM' ? 4 : 5,
      page_name: `${typeLabels[itemType]} 등록`,
      item_type: itemType,
      is_active: true,
    },
    sections: [
      {
        id: 301,
        title: '기본 정보',
        section_type: 'BASIC',
        order_no: 1,
        is_collapsible: false,
        is_default_open: true,
        fields: [
          {
            id: 3001,
            field_name: '품목코드',
            field_key: 'item_code',
            field_type: 'textbox',
            order_no: 1,
            is_required: true,
            is_readonly: true,
            placeholder: '자동 생성',
            grid_row: 1,
            grid_col: 1,
            grid_span: 1,
          },
          {
            id: 3002,
            field_name: '품목명',
            field_key: 'item_name',
            field_type: 'textbox',
            order_no: 2,
            is_required: true,
            placeholder: '품목명을 입력하세요',
            grid_row: 1,
            grid_col: 2,
            grid_span: 2,
          },
          {
            id: 3003,
            field_name: '단위',
            field_key: 'unit',
            field_type: 'dropdown',
            order_no: 3,
            is_required: true,
            dropdown_config: {
              options: [
                { value: 'EA', label: 'EA (개)' },
                { value: 'KG', label: 'KG (킬로그램)' },
                { value: 'M', label: 'M (미터)' },
                { value: 'L', label: 'L (리터)' },
                { value: 'BOX', label: 'BOX (박스)' },
              ],
            },
            grid_row: 1,
            grid_col: 4,
            grid_span: 1,
          },
          {
            id: 3004,
            field_name: '규격',
            field_key: 'specification',
            field_type: 'textbox',
            order_no: 4,
            is_required: false,
            placeholder: '규격을 입력하세요',
            grid_row: 2,
            grid_col: 1,
            grid_span: 2,
          },
          {
            id: 3005,
            field_name: '구매 단가',
            field_key: 'purchase_price',
            field_type: 'currency',
            order_no: 5,
            is_required: false,
            grid_row: 2,
            grid_col: 3,
            grid_span: 1,
          },
          {
            id: 3006,
            field_name: '안전재고',
            field_key: 'safety_stock',
            field_type: 'number',
            order_no: 6,
            is_required: false,
            placeholder: '0',
            grid_row: 2,
            grid_col: 4,
            grid_span: 1,
          },
        ],
      },
      {
        id: 302,
        title: '구매 정보',
        section_type: 'DETAIL',
        order_no: 2,
        is_collapsible: true,
        is_default_open: false,
        fields: [
          {
            id: 3010,
            field_name: '구매처',
            field_key: 'supplier',
            field_type: 'textbox',
            order_no: 1,
            is_required: false,
            placeholder: '구매처를 입력하세요',
            grid_row: 1,
            grid_col: 1,
            grid_span: 2,
          },
          {
            id: 3011,
            field_name: '리드타임 (일)',
            field_key: 'lead_time',
            field_type: 'number',
            order_no: 2,
            is_required: false,
            placeholder: '0',
            grid_row: 1,
            grid_col: 3,
            grid_span: 1,
          },
          {
            id: 3012,
            field_name: '비고',
            field_key: 'note',
            field_type: 'textarea',
            order_no: 3,
            is_required: false,
            placeholder: '비고를 입력하세요',
            grid_row: 2,
            grid_col: 1,
            grid_span: 4,
          },
        ],
      },
    ],
    conditionalSections: [],
    conditionalFields: [],
  };
}

/**
 * Mock 데이터 가져오기
 */
function getMockFormStructure(itemType: ItemType, partType?: PartType): FormStructure {
  switch (itemType) {
    case 'FG':
      return getMockFGFormStructure();
    case 'PT':
      return getMockPTFormStructure(partType);
    case 'RM':
    case 'SM':
    case 'CS':
      return getMockMaterialFormStructure(itemType);
    default:
      return getMockFGFormStructure();
  }
}

// ===== API 호출 =====

/**
 * 폼 구조 API 호출
 */
async function fetchFormStructure(
  itemType: ItemType,
  partType?: PartType
): Promise<FormStructure> {
  const endpoint = partType
    ? `/api/proxy/item-master/form-structure/${itemType}?part_type=${partType}`
    : `/api/proxy/item-master/form-structure/${itemType}`;

  try {
    const response = await fetch(endpoint);

    if (!response.ok) {
      // API가 404면 Mock 데이터 사용
      if (response.status === 404) {
        console.warn(`[useFormStructure] API not found, using mock data for ${itemType}`);
        return getMockFormStructure(itemType, partType);
      }
      throw new Error(`HTTP ${response.status}: ${response.statusText}`);
    }

    const result: FormStructureResponse = await response.json();

    if (!result.success) {
      throw new Error(result.message || 'API returned unsuccessful response');
    }

    // API 응답을 FormStructure 형식으로 변환
    return {
      page: result.data.page,
      sections: result.data.sections,
      conditionalSections: result.data.conditional_sections || [],
      conditionalFields: result.data.conditional_fields || [],
    };
  } catch (error) {
    console.warn(`[useFormStructure] API call failed, using mock data:`, error);
    // API 실패 시 Mock 데이터 폴백
    return getMockFormStructure(itemType, partType);
  }
}

// ===== 훅 구현 =====

interface UseFormStructureOptions {
  itemType: ItemType;
  partType?: PartType;
  enabled?: boolean;
  useMock?: boolean; // 강제로 Mock 데이터 사용
}

/**
 * useFormStructure Hook
 *
 * @param options - 훅 옵션
 * @returns 폼 구조 데이터 및 상태
 *
 * @example
 * const { formStructure, isLoading, error, refetch } = useFormStructure({
 *   itemType: 'FG',
 * });
 *
 * @example
 * const { formStructure } = useFormStructure({
 *   itemType: 'PT',
 *   partType: 'BENDING',
 * });
 */
export function useFormStructure(options: UseFormStructureOptions): UseFormStructureReturn {
  const { itemType, partType, enabled = true, useMock = false } = options;

  const [formStructure, setFormStructure] = useState<FormStructure | null>(null);
  const [isLoading, setIsLoading] = useState(false);
  const [error, setError] = useState<Error | null>(null);

  // 이전 요청 취소용
  const abortControllerRef = useRef<AbortController | null>(null);

  const cacheKey = getCacheKey(itemType, partType);

  /**
   * 폼 구조 로드
   */
  const loadFormStructure = useCallback(async () => {
    // 이전 요청 취소
    if (abortControllerRef.current) {
      abortControllerRef.current.abort();
    }
    abortControllerRef.current = new AbortController();

    // 캐시 확인
    const cached = getFromCache(cacheKey);
    if (cached) {
      setFormStructure(cached);
      setIsLoading(false);
      setError(null);
      return;
    }

    setIsLoading(true);
    setError(null);

    try {
      let data: FormStructure;

      if (useMock) {
        // 강제 Mock 모드
        data = getMockFormStructure(itemType, partType);
      } else {
        // API 호출 (실패 시 자동으로 Mock 폴백)
        data = await fetchFormStructure(itemType, partType);
      }

      // 캐시에 저장
      setToCache(cacheKey, data);

      setFormStructure(data);
      setError(null);
    } catch (err) {
      setError(err instanceof Error ? err : new Error('Unknown error'));
    } finally {
      setIsLoading(false);
    }
  }, [itemType, partType, cacheKey, useMock]);

  /**
   * 강제 새로고침
   */
  const refetch = useCallback(async () => {
    // 캐시 무효화
    formStructureCache.delete(cacheKey);
    await loadFormStructure();
  }, [cacheKey, loadFormStructure]);

  // 마운트 시 및 의존성 변경 시 로드
  useEffect(() => {
    if (enabled) {
      loadFormStructure();
    }

    return () => {
      // 언마운트 시 요청 취소
      if (abortControllerRef.current) {
        abortControllerRef.current.abort();
      }
    };
  }, [enabled, loadFormStructure]);

  return {
    formStructure,
    isLoading,
    error,
    refetch,
  };
}

// ===== 캐시 유틸리티 =====

/**
 * 폼 구조 캐시 초기화
 */
export function clearFormStructureCache(): void {
  formStructureCache.clear();
}

/**
 * 특정 품목 유형의 캐시 무효화
 */
export function invalidateFormStructureCache(itemType: ItemType, partType?: PartType): void {
  const key = getCacheKey(itemType, partType);
  formStructureCache.delete(key);
}

export default useFormStructure;