'use client';

import { useState, useCallback, useEffect } from 'react';
import { format } from 'date-fns';
import { Button } from '@/components/ui/button';
import { Input } from '@/components/ui/input';
import { DatePicker } from '@/components/ui/date-picker';
import { Label } from '@/components/ui/label';
import { Switch } from '@/components/ui/switch';
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from '@/components/ui/select';
import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
import { FileText, Eye } from 'lucide-react';
import { IntegratedDetailTemplate } from '@/components/templates/IntegratedDetailTemplate';
import { LineItemsTable, useLineItems } from '@/components/organisms/LineItemsTable';
import { purchaseConfig } from './purchaseConfig';
import { DocumentDetailModalV2 as DocumentDetailModal } from '@/components/approval/DocumentDetail';
import type { ProposalDocumentData, ExpenseReportDocumentData, ExpenseEstimateDocumentData } from '@/components/approval/DocumentDetail/types';
import { getApprovalById } from '@/components/approval/DocumentCreate/actions';
import type { PurchaseRecord, PurchaseItem } from './types';
import {
  getPurchaseById,
  createPurchase,
  updatePurchase,
  deletePurchase,
} from './actions';
import { getClients } from '../VendorManagement/actions';
import { invalidateDashboard } from '@/lib/dashboard-invalidation';
import { toast } from 'sonner';
import { formatNumber as formatAmount } from '@/lib/utils/amount';

interface PurchaseDetailProps {
  purchaseId: string;
  mode: 'view' | 'edit' | 'new';
}

// ===== 거래처 타입 =====
interface ClientOption {
  id: string;
  name: string;
}

// ===== 초기 품목 데이터 =====
const createEmptyItem = (): PurchaseItem => ({
  id: `item-${Date.now()}-${Math.random().toString(36).substr(2, 9)}`,
  itemName: '',
  quantity: 1,
  unitPrice: 0,
  supplyPrice: 0,
  vat: 0,
  note: '',
});

export function PurchaseDetail({ purchaseId, mode }: PurchaseDetailProps) {
  const isViewMode = mode === 'view';
  const isNewMode = mode === 'new';

  // ===== 로딩 상태 =====
  const [isLoading, setIsLoading] = useState(true);
  const [, setIsSaving] = useState(false);

  // ===== 거래처 목록 =====
  const [clients, setClients] = useState<ClientOption[]>([]);

  // ===== 폼 상태 =====
  const [purchaseNo, setPurchaseNo] = useState('');
  const [purchaseDate, setPurchaseDate] = useState(format(new Date(), 'yyyy-MM-dd'));
  const [vendorId, setVendorId] = useState('');
  const [, setVendorName] = useState('');
  // purchaseType 삭제됨 (기획서 P.109)
  const [items, setItems] = useState<PurchaseItem[]>([createEmptyItem()]);
  const [taxInvoiceReceived, setTaxInvoiceReceived] = useState(false);

  // ===== 문서 관련 상태 (sourceDocument는 API에서 아직 미지원) =====
  const [sourceDocument, setSourceDocument] = useState<PurchaseRecord['sourceDocument']>(undefined);
  const [, setWithdrawalAccount] = useState<PurchaseRecord['withdrawalAccount']>(undefined);
  const [, setCreatedAt] = useState('');

  // ===== 문서 열람 모달 상태 =====
  const [documentModalOpen, setDocumentModalOpen] = useState(false);
  const [modalData, setModalData] = useState<ProposalDocumentData | ExpenseReportDocumentData | ExpenseEstimateDocumentData | null>(null);
  const [, setIsModalLoading] = useState(false);
  const [approvalId, setApprovalId] = useState<string | undefined>(undefined);

  // ===== 품목 관리 (공통 훅) =====
  const { handleItemChange, handleAddItem, handleRemoveItem, totals } = useLineItems<PurchaseItem>({
    items,
    setItems,
    createEmptyItem,
    supplyKey: 'supplyPrice',
    vatKey: 'vat',
    minItems: 1,
  });

  // ===== 초기 데이터 로드 (거래처 + 매입 상세 병렬) =====
  useEffect(() => {
    async function loadInitialData() {
      const isEditMode = purchaseId && mode !== 'new';
      setIsLoading(true);

      const [clientsResult, purchaseResult] = await Promise.all([
        getClients({ size: 1000, only_active: true }),
        isEditMode ? getPurchaseById(purchaseId) : Promise.resolve(null),
      ]);

      // 거래처 목록
      if (clientsResult.success) {
        setClients(clientsResult.data.map(v => ({
          id: v.id,
          name: v.vendorName,
        })));
      }

      // 매입 상세
      if (purchaseResult) {
        if (purchaseResult.success && purchaseResult.data) {
          const data = purchaseResult.data;
          setPurchaseNo(data.purchaseNo);
          setPurchaseDate(data.purchaseDate);
          setVendorId(data.vendorId);
          setVendorName(data.vendorName);
          setItems(data.items.length > 0 ? data.items : [createEmptyItem()]);
          setTaxInvoiceReceived(data.taxInvoiceReceived);
          setSourceDocument(data.sourceDocument);
          setWithdrawalAccount(data.withdrawalAccount);
          setCreatedAt(data.createdAt);
          setApprovalId(data.approvalId);
        }
      } else if (isNewMode) {
        setPurchaseNo('(자동생성)');
      }

      setIsLoading(false);
    }
    loadInitialData();
  }, [purchaseId, mode, isNewMode]);

  // ===== 문서 열람 핸들러 (API 연동) =====
  const handleOpenDocument = useCallback(async () => {
    if (!approvalId) {
      toast.error('연결된 결재 문서가 없습니다.');
      return;
    }

    setIsModalLoading(true);
    setDocumentModalOpen(true);

    try {
      const result = await getApprovalById(parseInt(approvalId));
      if (result.success && result.data) {
        const formData = result.data;
        const docType = sourceDocument?.type === 'expense_report' ? 'expenseReport' : 'proposal';

        // 기안자 정보
        const drafter = {
          id: 'drafter-1',
          name: formData.basicInfo.drafter,
          position: formData.basicInfo.drafterPosition || '',
          department: formData.basicInfo.drafterDepartment || '',
          status: 'approved' as const,
        };

        // 결재자 정보
        const approvers = formData.approvalLine.map((person) => ({
          id: person.id,
          name: person.name,
          position: person.position,
          department: person.department,
          status: 'approved' as const,
        }));

        if (docType === 'expenseReport') {
          setModalData({
            documentNo: formData.basicInfo.documentNo,
            createdAt: formData.basicInfo.draftDate,
            requestDate: formData.expenseReportData?.requestDate || '',
            paymentDate: formData.expenseReportData?.paymentDate || '',
            items: formData.expenseReportData?.items.map((item, index) => ({
              id: item.id,
              no: index + 1,
              description: item.description,
              amount: item.amount,
              note: item.note,
            })) || [],
            cardInfo: formData.expenseReportData?.cardId || '-',
            totalAmount: formData.expenseReportData?.totalAmount || 0,
            attachments: formData.expenseReportData?.uploadedFiles?.map(f => f.name) || [],
            approvers,
            drafter,
          } as ExpenseReportDocumentData);
        } else {
          const uploadedFileUrls = (formData.proposalData?.uploadedFiles || []).map(f =>
            `/api/proxy/files/${f.id}/download`
          );
          setModalData({
            documentNo: formData.basicInfo.documentNo,
            createdAt: formData.basicInfo.draftDate,
            vendor: formData.proposalData?.vendor || '-',
            vendorPaymentDate: formData.proposalData?.vendorPaymentDate || '',
            title: formData.proposalData?.title || '',
            description: formData.proposalData?.description || '-',
            reason: formData.proposalData?.reason || '-',
            estimatedCost: formData.proposalData?.estimatedCost || 0,
            attachments: uploadedFileUrls,
            approvers,
            drafter,
          } as ProposalDocumentData);
        }
      } else {
        toast.error(result.error || '문서 조회에 실패했습니다.');
        setDocumentModalOpen(false);
      }
    } catch {
      toast.error('문서 조회 중 오류가 발생했습니다.');
      setDocumentModalOpen(false);
    } finally {
      setIsModalLoading(false);
    }
  }, [approvalId, sourceDocument]);

  // ===== 핸들러 =====
  const handleVendorChange = useCallback((clientId: string) => {
    const client = clients.find(c => c.id === clientId);
    if (client) {
      setVendorId(client.id);
      setVendorName(client.name);
    }
  }, [clients]);

  // ===== 저장 (IntegratedDetailTemplate 호환) =====
  const handleSubmit = useCallback(async (): Promise<{ success: boolean; error?: string }> => {
    if (!vendorId) {
      toast.warning('거래처를 선택해주세요.');
      return { success: false, error: '거래처를 선택해주세요.' };
    }

    setIsSaving(true);

    const purchaseData: Partial<PurchaseRecord> = {
      purchaseDate,
      vendorId,
      supplyAmount: totals.supplyAmount,
      vat: totals.vat,
      totalAmount: totals.total,
      taxInvoiceReceived,
    };

    try {
      let result;
      if (isNewMode) {
        result = await createPurchase(purchaseData);
      } else if (purchaseId) {
        result = await updatePurchase(purchaseId, purchaseData);
      }

      if (result?.success) {
        invalidateDashboard('purchase');
        toast.success(isNewMode ? '매입이 등록되었습니다.' : '매입이 수정되었습니다.');
        return { success: true };
      } else {
        toast.error(result?.error || '저장에 실패했습니다.');
        return { success: false, error: result?.error || '저장에 실패했습니다.' };
      }
    } catch {
      toast.error('저장 중 오류가 발생했습니다.');
      return { success: false, error: '저장 중 오류가 발생했습니다.' };
    } finally {
      setIsSaving(false);
    }
  }, [purchaseDate, vendorId, totals, taxInvoiceReceived, isNewMode, purchaseId]);

  // ===== 삭제 (IntegratedDetailTemplate 호환) =====
  const handleDelete = useCallback(async (): Promise<{ success: boolean; error?: string }> => {
    if (!purchaseId) return { success: false, error: 'ID가 없습니다.' };

    try {
      const result = await deletePurchase(purchaseId);

      if (result.success) {
        invalidateDashboard('purchase');
        toast.success('매입이 삭제되었습니다.');
        return { success: true };
      } else {
        toast.error(result.error || '삭제에 실패했습니다.');
        return { success: false, error: result.error || '삭제에 실패했습니다.' };
      }
    } catch {
      toast.error('삭제 중 오류가 발생했습니다.');
      return { success: false, error: '삭제 중 오류가 발생했습니다.' };
    }
  }, [purchaseId]);

  // ===== 폼 내용 렌더링 =====
  const renderFormContent = () => (
    <>
      <div className="space-y-6">
        {/* ===== 기본 정보 섹션 (품의서/지출결의서 + 예상비용) ===== */}
        <Card>
          <CardHeader className="pb-3">
            <CardTitle className="text-lg">기본 정보</CardTitle>
          </CardHeader>
          <CardContent>
            <div className="grid grid-cols-1 md:grid-cols-2 gap-6">
              {/* 품의서/지출결의서 */}
              <div className="space-y-2">
                <Label>품의서</Label>
                <div className="flex items-center gap-2">
                  <Input
                    value={sourceDocument ? `${sourceDocument.documentNo} ${sourceDocument.title}` : ''}
                    readOnly
                    disabled
                    placeholder="연결된 품의서 없음"
                    className="bg-gray-50"
                  />
                  <Button
                    variant="outline"
                    size="sm"
                    className="shrink-0"
                    onClick={handleOpenDocument}
                    disabled={!sourceDocument}
                  >
                    <Eye className="h-4 w-4 mr-1" />
                    열람
                  </Button>
                </div>
              </div>

              {/* 예상비용 */}
              <div className="space-y-2">
                <Label>예상비용</Label>
                <Input
                  value={sourceDocument ? `${formatAmount(sourceDocument.expectedCost)}원` : ''}
                  readOnly
                  disabled
                  placeholder="-"
                  className="bg-gray-50"
                />
              </div>
            </div>
          </CardContent>
        </Card>

        {/* ===== 매입 정보 섹션 ===== */}
        <Card>
          <CardHeader className="pb-3">
            <CardTitle className="text-lg">매입 정보</CardTitle>
          </CardHeader>
          <CardContent>
            <div className="grid grid-cols-1 md:grid-cols-3 gap-6">
              {/* 매입번호 */}
              <div className="space-y-2">
                <Label>매입번호</Label>
                <Input
                  value={purchaseNo}
                  readOnly
                  disabled
                  className="bg-gray-50"
                />
              </div>

              {/* 매입일 */}
              <div className="space-y-2">
                <Label>매입일</Label>
                <DatePicker
                  value={purchaseDate}
                  onChange={setPurchaseDate}
                  disabled={isViewMode}
                />
              </div>

              {/* 거래처명 */}
              <div className="space-y-2">
                <Label>거래처명</Label>
                <Select
                  value={vendorId}
                  onValueChange={handleVendorChange}
                  disabled={isViewMode}
                >
                  <SelectTrigger>
                    <SelectValue placeholder="거래처 선택" />
                  </SelectTrigger>
                  <SelectContent>
                    {clients.map((client) => (
                      <SelectItem key={client.id} value={client.id}>
                        {client.name}
                      </SelectItem>
                    ))}
                  </SelectContent>
                </Select>
              </div>
            </div>
          </CardContent>
        </Card>

        {/* ===== 품목 정보 섹션 ===== */}
        <Card>
          <CardHeader className="pb-3">
            <CardTitle className="text-lg">품목 정보</CardTitle>
          </CardHeader>
          <CardContent>
            <LineItemsTable<PurchaseItem>
              items={items}
              getItemName={(item) => item.itemName}
              getQuantity={(item) => item.quantity}
              getUnitPrice={(item) => item.unitPrice}
              getSupplyAmount={(item) => item.supplyPrice}
              getVat={(item) => item.vat}
              getNote={(item) => item.note ?? ''}
              onItemChange={handleItemChange}
              onAddItem={handleAddItem}
              onRemoveItem={handleRemoveItem}
              totals={totals}
              isViewMode={isViewMode}
            />
          </CardContent>
        </Card>

        {/* ===== 세금계산서 섹션 ===== */}
        <Card>
          <CardHeader className="pb-3">
            <CardTitle className="text-lg">세금계산서</CardTitle>
          </CardHeader>
          <CardContent>
            <div className="flex items-center justify-between">
              <div className="flex items-center gap-3">
                <Label htmlFor="taxInvoice">세금계산서 수취</Label>
                <Switch
                  id="taxInvoice"
                  checked={taxInvoiceReceived}
                  onCheckedChange={setTaxInvoiceReceived}
                  disabled={isViewMode}
                />
              </div>
              <div className="flex items-center gap-2">
                {taxInvoiceReceived ? (
                  <span className="text-sm text-green-600 flex items-center gap-1">
                    <FileText className="h-4 w-4" />
                    수취완료
                  </span>
                ) : (
                  <span className="text-sm text-gray-500 flex items-center gap-1">
                    <FileText className="h-4 w-4" />
                    미수취
                  </span>
                )}
              </div>
            </div>
          </CardContent>
        </Card>
      </div>

      {/* ===== 품의서/지출결의서 문서 열람 모달 ===== */}
      {modalData && (
        <DocumentDetailModal
          open={documentModalOpen}
          onOpenChange={(open) => {
            setDocumentModalOpen(open);
            if (!open) setModalData(null);
          }}
          mode="reference"
          documentType={sourceDocument?.type === 'expense_report' ? 'expenseReport' : 'proposal'}
          data={modalData}
        />
      )}

    </>
  );

  // ===== 모드 변환 =====
  const templateMode = isNewMode ? 'create' : mode;

  // ===== 동적 config =====
  const dynamicConfig = {
    ...purchaseConfig,
    title: isNewMode ? '매입' : '매입 상세',
    actions: {
      ...purchaseConfig.actions,
      submitLabel: isNewMode ? '등록' : '저장',
    },
  };

  return (
    <IntegratedDetailTemplate
      config={dynamicConfig}
      mode={templateMode}
      initialData={{}}
      itemId={purchaseId}
      isLoading={isLoading}
      onSubmit={handleSubmit}
      onDelete={purchaseId && !isNewMode ? handleDelete : undefined}
      renderView={() => renderFormContent()}
      renderForm={() => renderFormContent()}
    />
  );
}
