'use client';

import { useState, useMemo, useCallback, useTransition } from 'react';
import { useRouter } from 'next/navigation';
import {
  AlertTriangle,
  Pencil,
  Trash2,
  Eye,
} from 'lucide-react';
import { Button } from '@/components/ui/button';
import { Checkbox } from '@/components/ui/checkbox';
import { Badge } from '@/components/ui/badge';
import { Switch } from '@/components/ui/switch';
import {
  AlertDialog,
  AlertDialogAction,
  AlertDialogCancel,
  AlertDialogContent,
  AlertDialogDescription,
  AlertDialogFooter,
  AlertDialogHeader,
  AlertDialogTitle,
} from '@/components/ui/alert-dialog';
import { TableRow, TableCell } from '@/components/ui/table';
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from '@/components/ui/select';
import {
  IntegratedListTemplateV2,
  type TableColumn,
  type StatCard,
} from '@/components/templates/IntegratedListTemplateV2';
import { ListMobileCard, InfoField } from '@/components/organisms/ListMobileCard';
import type {
  BadDebtRecord,
  SortOption,
} from './types';
import {
  COLLECTION_STATUS_LABELS,
  STATUS_FILTER_OPTIONS,
  STATUS_BADGE_STYLES,
  SORT_OPTIONS,
} from './types';
import { deleteBadDebt, toggleBadDebt } from './actions';

// ===== Props 타입 정의 =====
interface BadDebtCollectionProps {
  initialData: BadDebtRecord[];
  initialSummary?: {
    total_amount: number;
    collecting_amount: number;
    legal_action_amount: number;
    recovered_amount: number;
    bad_debt_amount: number;
  } | null;
}

// 거래처 목록 추출 (필터용)
const getVendorOptions = (data: BadDebtRecord[]) => {
  const vendorMap = new Map<string, string>();
  data.forEach(item => {
    vendorMap.set(item.vendorId, item.vendorName);
  });
  return [
    { value: 'all', label: '전체' },
    ...Array.from(vendorMap.entries()).map(([id, name]) => ({
      value: id,
      label: name,
    })),
  ];
};

export function BadDebtCollection({ initialData, initialSummary }: BadDebtCollectionProps) {
  const router = useRouter();
  const [isPending, startTransition] = useTransition();

  // ===== 상태 관리 =====
  const [searchQuery, setSearchQuery] = useState('');
  const [sortOption, setSortOption] = useState<SortOption>('latest');
  const [vendorFilter, setVendorFilter] = useState<string>('all');
  const [statusFilter, setStatusFilter] = useState<string>('all');
  const [selectedItems, setSelectedItems] = useState<Set<string>>(new Set());
  const [currentPage, setCurrentPage] = useState(1);
  const itemsPerPage = 20;

  // 삭제 다이얼로그
  const [showDeleteDialog, setShowDeleteDialog] = useState(false);
  const [deleteTargetId, setDeleteTargetId] = useState<string | null>(null);

  // 데이터 (서버에서 받은 초기 데이터 사용)
  const [data, setData] = useState<BadDebtRecord[]>(initialData);

  // 거래처 옵션
  const vendorOptions = useMemo(() => getVendorOptions(data), [data]);

  // ===== 체크박스 핸들러 =====
  const toggleSelection = useCallback((id: string) => {
    setSelectedItems(prev => {
      const newSet = new Set(prev);
      if (newSet.has(id)) newSet.delete(id);
      else newSet.add(id);
      return newSet;
    });
  }, []);

  // ===== 필터링된 데이터 =====
  const filteredData = useMemo(() => {
    let result = data.filter(item =>
      item.vendorName.includes(searchQuery) ||
      item.vendorCode.includes(searchQuery) ||
      item.businessNumber.includes(searchQuery)
    );

    // 거래처 필터
    if (vendorFilter !== 'all') {
      result = result.filter(item => item.vendorId === vendorFilter);
    }

    // 상태 필터
    if (statusFilter !== 'all') {
      result = result.filter(item => item.status === statusFilter);
    }

    // 정렬
    switch (sortOption) {
      case 'latest':
        result.sort((a, b) => new Date(b.createdAt).getTime() - new Date(a.createdAt).getTime());
        break;
      case 'oldest':
        result.sort((a, b) => new Date(a.createdAt).getTime() - new Date(b.createdAt).getTime());
        break;
    }

    return result;
  }, [data, searchQuery, vendorFilter, statusFilter, sortOption]);

  const paginatedData = useMemo(() => {
    const startIndex = (currentPage - 1) * itemsPerPage;
    return filteredData.slice(startIndex, startIndex + itemsPerPage);
  }, [filteredData, currentPage, itemsPerPage]);

  const totalPages = Math.ceil(filteredData.length / itemsPerPage);

  // ===== 전체 선택 핸들러 =====
  const toggleSelectAll = useCallback(() => {
    if (selectedItems.size === filteredData.length && filteredData.length > 0) {
      setSelectedItems(new Set());
    } else {
      setSelectedItems(new Set(filteredData.map(item => item.id)));
    }
  }, [selectedItems.size, filteredData]);

  // ===== 액션 핸들러 =====
  const handleRowClick = useCallback((item: BadDebtRecord) => {
    router.push(`/ko/accounting/bad-debt-collection/${item.id}`);
  }, [router]);

  const handleEdit = useCallback((item: BadDebtRecord) => {
    router.push(`/ko/accounting/bad-debt-collection/${item.id}/edit`);
  }, [router]);

  const handleDeleteClick = useCallback((id: string) => {
    setDeleteTargetId(id);
    setShowDeleteDialog(true);
  }, []);

  const handleConfirmDelete = useCallback(() => {
    if (deleteTargetId) {
      startTransition(async () => {
        const result = await deleteBadDebt(deleteTargetId);
        if (result.success) {
          setData(prev => prev.filter(item => item.id !== deleteTargetId));
          setSelectedItems(prev => {
            const newSet = new Set(prev);
            newSet.delete(deleteTargetId);
            return newSet;
          });
        } else {
          console.error('[BadDebtCollection] Delete failed:', result.error);
        }
      });
    }
    setShowDeleteDialog(false);
    setDeleteTargetId(null);
  }, [deleteTargetId]);

  // 설정 토글 핸들러 (API 호출)
  const handleSettingToggle = useCallback((id: string, checked: boolean) => {
    // Optimistic update
    setData(prev => prev.map(item =>
      item.id === id ? { ...item, settingToggle: checked } : item
    ));

    startTransition(async () => {
      const result = await toggleBadDebt(id);
      if (!result.success) {
        // Rollback on error
        setData(prev => prev.map(item =>
          item.id === id ? { ...item, settingToggle: !checked } : item
        ));
        console.error('[BadDebtCollection] Toggle failed:', result.error);
      }
    });
  }, []);

  // ===== 통계 카드 (API 통계 또는 로컬 계산) =====
  const statCards: StatCard[] = useMemo(() => {
    if (initialSummary) {
      // API 통계 데이터 사용
      return [
        { label: '총 악성채권', value: `${initialSummary.total_amount.toLocaleString()}원`, icon: AlertTriangle, iconColor: 'text-red-500' },
        { label: '추심중', value: `${initialSummary.collecting_amount.toLocaleString()}원`, icon: AlertTriangle, iconColor: 'text-orange-500' },
        { label: '법적조치', value: `${initialSummary.legal_action_amount.toLocaleString()}원`, icon: AlertTriangle, iconColor: 'text-red-600' },
        { label: '회수완료', value: `${initialSummary.recovered_amount.toLocaleString()}원`, icon: AlertTriangle, iconColor: 'text-green-500' },
      ];
    }

    // 로컬 데이터로 계산 (fallback)
    const totalAmount = data.reduce((sum, d) => sum + d.debtAmount, 0);
    const collectingAmount = data.filter(d => d.status === 'collecting').reduce((sum, d) => sum + d.debtAmount, 0);
    const legalActionAmount = data.filter(d => d.status === 'legalAction').reduce((sum, d) => sum + d.debtAmount, 0);
    const recoveredAmount = data.filter(d => d.status === 'recovered').reduce((sum, d) => sum + d.debtAmount, 0);

    return [
      { label: '총 악성채권', value: `${totalAmount.toLocaleString()}원`, icon: AlertTriangle, iconColor: 'text-red-500' },
      { label: '추심중', value: `${collectingAmount.toLocaleString()}원`, icon: AlertTriangle, iconColor: 'text-orange-500' },
      { label: '법적조치', value: `${legalActionAmount.toLocaleString()}원`, icon: AlertTriangle, iconColor: 'text-red-600' },
      { label: '회수완료', value: `${recoveredAmount.toLocaleString()}원`, icon: AlertTriangle, iconColor: 'text-green-500' },
    ];
  }, [data, initialSummary]);

  // ===== 테이블 컬럼 =====
  const tableColumns: TableColumn[] = useMemo(() => [
    { key: 'no', label: 'No.', className: 'text-center w-[60px]' },
    { key: 'vendorName', label: '거래처' },
    { key: 'debtAmount', label: '채권금액', className: 'text-right w-[140px]' },
    { key: 'occurrenceDate', label: '발생일', className: 'text-center w-[110px]' },
    { key: 'overdueDays', label: '연체일수', className: 'text-center w-[100px]' },
    { key: 'managerName', label: '담당자', className: 'w-[100px]' },
    { key: 'status', label: '상태', className: 'text-center w-[100px]' },
    { key: 'setting', label: '설정', className: 'text-center w-[80px]' },
    { key: 'actions', label: '작업', className: 'text-center w-[120px]' },
  ], []);

  // ===== 테이블 행 렌더링 =====
  const renderTableRow = useCallback((item: BadDebtRecord, index: number, globalIndex: number) => {
    const isSelected = selectedItems.has(item.id);

    return (
      <TableRow
        key={item.id}
        className="hover:bg-muted/50 cursor-pointer"
        onClick={() => handleRowClick(item)}
      >
        <TableCell className="text-center" onClick={(e) => e.stopPropagation()}>
          <Checkbox checked={isSelected} onCheckedChange={() => toggleSelection(item.id)} />
        </TableCell>
        {/* No. */}
        <TableCell className="text-center text-sm text-gray-500">{globalIndex}</TableCell>
        {/* 거래처 */}
        <TableCell className="font-medium">{item.vendorName}</TableCell>
        {/* 채권금액 */}
        <TableCell className="text-right font-medium text-red-600">
          {item.debtAmount.toLocaleString()}원
        </TableCell>
        {/* 발생일 */}
        <TableCell className="text-center">{item.occurrenceDate}</TableCell>
        {/* 연체일수 */}
        <TableCell className="text-center">{item.overdueDays}일</TableCell>
        {/* 담당자 */}
        <TableCell>{item.assignedManager?.name || '-'}</TableCell>
        {/* 상태 */}
        <TableCell className="text-center">
          <Badge variant="outline" className={STATUS_BADGE_STYLES[item.status]}>
            {COLLECTION_STATUS_LABELS[item.status]}
          </Badge>
        </TableCell>
        {/* 설정 */}
        <TableCell className="text-center" onClick={(e) => e.stopPropagation()}>
          <Switch
            checked={item.settingToggle}
            onCheckedChange={(checked) => handleSettingToggle(item.id, checked)}
            disabled={isPending}
          />
        </TableCell>
        {/* 작업 */}
        <TableCell className="text-center" onClick={(e) => e.stopPropagation()}>
          {isSelected && (
            <div className="flex items-center justify-center gap-1">
              <Button
                variant="ghost"
                size="icon"
                className="h-8 w-8"
                onClick={() => handleEdit(item)}
              >
                <Pencil className="h-4 w-4" />
              </Button>
              <Button
                variant="ghost"
                size="icon"
                className="h-8 w-8 text-red-500 hover:text-red-600 hover:bg-red-50"
                onClick={() => handleDeleteClick(item.id)}
              >
                <Trash2 className="h-4 w-4" />
              </Button>
            </div>
          )}
        </TableCell>
      </TableRow>
    );
  }, [selectedItems, toggleSelection, handleRowClick, handleEdit, handleDeleteClick, handleSettingToggle, isPending]);

  // ===== 모바일 카드 렌더링 =====
  const renderMobileCard = useCallback((
    item: BadDebtRecord,
    index: number,
    globalIndex: number,
    isSelected: boolean,
    onToggle: () => void
  ) => {
    return (
      <ListMobileCard
        id={item.id}
        title={item.vendorName}
        headerBadges={
          <Badge variant="outline" className={STATUS_BADGE_STYLES[item.status]}>
            {COLLECTION_STATUS_LABELS[item.status]}
          </Badge>
        }
        isSelected={isSelected}
        onToggleSelection={onToggle}
        infoGrid={
          <div className="grid grid-cols-2 gap-3">
            <InfoField label="채권금액" value={`${item.debtAmount.toLocaleString()}원`} className="text-red-600" />
            <InfoField label="연체일수" value={`${item.overdueDays}일`} />
            <InfoField label="발생일" value={item.occurrenceDate} />
            <InfoField label="담당자" value={item.assignedManager?.name || '-'} />
          </div>
        }
        actions={
          isSelected ? (
            <div className="flex gap-2 w-full">
              <Button variant="outline" className="flex-1" onClick={() => handleRowClick(item)}>
                <Eye className="w-4 h-4 mr-2" /> 상세
              </Button>
              <Button variant="outline" className="flex-1" onClick={() => handleEdit(item)}>
                <Pencil className="w-4 h-4 mr-2" /> 수정
              </Button>
              <Button
                variant="outline"
                className="flex-1 text-red-500 border-red-200 hover:bg-red-50 hover:text-red-600"
                onClick={() => handleDeleteClick(item.id)}
              >
                <Trash2 className="w-4 h-4 mr-2" /> 삭제
              </Button>
            </div>
          ) : undefined
        }
        onClick={() => handleRowClick(item)}
      />
    );
  }, [handleRowClick, handleEdit, handleDeleteClick]);

  // ===== 테이블 헤더 액션 (3개 필터) =====
  const tableHeaderActions = (
    <div className="flex items-center gap-2 flex-wrap">
      {/* 거래처 필터 */}
      <Select value={vendorFilter} onValueChange={setVendorFilter}>
        <SelectTrigger className="w-[150px]">
          <SelectValue placeholder="전체" />
        </SelectTrigger>
        <SelectContent>
          {vendorOptions.map((option) => (
            <SelectItem key={option.value} value={option.value}>
              {option.label}
            </SelectItem>
          ))}
        </SelectContent>
      </Select>

      {/* 상태 필터 */}
      <Select value={statusFilter} onValueChange={setStatusFilter}>
        <SelectTrigger className="w-[120px]">
          <SelectValue placeholder="상태" />
        </SelectTrigger>
        <SelectContent>
          {STATUS_FILTER_OPTIONS.map((option) => (
            <SelectItem key={option.value} value={option.value}>
              {option.label}
            </SelectItem>
          ))}
        </SelectContent>
      </Select>

      {/* 정렬 */}
      <Select value={sortOption} onValueChange={(value) => setSortOption(value as SortOption)}>
        <SelectTrigger className="w-[120px]">
          <SelectValue placeholder="정렬" />
        </SelectTrigger>
        <SelectContent>
          {SORT_OPTIONS.map((option) => (
            <SelectItem key={option.value} value={option.value}>
              {option.label}
            </SelectItem>
          ))}
        </SelectContent>
      </Select>
    </div>
  );

  return (
    <>
      <IntegratedListTemplateV2
        title="악성채권 추심관리"
        description="연체 및 악성채권 현황을 추적하고 관리합니다"
        icon={AlertTriangle}
        stats={statCards}
        searchValue={searchQuery}
        onSearchChange={setSearchQuery}
        searchPlaceholder="거래처명, 거래처코드, 사업자번호 검색..."
        tableHeaderActions={tableHeaderActions}
        tableColumns={tableColumns}
        data={paginatedData}
        totalCount={filteredData.length}
        allData={filteredData}
        selectedItems={selectedItems}
        onToggleSelection={toggleSelection}
        onToggleSelectAll={toggleSelectAll}
        getItemId={(item: BadDebtRecord) => item.id}
        renderTableRow={renderTableRow}
        renderMobileCard={renderMobileCard}
        pagination={{
          currentPage,
          totalPages,
          totalItems: filteredData.length,
          itemsPerPage,
          onPageChange: setCurrentPage,
        }}
      />

      {/* 삭제 확인 다이얼로그 */}
      <AlertDialog open={showDeleteDialog} onOpenChange={setShowDeleteDialog}>
        <AlertDialogContent>
          <AlertDialogHeader>
            <AlertDialogTitle>악성채권 삭제</AlertDialogTitle>
            <AlertDialogDescription>
              이 악성채권 기록을 삭제하시겠습니까? 이 작업은 취소할 수 없습니다.
            </AlertDialogDescription>
          </AlertDialogHeader>
          <AlertDialogFooter>
            <AlertDialogCancel>취소</AlertDialogCancel>
            <AlertDialogAction
              onClick={handleConfirmDelete}
              className="bg-red-600 hover:bg-red-700"
              disabled={isPending}
            >
              {isPending ? '삭제 중...' : '삭제'}
            </AlertDialogAction>
          </AlertDialogFooter>
        </AlertDialogContent>
      </AlertDialog>
    </>
  );
}