'use client'

/**
 * 국가 다중 선택 다이얼로그
 * 
 * @description
 * - 여러 국가를 선택할 수 있는 다이얼로그
 * - 체크박스를 통한 다중 선택
 * - 선택된 국가들을 상단에 표시
 * - 확인/취소 버튼으로 선택 확정
 */

import { useState, useCallback, useMemo, useTransition } from 'react'
import { Button } from '@/components/ui/button'
import { Dialog, DialogContent, DialogHeader, DialogTitle, DialogFooter } from '@/components/ui/dialog'
import { Input } from '@/components/ui/input'
import { Checkbox } from '@/components/ui/checkbox'
import { Badge } from '@/components/ui/badge'
import { Search, Check, X, Trash2 } from 'lucide-react'
import { 
  ColumnDef,
  flexRender,
  getCoreRowModel,
  getFilteredRowModel,
  getPaginationRowModel,
  getSortedRowModel,
  useReactTable,
  SortingState,
  ColumnFiltersState,
  VisibilityState,
  RowSelectionState,
} from '@tanstack/react-table'
import {
  Table,
  TableBody,
  TableCell,
  TableHead,
  TableHeader,
  TableRow,
} from '@/components/ui/table'
import { getNationCodes, NationCode, NationSearchOptions } from './nation-service'
import { toast } from 'sonner'

// 간단한 디바운스 함수
function debounce<T extends (...args: unknown[]) => void>(func: T, delay: number): T {
  let timeoutId: NodeJS.Timeout
  return ((...args: Parameters<T>) => {
    clearTimeout(timeoutId)
    timeoutId = setTimeout(() => func(...args), delay)
  }) as T
}

export interface NationMultiSelectorProps {
  open: boolean
  onOpenChange: (open: boolean) => void
  selectedNations?: NationCode[]
  onNationsSelect: (nations: NationCode[]) => void
  onConfirm?: (nations: NationCode[]) => void
  onCancel?: () => void
  searchOptions?: Partial<NationSearchOptions>
  title?: string
  description?: string
  maxSelection?: number
}

export function NationMultiSelector({ 
  open,
  onOpenChange,
  selectedNations = [], 
  onNationsSelect, 
  onConfirm,
  onCancel,
  searchOptions = {},
  title = "국가 다중 선택",
  description = "여러 국가를 선택하세요",
  maxSelection
}: NationMultiSelectorProps) {
  const [nations, setNations] = useState<NationCode[]>([])
  const [sorting, setSorting] = useState<SortingState>([])
  const [columnFilters, setColumnFilters] = useState<ColumnFiltersState>([])
  const [columnVisibility, setColumnVisibility] = useState<VisibilityState>({})
  const [rowSelection, setRowSelection] = useState<RowSelectionState>({})
  const [globalFilter, setGlobalFilter] = useState('')
  const [isPending, startTransition] = useTransition()
  const [tempSelectedNations, setTempSelectedNations] = useState<NationCode[]>(selectedNations)

  // searchOptions 안정화
  const stableSearchOptions = useMemo(() => ({
    limit: 100,
    ...searchOptions
  }), [searchOptions])

  // 국가 선택/해제 핸들러
  const handleNationToggle = useCallback((nation: NationCode, checked: boolean) => {
    setTempSelectedNations(prev => {
      if (checked) {
        // 최대 선택 수 제한 확인
        if (maxSelection && prev.length >= maxSelection) {
          toast.warning(`최대 ${maxSelection}개까지 선택할 수 있습니다.`)
          return prev
        }
        // 이미 선택된 국가인지 확인
        if (prev.some(n => n.CD === nation.CD)) {
          return prev
        }
        return [...prev, nation]
      } else {
        return prev.filter(n => n.CD !== nation.CD)
      }
    })
  }, [maxSelection])

  // 개별 국가 제거 핸들러
  const handleRemoveNation = useCallback((nationCode: string) => {
    setTempSelectedNations(prev => prev.filter(n => n.CD !== nationCode))
  }, [])

  // 모든 선택 해제 핸들러
  const handleClearAll = useCallback(() => {
    setTempSelectedNations([])
  }, [])

  // 확인 버튼 핸들러
  const handleConfirm = useCallback(() => {
    onNationsSelect(tempSelectedNations)
    onConfirm?.(tempSelectedNations)
    onOpenChange(false)
  }, [tempSelectedNations, onNationsSelect, onConfirm, onOpenChange])

  // 취소 버튼 핸들러
  const handleCancel = useCallback(() => {
    setTempSelectedNations(selectedNations)
    onCancel?.()
    onOpenChange(false)
  }, [selectedNations, onCancel, onOpenChange])

  // 테이블 컬럼 정의
  const columns: ColumnDef<NationCode>[] = useMemo(() => [
    {
      id: 'select',
      header: ({ table }) => (
        <Checkbox
          checked={table.getIsAllPageRowsSelected()}
          onCheckedChange={(value) => {
            if (value) {
              // 페이지의 모든 행을 선택하되, 최대 선택 수 제한 확인
              const currentPageRows = table.getRowModel().rows
              const newSelections = currentPageRows
                .map(row => row.original)
                .filter(nation => !tempSelectedNations.some(n => n.CD === nation.CD))
              
              if (maxSelection) {
                const remainingSlots = maxSelection - tempSelectedNations.length
                if (newSelections.length > remainingSlots) {
                  toast.warning(`최대 ${maxSelection}개까지 선택할 수 있습니다.`)
                  return
                }
              }
              
              setTempSelectedNations(prev => [...prev, ...newSelections])
            } else {
              // 페이지의 모든 행 선택 해제
              const currentPageNationCodes = table.getRowModel().rows.map(row => row.original.CD)
              setTempSelectedNations(prev => prev.filter(n => !currentPageNationCodes.includes(n.CD)))
            }
          }}
          aria-label="모든 행 선택"
        />
      ),
      cell: ({ row }) => {
        const isSelected = tempSelectedNations.some(n => n.CD === row.original.CD)
        return (
          <Checkbox
            checked={isSelected}
            onCheckedChange={(value) => handleNationToggle(row.original, !!value)}
            aria-label="행 선택"
          />
        )
      },
      enableSorting: false,
      enableHiding: false,
    },
    {
      accessorKey: 'CD',
      header: '2글자코드',
      cell: ({ row }) => (
        <div className="font-mono text-sm">{row.getValue('CD')}</div>
      ),
    },
    {
      accessorKey: 'CD2',
      header: '3글자코드',
      cell: ({ row }) => (
        <div className="font-mono text-sm">{row.getValue('CD2')}</div>
      ),
    },
    {
      accessorKey: 'CD3',
      header: '숫자코드',
      cell: ({ row }) => (
        <div className="font-mono text-sm">{row.getValue('CD3')}</div>
      ),
    },
    {
      accessorKey: 'CDNM',
      header: '한국어명',
      cell: ({ row }) => (
        <div className="max-w-[120px] truncate">{row.getValue('CDNM')}</div>
      ),
    },
    {
      accessorKey: 'GRP_DSC',
      header: '영문명',
      cell: ({ row }) => (
        <div className="max-w-[150px] truncate">{row.getValue('GRP_DSC')}</div>
      ),
    },
  ], [handleNationToggle, tempSelectedNations, maxSelection])

  // 국가 테이블 설정
  const table = useReactTable({
    data: nations,
    columns,
    onSortingChange: setSorting,
    onColumnFiltersChange: setColumnFilters,
    onColumnVisibilityChange: setColumnVisibility,
    onRowSelectionChange: setRowSelection,
    onGlobalFilterChange: setGlobalFilter,
    getCoreRowModel: getCoreRowModel(),
    getPaginationRowModel: getPaginationRowModel(),
    getSortedRowModel: getSortedRowModel(),
    getFilteredRowModel: getFilteredRowModel(),
    state: {
      sorting,
      columnFilters,
      columnVisibility,
      rowSelection,
      globalFilter,
    },
  })

  // 서버 액션을 사용한 국가 목록 로드
  const loadNations = useCallback(async (searchTerm?: string) => {
    startTransition(async () => {
      try {
        const result = await getNationCodes({
          ...stableSearchOptions,
          searchTerm: searchTerm
        })
        
        if (result.success) {
          setNations(result.data)
        } else {
          toast.error(result.error || '국가코드를 불러오는데 실패했습니다.')
          setNations([])
        }
      } catch (error) {
        console.error('국가코드 목록 로드 실패:', error)
        toast.error('국가코드를 불러오는 중 오류가 발생했습니다.')
        setNations([])
      }
    })
  }, [stableSearchOptions])

  // 디바운스된 검색
  const debouncedSearch = useMemo(
    () => debounce((searchTerm: string) => {
      loadNations(searchTerm)
    }, 300),
    [loadNations]
  )

  // 다이얼로그 열기/닫기 핸들러
  const handleDialogOpenChange = useCallback((newOpen: boolean) => {
    onOpenChange(newOpen)
    if (newOpen) {
      setTempSelectedNations(selectedNations)
      if (nations.length === 0) {
        loadNations()
      }
    }
  }, [onOpenChange, selectedNations, loadNations, nations.length])

  // 검색어 변경 핸들러
  const handleSearchChange = useCallback((value: string) => {
    setGlobalFilter(value)
    if (open) {
      debouncedSearch(value)
    }
  }, [open, debouncedSearch])

  return (
    <Dialog open={open} onOpenChange={handleDialogOpenChange}>
      <DialogContent className="max-w-6xl max-h-[85vh]">
        <DialogHeader>
          <DialogTitle>{title}</DialogTitle>
          <div className="text-sm text-muted-foreground">
            {description}
            {maxSelection && ` (최대 ${maxSelection}개)`}
          </div>
        </DialogHeader>
        
        <div className="space-y-4">
          {/* 선택된 국가들 표시 */}
          {tempSelectedNations.length > 0 && (
            <div className="space-y-2">
              <div className="flex items-center justify-between">
                <div className="text-sm font-medium">
                  선택된 국가 ({tempSelectedNations.length}개)
                  {maxSelection && ` / ${maxSelection}`}
                </div>
                <Button
                  variant="outline"
                  size="sm"
                  onClick={handleClearAll}
                  disabled={tempSelectedNations.length === 0}
                >
                  <Trash2 className="h-4 w-4 mr-2" />
                  모두 제거
                </Button>
              </div>
              <div className="flex flex-wrap gap-2 max-h-24 overflow-y-auto p-2 border rounded-md bg-muted/30">
                {tempSelectedNations.map((nation) => (
                  <Badge
                    key={nation.CD}
                    variant="secondary"
                    className="text-xs"
                  >
                    [{nation.CD}] {nation.CDNM}
                    <button
                      onClick={() => handleRemoveNation(nation.CD)}
                      className="ml-1 hover:text-destructive"
                    >
                      <X className="h-3 w-3" />
                    </button>
                  </Badge>
                ))}
              </div>
            </div>
          )}

          <div className="flex items-center space-x-2">
            <Search className="h-4 w-4" />
            <Input
              placeholder="국가코드, 국가명으로 검색..."
              value={globalFilter}
              onChange={(e) => handleSearchChange(e.target.value)}
              className="flex-1"
            />
          </div>

          {isPending ? (
            <div className="flex justify-center py-8">
              <div className="text-sm text-muted-foreground">국가코드를 불러오는 중...</div>
            </div>
          ) : (
            <div className="border rounded-md">
              <Table>
                <TableHeader>
                  {table.getHeaderGroups().map((headerGroup) => (
                    <TableRow key={headerGroup.id}>
                      {headerGroup.headers.map((header) => (
                        <TableHead key={header.id}>
                          {header.isPlaceholder
                            ? null
                            : flexRender(
                                header.column.columnDef.header,
                                header.getContext()
                              )}
                        </TableHead>
                      ))}
                    </TableRow>
                  ))}
                </TableHeader>
                <TableBody>
                  {table.getRowModel().rows?.length ? (
                    table.getRowModel().rows.map((row) => {
                      const isSelected = tempSelectedNations.some(n => n.CD === row.original.CD)
                      return (
                        <TableRow
                          key={row.id}
                          data-state={isSelected && "selected"}
                          className={`cursor-pointer hover:bg-muted/50 ${
                            isSelected ? 'bg-muted/30' : ''
                          }`}
                          onClick={() => {
                            const isCurrentlySelected = tempSelectedNations.some(n => n.CD === row.original.CD)
                            handleNationToggle(row.original, !isCurrentlySelected)
                          }}
                        >
                          {row.getVisibleCells().map((cell) => (
                            <TableCell key={cell.id}>
                              {flexRender(
                                cell.column.columnDef.cell,
                                cell.getContext()
                              )}
                            </TableCell>
                          ))}
                        </TableRow>
                      )
                    })
                  ) : (
                    <TableRow>
                      <TableCell
                        colSpan={columns.length}
                        className="h-24 text-center"
                      >
                        검색 결과가 없습니다.
                      </TableCell>
                    </TableRow>
                  )}
                </TableBody>
              </Table>
            </div>
          )}

          <div className="flex items-center justify-between">
            <div className="text-sm text-muted-foreground">
              총 {table.getFilteredRowModel().rows.length}개 국가
            </div>
            <div className="flex items-center space-x-2">
              <Button
                variant="outline"
                size="sm"
                onClick={() => table.previousPage()}
                disabled={!table.getCanPreviousPage()}
              >
                이전
              </Button>
              <div className="text-sm">
                {table.getState().pagination.pageIndex + 1} / {table.getPageCount()}
              </div>
              <Button
                variant="outline"
                size="sm"
                onClick={() => table.nextPage()}
                disabled={!table.getCanNextPage()}
              >
                다음
              </Button>
            </div>
          </div>
        </div>

        <DialogFooter>
          <Button variant="outline" onClick={handleCancel}>
            <X className="h-4 w-4 mr-2" />
            취소
          </Button>
          <Button onClick={handleConfirm}>
            <Check className="h-4 w-4 mr-2" />
            확인 ({tempSelectedNations.length}개 선택)
          </Button>
        </DialogFooter>
      </DialogContent>
    </Dialog>
  )
}
