"use client";

import { useState, useEffect, useCallback, useMemo } from "react";
import {
  Dialog,
  DialogContent,
  DialogHeader,
  DialogTitle,
  DialogDescription,
  DialogFooter,
} from "@/components/ui/dialog";
import { Button } from "@/components/ui/button";
import { Checkbox } from "@/components/ui/checkbox";
import { Input } from "@/components/ui/input";
import { ScrollArea } from "@/components/ui/scroll-area";
import { Loader2, Search, ChevronRight, ChevronDown, FolderOpen, FileText } from "lucide-react";
import { menuApi } from "@/lib/api/menu";
import { MenuItem } from "@/types/menu";
import { cn } from "@/lib/utils";

interface MenuSelectModalProps {
  isOpen: boolean;
  onClose: () => void;
  onConfirm: (menuObjids: number[]) => void;
  selectedMenuObjids?: number[];
}

// 트리 구조의 메뉴 노드
interface MenuTreeNode {
  objid: string;
  menuNameKor: string;
  menuUrl: string;
  level: number;
  children: MenuTreeNode[];
  parentObjId: string;
}

export function MenuSelectModal({
  isOpen,
  onClose,
  onConfirm,
  selectedMenuObjids = [],
}: MenuSelectModalProps) {
  const [menus, setMenus] = useState<MenuItem[]>([]);
  const [isLoading, setIsLoading] = useState(false);
  const [searchText, setSearchText] = useState("");
  const [selectedIds, setSelectedIds] = useState<Set<number>>(new Set(selectedMenuObjids));
  const [expandedIds, setExpandedIds] = useState<Set<string>>(new Set());

  // 초기 선택 상태 동기화
  useEffect(() => {
    if (isOpen) {
      setSelectedIds(new Set(selectedMenuObjids));
    }
  }, [isOpen, selectedMenuObjids]);

  // 메뉴 목록 로드
  useEffect(() => {
    if (isOpen) {
      fetchMenus();
    }
  }, [isOpen]);

  const fetchMenus = async () => {
    setIsLoading(true);
    try {
      const response = await menuApi.getUserMenus();
      if (response.success && response.data) {
        setMenus(response.data);
        // 처음 2레벨까지 자동 확장
        const initialExpanded = new Set<string>();
        response.data.forEach((menu) => {
          const level = menu.lev || menu.LEV || 1;
          if (level <= 2) {
            initialExpanded.add(menu.objid || menu.OBJID || "");
          }
        });
        setExpandedIds(initialExpanded);
      }
    } catch (error) {
      console.error("메뉴 로드 오류:", error);
    } finally {
      setIsLoading(false);
    }
  };

  // 메뉴 트리 구조 생성
  const menuTree = useMemo(() => {
    const menuMap = new Map<string, MenuTreeNode>();
    const rootMenus: MenuTreeNode[] = [];

    // 모든 메뉴를 노드로 변환
    menus.forEach((menu) => {
      const objid = menu.objid || menu.OBJID || "";
      const parentObjId = menu.parentObjId || menu.PARENT_OBJ_ID || "";
      const menuNameKor = menu.menuNameKor || menu.MENU_NAME_KOR || menu.translated_name || menu.TRANSLATED_NAME || "";
      const menuUrl = menu.menuUrl || menu.MENU_URL || "";
      const level = menu.lev || menu.LEV || 1;

      menuMap.set(objid, {
        objid,
        menuNameKor,
        menuUrl,
        level,
        children: [],
        parentObjId,
      });
    });

    // 부모-자식 관계 설정
    menus.forEach((menu) => {
      const objid = menu.objid || menu.OBJID || "";
      const parentObjId = menu.parentObjId || menu.PARENT_OBJ_ID || "";
      const node = menuMap.get(objid);

      if (!node) return;

      // 최상위 메뉴인지 확인 (parent가 없거나, 특정 루트 ID)
      const parent = menuMap.get(parentObjId);
      if (parent) {
        parent.children.push(node);
      } else {
        rootMenus.push(node);
      }
    });

    // 자식 메뉴 정렬
    const sortChildren = (nodes: MenuTreeNode[]) => {
      nodes.sort((a, b) => a.menuNameKor.localeCompare(b.menuNameKor, "ko"));
      nodes.forEach((node) => sortChildren(node.children));
    };
    sortChildren(rootMenus);

    return rootMenus;
  }, [menus]);

  // 검색 필터링
  const filteredTree = useMemo(() => {
    if (!searchText.trim()) return menuTree;

    const searchLower = searchText.toLowerCase();

    // 검색어에 맞는 노드와 그 조상 노드를 포함
    const filterNodes = (nodes: MenuTreeNode[]): MenuTreeNode[] => {
      return nodes
        .map((node) => {
          const filteredChildren = filterNodes(node.children);
          const matches = node.menuNameKor.toLowerCase().includes(searchLower);

          if (matches || filteredChildren.length > 0) {
            return {
              ...node,
              children: filteredChildren,
            };
          }
          return null;
        })
        .filter((node): node is MenuTreeNode => node !== null);
    };

    return filterNodes(menuTree);
  }, [menuTree, searchText]);

  // 체크박스 토글
  const toggleSelect = useCallback((objid: string) => {
    const numericId = Number(objid);
    setSelectedIds((prev) => {
      const next = new Set(prev);
      if (next.has(numericId)) {
        next.delete(numericId);
      } else {
        next.add(numericId);
      }
      return next;
    });
  }, []);

  // 확장/축소 토글
  const toggleExpand = useCallback((objid: string) => {
    setExpandedIds((prev) => {
      const next = new Set(prev);
      if (next.has(objid)) {
        next.delete(objid);
      } else {
        next.add(objid);
      }
      return next;
    });
  }, []);

  // 확인 버튼 클릭
  const handleConfirm = () => {
    onConfirm(Array.from(selectedIds));
    onClose();
  };

  // 메뉴 노드 렌더링
  const renderMenuNode = (node: MenuTreeNode, depth: number = 0) => {
    const hasChildren = node.children.length > 0;
    const isExpanded = expandedIds.has(node.objid);
    const isSelected = selectedIds.has(Number(node.objid));

    return (
      <div key={node.objid}>
        <div
          className={cn(
            "flex items-center gap-2 py-1.5 px-2 rounded-md hover:bg-muted/50 cursor-pointer",
            isSelected && "bg-primary/10",
          )}
          style={{ paddingLeft: `${depth * 20 + 8}px` }}
          onClick={() => toggleSelect(node.objid)}
        >
          {/* 확장/축소 버튼 */}
          {hasChildren ? (
            <button
              type="button"
              onClick={(e) => {
                e.stopPropagation();
                toggleExpand(node.objid);
              }}
              className="p-0.5 hover:bg-muted rounded"
            >
              {isExpanded ? (
                <ChevronDown className="h-4 w-4 text-muted-foreground" />
              ) : (
                <ChevronRight className="h-4 w-4 text-muted-foreground" />
              )}
            </button>
          ) : (
            <div className="w-5" />
          )}

          {/* 체크박스 - 모든 메뉴에서 선택 가능 */}
          <Checkbox
            checked={isSelected}
            onCheckedChange={() => toggleSelect(node.objid)}
            onClick={(e) => e.stopPropagation()}
          />

          {/* 아이콘 */}
          {hasChildren ? (
            <FolderOpen className="h-4 w-4 text-amber-500" />
          ) : (
            <FileText className="h-4 w-4 text-muted-foreground" />
          )}

          {/* 메뉴명 */}
          <span
            className={cn(
              "text-sm flex-1 truncate",
              isSelected && "font-medium text-primary",
            )}
          >
            {node.menuNameKor}
          </span>
        </div>

        {/* 자식 메뉴 */}
        {hasChildren && isExpanded && (
          <div>{node.children.map((child) => renderMenuNode(child, depth + 1))}</div>
        )}
      </div>
    );
  };

  return (
    <Dialog open={isOpen} onOpenChange={onClose}>
      <DialogContent className="max-w-[600px] max-h-[80vh] flex flex-col">
        <DialogHeader>
          <DialogTitle>사용 메뉴 선택</DialogTitle>
          <DialogDescription>
            이 리포트를 사용할 메뉴를 선택하세요. 선택한 메뉴에서 이 리포트를 사용할 수 있습니다.
          </DialogDescription>
        </DialogHeader>

        {/* 검색 */}
        <div className="relative">
          <Search className="absolute left-3 top-1/2 -translate-y-1/2 h-4 w-4 text-muted-foreground" />
          <Input
            placeholder="메뉴 검색..."
            value={searchText}
            onChange={(e) => setSearchText(e.target.value)}
            className="pl-10"
          />
        </div>

        {/* 선택된 메뉴 수 */}
        <div className="text-sm text-muted-foreground">
          {selectedIds.size}개 메뉴 선택됨
        </div>

        {/* 메뉴 트리 */}
        <ScrollArea className="flex-1 border rounded-md">
          {isLoading ? (
            <div className="flex items-center justify-center py-8">
              <Loader2 className="h-6 w-6 animate-spin text-muted-foreground" />
              <span className="ml-2 text-sm text-muted-foreground">메뉴 로드 중...</span>
            </div>
          ) : filteredTree.length === 0 ? (
            <div className="flex items-center justify-center py-8 text-sm text-muted-foreground">
              {searchText ? "검색 결과가 없습니다." : "표시할 메뉴가 없습니다."}
            </div>
          ) : (
            <div className="p-2">{filteredTree.map((node) => renderMenuNode(node))}</div>
          )}
        </ScrollArea>

        <DialogFooter>
          <Button variant="outline" onClick={onClose}>
            취소
          </Button>
          <Button onClick={handleConfirm}>
            확인 ({selectedIds.size}개 선택)
          </Button>
        </DialogFooter>
      </DialogContent>
    </Dialog>
  );
}