"use client";

import { useState, useEffect, useCallback, useMemo, useRef } from "react";
import {
  Dialog,
  DialogContent,
  DialogHeader,
  DialogTitle,
  DialogDescription,
  DialogFooter,
} from "@/components/ui/dialog";
import { Button } from "@/components/ui/button";
import { useUnsavedChangesGuard, UnsavedChangesDialog } from "@/components/common/UnsavedChangesGuard";
import { Checkbox } from "@/components/ui/checkbox";
import { Input } from "@/components/ui/input";
import { ScrollArea } from "@/components/ui/scroll-area";
import { Loader2, Search, 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[];
}

interface FlatMenuEntry {
  objid: string;
  menuNameKor: string;
  parentNameKor: 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 initialSelectionRef = useRef<string>("");

  const hasChanges = useCallback(() => {
    const currentSelection = JSON.stringify(Array.from(selectedIds).sort());
    return currentSelection !== initialSelectionRef.current;
  }, [selectedIds]);

  const guard = useUnsavedChangesGuard({
    hasChanges,
    onClose,
    description: "변경된 선택 내용이 저장되지 않습니다. 정말 닫으시겠습니까?",
  });

  useEffect(() => {
    if (isOpen) {
      setSelectedIds(new Set(selectedMenuObjids));
      initialSelectionRef.current = JSON.stringify(Array.from(new Set(selectedMenuObjids)).sort());
    }
  }, [isOpen, selectedMenuObjids]);

  useEffect(() => {
    if (isOpen) {
      fetchMenus();
    }
  }, [isOpen]);

  const fetchMenus = async () => {
    setIsLoading(true);
    try {
      const response = await menuApi.getUserMenus();
      if (response.success && response.data) {
        setMenus(response.data as MenuItem[]);
      }
    } catch (error) {
      console.error("메뉴 로드 오류:", error);
    } finally {
      setIsLoading(false);
    }
  };

  const level2List = useMemo<FlatMenuEntry[]>(() => {
    const byObjid = new Map<string, any>();
    menus.forEach((menu: any) => {
      const objid = String(menu.objid || menu.OBJID || "");
      byObjid.set(objid, menu);
    });

    return menus
      .filter((menu: any) => Number(menu.lev ?? menu.LEV ?? 0) === 2)
      .map((menu: any) => {
        const objid = String(menu.objid || menu.OBJID || "");
        const parentObjId = String(menu.parent_obj_id || menu.PARENT_OBJ_ID || "");
        const parent = byObjid.get(parentObjId);
        const parentNameKor = parent
          ? parent.menu_name_kor || parent.MENU_NAME_KOR || parent.translated_name || parent.TRANSLATED_NAME || ""
          : "";
        const menuNameKor = menu.menu_name_kor || menu.MENU_NAME_KOR || menu.translated_name || menu.TRANSLATED_NAME || "";
        return { objid, menuNameKor, parentNameKor };
      })
      .sort((a, b) => a.menuNameKor.localeCompare(b.menuNameKor, "ko"));
  }, [menus]);

  const filteredList = useMemo(() => {
    if (!searchText.trim()) return level2List;
    const q = searchText.toLowerCase();
    return level2List.filter(
      (m) =>
        m.menuNameKor.toLowerCase().includes(q) || m.parentNameKor.toLowerCase().includes(q),
    );
  }, [level2List, searchText]);

  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;
    });
  }, []);

  const handleConfirm = () => {
    onConfirm(Array.from(selectedIds));
    onClose();
  };

  return (
    <>
      <Dialog open={isOpen} onOpenChange={guard.handleOpenChange}>
        <DialogContent className="flex h-[80vh] max-w-[600px] flex-col overflow-hidden">
          <DialogHeader>
            <DialogTitle>사용 메뉴 선택 (대분류)</DialogTitle>
            <DialogDescription>
              이 리포트가 속할 2레벨(대분류) 메뉴를 선택하세요. 선택한 대분류의 하위 메뉴에서 이 리포트를 사용할 수
              있습니다. 아무 것도 선택하지 않으면 모든 메뉴에서 보입니다.
            </DialogDescription>
          </DialogHeader>

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

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

          <ScrollArea className="min-h-0 flex-1 rounded-md border">
            {isLoading ? (
              <div className="flex items-center justify-center py-8">
                <Loader2 className="text-muted-foreground h-6 w-6 animate-spin" />
                <span className="text-muted-foreground ml-2 text-sm">메뉴 로드 중...</span>
              </div>
            ) : filteredList.length === 0 ? (
              <div className="text-muted-foreground flex items-center justify-center py-8 text-sm">
                {searchText ? "검색 결과가 없습니다." : "표시할 2레벨 메뉴가 없습니다."}
              </div>
            ) : (
              <div className="p-2">
                {filteredList.map((node) => {
                  const isSelected = selectedIds.has(Number(node.objid));
                  return (
                    <div
                      key={node.objid}
                      className={cn(
                        "hover:bg-muted/50 flex cursor-pointer items-center gap-2 rounded-md px-2 py-2",
                        isSelected && "bg-primary/10",
                      )}
                      onClick={() => toggleSelect(node.objid)}
                    >
                      <Checkbox
                        checked={isSelected}
                        onCheckedChange={() => toggleSelect(node.objid)}
                        onClick={(e) => e.stopPropagation()}
                      />
                      <FileText className="text-muted-foreground h-4 w-4" />
                      <span className={cn("flex-1 truncate text-sm", isSelected && "text-primary font-medium")}>
                        {node.menuNameKor}
                      </span>
                      {node.parentNameKor && (
                        <span className="text-muted-foreground text-xs">{node.parentNameKor}</span>
                      )}
                    </div>
                  );
                })}
              </div>
            )}
          </ScrollArea>

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

      <UnsavedChangesDialog guard={guard} />
    </>
  );
}