"use client";

import { useState, useCallback, useEffect } from "react";
import { DndProvider } from "react-dnd";
import { HTML5Backend } from "react-dnd-html5-backend";
import { ArrowLeft, Save, Smartphone, Tablet, Columns2, RotateCcw } from "lucide-react";
import { Button } from "@/components/ui/button";
import { Tabs, TabsList, TabsTrigger } from "@/components/ui/tabs";
import {
  ResizableHandle,
  ResizablePanel,
  ResizablePanelGroup,
} from "@/components/ui/resizable";
import { toast } from "sonner";

import { PopCanvas } from "./PopCanvas";
import { PopPanel } from "./panels/PopPanel";
import {
  PopLayoutData,
  PopSectionData,
  PopComponentData,
  PopComponentType,
  createEmptyPopLayout,
  createPopSection,
  createPopComponent,
  GridPosition,
} from "./types/pop-layout";
import { screenApi } from "@/lib/api/screen";
import { ScreenDefinition } from "@/types/screen";

// 디바이스 타입
type DeviceType = "mobile" | "tablet";

interface PopDesignerProps {
  selectedScreen: ScreenDefinition;
  onBackToList: () => void;
  onScreenUpdate?: (updatedScreen: Partial<ScreenDefinition>) => void;
}

export default function PopDesigner({
  selectedScreen,
  onBackToList,
  onScreenUpdate,
}: PopDesignerProps) {
  // 레이아웃 상태
  const [layout, setLayout] = useState<PopLayoutData>(createEmptyPopLayout());
  const [isLoading, setIsLoading] = useState(true);
  const [isSaving, setIsSaving] = useState(false);
  const [hasChanges, setHasChanges] = useState(false);

  // 디바이스 프리뷰 상태
  const [activeDevice, setActiveDevice] = useState<DeviceType>("tablet");
  const [showBothDevices, setShowBothDevices] = useState(false);
  const [isLandscape, setIsLandscape] = useState(true);

  // 선택된 섹션/컴포넌트
  const [selectedSectionId, setSelectedSectionId] = useState<string | null>(null);
  const [selectedComponentId, setSelectedComponentId] = useState<string | null>(null);

  // 선택된 섹션 객체
  const selectedSection = selectedSectionId
    ? layout.sections.find((s) => s.id === selectedSectionId) || null
    : null;

  // 레이아웃 로드
  // API는 이미 언래핑된 layout_data를 반환하므로 response 자체가 레이아웃 데이터
  useEffect(() => {
    const loadLayout = async () => {
      if (!selectedScreen?.screenId) return;

      setIsLoading(true);
      try {
        // API가 layout_data 내용을 직접 반환함 (언래핑된 상태)
        const loadedLayout = await screenApi.getLayoutPop(selectedScreen.screenId);

        if (loadedLayout && loadedLayout.version === "pop-1.0") {
          // 유효한 POP 레이아웃
          setLayout(loadedLayout as PopLayoutData);
          console.log("POP 레이아웃 로드 성공:", loadedLayout.sections?.length || 0, "개 섹션");
        } else if (loadedLayout && loadedLayout.sections) {
          // 버전 태그 없지만 sections 구조가 있으면 사용
          console.warn("버전 태그 없음, sections 구조 감지하여 사용");
          setLayout({
            ...createEmptyPopLayout(),
            ...loadedLayout,
            version: "pop-1.0",
          } as PopLayoutData);
        } else {
          // 레이아웃 없음 - 빈 레이아웃 생성
          console.log("POP 레이아웃 없음, 빈 레이아웃 생성");
          setLayout(createEmptyPopLayout());
        }
      } catch (error) {
        console.error("레이아웃 로드 실패:", error);
        toast.error("레이아웃을 불러오는데 실패했습니다");
        setLayout(createEmptyPopLayout());
      } finally {
        setIsLoading(false);
      }
    };

    loadLayout();
  }, [selectedScreen?.screenId]);

  // 저장
  const handleSave = useCallback(async () => {
    if (!selectedScreen?.screenId) return;

    setIsSaving(true);
    try {
      await screenApi.saveLayoutPop(selectedScreen.screenId, layout);
      toast.success("저장되었습니다");
      setHasChanges(false);
    } catch (error) {
      console.error("저장 실패:", error);
      toast.error("저장에 실패했습니다");
    } finally {
      setIsSaving(false);
    }
  }, [selectedScreen?.screenId, layout]);

  // 섹션 드롭 (팔레트 → 캔버스)
  const handleDropSection = useCallback((gridPosition: GridPosition) => {
    const newId = `section-${Date.now()}`;
    const newSection = createPopSection(newId, gridPosition);

    setLayout((prev) => ({
      ...prev,
      sections: [...prev.sections, newSection],
    }));
    setSelectedSectionId(newId);
    setHasChanges(true);
  }, []);

  // 컴포넌트 드롭 (팔레트 → 섹션)
  const handleDropComponent = useCallback(
    (sectionId: string, type: PopComponentType, gridPosition: GridPosition) => {
      const newId = `${type}-${Date.now()}`;
      const newComponent = createPopComponent(newId, type, gridPosition);

      setLayout((prev) => ({
        ...prev,
        sections: prev.sections.map((s) =>
          s.id === sectionId
            ? { ...s, components: [...s.components, newComponent] }
            : s
        ),
      }));
      setSelectedComponentId(newId);
      setHasChanges(true);
    },
    []
  );

  // 섹션 업데이트
  const handleUpdateSection = useCallback(
    (id: string, updates: Partial<PopSectionData>) => {
      setLayout((prev) => ({
        ...prev,
        sections: prev.sections.map((s) =>
          s.id === id ? { ...s, ...updates } : s
        ),
      }));
      setHasChanges(true);
    },
    []
  );

  // 섹션 삭제
  const handleDeleteSection = useCallback((id: string) => {
    setLayout((prev) => ({
      ...prev,
      sections: prev.sections.filter((s) => s.id !== id),
    }));
    setSelectedSectionId(null);
    setHasChanges(true);
  }, []);

  // 레이아웃 변경 (드래그/리사이즈)
  const handleLayoutChange = useCallback((sections: PopSectionData[]) => {
    setLayout((prev) => ({
      ...prev,
      sections,
    }));
    setHasChanges(true);
  }, []);

  // 컴포넌트 업데이트
  const handleUpdateComponent = useCallback(
    (sectionId: string, componentId: string, updates: Partial<PopComponentData>) => {
      setLayout((prev) => ({
        ...prev,
        sections: prev.sections.map((s) =>
          s.id === sectionId
            ? {
                ...s,
                components: s.components.map((c) =>
                  c.id === componentId ? { ...c, ...updates } : c
                ),
              }
            : s
        ),
      }));
      setHasChanges(true);
    },
    []
  );

  // 컴포넌트 삭제
  const handleDeleteComponent = useCallback(
    (sectionId: string, componentId: string) => {
      setLayout((prev) => ({
        ...prev,
        sections: prev.sections.map((s) =>
          s.id === sectionId
            ? { ...s, components: s.components.filter((c) => c.id !== componentId) }
            : s
        ),
      }));
      setSelectedComponentId(null);
      setHasChanges(true);
    },
    []
  );

  // 뒤로가기
  const handleBack = useCallback(() => {
    if (hasChanges) {
      if (confirm("저장하지 않은 변경사항이 있습니다. 나가시겠습니까?")) {
        onBackToList();
      }
    } else {
      onBackToList();
    }
  }, [hasChanges, onBackToList]);

  if (isLoading) {
    return (
      <div className="flex h-screen items-center justify-center">
        <div className="text-muted-foreground">로딩 중...</div>
      </div>
    );
  }

  return (
    <DndProvider backend={HTML5Backend}>
      <div className="flex h-screen flex-col bg-background">
        {/* 툴바 */}
        <div className="flex h-12 items-center justify-between border-b px-4">
          {/* 왼쪽: 뒤로가기 + 화면명 */}
          <div className="flex items-center gap-3">
            <Button variant="ghost" size="sm" onClick={handleBack}>
              <ArrowLeft className="mr-1 h-4 w-4" />
              목록
            </Button>
            <span className="text-sm font-medium">
              {selectedScreen?.screenName || "POP 화면"}
            </span>
            {hasChanges && (
              <span className="text-xs text-orange-500">*변경됨</span>
            )}
          </div>

          {/* 중앙: 디바이스 전환 */}
          <div className="flex items-center gap-2">
            <Tabs
              value={activeDevice}
              onValueChange={(v) => setActiveDevice(v as DeviceType)}
            >
              <TabsList className="h-8">
                <TabsTrigger value="tablet" className="h-7 px-3 text-xs">
                  <Tablet className="mr-1 h-3.5 w-3.5" />
                  태블릿
                </TabsTrigger>
                <TabsTrigger value="mobile" className="h-7 px-3 text-xs">
                  <Smartphone className="mr-1 h-3.5 w-3.5" />
                  모바일
                </TabsTrigger>
              </TabsList>
            </Tabs>

            <Button
              variant="ghost"
              size="sm"
              onClick={() => setIsLandscape(!isLandscape)}
              title={isLandscape ? "세로 모드로 전환" : "가로 모드로 전환"}
            >
              <RotateCcw className="h-4 w-4" />
            </Button>

            <Button
              variant={showBothDevices ? "secondary" : "ghost"}
              size="sm"
              onClick={() => setShowBothDevices(!showBothDevices)}
              title="나란히 보기"
            >
              <Columns2 className="h-4 w-4" />
            </Button>
          </div>

          {/* 오른쪽: 저장 */}
          <div>
            <Button
              size="sm"
              onClick={handleSave}
              disabled={isSaving || !hasChanges}
            >
              <Save className="mr-1 h-4 w-4" />
              {isSaving ? "저장 중..." : "저장"}
            </Button>
          </div>
        </div>

        {/* 메인 영역: 리사이즈 가능한 패널 */}
        <ResizablePanelGroup direction="horizontal" className="flex-1">
          {/* 왼쪽: 패널 (컴포넌트/편집 탭) */}
          <ResizablePanel
            defaultSize={20}
            minSize={15}
            maxSize={30}
            className="border-r"
          >
            <PopPanel
              layout={layout}
              selectedSectionId={selectedSectionId}
              selectedSection={selectedSection}
              onUpdateSection={handleUpdateSection}
              onDeleteSection={handleDeleteSection}
              activeDevice={activeDevice}
            />
          </ResizablePanel>

          <ResizableHandle withHandle />

          {/* 오른쪽: 캔버스 */}
          <ResizablePanel defaultSize={80}>
            <PopCanvas
              layout={layout}
              activeDevice={activeDevice}
              showBothDevices={showBothDevices}
              isLandscape={isLandscape}
              selectedSectionId={selectedSectionId}
              selectedComponentId={selectedComponentId}
              onSelectSection={setSelectedSectionId}
              onSelectComponent={setSelectedComponentId}
              onUpdateSection={handleUpdateSection}
              onDeleteSection={handleDeleteSection}
              onLayoutChange={handleLayoutChange}
              onDropSection={handleDropSection}
              onDropComponent={handleDropComponent}
              onUpdateComponent={handleUpdateComponent}
              onDeleteComponent={handleDeleteComponent}
            />
          </ResizablePanel>
        </ResizablePanelGroup>
      </div>
    </DndProvider>
  );
}