"use client";

import { useCallback, useMemo, useRef } from "react";
import { useDrop } from "react-dnd";
import GridLayout, { Layout } from "react-grid-layout";
import { cn } from "@/lib/utils";
import {
  PopLayoutData,
  PopSectionData,
  PopComponentData,
  PopComponentType,
  GridPosition,
} from "./types/pop-layout";
import { DND_ITEM_TYPES, DragItemSection, DragItemComponent } from "./panels/PopPanel";
import { GripVertical, Trash2 } from "lucide-react";
import { Button } from "@/components/ui/button";
import { SectionGrid } from "./SectionGrid";

import "react-grid-layout/css/styles.css";
import "react-resizable/css/styles.css";

type DeviceType = "mobile" | "tablet";

// 디바이스별 캔버스 크기 (dp)
const DEVICE_SIZES = {
  mobile: {
    portrait: { width: 360, height: 640 },
    landscape: { width: 640, height: 360 },
  },
  tablet: {
    portrait: { width: 768, height: 1024 },
    landscape: { width: 1024, height: 768 },
  },
} as const;

interface PopCanvasProps {
  layout: PopLayoutData;
  activeDevice: DeviceType;
  showBothDevices: boolean;
  isLandscape: boolean;
  selectedSectionId: string | null;
  selectedComponentId: string | null;
  onSelectSection: (id: string | null) => void;
  onSelectComponent: (id: string | null) => void;
  onUpdateSection: (id: string, updates: Partial<PopSectionData>) => void;
  onDeleteSection: (id: string) => void;
  onLayoutChange: (sections: PopSectionData[]) => void;
  onDropSection: (gridPosition: GridPosition) => void;
  onDropComponent: (sectionId: string, type: PopComponentType, gridPosition: GridPosition) => void;
  onUpdateComponent: (sectionId: string, componentId: string, updates: Partial<PopComponentData>) => void;
  onDeleteComponent: (sectionId: string, componentId: string) => void;
}

export function PopCanvas({
  layout,
  activeDevice,
  showBothDevices,
  isLandscape,
  selectedSectionId,
  selectedComponentId,
  onSelectSection,
  onSelectComponent,
  onUpdateSection,
  onDeleteSection,
  onLayoutChange,
  onDropSection,
  onDropComponent,
  onUpdateComponent,
  onDeleteComponent,
}: PopCanvasProps) {
  const { canvasGrid, sections } = layout;

  // GridLayout용 레이아웃 변환
  const gridLayoutItems: Layout[] = useMemo(() => {
    return sections.map((section) => ({
      i: section.id,
      x: section.grid.col - 1,
      y: section.grid.row - 1,
      w: section.grid.colSpan,
      h: section.grid.rowSpan,
      minW: 2,  // 최소 너비 2칸
      minH: 1,  // 최소 높이 1행 (20px) - 헤더만 보임
    }));
  }, [sections]);

  // 드래그/리사이즈 완료 핸들러 (onDragStop, onResizeStop 사용)
  const handleDragResizeStop = useCallback(
    (layout: Layout[], oldItem: Layout, newItem: Layout) => {
      const section = sections.find((s) => s.id === newItem.i);
      if (!section) return;

      const newGrid: GridPosition = {
        col: newItem.x + 1,
        row: newItem.y + 1,
        colSpan: newItem.w,
        rowSpan: newItem.h,
      };

      // 변경된 경우에만 업데이트
      if (
        section.grid.col !== newGrid.col ||
        section.grid.row !== newGrid.row ||
        section.grid.colSpan !== newGrid.colSpan ||
        section.grid.rowSpan !== newGrid.rowSpan
      ) {
        const updatedSections = sections.map((s) =>
          s.id === newItem.i ? { ...s, grid: newGrid } : s
        );
        onLayoutChange(updatedSections);
      }
    },
    [sections, onLayoutChange]
  );

  // 디바이스 프레임 렌더링
  const renderDeviceFrame = (device: DeviceType) => {
    const orientation = isLandscape ? "landscape" : "portrait";
    const size = DEVICE_SIZES[device][orientation];
    const isActive = device === activeDevice;

    const cols = canvasGrid.columns;
    const rowHeight = canvasGrid.rowHeight;
    const margin: [number, number] = [canvasGrid.gap, canvasGrid.gap];

    const sizeLabel = `${size.width}x${size.height}`;
    const deviceLabel =
      device === "mobile" ? `모바일 (${sizeLabel})` : `태블릿 (${sizeLabel})`;

    return (
      <div
        className={cn(
          "relative rounded-[2rem] border-4 bg-white shadow-xl transition-all",
          isActive ? "border-primary" : "border-gray-300",
          device === "mobile" ? "rounded-[1.5rem]" : "rounded-[2rem]"
        )}
        style={{
          width: size.width,
          height: size.height,
        }}
      >
        {/* 디바이스 라벨 */}
        <div
          className={cn(
            "absolute -top-6 left-1/2 -translate-x-1/2 whitespace-nowrap text-xs font-medium",
            isActive ? "text-primary" : "text-muted-foreground"
          )}
        >
          {deviceLabel}
        </div>

        {/* 드롭 영역 */}
        <CanvasDropZone
          device={device}
          isActive={isActive}
          size={size}
          cols={cols}
          rowHeight={rowHeight}
          margin={margin}
          sections={sections}
          gridLayoutItems={gridLayoutItems}
          selectedSectionId={selectedSectionId}
          selectedComponentId={selectedComponentId}
          onSelectSection={onSelectSection}
          onSelectComponent={onSelectComponent}
          onDragResizeStop={handleDragResizeStop}
          onDropSection={onDropSection}
          onDropComponent={onDropComponent}
          onDeleteSection={onDeleteSection}
          onUpdateComponent={onUpdateComponent}
          onDeleteComponent={onDeleteComponent}
        />
      </div>
    );
  };

  return (
    <div className="flex h-full items-center justify-center gap-8 overflow-auto bg-gray-50 p-8">
      {showBothDevices ? (
        <>
          {renderDeviceFrame("tablet")}
          {renderDeviceFrame("mobile")}
        </>
      ) : (
        renderDeviceFrame(activeDevice)
      )}
    </div>
  );
}

// 캔버스 드롭 영역
interface CanvasDropZoneProps {
  device: DeviceType;
  isActive: boolean;
  size: { width: number; height: number };
  cols: number;
  rowHeight: number;
  margin: [number, number];
  sections: PopSectionData[];
  gridLayoutItems: Layout[];
  selectedSectionId: string | null;
  selectedComponentId: string | null;
  onSelectSection: (id: string | null) => void;
  onSelectComponent: (id: string | null) => void;
  onDragResizeStop: (layout: Layout[], oldItem: Layout, newItem: Layout) => void;
  onDropSection: (gridPosition: GridPosition) => void;
  onDropComponent: (sectionId: string, type: PopComponentType, gridPosition: GridPosition) => void;
  onDeleteSection: (id: string) => void;
  onUpdateComponent: (sectionId: string, componentId: string, updates: Partial<PopComponentData>) => void;
  onDeleteComponent: (sectionId: string, componentId: string) => void;
}

function CanvasDropZone({
  device,
  isActive,
  size,
  cols,
  rowHeight,
  margin,
  sections,
  gridLayoutItems,
  selectedSectionId,
  selectedComponentId,
  onSelectSection,
  onSelectComponent,
  onDragResizeStop,
  onDropSection,
  onDropComponent,
  onDeleteSection,
  onUpdateComponent,
  onDeleteComponent,
}: CanvasDropZoneProps) {
  const dropRef = useRef<HTMLDivElement>(null);

  // 섹션 드롭 핸들러
  const [{ isOver, canDrop }, drop] = useDrop(() => ({
    accept: DND_ITEM_TYPES.SECTION,
    drop: (item: DragItemSection, monitor) => {
      if (!isActive) return;
      
      // 드롭 위치 계산
      const clientOffset = monitor.getClientOffset();
      if (!clientOffset || !dropRef.current) return;

      const dropRect = dropRef.current.getBoundingClientRect();
      const x = clientOffset.x - dropRect.left;
      const y = clientOffset.y - dropRect.top;

      // 그리드 위치 계산
      const colWidth = (size.width - 16) / cols;
      const col = Math.max(1, Math.min(cols, Math.floor(x / colWidth) + 1));
      const row = Math.max(1, Math.floor(y / rowHeight) + 1);

      onDropSection({
        col,
        row,
        colSpan: 3,  // 기본 너비
        rowSpan: 4,  // 기본 높이 (20px * 4 = 80px)
      });
    },
    canDrop: () => isActive,
    collect: (monitor) => ({
      isOver: monitor.isOver(),
      canDrop: monitor.canDrop(),
    }),
  }), [isActive, size, cols, rowHeight, onDropSection]);

  // ref 결합
  drop(dropRef);

  return (
    <div
      ref={dropRef}
      className={cn(
        "h-full w-full overflow-auto rounded-[1.5rem] bg-gray-100 p-2 transition-colors",
        isOver && canDrop && "bg-primary/10 ring-2 ring-primary ring-inset"
      )}
      onClick={(e) => {
        if (e.target === e.currentTarget) {
          onSelectSection(null);
          onSelectComponent(null);
        }
      }}
    >
      {sections.length > 0 ? (
        <GridLayout
          className="layout"
          layout={gridLayoutItems}
          cols={cols}
          rowHeight={rowHeight}
          width={size.width - 16}
          margin={margin}
          containerPadding={[0, 0]}
          onDragStop={onDragResizeStop}
          onResizeStop={onDragResizeStop}
          isDraggable={isActive}
          isResizable={isActive}
          compactType={null}
          preventCollision={false}
          useCSSTransforms={true}
          draggableHandle=".section-drag-handle"
        >
          {sections.map((section) => (
            <div
              key={section.id}
              className={cn(
                "group relative flex flex-col rounded-lg border-2 bg-white transition-all overflow-hidden",
                selectedSectionId === section.id
                  ? "border-primary ring-2 ring-primary/30"
                  : "border-gray-200 hover:border-gray-400"
              )}
              onClick={(e) => {
                e.stopPropagation();
                onSelectSection(section.id);
              }}
            >
              {/* 섹션 헤더 - 고정 높이 */}
              <div
                className={cn(
                  "section-drag-handle flex h-7 shrink-0 cursor-move items-center justify-between border-b px-2",
                  selectedSectionId === section.id
                    ? "bg-primary/10"
                    : "bg-gray-50"
                )}
              >
                <div className="flex items-center gap-1">
                  <GripVertical className="h-3 w-3 text-gray-400" />
                  <span className="text-xs font-medium text-gray-600">
                    {section.label || `섹션`}
                  </span>
                </div>
                {selectedSectionId === section.id && (
                  <Button
                    variant="ghost"
                    size="icon"
                    className="h-5 w-5 text-destructive hover:bg-destructive/10"
                    onClick={(e) => {
                      e.stopPropagation();
                      onDeleteSection(section.id);
                    }}
                  >
                    <Trash2 className="h-3 w-3" />
                  </Button>
                )}
              </div>

              {/* 섹션 내부 - 나머지 영역 전부 차지 */}
              <div className="relative flex-1">
                <SectionGrid
                  section={section}
                  isActive={isActive}
                  selectedComponentId={selectedComponentId}
                  onSelectComponent={onSelectComponent}
                  onDropComponent={onDropComponent}
                  onUpdateComponent={onUpdateComponent}
                  onDeleteComponent={onDeleteComponent}
                />
              </div>
            </div>
          ))}
        </GridLayout>
      ) : (
        <div
          className={cn(
            "flex h-full items-center justify-center rounded-lg border-2 border-dashed text-sm",
            isOver && canDrop
              ? "border-primary bg-primary/5 text-primary"
              : "border-gray-300 text-gray-400"
          )}
        >
          {isOver && canDrop
            ? "여기에 섹션을 놓으세요"
            : "왼쪽 패널에서 섹션을 드래그하세요"}
        </div>
      )}
    </div>
  );
}