'use client';

import React, { forwardRef, useState, useCallback } from 'react';
import { DashboardElement, ElementType, ElementSubtype, DragData } from './types';
import { CanvasElement } from './CanvasElement';

interface DashboardCanvasProps {
  elements: DashboardElement[];
  selectedElement: string | null;
  onCreateElement: (type: ElementType, subtype: ElementSubtype, x: number, y: number) => void;
  onUpdateElement: (id: string, updates: Partial<DashboardElement>) => void;
  onRemoveElement: (id: string) => void;
  onSelectElement: (id: string | null) => void;
  onConfigureElement?: (element: DashboardElement) => void;
}

/**
 * 대시보드 캔버스 컴포넌트
 * - 드래그 앤 드롭 영역
 * - 그리드 배경
 * - 요소 배치 및 관리
 */
export const DashboardCanvas = forwardRef<HTMLDivElement, DashboardCanvasProps>(
  ({ elements, selectedElement, onCreateElement, onUpdateElement, onRemoveElement, onSelectElement, onConfigureElement }, ref) => {
    const [isDragOver, setIsDragOver] = useState(false);

    // 드래그 오버 처리
    const handleDragOver = useCallback((e: React.DragEvent) => {
      e.preventDefault();
      e.dataTransfer.dropEffect = 'copy';
      setIsDragOver(true);
    }, []);

    // 드래그 리브 처리
    const handleDragLeave = useCallback((e: React.DragEvent) => {
      if (e.currentTarget === e.target) {
        setIsDragOver(false);
      }
    }, []);

    // 드롭 처리
    const handleDrop = useCallback((e: React.DragEvent) => {
      e.preventDefault();
      setIsDragOver(false);

      try {
        const dragData: DragData = JSON.parse(e.dataTransfer.getData('application/json'));
        
        if (!ref || typeof ref === 'function') return;
        
        const rect = ref.current?.getBoundingClientRect();
        if (!rect) return;

        // 캔버스 스크롤을 고려한 정확한 위치 계산
        const x = e.clientX - rect.left + (ref.current?.scrollLeft || 0);
        const y = e.clientY - rect.top + (ref.current?.scrollTop || 0);

        onCreateElement(dragData.type, dragData.subtype, x, y);
      } catch (error) {
        // console.error('드롭 데이터 파싱 오류:', error);
      }
    }, [ref, onCreateElement]);

    // 캔버스 클릭 시 선택 해제
    const handleCanvasClick = useCallback((e: React.MouseEvent) => {
      if (e.target === e.currentTarget) {
        onSelectElement(null);
      }
    }, [onSelectElement]);

    return (
      <div
        ref={ref}
        className={`
          w-full min-h-full relative
          bg-gray-100
          bg-grid-pattern
          ${isDragOver ? 'bg-accent' : ''}
        `}
        style={{
          backgroundImage: `
            linear-gradient(rgba(200, 200, 200, 0.3) 1px, transparent 1px),
            linear-gradient(90deg, rgba(200, 200, 200, 0.3) 1px, transparent 1px)
          `,
          backgroundSize: '20px 20px'
        }}
        onDragOver={handleDragOver}
        onDragLeave={handleDragLeave}
        onDrop={handleDrop}
        onClick={handleCanvasClick}
      >
        {/* 배치된 요소들 렌더링 */}
        {elements.map((element) => (
          <CanvasElement
            key={element.id}
            element={element}
            isSelected={selectedElement === element.id}
            onUpdate={onUpdateElement}
            onRemove={onRemoveElement}
            onSelect={onSelectElement}
            onConfigure={onConfigureElement}
          />
        ))}
      </div>
    );
  }
);

DashboardCanvas.displayName = 'DashboardCanvas';