"use client";

import React, { useEffect, useRef } from "react";
import { ScrollArea } from "@/components/ui/scroll-area";
import { Badge } from "@/components/ui/badge";
import { Link, GripVertical } from "lucide-react";

// 타입 import
import { ColumnInfo } from "@/lib/types/multiConnection";

interface FieldColumnProps {
  fields: ColumnInfo[];
  type: "from" | "to";
  selectedField: ColumnInfo | null;
  onFieldSelect: (field: ColumnInfo | null) => void;
  onFieldPositionUpdate: (fieldId: string, element: HTMLElement) => void;
  isFieldMapped: (field: ColumnInfo, type: "from" | "to") => boolean;
  onDragStart?: (field: ColumnInfo) => void;
  onDragEnd?: () => void;
  onDrop?: (targetField: ColumnInfo, sourceField: ColumnInfo) => void;
  isDragOver?: boolean;
  draggedField?: ColumnInfo | null;
}

/**
 * 📋 필드 컬럼 컴포넌트
 * - 필드 목록 표시
 * - 선택 상태 관리
 * - 위치 정보 업데이트
 */
const FieldColumn: React.FC<FieldColumnProps> = ({
  fields,
  type,
  selectedField,
  onFieldSelect,
  onFieldPositionUpdate,
  isFieldMapped,
  onDragStart,
  onDragEnd,
  onDrop,
  isDragOver,
  draggedField,
}) => {
  const fieldRefs = useRef<Record<string, HTMLDivElement>>({});

  // 필드 위치 업데이트
  useEffect(() => {
    const updatePositions = () => {
      Object.entries(fieldRefs.current).forEach(([fieldId, element]) => {
        if (element) {
          onFieldPositionUpdate(fieldId, element);
        }
      });
    };

    // 약간의 지연을 두어 DOM이 완전히 렌더링된 후 위치 업데이트
    const timeoutId = setTimeout(updatePositions, 100);

    return () => clearTimeout(timeoutId);
  }, [fields.length]); // fields 배열 대신 length만 의존성으로 사용

  // 드래그 앤 드롭 핸들러
  const handleDragStart = (e: React.DragEvent, field: ColumnInfo) => {
    if (type === "from" && onDragStart) {
      e.dataTransfer.setData("text/plain", JSON.stringify(field));
      e.dataTransfer.effectAllowed = "copy";
      onDragStart(field);
    }
  };

  const handleDragEnd = (e: React.DragEvent) => {
    if (onDragEnd) {
      onDragEnd();
    }
  };

  const handleDragOver = (e: React.DragEvent) => {
    if (type === "to") {
      e.preventDefault();
      e.dataTransfer.dropEffect = "copy";
    }
  };

  const handleDrop = (e: React.DragEvent, targetField: ColumnInfo) => {
    if (type === "to" && onDrop) {
      e.preventDefault();

      // 이미 매핑된 TO 필드인지 확인
      const isMapped = isFieldMapped(targetField, "to");
      if (isMapped) {
        // 이미 매핑된 필드에는 드롭할 수 없음을 시각적으로 표시
        return;
      }

      try {
        const sourceFieldData = e.dataTransfer.getData("text/plain");
        const sourceField = JSON.parse(sourceFieldData) as ColumnInfo;
        onDrop(targetField, sourceField);
      } catch (error) {
        console.error("드롭 처리 중 오류:", error);
      }
    }
  };

  // 필드 렌더링
  const renderField = (field: ColumnInfo, index: number) => {
    const fieldId = `${type}_${field.columnName}`;
    const isSelected = selectedField?.columnName === field.columnName;
    const isMapped = isFieldMapped(field, type);
    const displayName = field.displayName || field.columnName;
    const isDragging = draggedField?.columnName === field.columnName;
    const isDropTarget = type === "to" && isDragOver && draggedField && !isMapped;
    const isBlockedDropTarget = type === "to" && isDragOver && draggedField && isMapped;

    return (
      <div
        key={`${type}_${field.columnName}_${index}`}
        ref={(el) => {
          if (el) {
            fieldRefs.current[fieldId] = el;
          }
        }}
        className={`relative cursor-pointer rounded-lg border p-3 transition-all duration-200 ${
          isDragging
            ? "border-primary bg-primary/20 scale-105 transform opacity-50 shadow-lg"
            : isSelected
              ? "border-primary bg-primary/10 shadow-md"
              : isMapped
                ? "border-emerald-500 bg-emerald-50 shadow-sm"
                : isBlockedDropTarget
                  ? "border-destructive/60 bg-destructive/10 shadow-md"
                  : isDropTarget
                    ? "border-primary/60 bg-accent shadow-md"
                    : "border-border hover:bg-muted/50 hover:shadow-sm"
        } `}
        draggable={type === "from" && !isMapped}
        onDragStart={(e) => handleDragStart(e, field)}
        onDragEnd={handleDragEnd}
        onDragOver={handleDragOver}
        onDrop={(e) => handleDrop(e, field)}
        onClick={() => onFieldSelect(isSelected ? null : field)}
      >
        {/* 연결점 표시 */}
        <div
          className={`absolute ${type === "from" ? "right-0" : "left-0"} top-1/2 h-3 w-3 -translate-y-1/2 transform rounded-full border-2 transition-colors ${
            isSelected
              ? "bg-primary border-primary"
              : isMapped
                ? "border-emerald-500 bg-emerald-500"
                : "border-input bg-white"
          } `}
          style={{
            [type === "from" ? "right" : "left"]: "-6px",
          }}
        />

        <div className="flex items-center justify-between">
          <div className="flex min-w-0 flex-1 items-center gap-2">
            {type === "from" && !isMapped && <GripVertical className="h-3 w-3 flex-shrink-0 text-muted-foreground/70" />}
            <span className="truncate text-sm font-medium">{displayName}</span>
            {isMapped && <Link className="h-3 w-3 flex-shrink-0 text-emerald-600" />}
          </div>
          <Badge variant="outline" className="flex-shrink-0 text-xs">
            {field.webType || field.dataType || "unknown"}
          </Badge>
        </div>

        {field.description && <p className="text-muted-foreground mt-1 truncate text-xs">{field.description}</p>}

        {/* 선택 상태 표시 */}
        {isSelected && <div className="border-primary pointer-events-none absolute inset-0 rounded-lg border-2" />}
      </div>
    );
  };

  return (
    <div className="h-full">
      <ScrollArea className="h-full rounded-lg border">
        <div className="space-y-2 p-2">
          {fields.map((field, index) => renderField(field, index))}

          {fields.length === 0 && (
            <div className="text-muted-foreground py-8 text-center text-sm">
              <p>필드가 없습니다.</p>
              <p className="mt-1 text-xs">테이블을 선택해주세요.</p>
            </div>
          )}
        </div>
      </ScrollArea>
    </div>
  );
};

export default FieldColumn;
