import React, { useState } from "react";
import { useTableOptions } from "@/contexts/TableOptionsContext";
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogFooter,
  DialogHeader,
  DialogTitle,
} from "@/components/ui/dialog";
import { Button } from "@/components/ui/button";
import { Checkbox } from "@/components/ui/checkbox";
import { ScrollArea } from "@/components/ui/scroll-area";
import { ArrowRight, GripVertical, X } from "lucide-react";

interface Props {
  isOpen: boolean;
  onClose: () => void;
}

export const GroupingPanel: React.FC<Props> = ({
  isOpen,
  onClose,
}) => {
  const { getTable, selectedTableId } = useTableOptions();
  const table = selectedTableId ? getTable(selectedTableId) : undefined;

  const [selectedColumns, setSelectedColumns] = useState<string[]>([]);
  const [draggedIndex, setDraggedIndex] = useState<number | null>(null);

  const toggleColumn = (columnName: string) => {
    if (selectedColumns.includes(columnName)) {
      setSelectedColumns(selectedColumns.filter((c) => c !== columnName));
    } else {
      setSelectedColumns([...selectedColumns, columnName]);
    }
  };

  const removeColumn = (columnName: string) => {
    setSelectedColumns(selectedColumns.filter((c) => c !== columnName));
  };

  const moveColumn = (fromIndex: number, toIndex: number) => {
    const newColumns = [...selectedColumns];
    const [movedItem] = newColumns.splice(fromIndex, 1);
    newColumns.splice(toIndex, 0, movedItem);
    setSelectedColumns(newColumns);
  };

  const handleDragStart = (index: number) => {
    setDraggedIndex(index);
  };

  const handleDragOver = (e: React.DragEvent, index: number) => {
    e.preventDefault();
    if (draggedIndex === null || draggedIndex === index) return;
    moveColumn(draggedIndex, index);
    setDraggedIndex(index);
  };

  const handleDragEnd = () => {
    setDraggedIndex(null);
  };

  const applyGrouping = () => {
    table?.onGroupChange(selectedColumns);
    onClose();
  };

  const clearGrouping = () => {
    setSelectedColumns([]);
    table?.onGroupChange([]);
  };

  return (
    <Dialog open={isOpen} onOpenChange={onClose}>
      <DialogContent className="max-w-[95vw] sm:max-w-xl">
        <DialogHeader>
          <DialogTitle className="text-base sm:text-lg">그룹 설정</DialogTitle>
          <DialogDescription className="text-xs sm:text-sm">
            데이터를 그룹화할 컬럼을 선택하세요
          </DialogDescription>
        </DialogHeader>

        <div className="space-y-3 sm:space-y-4">
          {/* 선택된 컬럼 (드래그 가능) */}
          {selectedColumns.length > 0 && (
            <div>
              <div className="mb-2 flex items-center justify-between">
                <div className="text-xs font-medium sm:text-sm">
                  그룹화 순서 ({selectedColumns.length}개)
                </div>
                <Button
                  variant="ghost"
                  size="sm"
                  onClick={clearGrouping}
                  className="h-7 text-xs"
                >
                  전체 해제
                </Button>
              </div>
              <div className="space-y-2">
                {selectedColumns.map((colName, index) => {
                  const col = table?.columns.find(
                    (c) => c.columnName === colName
                  );
                  if (!col) return null;

                  return (
                    <div
                      key={colName}
                      draggable
                      onDragStart={() => handleDragStart(index)}
                      onDragOver={(e) => handleDragOver(e, index)}
                      onDragEnd={handleDragEnd}
                      className="flex items-center gap-2 rounded-lg border bg-primary/5 p-2 sm:p-3 transition-colors hover:bg-primary/10 cursor-move"
                    >
                      <GripVertical className="h-4 w-4 text-muted-foreground flex-shrink-0" />
                      
                      <div className="flex h-5 w-5 sm:h-6 sm:w-6 items-center justify-center rounded-full bg-primary text-xs text-primary-foreground flex-shrink-0">
                        {index + 1}
                      </div>

                      <div className="flex-1 min-w-0">
                        <div className="text-xs font-medium sm:text-sm truncate">
                          {col.columnLabel}
                        </div>
                      </div>

                      <Button
                        variant="ghost"
                        size="sm"
                        onClick={() => removeColumn(colName)}
                        className="h-6 w-6 p-0 flex-shrink-0"
                      >
                        <X className="h-3 w-3" />
                      </Button>
                    </div>
                  );
                })}
              </div>

              {/* 그룹화 순서 미리보기 */}
              <div className="mt-2 rounded-lg border bg-muted/30 p-2">
                <div className="flex flex-wrap items-center gap-2 text-xs">
                  {selectedColumns.map((colName, index) => {
                    const col = table?.columns.find(
                      (c) => c.columnName === colName
                    );
                    return (
                      <React.Fragment key={colName}>
                        <span className="font-medium">{col?.columnLabel}</span>
                        {index < selectedColumns.length - 1 && (
                          <ArrowRight className="h-3 w-3 text-muted-foreground" />
                        )}
                      </React.Fragment>
                    );
                  })}
                </div>
              </div>
            </div>
          )}

          {/* 사용 가능한 컬럼 */}
          <div>
            <div className="mb-2 text-xs font-medium sm:text-sm">
              사용 가능한 컬럼
            </div>
            <ScrollArea className={selectedColumns.length > 0 ? "h-[280px] sm:h-[320px]" : "h-[400px] sm:h-[450px]"}>
              <div className="space-y-2 pr-4">
                {table?.columns
                  .filter((col) => !selectedColumns.includes(col.columnName))
                  .map((col) => {
                    return (
                      <div
                        key={col.columnName}
                        className="flex items-center gap-3 rounded-lg border bg-background p-2 sm:p-3 transition-colors hover:bg-muted/50 cursor-pointer"
                        onClick={() => toggleColumn(col.columnName)}
                      >
                        <Checkbox
                          checked={false}
                          onCheckedChange={() => toggleColumn(col.columnName)}
                          className="flex-shrink-0"
                        />

                        <div className="flex-1 min-w-0">
                          <div className="text-xs font-medium sm:text-sm truncate">
                            {col.columnLabel}
                          </div>
                          <div className="text-[10px] text-muted-foreground sm:text-xs truncate">
                            {col.columnName}
                          </div>
                        </div>
                      </div>
                    );
                  })}
              </div>
            </ScrollArea>
          </div>
        </div>

        <DialogFooter className="gap-2 sm:gap-0">
          <Button
            variant="outline"
            onClick={onClose}
            className="h-8 flex-1 text-xs sm:h-10 sm:flex-none sm:text-sm"
          >
            취소
          </Button>
          <Button
            onClick={applyGrouping}
            className="h-8 flex-1 text-xs sm:h-10 sm:flex-none sm:text-sm"
          >
            저장
          </Button>
        </DialogFooter>
      </DialogContent>
    </Dialog>
  );
};