import React, { useCallback, useState } from 'react';
import { Upload as UploadIcon, FileText, Image as ImageIcon, Folder } from 'lucide-react';
import { useLanguage } from '../contexts/LanguageContext';
import { GROUP_ALLOWED_EXTENSIONS, IMAGE_MIME_TYPES } from '../constants/fileSupport';

interface NotebookDragDropUploadProps {
  onFilesSelected: (files: FileList) => void;
  isAdmin: boolean;
  globalMode?: boolean;
}

export const NotebookDragDropUpload: React.FC<NotebookDragDropUploadProps> = ({ onFilesSelected, isAdmin, globalMode = false }) => {
  const { t } = useLanguage();
  const [isDragging, setIsDragging] = useState(false);

  const handleDragEnter = useCallback((e: React.DragEvent) => {
    e.preventDefault();
    e.stopPropagation();
    if (e.dataTransfer.items && e.dataTransfer.items.length > 0) {
      setIsDragging(true);
    }
  }, []);

  const handleDragLeave = useCallback((e: React.DragEvent) => {
    e.preventDefault();
    e.stopPropagation();
    // マウスが実際にドラッグ領域を離れた場合のみfalseに設定
    setTimeout(() => setIsDragging(false), 100);
  }, []);

  const handleDragOver = useCallback((e: React.DragEvent) => {
    e.preventDefault();
    e.stopPropagation();
    e.dataTransfer.dropEffect = 'copy';
  }, []);

  const handleDrop = useCallback((e: React.DragEvent) => {
    e.preventDefault();
    e.stopPropagation();
    setIsDragging(false);

    if (e.dataTransfer.files && e.dataTransfer.files.length > 0) {
      onFilesSelected(e.dataTransfer.files);
      e.dataTransfer.clearData();
    }
  }, [onFilesSelected]);

  const handleFileInput = (e: React.ChangeEvent<HTMLInputElement>) => {
    if (e.target.files && e.target.files.length > 0) {
      onFilesSelected(e.target.files);
      // Reset the input so the same file can be selected again
      e.target.value = '';
    }
  };

  if (!isAdmin) {
    return null;
  }

  // モードに応じてCSSクラスを決定
  const containerClass = globalMode
    ? `fixed inset-0 bg-black bg-opacity-50 flex items-center justify-center z-50 transition-opacity duration-300 ${isDragging ? 'opacity-100' : 'opacity-0 pointer-events-none'}`
    : `border-2 border-dashed rounded-xl p-8 text-center transition-all duration-200 cursor-pointer ${isDragging
      ? 'border-blue-500 bg-blue-50 scale-[1.02] shadow-lg'
      : 'border-slate-300 bg-slate-50 hover:border-blue-400 hover:bg-blue-25'
    }`;

  const contentClass = globalMode
    ? "w-3/4 max-w-2xl"
    : "";

  return (
    <div className={containerClass}>
      <div className={contentClass}>
        <div
          className={`border-2 border-dashed rounded-xl p-8 text-center transition-all duration-200 cursor-pointer ${isDragging
            ? 'border-blue-500 bg-blue-50 scale-[1.02] shadow-lg'
            : 'border-slate-300 bg-slate-50 hover:border-blue-400 hover:bg-blue-25'
            }`}
          onDragEnter={handleDragEnter}
          onDragOver={handleDragOver}
          onDragLeave={handleDragLeave}
          onDrop={handleDrop}
          onClick={() => document.getElementById('notebook-file-upload-input')?.click()}
        >
          <div className="flex flex-col items-center justify-center gap-6">
            <div className="p-4 bg-blue-100 rounded-full">
              <UploadIcon className="w-10 h-10 text-blue-600" />
            </div>
            <div className="space-y-2">
              <h3 className="text-lg font-semibold text-slate-700">
                {t('dragDropUploadTitle')}
              </h3>
              <p className="text-sm text-slate-500">
                {t('dragDropUploadDesc')}
              </p>
            </div>
            <div className="flex items-center gap-6 mt-2">
              <div className="flex items-center gap-2 text-xs text-slate-500 bg-white px-3 py-1.5 rounded-full border border-slate-200">
                <FileText className="w-4 h-4" />
                <span>{t('supportedFormats')}</span>
              </div>
              <div className="flex items-center gap-2 text-xs text-slate-500 bg-white px-3 py-1.5 rounded-full border border-slate-200">
                <ImageIcon className="w-4 h-4" />
                <span>{GROUP_ALLOWED_EXTENSIONS.slice(0, 10).join(', ').toUpperCase()}...</span>
              </div>
            </div>
            <div className="pt-2">
              <button
                type="button"
                className="flex items-center gap-2 px-5 py-2.5 bg-blue-600 text-white rounded-lg hover:bg-blue-700 transition-colors text-sm font-medium shadow-sm"
              >
                <Folder className="w-4 h-4" />
                {t('browseFiles')}
              </button>
              <input
                type="file"
                multiple
                onChange={handleFileInput}
                className="hidden"
                id="notebook-file-upload-input"
                accept={GROUP_ALLOWED_EXTENSIONS.map(ext => `.${ext}`).join(',') + ',' + IMAGE_MIME_TYPES.join(',')}
              />
            </div>
          </div>
        </div>
      </div>
    </div>
  );
};