import React from 'react';
import { KnowledgeGroup } from '../types';
import { Check, ChevronDown, Search } from 'lucide-react';

interface GroupSelectorProps {
  groups: KnowledgeGroup[];
  selectedGroups: string[];
  onSelectionChange: (groupIds: string[]) => void;
  showSelectAll?: boolean;
  placeholder?: string;
  minimal?: boolean;
  direction?: 'up' | 'bottom'; // Added direction prop
}

export const GroupSelector: React.FC<GroupSelectorProps> = ({
  groups,
  selectedGroups,
  onSelectionChange,
  showSelectAll = true,
  placeholder = '选择分组范围',
  minimal = false,
  direction = 'bottom'
}) => {
  const [isOpen, setIsOpen] = React.useState(false);
  const [dropdownStyle, setDropdownStyle] = React.useState<React.CSSProperties>({});
  const [searchTerm, setSearchTerm] = React.useState('');
  const containerRef = React.useRef<HTMLDivElement>(null);
  const searchInputRef = React.useRef<HTMLInputElement>(null);

  React.useEffect(() => {
    if (isOpen && containerRef.current) {
      const button = containerRef.current.querySelector('button') as HTMLElement;
      if (button) {
        const rect = button.getBoundingClientRect();

        // Calculate style based on direction
        const style: React.CSSProperties = {
          left: rect.left,
          width: Math.max(rect.width, 240), // Min width for readability
        };

        if (direction === 'up') {
          style.bottom = window.innerHeight - rect.top + 4;
          style.maxHeight = '320px'; // Increased height for search + list
        } else {
          style.top = rect.bottom + 4;
          style.maxHeight = '320px';
        }

        setDropdownStyle(style);

        // Auto-focus search input when opening
        setTimeout(() => searchInputRef.current?.focus(), 50);
      }
    } else {
      setSearchTerm(''); // Reset search on close
    }
  }, [isOpen, direction]);

  const filteredGroups = groups.filter(g =>
    g.name.toLowerCase().includes(searchTerm.toLowerCase())
  );

  const isAllSelected = selectedGroups.length === 0;

  // Optimized display logic
  let selectedGroupNames = '';
  if (selectedGroups.length === 0) {
    selectedGroupNames = '全部分组';
  } else if (selectedGroups.length <= 2) {
    selectedGroupNames = selectedGroups.map(id => groups.find(g => g.id === id)?.name).filter(Boolean).join(', ');
  } else {
    selectedGroupNames = `已选 ${selectedGroups.length} 个分组`;
  }

  const handleToggleGroup = (groupId: string) => {
    if (selectedGroups.includes(groupId)) {
      onSelectionChange(selectedGroups.filter(id => id !== groupId));
    } else {
      onSelectionChange([...selectedGroups, groupId]);
    }
  };

  const handleSelectAll = () => {
    onSelectionChange([]);
  };

  return (
    <div className={`relative ${minimal ? '' : 'w-full'} `} ref={containerRef}>
      <button
        onClick={() => setIsOpen(!isOpen)}
        className={`flex items - center justify - between px - 3 py - 2 bg - white border border - gray - 300 rounded - md text - left focus: outline - none focus: ring - 2 focus: ring - blue - 500 ${minimal ? 'h-9 text-sm min-w-[120px]' : 'w-full'} `}
        title={selectedGroups.length > 2 ? selectedGroups.map(id => groups.find(g => g.id === id)?.name).join(', ') : undefined}
      >
        <span className={`truncate mr - 2 ${selectedGroups.length === 0 ? 'text-gray-500' : 'text-gray-900'} `} style={{ maxWidth: minimal ? '120px' : 'none' }}>
          {selectedGroupNames || placeholder}
        </span>
        <ChevronDown size={14} className={`text - gray - 400 text - xs transition - transform flex - shrink - 0 ${isOpen ? 'rotate-180' : ''} `} />
      </button>

      {isOpen && (
        <>
          <div
            className="fixed inset-0 z-[9998]"
            onClick={() => setIsOpen(false)}
          />
          <div className="fixed bg-white border border-gray-300 rounded-lg shadow-xl z-[9999] flex flex-col animate-in fade-in zoom-in-95 duration-100"
            style={dropdownStyle}>

            {/* Search Box */}
            <div className="p-2 border-b border-gray-100 shrink-0">
              <div className="relative">
                <Search className="absolute left-2.5 top-1/2 -translate-y-1/2 w-3.5 h-3.5 text-gray-400" />
                <input
                  ref={searchInputRef}
                  type="text"
                  placeholder="搜索分组..."
                  value={searchTerm}
                  onChange={(e) => setSearchTerm(e.target.value)}
                  className="w-full pl-8 pr-3 py-1.5 text-sm border border-gray-200 rounded-md focus:outline-none focus:border-blue-500 focus:ring-1 focus:ring-blue-500 bg-gray-50"
                  onClick={(e) => e.stopPropagation()}
                />
              </div>
            </div>

            <div className="overflow-y-auto flex-1 p-0">
              {!searchTerm && showSelectAll && (
                <div
                  onClick={handleSelectAll}
                  className={`flex items - center px - 3 py - 2 cursor - pointer hover: bg - gray - 50 border - b border - gray - 100 ${isAllSelected ? 'bg-blue-50 text-blue-700' : 'text-gray-700'
                    } `}
                >
                  <div className={`w - 4 h - 4 mr - 3 border rounded flex items - center justify - center ${isAllSelected ? 'bg-blue-600 border-blue-600' : 'border-gray-300'
                    } `}>
                    {isAllSelected && <Check size={12} className="text-white" />}
                  </div>
                  <span className="font-medium text-sm">全部分组</span>
                </div>
              )}

              <div className="py-1">
                {filteredGroups.map((group) => {
                  const isSelected = selectedGroups.includes(group.id);
                  return (
                    <div
                      key={group.id}
                      onClick={() => handleToggleGroup(group.id)}
                      className={`flex items - center px - 3 py - 2 cursor - pointer hover: bg - gray - 50 transition - colors ${isSelected ? 'bg-blue-50' : ''
                        } `}
                    >
                      <div className={`w - 4 h - 4 mr - 3 border rounded flex items - center justify - center flex - shrink - 0 ${isSelected ? 'bg-blue-600 border-blue-600' : 'border-gray-300'
                        } `}>
                        {isSelected && <Check size={12} className="text-white" />}
                      </div>
                      <div
                        className="w-2.5 h-2.5 rounded-full mr-2 flex-shrink-0"
                        style={{ backgroundColor: group.color }}
                      />
                      <div className="flex-1 min-w-0">
                        <div className={`text - sm truncate ${isSelected ? 'text-blue-700 font-medium' : 'text-gray-700'} `}>
                          {group.name}
                        </div>
                        <div className="text-[10px] text-gray-400">
                          {group.fileCount} 文件
                        </div>
                      </div>
                    </div>
                  );
                })}

                {filteredGroups.length === 0 && (
                  <div className="px-3 py-6 text-center text-gray-400 text-xs">
                    {searchTerm ? '未找到相关分组' : '暂无分组'}
                  </div>
                )}
              </div>
            </div>
          </div>
        </>
      )}
    </div>
  );
};