"use client";

import { useState } from "react";
import { Button } from "@/components/ui/button";
import {
  DropdownMenu,
  DropdownMenuContent,
  DropdownMenuItem,
  DropdownMenuTrigger,
  DropdownMenuSeparator,
  DropdownMenuCheckboxItem,
} from "@/components/ui/dropdown-menu";
import { Badge } from "@/components/ui/badge";
import { ChevronDown, Database, FileText, BookOpen, Scale } from "lucide-react";
import { cn } from "@/lib/utils";

// 系统知识库图标映射
const getSystemKnowledgeBaseIcon = (name: string) => {
  if (name.includes("法律法规")) return Scale;
  if (name.includes("原理")) return BookOpen;
  if (name.includes("案例")) return FileText;
  return Database;
};

export interface KnowledgeBase {
  id: string;
  name: string;
  description: string;
  documentCount: number;
  enabled: boolean;
  isSystem?: boolean; // 是否为系统知识库
  icon?: React.ComponentType<{ className?: string }>;
}

interface KnowledgeSelectorProps {
  selectedBases: string[];
  onBasesChange: (baseIds: string[]) => void;
  systemKnowledgeBases?: KnowledgeBase[]; // 系统知识库列表（从后端动态加载）
  userKnowledgeBases?: KnowledgeBase[]; // 用户的知识库列表
  className?: string;
}

export default function KnowledgeSelector({ 
  selectedBases, 
  onBasesChange, 
  systemKnowledgeBases = [],
  userKnowledgeBases = [],
  className 
}: KnowledgeSelectorProps) {
  const [isOpen, setIsOpen] = useState(false);
  
  // 为系统知识库添加图标（如果还没有的话）
  const systemBasesWithIcons = systemKnowledgeBases.map(kb => ({
    ...kb,
    icon: kb.icon || getSystemKnowledgeBaseIcon(kb.name),
    isSystem: true,
  }));
  
  // 合并系统知识库和用户知识库
  const allKnowledgeBases = [
    ...systemBasesWithIcons,
    ...userKnowledgeBases.map(kb => ({
      ...kb,
      isSystem: false, // 用户知识库标记为非系统
    }))
  ];
  
  const enabledBases = allKnowledgeBases.filter(base => base.enabled);
  const selectedCount = selectedBases.length;
  const totalEnabled = enabledBases.length;

  const handleToggleBase = (baseId: string) => {
    const newSelectedBases = selectedBases.includes(baseId)
      ? selectedBases.filter(id => id !== baseId)
      : [...selectedBases, baseId];
    onBasesChange(newSelectedBases);
  };

  const handleSelectAll = () => {
    const allEnabledIds = enabledBases.map(base => base.id);
    onBasesChange(allEnabledIds);
  };

  const handleSelectNone = () => {
    onBasesChange([]);
  };

  return (
    <DropdownMenu open={isOpen} onOpenChange={setIsOpen}>
      <DropdownMenuTrigger asChild>
        <Button
          variant="outline"
          className={cn(
            "h-9 px-3 text-sm font-medium",
            "border-border/50 bg-background/80 hover:bg-muted/50",
            "transition-all duration-200",
            className
          )}
        >
          <Database className="w-4 h-4 mr-2" />
          <span className="hidden sm:inline">
            知识库 {selectedCount > 0 && `(${selectedCount})`}
          </span>
          <span className="sm:hidden">
            知识库 {selectedCount > 0 && `(${selectedCount})`}
          </span>
          <ChevronDown className="w-3 h-3 ml-1 opacity-50" />
        </Button>
      </DropdownMenuTrigger>
      <DropdownMenuContent align="start" className="w-72">
        <div className="px-2 py-1.5 text-xs font-medium text-muted-foreground">
          选择知识库
        </div>
        <DropdownMenuSeparator />
        
        {/* 快速操作 */}
        <div className="px-2 py-1.5">
          <div className="flex space-x-2">
            <Button
              variant="ghost"
              size="sm"
              onClick={handleSelectAll}
              className="h-7 px-2 text-xs"
            >
              全选
            </Button>
            <Button
              variant="ghost"
              size="sm"
              onClick={handleSelectNone}
              className="h-7 px-2 text-xs"
            >
              清空
            </Button>
          </div>
        </div>
        
        <DropdownMenuSeparator />
        
        {/* 系统知识库 */}
        {systemBasesWithIcons.length > 0 && (
          <div className="px-2 py-1">
            <div className="text-xs font-medium text-muted-foreground mb-2 flex items-center">
              <Database className="w-3 h-3 mr-1" />
              系统知识库
            </div>
            {systemBasesWithIcons.map((base) => {
            const BaseIcon = base.icon || Database;
            const isSelected = selectedBases.includes(base.id);
            const isDisabled = !base.enabled;
            
            return (
              <DropdownMenuCheckboxItem
                key={base.id}
                checked={isSelected}
                onCheckedChange={() => handleToggleBase(base.id)}
                disabled={isDisabled}
                className={cn(
                  "flex items-start space-x-3 p-3 cursor-pointer",
                  isDisabled && "opacity-50 cursor-not-allowed"
                )}
              >
                <BaseIcon className="w-4 h-4 mt-0.5 flex-shrink-0" />
                <div className="flex-1 min-w-0">
                  <div className="flex items-center space-x-2">
                    <span className="font-medium text-sm">{base.name}</span>
                    {isSelected && (
                      <Badge variant="secondary" className="text-xs">
                        已选
                      </Badge>
                    )}
                    {isDisabled && (
                      <Badge variant="outline" className="text-xs">
                        不可用
                      </Badge>
                    )}
                  </div>
                  <p className="text-xs text-muted-foreground mt-0.5">
                    {base.description}
                  </p>
                  <div className="flex items-center space-x-1 mt-1">
                    <span className="text-xs text-muted-foreground">
                      {base.documentCount} 个文档
                    </span>
                  </div>
                </div>
              </DropdownMenuCheckboxItem>
            );
            })}
          </div>
        )}
        
        {/* 用户知识库 */}
        {userKnowledgeBases.length > 0 && (
          <>
            <DropdownMenuSeparator />
            <div className="px-2 py-1">
              <div className="text-xs font-medium text-muted-foreground mb-2 flex items-center">
                <FileText className="w-3 h-3 mr-1" />
                我的知识库
              </div>
              {userKnowledgeBases.map((base) => {
                const isSelected = selectedBases.includes(base.id);
                const isDisabled = !base.enabled;
                
                return (
                  <DropdownMenuCheckboxItem
                    key={base.id}
                    checked={isSelected}
                    onCheckedChange={() => handleToggleBase(base.id)}
                    disabled={isDisabled}
                    className={cn(
                      "flex items-start space-x-3 p-3 cursor-pointer",
                      isDisabled && "opacity-50 cursor-not-allowed"
                    )}
                  >
                    <BookOpen className="w-4 h-4 mt-0.5 flex-shrink-0 text-green-500" />
                    <div className="flex-1 min-w-0">
                      <div className="flex items-center space-x-2">
                        <span className="font-medium text-sm">{base.name}</span>
                        {isSelected && (
                          <Badge variant="secondary" className="text-xs">
                            已选
                          </Badge>
                        )}
                        {isDisabled && (
                          <Badge variant="outline" className="text-xs">
                            不可用
                          </Badge>
                        )}
                      </div>
                      <p className="text-xs text-muted-foreground mt-0.5">
                        {base.description}
                      </p>
                      <div className="flex items-center space-x-1 mt-1">
                        <span className="text-xs text-muted-foreground">
                          {base.documentCount} 个文档
                        </span>
                      </div>
                    </div>
                  </DropdownMenuCheckboxItem>
                );
              })}
            </div>
          </>
        )}
        
        {selectedCount > 0 && (
          <>
            <DropdownMenuSeparator />
            <div className="px-2 py-1.5 text-xs text-muted-foreground text-center">
              已选择 {selectedCount} 个知识库
            </div>
          </>
        )}
      </DropdownMenuContent>
    </DropdownMenu>
  );
}