"use client";

import { useEffect, useState } from "react";
import { useRouter } from "next/navigation";
import { useAuthStore } from "@/store/auth";
import { Button } from "@/components/ui/button";
import MobileNav from "@/components/layout/mobile-nav";
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
import { Input } from "@/components/ui/input";
import { Label } from "@/components/ui/label";
import { Alert, AlertDescription } from "@/components/ui/alert";
import { Dialog, DialogContent, DialogDescription, DialogFooter, DialogHeader, DialogTitle, DialogTrigger } from "@/components/ui/dialog";
import { 
  Upload, 
  FileText, 
  Search, 
  Plus, 
  Trash2, 
  Eye,
  CheckCircle,
  Clock,
  Loader2,
  BookOpen,
  Settings,
  FolderOpen
} from "lucide-react";
import { formatFileSize, formatDate } from "@/lib/utils";
import { knowledgeBaseAPI } from "@/lib/api";
import { KnowledgeBase } from "@/types";

export default function KnowledgePage() {
  const router = useRouter();
  const { isAuthenticated, isLoading: authLoading } = useAuthStore();
  const [knowledgeBases, setKnowledgeBases] = useState<KnowledgeBase[]>([]);
  const [isLoading, setIsLoading] = useState(true);
  const [searchQuery, setSearchQuery] = useState("");
  const [error, setError] = useState<string | null>(null);
  
  // 创建知识库对话框状态
  const [isCreateDialogOpen, setIsCreateDialogOpen] = useState(false);
  const [createName, setCreateName] = useState("");
  const [createDescription, setCreateDescription] = useState("");
  const [isCreating, setIsCreating] = useState(false);

  useEffect(() => {
    if (!authLoading && !isAuthenticated) {
      router.push("/login");
      return;
    }

    if (isAuthenticated) {
      loadKnowledgeBases();
    }
  }, [isAuthenticated, authLoading, router]);

  const loadKnowledgeBases = async () => {
    try {
      setIsLoading(true);
      setError(null);
      const bases = await knowledgeBaseAPI.getKnowledgeBases();
      // 过滤掉系统知识库，只显示用户创建的知识库
      const userBases = bases.filter(kb => !kb.is_system);
      setKnowledgeBases(userBases);
    } catch (err) {
      console.error("加载知识库失败:", err);
      setError("加载知识库失败");
    } finally {
      setIsLoading(false);
    }
  };

  const handleCreateKnowledgeBase = async () => {
    if (!createName.trim()) return;

    try {
      setIsCreating(true);
      setError(null);

      await knowledgeBaseAPI.createKnowledgeBase({
        name: createName.trim(),
        description: createDescription.trim() || undefined,
      });
      
      // 重新加载知识库列表
      await loadKnowledgeBases();
      
      // 重置表单并关闭对话框
      setCreateName("");
      setCreateDescription("");
      setIsCreateDialogOpen(false);
      
    } catch (err) {
      console.error("创建知识库失败:", err);
      setError("创建知识库失败");
    } finally {
      setIsCreating(false);
    }
  };

  const handleDeleteKnowledgeBase = async (knowledgeBaseId: number) => {
    if (!confirm("确定要删除这个知识库吗？这将删除其中的所有文档。")) return;

    try {
      await knowledgeBaseAPI.deleteKnowledgeBase(knowledgeBaseId.toString());
      await loadKnowledgeBases();
    } catch (err) {
      console.error("删除知识库失败:", err);
      setError("删除知识库失败");
    }
  };

  const filteredKnowledgeBases = knowledgeBases.filter(kb =>
    kb.name.toLowerCase().includes(searchQuery.toLowerCase()) ||
    (kb.description && kb.description.toLowerCase().includes(searchQuery.toLowerCase()))
  );

  if (authLoading || isLoading) {
    return (
      <div className="min-h-screen flex items-center justify-center">
        <Loader2 className="w-8 h-8 animate-spin" />
      </div>
    );
  }

  if (!isAuthenticated) {
    return null;
  }

  return (
    <div className="min-h-screen bg-app pb-16 lg:pb-0">
      <div className="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8 py-8">
        {/* 页面头部 */}
        <div className="mb-8">
          <h1 className="text-3xl font-bold mb-2">知识库管理</h1>
          <p className="text-muted-foreground">创建和管理您的知识库，组织文档内容</p>
        </div>

        {/* 错误提示 */}
        {error && (
          <Alert variant="destructive" className="mb-6">
            <AlertDescription>{error}</AlertDescription>
          </Alert>
        )}

        {/* 操作栏 */}
        <div className="flex flex-col sm:flex-row justify-between items-start sm:items-center mb-6">
          <div className="flex items-center space-x-4 mb-4 sm:mb-0">
            {/* 创建知识库按钮 */}
            <Dialog open={isCreateDialogOpen} onOpenChange={setIsCreateDialogOpen}>
              <DialogTrigger asChild>
                <Button className="bg-gradient-to-r from-blue-600 to-purple-600 hover:from-blue-700 hover:to-purple-700">
                  <Plus className="w-4 h-4 mr-2" />
                  创建知识库
                </Button>
              </DialogTrigger>
              <DialogContent>
                <DialogHeader>
                  <DialogTitle>创建新知识库</DialogTitle>
                  <DialogDescription>
                    创建一个新的知识库来组织您的文档
                  </DialogDescription>
                </DialogHeader>
                <div className="space-y-4">
                  <div>
                    <Label htmlFor="kb-name">知识库名称</Label>
                    <Input
                      id="kb-name"
                      value={createName}
                      onChange={(e) => setCreateName(e.target.value)}
                      placeholder="请输入知识库名称"
                      disabled={isCreating}
                    />
                  </div>
                  <div>
                    <Label htmlFor="kb-description">描述（可选）</Label>
                    <Input
                      id="kb-description"
                      value={createDescription}
                      onChange={(e) => setCreateDescription(e.target.value)}
                      placeholder="请输入知识库描述"
                      disabled={isCreating}
                    />
                  </div>
                </div>
                <DialogFooter>
                  <Button
                    variant="outline"
                    onClick={() => setIsCreateDialogOpen(false)}
                    disabled={isCreating}
                  >
                    取消
                  </Button>
                  <Button
                    onClick={handleCreateKnowledgeBase}
                    disabled={!createName.trim() || isCreating}
                  >
                    {isCreating ? (
                      <>
                        <Loader2 className="w-4 h-4 mr-2 animate-spin" />
                        创建中...
                      </>
                    ) : (
                      "创建"
                    )}
                  </Button>
                </DialogFooter>
              </DialogContent>
            </Dialog>
          </div>
          
          <div className="flex items-center space-x-4">
            <div className="relative">
              <Search className="absolute left-3 top-1/2 transform -translate-y-1/2 text-gray-400 w-4 h-4" />
              <Input
                placeholder="搜索知识库..."
                value={searchQuery}
                onChange={(e) => setSearchQuery(e.target.value)}
                className="pl-10 w-64"
              />
            </div>
            <div className="text-sm text-muted-foreground">
              共 {filteredKnowledgeBases.length} 个知识库
            </div>
          </div>
        </div>

        {/* 知识库列表 */}
        {filteredKnowledgeBases.length === 0 ? (
          <Card className="backdrop-blur-sm bg-card/80 border-border/50 shadow-xl">
            <CardContent className="text-center py-12">
              <BookOpen className="w-12 h-12 text-muted-foreground mx-auto mb-4" />
              <h3 className="text-lg font-medium mb-2">
                {searchQuery ? "没有找到匹配的知识库" : "还没有创建知识库"}
              </h3>
              <p className="text-muted-foreground mb-4">
                {searchQuery ? "尝试使用其他关键词搜索" : "创建您的第一个知识库来组织文档"}
              </p>
              {!searchQuery && (
                <Button onClick={() => setIsCreateDialogOpen(true)}>
                  <Plus className="w-4 h-4 mr-2" />
                  创建知识库
                </Button>
              )}
            </CardContent>
          </Card>
        ) : (
          <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-6">
            {filteredKnowledgeBases.map((kb) => (
              <Card key={kb.id} className="hover:shadow-lg transition-shadow backdrop-blur-sm bg-card/80 border-border/50">
                <CardHeader>
                  <div className="flex items-start justify-between">
                    <div className="flex items-center space-x-2">
                      <BookOpen className="w-5 h-5 text-blue-600" />
                      <div>
                        <CardTitle className="text-lg">{kb.name}</CardTitle>
                        <CardDescription className="text-sm">
                          {kb.description || "暂无描述"}
                        </CardDescription>
                      </div>
                    </div>
                    <div className="flex items-center space-x-1">
                      {kb.document_count > 0 ? (
                        <CheckCircle className="w-4 h-4 text-green-600" />
                      ) : (
                        <Clock className="w-4 h-4 text-gray-400" />
                      )}
                    </div>
                  </div>
                </CardHeader>
                <CardContent>
                  <div className="space-y-2">
                    <div className="flex justify-between text-sm text-muted-foreground">
                      <span>文档数量</span>
                      <span>{kb.document_count} 个文档</span>
                    </div>
                    <div className="flex justify-between text-sm text-muted-foreground">
                      <span>创建时间</span>
                      <span>{formatDate(kb.created_at)}</span>
                    </div>
                    <div className="flex justify-between text-sm">
                      <span>状态</span>
                      <span className={kb.document_count > 0 ? "text-green-600" : "text-gray-500"}>
                        {kb.document_count > 0 ? "已就绪" : "空知识库"}
                      </span>
                    </div>
                  </div>
                  
                  <div className="flex space-x-2 mt-4">
                    <Button 
                      variant="outline" 
                      size="sm" 
                      className="flex-1"
                      onClick={() => router.push(`/knowledge/${kb.id}`)}
                    >
                      <Settings className="w-4 h-4 mr-1" />
                      管理
                    </Button>
                    <Button 
                      variant="outline" 
                      size="sm"
                      onClick={() => handleDeleteKnowledgeBase(kb.id)}
                      className="text-red-600 hover:text-red-700"
                    >
                      <Trash2 className="w-4 h-4" />
                    </Button>
                  </div>
                </CardContent>
              </Card>
            ))}
          </div>
        )}
      </div>
      
      {/* 移动端导航 */}
      <MobileNav />
    </div>
  );
}