feat: 引入 AI 聊天总结功能，并新增聊天会话、消息管理接口及前端组件。

src/backend/api.ts

@@ -1,5 +1,7 @@
 import { Elysia } from "elysia";
 import { db } from "./db";
+import { generateSummary } from "./llm";
+import { randomUUID } from "crypto";
 
 // Define the API app
 export const api = new Elysia({ prefix: "/api" })
@@ -101,6 +103,57 @@ export const api = new Elysia({ prefix: "/api" })
             console.error('Import failed:', err);
             throw new Error(err.message);
         }
+    })
+    .post("/summary", async ({ body }) => {
+        const { conversationId, startTime, endTime } = body as { conversationId: string, startTime: number, endTime: number };
+
+        // 1. Check cache (summaries table)
+        // Format date string YYYY-MM-DD from startTime for simple caching key
+        const dateObj = new Date(startTime);
+        const dateStr = `${dateObj.getFullYear()}-${String(dateObj.getMonth() + 1).padStart(2, '0')}-${String(dateObj.getDate()).padStart(2, '0')}`;
+
+        const cached = db.query("SELECT * FROM summaries WHERE conversation_id = $cid AND date = $date").get({
+            $cid: conversationId,
+            $date: dateStr
+        }) as any;
+
+        if (cached) {
+            console.log("Returning cached summary for", dateStr);
+            return { content: cached.content };
+        }
+
+        // 2. Fetch messages
+        const messages = db.query(`
+            SELECT m.content, u.name as senderName 
+            FROM messages m
+            LEFT JOIN users u ON m.sender_id = u.id
+            WHERE conversation_id = $cid AND timestamp >= $start AND timestamp <= $end
+            ORDER BY timestamp ASC
+        `).all({
+            $cid: conversationId,
+            $start: startTime,
+            $end: endTime
+        }) as any[];
+
+        if (messages.length === 0) {
+            return { content: "该时间段内没有消息。" };
+        }
+
+        // 3. Generate summary
+        const messageTexts = messages.map(m => `${m.senderName || 'Unknown'}: ${m.content}`);
+        const summaryContent = await generateSummary(messageTexts);
+
+        // 4. Save to cache
+        const insertSummary = db.prepare("INSERT INTO summaries (id, conversation_id, date, content, created_at) VALUES ($id, $cid, $date, $content, $createdAt)");
+        insertSummary.run({
+            $id: randomUUID(),
+            $cid: conversationId,
+            $date: dateStr,
+            $content: summaryContent,
+            $createdAt: Date.now()
+        });
+
+        return { content: summaryContent };
     });
 
 export type App = typeof api;

src/backend/db.ts

@@ -42,6 +42,18 @@ export function initDB() {
     )
   `);
 
+  // Summaries
+  db.run(`
+    CREATE TABLE IF NOT EXISTS summaries (
+      id TEXT PRIMARY KEY,
+      conversation_id TEXT NOT NULL,
+      date TEXT NOT NULL,
+      content TEXT NOT NULL,
+      created_at INTEGER NOT NULL,
+      FOREIGN KEY (conversation_id) REFERENCES conversations(id)
+    )
+  `);
+
   // Seed data if empty
   const userCount = db.query("SELECT count(*) as count FROM users").get() as { count: number };
   if (userCount.count === 0) {

src/backend/llm.ts

@@ -0,0 +1,48 @@
+export interface LLMResponse {
+    content: string;
+}
+
+const API_KEY = process.env.LLM_API_KEY || 'sk-xxxx'; // Default or from env
+const BASE_URL = process.env.LLM_BASE_URL || 'https://api.openai.com/v1';
+const MODEL = process.env.LLM_MODEL || 'gpt-3.5-turbo';
+
+export async function generateSummary(messages: string[]): Promise<string> {
+    if (messages.length === 0) return "没有足够的消息进行总结。";
+
+    const prompt = `
+请总结以下聊天记录，使用中文，简洁明了，列出关键点：
+
+${messages.join('\n')}
+    `.trim();
+
+    try {
+        const response = await fetch(`${BASE_URL}/chat/completions`, {
+            method: 'POST',
+            headers: {
+                'Content-Type': 'application/json',
+                'Authorization': `Bearer ${API_KEY}`
+            },
+            body: JSON.stringify({
+                model: MODEL,
+                messages: [
+                    { role: 'system', content: '你是一个乐于助人的AI助手，善于总结聊天内容。' },
+                    { role: 'user', content: prompt }
+                ],
+                temperature: 0.7
+            })
+        });
+
+        if (!response.ok) {
+            const error = await response.text();
+            console.error('LLM API Error:', error);
+            throw new Error(`LLM request failed: ${response.statusText}`);
+        }
+
+        const data = await response.json() as any;
+        return data.choices?.[0]?.message?.content || "无法生成总结。";
+
+    } catch (error) {
+        console.error('Generate Summary Error:', error);
+        return "生成总结时发生错误，请稍后再试。";
+    }
+}

src/frontend/components/ChatWindow.tsx

@@ -1,7 +1,8 @@
-import { MoreHorizontal, Smile, FolderOpen, Scissors, Clipboard, Search, X } from 'lucide-react';
+import { MoreHorizontal, Smile, FolderOpen, Scissors, Clipboard, Search, X, Sparkles } from 'lucide-react';
 import { client } from '../client';
 import type { Conversation } from '../data/mock';
 import { MessageBubble } from './MessageBubble';
+import { SummaryModal } from './SummaryModal';
 import { clsx } from 'clsx';
 import { useEffect, useRef, useState } from 'react';
 
@@ -22,6 +23,10 @@ export function ChatWindow({ conversation }: ChatWindowProps) {
     const [startDate, setStartDate] = useState('');
     const [endDate, setEndDate] = useState('');
 
+    // Summary modal
+    const [showSummary, setShowSummary] = useState(false);
+
+
     const fetchMessages = async (isLoadMore = false, query = '', start = '', end = '') => {
         if (!conversation?.id || loading) return;
 
@@ -106,6 +111,11 @@ export function ChatWindow({ conversation }: ChatWindowProps) {
         }
     }, [searchQuery, isSearching, startDate, endDate]); // Be careful with dependency loops, but this seems okay
 
+    // Reset modal when conversation changes
+    useEffect(() => {
+        setShowSummary(false);
+    }, [conversation?.id]);
+
     // Initial load when conversation changes
     useEffect(() => {
         setMessages([]);
@@ -194,6 +204,14 @@ export function ChatWindow({ conversation }: ChatWindowProps) {
                 </div>
             </div>
 
+            {/* AI Summary Modal */}
+            {showSummary && conversation && (
+                <SummaryModal
+                    conversationId={conversation.id}
+                    onClose={() => setShowSummary(false)}
+                />
+            )}
+
             {/* Messages */}
             <div
                 className="flex-1 overflow-y-auto p-6 scrollbar-thin"
@@ -236,7 +254,13 @@ export function ChatWindow({ conversation }: ChatWindowProps) {
                 <div className="h-10 flex items-center px-4 gap-4 text-[#666]">
                     <Smile className="w-5 h-5 cursor-pointer hover:text-[#333]" />
                     <FolderOpen className="w-5 h-5 cursor-pointer hover:text-[#333]" />
-                    {/* Fake scissors icon using a character or placeholder if icon missing, but lucide has Scissors usually. Using generic placeholders if not sure */}
+                    <button
+                        onClick={() => setShowSummary(true)}
+                        className="flex items-center gap-1 text-purple-600 hover:text-purple-700 transition-colors ml-auto text-sm font-medium"
+                        title="AI Chat Summary"
+                    >
+                        <Sparkles className="w-4 h-4" /> AI 总结
+                    </button>
                 </div>
 
                 {/* Text Area */}

src/frontend/components/SummaryModal.tsx

@@ -0,0 +1,134 @@
+import { useState } from 'react';
+import { X, Calendar, Sparkles, Loader2, Copy } from 'lucide-react';
+import { client } from '../client';
+import { clsx } from 'clsx';
+
+interface SummaryModalProps {
+    conversationId: string;
+    onClose: () => void;
+}
+
+export function SummaryModal({ conversationId, onClose }: SummaryModalProps) {
+    const [step, setStep] = useState<'date' | 'result'>('date');
+    const [selectedDate, setSelectedDate] = useState(() => {
+        const yesterday = new Date();
+        yesterday.setDate(yesterday.getDate() - 1);
+        return yesterday.toISOString().split('T')[0];
+    });
+    const [loading, setLoading] = useState(false);
+    const [summary, setSummary] = useState('');
+    const [error, setError] = useState('');
+
+    const handleGenerate = async () => {
+        setLoading(true);
+        setError('');
+        try {
+            const start = new Date(selectedDate);
+            start.setHours(0, 0, 0, 0);
+
+            const end = new Date(selectedDate);
+            end.setHours(23, 59, 59, 999);
+
+            const { data, error: apiError } = await client.api.summary.post({
+                conversationId,
+                startTime: start.getTime(),
+                endTime: end.getTime()
+            });
+
+            if (apiError) throw apiError;
+
+            // @ts-ignore
+            if (data?.content) {
+                // @ts-ignore
+                setSummary(data.content);
+                setStep('result');
+            } else {
+                throw new Error("Failed to get summary");
+            }
+        } catch (err: any) {
+            setError(err.message || "生成总结失败");
+        } finally {
+            setLoading(false);
+        }
+    };
+
+    const handleCopy = () => {
+        navigator.clipboard.writeText(summary);
+    };
+
+    return (
+        <div className="fixed inset-0 bg-black/50 z-50 flex items-center justify-center p-4">
+            <div className="bg-white rounded-lg shadow-xl w-full max-w-md flex flex-col max-h-[85vh]">
+                {/* Header */}
+                <div className="flex items-center justify-between p-4 border-b shrink-0">
+                    <h3 className="text-lg font-medium flex items-center gap-2">
+                        <Sparkles className="w-5 h-5 text-purple-600" />
+                        AI 聊天总结
+                    </h3>
+                    <button onClick={onClose} className="p-1 hover:bg-gray-100 rounded-full">
+                        <X className="w-5 h-5 text-gray-500" />
+                    </button>
+                </div>
+
+                {/* Content */}
+                <div className="p-6 overflow-y-auto flex-1">
+                    {step === 'date' ? (
+                        <div className="space-y-4">
+                            <p className="text-sm text-gray-600">请选择要总结的日期（默认昨天）：</p>
+                            <div className="flex items-center gap-2 border p-2 rounded-md hover:border-blue-500 transition-colors">
+                                <Calendar className="w-5 h-5 text-gray-400" />
+                                <input
+                                    type="date"
+                                    className="flex-1 outline-none text-gray-700"
+                                    value={selectedDate}
+                                    onChange={(e) => setSelectedDate(e.target.value)}
+                                    max={new Date().toISOString().split('T')[0]}
+                                />
+                            </div>
+                            {error && (
+                                <div className="text-sm text-red-500 bg-red-50 p-2 rounded">
+                                    {error}
+                                </div>
+                            )}
+                        </div>
+                    ) : (
+                        <div className="space-y-4">
+                            <div className="flex items-center justify-between text-sm text-gray-500">
+                                <span>{selectedDate} 的总结：</span>
+                                <button onClick={handleCopy} className="flex items-center gap-1 hover:text-blue-600">
+                                    <Copy className="w-3 h-3" /> 复制
+                                </button>
+                            </div>
+                            <div className="prose prose-sm max-w-none bg-gray-50 p-4 rounded-md text-gray-700 whitespace-pre-wrap leading-relaxed">
+                                {summary}
+                            </div>
+                        </div>
+                    )}
+                </div>
+
+                {/* Footer */}
+                <div className="p-4 border-t bg-gray-50 rounded-b-lg flex justify-end gap-3 shrink-0">
+                    <button
+                        onClick={onClose}
+                        className="px-4 py-2 text-sm text-gray-600 hover:bg-gray-200 rounded-md transition-colors"
+                    >
+                        {step === 'result' ? '关闭' : '取消'}
+                    </button>
+                    {step === 'date' && (
+                        <button
+                            onClick={handleGenerate}
+                            disabled={loading}
+                            className={clsx(
+                                "px-4 py-2 text-sm text-white rounded-md flex items-center gap-2 transition-all",
+                                loading ? "bg-purple-400 cursor-not-allowed" : "bg-purple-600 hover:bg-purple-700 shadow-md hover:shadow-lg"
+                            )}
+                        >
+                            {loading && <Loader2 className="w-4 h-4 animate-spin" />}
+                            {loading ? '生成中...' : '开始生成'}
+                        </button>
+                    )}
+                </div>
+            </div>
+        </div>
+    );
+}