feat(ai): integrate new AI SDK and refactor AI services

- Replaced @langchain/openai with @ai-sdk/openai for improved functionality.
- Updated AI service methods to utilize the new SDK, including getOpenAiProvider and getOpenAiModel.
- Refactored AI agent and deep reading services to implement new tool definitions and execution logic.
- Enhanced comment service to utilize the new AI model for content review and spam detection.
- Added new AI prompts for summarization and title generation.

Signed-off-by: Innei <[email protected]>

Author: Innei

apps/core/package.json

@@ -48,6 +48,7 @@
     "changelog": true
   },
   "dependencies": {
+    "@ai-sdk/openai": "1.3.23",
     "@algolia/client-search": "^4.22.1",
     "@babel/core": "7.27.4",
     "@babel/plugin-transform-modules-commonjs": "7.27.1",
@@ -59,7 +60,6 @@
     "@innei/next-async": "0.3.0",
     "@innei/pretty-logger-nestjs": "0.3.4",
     "@keyv/redis": "4.4.0",
-    "@langchain/openai": "0.5.10",
     "@mx-space/compiled": "workspace:*",
     "@nestjs/cache-manager": "3.0.1",
     "@nestjs/common": "11.1.3",
@@ -77,6 +77,7 @@
     "@typegoose/auto-increment": "4.13.0",
     "@typegoose/typegoose": "12.16.0",
     "@types/jsonwebtoken": "9.0.9",
+    "ai": "4.3.17",
     "algoliasearch": "4.24.0",
     "axios": "^1.9.0",
     "axios-retry": "4.5.0",
@@ -98,7 +99,6 @@
     "jsonwebtoken": "9.0.2",
     "jszip": "3.10.1",
     "keyv": "5.3.4",
-    "langchain": "0.3.25",
     "linkedom": "0.18.11",
     "lodash": "^4.17.21",
     "lru-cache": "11.1.0",
@@ -131,8 +131,6 @@
     "zx-cjs": "7.0.7-0"
   },
   "devDependencies": {
-    "@langchain/core": "0.3.55",
-    "@langchain/langgraph": "0.2.72",
     "@nestjs/cli": "11.0.7",
     "@nestjs/schematics": "11.0.5",
     "@nestjs/testing": "11.1.3",

apps/core/src/modules/ai/ai-agent/README.md

@@ -0,0 +1,148 @@
+# AI Agent API Documentation
+
+## Overview
+The AI Agent module provides a chat bot API that can answer questions about your blog content using AI. It supports both streaming and synchronous responses.
+
+## Configuration
+To enable the AI Agent, you need to configure the following in the admin panel:
+
+1. Go to Settings > AI Settings
+2. Set `openAiKey` - Your OpenAI API key
+3. Set `openAiEndpoint` (optional) - Custom OpenAI endpoint if needed
+4. Set `openAiPreferredModel` - Default: `gpt-4o-mini`
+5. Enable `enableAIAgent` - Toggle to enable the AI Agent feature
+
+## API Endpoints
+
+### POST `/api/ai/agent/chat` (Streaming)
+Chat with the AI agent about your blog content with streaming responses.
+
+**Authentication**: Required (must be logged in)
+
+**Request Body**:
+```json
+{
+  "message": "What are your latest blog posts?",
+  "context": [  // Optional conversation history
+    {
+      "role": "user",
+      "content": "Previous question"
+    },
+    {
+      "role": "assistant", 
+      "content": "Previous answer"
+    }
+  ]
+}
+```
+
+**Response**: Server-Sent Events (SSE) stream
+```
+data: {"type":"text","text":"Here are the latest blog posts"}
+data: {"type":"text","text":"..."}
+data: {"type":"finish","finishReason":"stop"}
+```
+
+### POST `/api/ai/agent/chat/sync` (Non-Streaming)
+Chat with the AI agent synchronously (waits for complete response).
+
+**Authentication**: Required
+
+**Request Body**: Same as streaming endpoint
+
+**Response**:
+```json
+{
+  "message": "Here are the latest blog posts...",
+  "timestamp": "2024-01-01T12:00:00.000Z"
+}
+```
+
+### GET `/api/ai/agent/status`
+Check if the AI Agent is enabled and configured.
+
+**Authentication**: Required
+
+**Response**:
+```json
+{
+  "enabled": true,
+  "service": "AI Agent Chat"
+}
+```
+
+## Available Tools
+The AI Agent has access to the following tools to query your blog data:
+
+- **Posts**: Get posts by ID, list posts, get latest post, get posts by category/tag
+- **Notes**: Get notes by ID, list notes, get latest notes
+- **Categories**: Get category info, list all categories
+- **Tags**: Get tag summary, get posts by tag
+- **Pages**: Get page by ID, list all pages
+- **Says**: Get all says, get random say
+- **Recently**: Get recent activities
+- **Comments**: Get comments, get comments by content
+
+## Example Usage
+
+### Streaming Chat (JavaScript/TypeScript)
+```javascript
+const response = await fetch('http://localhost:2333/api/ai/agent/chat', {
+  method: 'POST',
+  headers: {
+    'Authorization': 'Bearer YOUR_TOKEN',
+    'Content-Type': 'application/json'
+  },
+  body: JSON.stringify({
+    message: 'What blog posts do you have about TypeScript?'
+  })
+})
+
+const reader = response.body.getReader()
+const decoder = new TextDecoder()
+
+while (true) {
+  const { done, value } = await reader.read()
+  if (done) break
+  
+  const text = decoder.decode(value)
+  const lines = text.split('\n')
+  
+  for (const line of lines) {
+    if (line.startsWith('data: ')) {
+      const data = JSON.parse(line.slice(6))
+      if (data.type === 'text') {
+        console.log(data.text)
+      }
+    }
+  }
+}
+```
+
+### Synchronous Chat
+```bash
+curl -X POST http://localhost:2333/api/ai/agent/chat/sync \
+  -H "Authorization: Bearer YOUR_TOKEN" \
+  -H "Content-Type: application/json" \
+  -d '{
+    "message": "What blog posts do you have about TypeScript?"
+  }'
+```
+
+### Check AI Agent Status
+```bash
+curl -X GET http://localhost:2333/api/ai/agent/status \
+  -H "Authorization: Bearer YOUR_TOKEN"
+```
+
+## Streaming Response Format
+The streaming endpoint uses Server-Sent Events (SSE) format. Each message is prefixed with `data: ` and contains a JSON object:
+
+- `{"type":"text","text":"..."}` - Partial text response
+- `{"type":"tool-call","toolCall":{...}}` - Tool invocation information
+- `{"type":"tool-result","toolResult":{...}}` - Tool execution result
+- `{"type":"finish","finishReason":"stop"}` - Stream completion
+
+## Error Codes
+- `ErrorCodeEnum.AINotEnabled` - AI Agent is not enabled in the configuration
+- Authentication errors - User must be logged in to use the AI Agent

apps/core/src/modules/ai/ai-agent/ai-agent.controller.ts

@@ -0,0 +1,44 @@
+import { Readable } from 'node:stream'
+import { FastifyReply } from 'fastify'
+
+import { Body, Get, Post, Res } from '@nestjs/common'
+
+import { ApiController } from '~/common/decorators/api-controller.decorator'
+import { Auth } from '~/common/decorators/auth.decorator'
+import { BizException } from '~/common/exceptions/biz.exception'
+import { ErrorCodeEnum } from '~/constants/error-code.constant'
+
+import { ConfigsService } from '../../configs/configs.service'
+import { ChatRequestDto, ChatResponseDto } from './ai-agent.dto'
+import { AIAgentService } from './ai-agent.service'
+
+@ApiController('ai/agent')
+export class AIAgentController {
+  constructor(
+    private readonly aiAgentService: AIAgentService,
+    private readonly configService: ConfigsService,
+  ) {}
+
+  @Post('chat')
+  @Auth()
+  async chat(
+    @Body() chatRequest: ChatRequestDto,
+    @Res() reply: FastifyReply,
+  ): Promise<void> {
+    const result = await this.aiAgentService.chatWithTools(chatRequest.message)
+
+    // 使用 toDataStreamResponse 获取 SSE 格式的响应
+    const response = result.toDataStreamResponse()
+
+    // 设置响应头
+    response.headers.forEach((value, key) => {
+      reply.header(key, value)
+    })
+
+    // 将 Web Response 的 ReadableStream 转换为 Node.js Readable 流
+    if (response.body) {
+      const nodeStream = Readable.fromWeb(response.body as any)
+      return reply.send(nodeStream)
+    }
+  }
+}

apps/core/src/modules/ai/ai-agent/ai-agent.dto.ts

@@ -0,0 +1,19 @@
+import { IsArray, IsNotEmpty, IsOptional, IsString } from 'class-validator'
+
+export class ChatRequestDto {
+  @IsString()
+  @IsNotEmpty()
+  message: string
+
+  @IsArray()
+  @IsOptional()
+  context?: Array<{
+    role: 'user' | 'assistant'
+    content: string
+  }>
+}
+
+export class ChatResponseDto {
+  message: string
+  timestamp: Date
+}