⚙️ LifeSolve AI — Backend

The RESTful API powering LifeSolve AI's community platform.

LifeSolve AI is a community-driven platform where people share life challenges, receive instant AI-powered guidance, and connect with others who genuinely understand. This repository contains the Express + TypeScript backend that handles all server-side logic.

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📖 Description

The LifeSolve AI Backend provides every server-side feature of the platform — problem management, comments, reactions, direct messaging, notifications, authentication, analytics, and streaming AI responses powered by Groq. It exposes a clean REST API consumed by the LifeSolve AI Frontend.

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🎯 Overview

The backend is organized around domain modules and provides:

Area	What it does
📝 Problems	CRUD, search, filter, sort, pagination for community posts
💬 Comments & Reactions	Full comment CRUD + like/love/sad reaction toggles
🤖 AI Integration	Streaming AI responses in three modes (solver, chat, quick-chat)
⚡ AI Quick Chat	Ephemeral endpoint — answers are never saved to the database
✉️ Messaging	Real-time private conversations between users
🔔 Notifications	Event-driven notifications for comments, reactions, messages
🔐 Authentication	Bearer token session validation via Better Auth
📊 Statistics	Platform-wide and per-user analytics with daily breakdowns

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🎯 Purpose

The backend exists to give LifeSolve AI a secure, scalable, and real-time foundation:

• Serve AI responses with streaming (SSE) for a smooth chat experience.
• Offer an ephemeral quick-chat mode for the floating widget so anyone can ask the AI anything without any data being persisted.
• Persist user content — problems, comments, conversations, notifications — in MongoDB.
• Protect user data with session-based authentication on every mutating route.

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✨ Key Features

Feature	Description
Problem CRUD	Full create, read, update, delete with search, filter, pagination
Comment System	Create, edit, delete comments on problems
Reactions	Like, Love, Sad toggle with per-user tracking
AI Solver	Streaming AI responses for structured problem-solving (saved sessions)
AI Chat	Streaming conversational AI for general support (saved sessions)
AI Quick Chat	Streaming AI for the floating widget — no DB writes, no auth required
Direct Messages	Private conversations with user discovery
Notifications	5 event types: problem posted, resolved, comment, reaction, message
User Stats	Per-user post/comment counts with 7-day activity
Platform Stats	Global counts for posts, comments, messages, AI chats, users
Auth Middleware	Session-based authentication via Better Auth tokens
Health Check	API health endpoint

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🛠️ Technology Stack

Technology	Purpose
Express 5	Web framework
TypeScript	Type safety
Mongoose 9	MongoDB ODM
MongoDB	Database (Atlas)
Groq API	AI inference (OpenAI-compatible, streaming)
Better Auth	Session management (MongoDB adapter)
CORS	Cross-Origin Resource Sharing
tsx	TypeScript execution in development

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📁 Project Structure

backend/
├── api/                            # Vercel serverless entry point
├── src/
│   ├── index.ts                    # Entry point — DNS, dotenv, DB connect, listen
│   ├── app.ts                      # Express app — CORS, JSON, routes, error handler
│   ├── config/
│   │   └── db.ts                   # MongoDB connection via Mongoose
│   ├── types/
│   │   └── index.ts                # AuthUser & AuthRequest type definitions
│   ├── middleware/
│   │   └── auth.ts                 # Bearer token authentication middleware
│   ├── lib/
│   │   └── createNotification.ts   # Utility to persist notifications
│   ├── models/
│   │   ├── Problem.ts              # Problem schema (title, description, category, etc.)
│   │   ├── Comment.ts              # Comment schema (problemId, userId, content)
│   │   ├── Message.ts              # Conversation + Message schemas (messaging)
│   │   ├── Notification.ts         # Notification schema (userId, type, message)
│   │   └── ChatSession.ts          # AI Chat Session schema (solver + chat)
│   ├── controllers/
│   │   ├── problemController.ts    # Problem CRUD + stats
│   │   ├── commentController.ts    # Comment CRUD
│   │   ├── reactionController.ts   # Toggle like/love/sad
│   │   ├── aiController.ts         # AI solver, chat, sessions, quick-chat
│   │   ├── messageController.ts    # Users, conversations, messages
│   │   └── notificationController.ts # Fetch, mark read, mark all read
│   └── routes/
│       ├── problems.ts             # Problems, comments, reactions, stats
│       ├── ai.ts                   # AI solver, chat, sessions + quick-chat
│       ├── messages.ts             # Users, conversations, messages
│       └── notifications.ts        # Notifications
├── vercel.json                     # Vercel deployment config
├── tsconfig.json                   # TypeScript configuration
└── package.json                    # Dependencies & scripts

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🔌 API Endpoints

Health

Method	Path	Auth	Description
GET	/api/health	—	Health check (status + timestamp)

AI — /api/ai

Method	Path	Auth	Description
POST	/api/ai/quick-chat	—	Ephemeral AI chat (streaming, nothing saved)
POST	/api/ai/solver	Bearer	AI problem solver (streaming)
GET	/api/ai/solver/sessions	Bearer	List solver sessions
GET	/api/ai/solver/sessions/:id	Bearer	Get solver session detail
POST	/api/ai/chat	Bearer	AI chat assistant (streaming)
GET	/api/ai/chat/sessions	Bearer	List chat sessions
GET	/api/ai/chat/sessions/:id	Bearer	Get chat session detail
DELETE	/api/ai/chat/sessions/:id	Bearer	Delete chat session

POST /api/ai/quick-chat accepts { messages: [{ role, content }] } and streams an answer back. It requires no authentication and performs no database writes — the conversation history is sent by the client and kept only in memory for the duration of the request.

Problems — /api/problems

Method	Path	Auth	Description
GET	/api/problems	—	List problems (search, category, sort, page, limit)
GET	/api/problems/:id	—	Get single problem by ID
POST	/api/problems	Bearer	Create a new problem
PUT	/api/problems/:id	Bearer	Update problem (owner only)
DELETE	/api/problems/:id	Bearer	Delete problem (owner only)
GET	/api/problems/my	Bearer	Get current user's problems
GET	/api/problems/stats/my	Bearer	Get current user's stats
GET	/api/problems/stats/overview	—	Get platform-wide stats

Reactions — /api/problems/:id/react

Method	Path	Auth	Description
POST	/api/problems/:id/react	Bearer	Toggle like/love/sad reaction

Comments — /api/problems/:id/comments

Method	Path	Auth	Description
GET	/api/problems/:id/comments	—	List comments for a problem
POST	/api/problems/:id/comments	Bearer	Create a comment
PUT	/api/problems/:id/comments/:commentId	Bearer	Update comment (owner only)
DELETE	/api/problems/:id/comments/:commentId	Bearer	Delete comment (owner only)

Messages — /api

Method	Path	Auth	Description
GET	/api/users	Bearer	List all users (except current)
GET	/api/messages/conversations	Bearer	List current user's conversations
POST	/api/messages/conversations	Bearer	Get or create conversation with a user
GET	/api/messages/conversations/:id	Bearer	Get messages in a conversation
POST	/api/messages/conversations/:id	Bearer	Send a message

Notifications — /api

Method	Path	Auth	Description
GET	/api/notifications	Bearer	Get notifications (paginated)
GET	/api/notifications/unread-count	Bearer	Get unread notification count
POST	/api/notifications/:id/read	Bearer	Mark notification as read
POST	/api/notifications/read-all	Bearer	Mark all notifications as read

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🗄️ Database Models

Problem

Field	Type	Details
title	String	Required, trimmed
shortDescription	String	Required, trimmed
fullDescription	String	Required, trimmed
category	String	Required
priority	String	Enum: Low, Medium, High, Emergency
images	String[]	Array of image URLs
userId	String	Required (Better Auth user ID)
userName	String	Required
userImage	String	Optional
status	String	Enum: open, resolved (default: open)
reactions	Object	{ likes: String[], loves: String[], sads: String[] }

Comment

Field	Type	Details
problemId	ObjectId	Ref: Problem, indexed
userId	String	Required
userName	String	Required
userImage	String	Optional
content	String	Required, trimmed

Conversation

Field	Type	Details
participants	String[2]	Exactly 2 user IDs, validated
lastMessage	String	Optional, message preview
lastMessageBy	String	User ID of last sender
lastMessageAt	Date	Timestamp of last message

Message

Field	Type	Details
conversationId	ObjectId	Ref: Conversation, indexed
senderId	String	Required
senderName	String	Required
senderImage	String	Optional
receiverId	String	Required
receiverName	String	Required
content	String	Required, trimmed
read	Boolean	Default: false

Notification

Field	Type	Details
userId	String	Required, indexed
type	String	Enum: problem_created, problem_resolved, new_comment, new_reaction, new_message
title	String	Required
message	String	Required
referenceId	String	Required (links to related entity)
read	Boolean	Default: false

ChatSession

Field	Type	Details
userId	String	Required, indexed
sessionType	String	Enum: solver, chat, indexed
title	String	Default: "New Session"
messages	SubDoc[]	Array of { role, content } with timestamps

The quick-chat mode intentionally uses no model — it never touches the database.

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💻 Installation

Prerequisites

• Node.js 18+
• npm or yarn
• MongoDB instance (local or Atlas)
• Groq API key (for AI features)

Setup

# Clone the repository
git clone <repository-url>
cd backend

# Install dependencies
npm install

# Create environment file
cp .env.example .env

# Edit .env with your configuration
# Required variables:
#   MONGODB_URI
#   GROQ_API_KEY (for AI features)
# Optional:
#   PORT
#   CORS_ORIGIN

# Start development server with hot reload
npm run dev

The server will start at http://localhost:5000.

Available Scripts

Script	Command	Description
npm run dev	tsx watch src/index.ts	Development with hot reload
npm run build	tsc	Compile TypeScript to dist/
npm start	node dist/index.js	Run compiled production build

Environment Variables

Variable	Required	Default	Description
PORT	No	5000	Server port
MONGODB_URI	Yes	—	MongoDB connection string
CORS_ORIGIN	No	http://localhost:3000	Allowed CORS origin
GROQ_API_KEY	Yes (for AI)	—	Groq API key for AI features

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🔐 Authentication Flow

1. The frontend handles user registration/login via Better Auth (handled by Next.js API routes)
2. Better Auth stores sessions in the session MongoDB collection
3. All protected API routes require an Authorization: Bearer <token> header
4. The authenticate middleware validates the token, checks expiry, and attaches req.user
5. User IDs are used throughout the system for ownership and notification routing

The /api/ai/quick-chat endpoint is intentionally public so the floating chat widget works for both visitors and logged-in users — it performs no DB writes and stores nothing.

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🔔 Notification Triggers

Notifications are automatically created by controllers when these events occur:

Event	Triggered By	Receiver
Problem created	createProblem	Post author
Problem resolved	updateProblem (status → resolved)	Post author
New comment	createComment	Problem owner (if not self)
New reaction	toggleReaction	Problem owner (if not self)
New message	sendMessage	Message recipient

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🩺 Health Check

GET /api/health
Response: { "status": "ok", "timestamp": "2024-01-01T00:00:00.000Z" }

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🤝 Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

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📄 License

This project is private and not licensed for public distribution.