# WhatsApp AI Task Scheduling Service

A Node.js/Express/TypeScript application that provides intelligent task scheduling with WhatsApp notifications and AI-powered optimization.

## Features

- **Task Management**: Create, update, delete, and track tasks with priorities and due dates
- **AI-Powered Scheduling**: Uses OpenAI to suggest optimal times for task completion
- **WhatsApp Integration**: Sends task reminders and notifications via WhatsApp using Twilio
- **User Authentication**: JWT-based authentication system
- **Automated Scheduling**: Background jobs for daily reminders and overdue task notifications
- **Health Monitoring**: Built-in health check endpoints

## Tech Stack

- **Runtime**: Node.js with TypeScript
- **Framework**: Express.js
- **Database**: SQLite with Prisma ORM  
- **Authentication**: JWT tokens with bcrypt password hashing
- **WhatsApp**: Twilio WhatsApp Business API
- **AI**: OpenAI GPT-3.5 for intelligent scheduling
- **Scheduling**: node-cron for background jobs
- **Logging**: Winston for structured logging

## Prerequisites

- Node.js 18+ and npm
- Environment variables (see below)

## Installation

1. Clone the repository
2. Install dependencies:
```bash
npm install
```

3. Copy environment configuration:
```bash
cp .env.example .env
```

4. Configure environment variables in `.env` file

5. Generate Prisma client and run migrations:
```bash
npm run prisma:generate
npm run prisma:migrate
```

6. Build the application:
```bash
npm run build
```

7. Start the server:
```bash
npm start
```

For development:
```bash
npm run dev
```

## Required Environment Variables

```env
# Database
DATABASE_URL="file:./storage/db/database.db"

# JWT Authentication
JWT_SECRET="your-super-secret-jwt-key-here"
JWT_EXPIRES_IN="24h"

# Twilio WhatsApp Integration
TWILIO_ACCOUNT_SID="your-twilio-account-sid"
TWILIO_AUTH_TOKEN="your-twilio-auth-token"
TWILIO_WHATSAPP_FROM="whatsapp:+14155238886"

# OpenAI for AI Features
OPENAI_API_KEY="your-openai-api-key"

# Server Configuration
PORT=3000
NODE_ENV="development"
```

## API Endpoints

### Base URL
- **GET** `/` - Service information and documentation links
- **GET** `/docs` - API documentation
- **GET** `/api/health` - Health check endpoint

### Authentication
- **POST** `/api/auth/register` - Register new user
- **POST** `/api/auth/login` - User login

### Tasks (Protected Routes)
- **POST** `/api/tasks` - Create new task
- **GET** `/api/tasks` - Get user's tasks (with pagination and filtering)
- **GET** `/api/tasks/:id` - Get specific task
- **PUT** `/api/tasks/:id` - Update task
- **DELETE** `/api/tasks/:id` - Delete task
- **POST** `/api/tasks/:id/remind` - Send WhatsApp reminder for task

## Usage Examples

### Register User
```bash
curl -X POST http://localhost:3000/api/auth/register \
  -H "Content-Type: application/json" \
  -d '{
    "email": "user@example.com",
    "password": "securepassword",
    "fullName": "John Doe",
    "whatsappNumber": "+1234567890"
  }'
```

### Create Task
```bash
curl -X POST http://localhost:3000/api/tasks \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_JWT_TOKEN" \
  -d '{
    "title": "Complete project proposal",
    "description": "Write and review the Q1 project proposal",
    "priority": "HIGH",
    "dueDate": "2024-02-15T17:00:00.000Z"
  }'
```

## Features Details

### AI-Powered Scheduling
The service uses OpenAI to analyze task priority, due dates, and optimal work hours to suggest the best time to work on tasks.

### WhatsApp Notifications
- Daily reminders for scheduled tasks (9 AM UTC)
- Overdue task notifications (6 PM UTC)
- Manual reminder triggers via API

### Background Jobs
- **Daily Reminders**: Sends WhatsApp reminders for tasks scheduled for today
- **Overdue Checks**: Notifies users about overdue tasks

## Database Schema

### Users Table
- `id`, `email`, `password` (hashed)
- `fullName`, `phoneNumber`, `whatsappNumber`
- `isActive`, `createdAt`, `updatedAt`

### Tasks Table
- `id`, `title`, `description`
- `status` (PENDING, IN_PROGRESS, COMPLETED, CANCELLED)
- `priority` (LOW, MEDIUM, HIGH, URGENT)
- `dueDate`, `scheduledAt`, `aiSuggestedTime`
- `whatsappReminderSent`, `whatsappCompletionSent`
- `ownerId`, timestamps

## Development

### Available Scripts
- `npm run dev` - Start development server with hot reload
- `npm run build` - Build TypeScript to JavaScript
- `npm start` - Start production server
- `npm run lint` - Run ESLint
- `npm run lint:fix` - Fix ESLint issues
- `npm run prisma:generate` - Generate Prisma client
- `npm run prisma:migrate` - Run database migrations
- `npm run prisma:studio` - Open Prisma Studio

### Project Structure
```
src/
├── controllers/     # Request handlers
├── middleware/      # Express middleware
├── models/         # Database models (Prisma)
├── routes/         # API route definitions
├── services/       # Business logic services
├── types/          # TypeScript type definitions
└── utils/          # Utility functions
```

## Error Handling

The application includes comprehensive error handling with:
- Structured error responses
- Request validation using Joi
- Database error handling
- Authentication error handling
- Rate limiting protection

## Logging

Winston logger provides structured logging with different levels:
- Development: Console output with colors
- Production: File-based logging (error.log, combined.log)

## Contributing

This project was generated by BackendIM, an AI-powered backend generation platform.