Task WhatsApp Chatbot

A WhatsApp chatbot for task management, designed to work with Evolution API in a secure internal network environment.

📌 Overview

This service provides a WhatsApp interface for task management within WhatsApp groups. It:

• Listens for /tarea commands in WhatsApp groups via Evolution API webhooks.
• Stores tasks, users, and groups in a SQLite database.
• Synchronizes group information periodically from the Evolution API.
• Manages user permissions and group membership (partially implemented).
• Integrates with Evolution API for WhatsApp connectivity.

🔐 Security Model

• Internal Networking: The webhook should ideally only accept connections from Evolution API via internal Docker networking (configuration dependent).
• Environment Variables: Sensitive configuration (API keys, URLs) is managed through environment variables.
• Group Restrictions: Designed to operate within pre-approved WhatsApp groups (validation logic pending integration).
• Input Validation: Basic validation exists for webhook structure; needs enhancement for command arguments and user/group IDs.

🧱 Architecture

graph TD
    A[Webhook Received] --> B{Valid Payload?}
    B -->|No| C[Ignore]
    B -->|Yes| D{Normalize IDs & Check Group Active?}
    D -->|No| C[Ignore/Log]
    D -->|Yes| E[Ensure User Exists in DB]
    E --> G{/tarea Command?}
    G -->|No| C
    G -->|Yes| J[Process Command Logic]
    J -- Success/Error --> K[Queue Response(s)]
    K --> L[Process Queue & Send Response via API]

    subgraph Database Interaction
        E --> DB[(SQLite DB)]
        J --> DB
    end
    subgraph Evolution API
        L --> EA((Evolution API))
        EA -- Webhook --> A
    end

(Diagram updated for planned flow)

Decisiones de diseño de la cola de respuestas (MVP)

1. Persistencia: 100% persistente (tabla única).
2. Worker: continuo en background.
3. Locking: status=processing (sin lease).
4. Orden: sin orden estricto por chat.
5. Reintentos: sin reintentos en MVP.
6. Errores: 4xx = fallo definitivo; 5xx/red = fallo (sin reintentos).
7. Idempotencia: no.
8. Esquema DB: tabla única response_queue.
9. Transporte: envío desde ResponseQueue (fetch directo a Evolution API).
10. Concurrencia: N workers globales.
11. Integración: encolar y worker continuo (arranca con el servidor).
12. Configuración: defaults fijos (sin nuevas env vars por ahora).
13. Limpieza: sin limpieza/retención de historiales (por ahora).
14. Seguridad: no enviar al número del bot (CHATBOT_PHONE_NUMBER).
15. Pruebas: unitarias de cola con mocks de fetch.

Arquitectura de la cola persistente (MVP)

• Estados: queued | processing | sent | failed.
• Campos mínimos por mensaje: id (PK), recipient, type (text), message, status, attempts (0), last_error (nullable), created_at, updated_at.
• Índices recomendados: (status, created_at) para seleccionar pendientes rápidamente.
• Sin orden estricto por chat; el envío puede intercalarse entre destinatarios.
• Concurrencia: N workers globales operando en bucle, cada uno toma mensajes en estado queued y los marca processing. Estado: la tabla response_queue ya está creada e incluida en los tests de DB.

Flujo del worker continuo (MVP)

• Se inicia al arrancar el servidor (desactivado en tests).
• Ciclo: seleccionar hasta un pequeño batch de mensajes queued, marcar processing, enviar a Evolution API, marcar sent o failed según respuesta.
• Sin reintentos; logs mínimos y no sensibles.

Limitaciones explícitas del MVP

• Sin backoff ni reintentos.
• Sin orden garantizado por chat.
• Sin idempotencia ni limpieza automática.
• Sin lease; en caso de crash podrían quedar mensajes en processing que requerirán recuperación manual en una iteración futura.

Plan incremental posterior

• Añadir reintentos con backoff exponencial y jitter.
• Garantizar orden por chat (serialización por recipient).
• Introducir lease (lease_until) para tolerancia a fallos y recuperación.
• Limpieza/retención y métricas/observabilidad.
• Opcional: idempotencia e índices adicionales.

✅ Current Status (as of latest commit)

Implemented

• Webhook server setup (src/server.ts) receiving Evolution API events.
• Database schema definition and initialization (src/db.ts), including lightweight migration to add response_queue.metadata.
• Group synchronization service (src/services/group-sync.ts) to fetch/store/cache groups. Includes active group caching and isGroupActive checks in server.
• Webhook registration and verification with Evolution API (src/services/webhook-manager.ts).
• WhatsApp ID normalization utility (src/utils/whatsapp.ts).
• User creation/update function (src/db.ts::ensureUserExists) integrated into the main flow.
• Command handling for /tarea nueva end-to-end (src/services/command.ts):
  • Parses description and selects the last future date (YYYY-MM-DD) as due date.
  • Extracts assignees from explicit mentions and plain-text @tokens; defaults to creator only when none found.
  • Cleans description to remove @mentions tokens.
  • Persists task and assignments atomically via TaskService.
  • Builds response with assignment list and includes Evolution API “mentioned” JIDs via ResponseQueue.
• Task persistence service (src/tasks/service.ts) with created_by and assignment inserts in a transaction; supports DB injection for tests.
• Response queue persistente con workers en background y envío vía Evolution API (src/services/response-queue.ts), persistiendo metadata { mentioned: [...] } y enviándola como mentioned en el payload.
• Environment variable validation (src/server.ts, src/services/webhook-manager.ts).
• Health check endpoint (/health).
• Database isolation in unit tests: Using in-memory instances to avoid conflicts.

Incomplete / Missing Core Functionality

• Additional commands: /tarea mostrar (list) y /tarea completar.
• ResponseQueue reliability: reintentos con backoff, recuperación de processing, métricas y limpieza/retención.
• Contact names: optional service/cache to resolve friendly names from Evolution API for nicer “@Nombre” rendering in text (the app already sends mentioned JIDs).
• Database migrations system (beyond current lightweight on-boot checks).
• More robust error handling and observability around API/DB operations.

Known Issues

• Mentions UX: although we send mentioned JIDs, WhatsApp still shows “@número” in the text. This is expected unless we replace the text with a friendly name known to the bot; the client renders the highlight but doesn’t rewrite the text to each user’s local contact name.
• Test suite: currently 1 failing test — “Database > Table Schemas > response_queue table should have required columns”.

🛠️ Setup

Environment Variables

(Ensure these are set correctly)

# Evolution API Connection
EVOLUTION_API_URL=http://evolution-api:3000 # Or your API URL
EVOLUTION_API_KEY=your-api-key
EVOLUTION_API_INSTANCE=main # Your instance name

# WhatsApp Specific
WHATSAPP_COMMUNITY_ID=your-community-id # ID of the main community to sync groups from
CHATBOT_PHONE_NUMBER=1234567890 # Bot's normalized phone number (e.g., for assigning tasks)

# Webhook Configuration
WEBHOOK_URL=http://your-service-internal-url:3007 # URL Evolution API calls *back* to this service
PORT=3007 # Port this service listens on

# Runtime Environment
NODE_ENV=production # Or development

# Optional
# GROUP_SYNC_INTERVAL_MS=3600000 # Sync interval in ms (default: 24h)

Development Setup

# Install dependencies
bun install

# Copy .env.example to .env and fill in values
cp .env.example .env

# Start development server (watches for changes)
bun run dev

# Run tests
bun test

📅 Roadmap & Priorities (Updated Plan)

Phase 1: User & Group Foundation (Highest Priority - In Progress)

• Create WhatsApp ID Normalization Utility: (src/utils/whatsapp.ts) Handle different ID formats.
• Implement ensureUserExists: (src/db.ts) Add users to DB on first interaction.
• Implement isGroupActive Check: (src/services/group-sync.ts, src/server.ts) Cache exists in group-sync.ts. Needs integration into src/server.ts.
• Integrate Validation in Server: (src/server.ts) Use normalization, ensureUserExists, and active group check before processing commands.
• Implement DB isolation in tests: (tests/unit/services/group-sync.test.ts) Use in-memory instances to avoid conflicts.

Phase 2: Refinar /tarea nueva (Alta prioridad)

• Completar TaskService.createTask con created_by y asignaciones (incluyendo ensureUserExists para asignados) y transacción atómica.
• Mejorar CommandService para parsear menciones y devolver el id de la tarea creada y resumen de asignados.

Phase 3: Comandos adicionales y refinamientos (Alta prioridad)

• Implementar /tarea mostrar [group|mine] para listar pendientes.
• Implementar /tarea completar <task_id> con validaciones básicas.
• Soportar mensajes de texto extendido y captions de media (además de conversation).

Phase 4: Fiabilidad de la cola y observabilidad (Media)

• Añadir reintentos con backoff exponencial y jitter.
• Recuperar ítems en estado processing tras reinicios (lease o expiración y requeue).
• Métricas y logging mejorado (contadores de enviados/fallidos, tiempos).
• Limpieza/retención de historiales.

Phase 5: Advanced Features (Low Priority)

• Add task reminders system.
• Implement user permissions system.
• Add rate limiting.
• Create task history tracking.

🔑 Key Considerations & Caveats

• WhatsApp ID Normalization: Crucial for consistently identifying users and groups. Needs careful implementation to handle edge cases. (Utility function exists).
• Response Latency: Sending responses requires an API call back to Evolution. Ensure the ResponseQueue processing is efficient.
• Cola de respuestas: Persistente en DB; pendiente añadir reintentos/backoff y limpieza/retención.
• Group Sync: The current full sync might be slow or rate-limited with many groups. Delta updates are recommended long-term.
• Error Handling: Failures in command processing or response sending should be logged clearly and potentially reported back to the user. Database operations should use transactions for atomicity (especially task+assignment creation).
• State Management: The current design is stateless. Complex interactions might require state persistence later.
• Security: Ensure group/user validation logic is robust once integrated.

🧪 Testing

Running Tests

bun test

Test Coverage

• Database initialization and basic operations (db.test.ts).
• Webhook validation (basic) (webhook-manager.test.ts).
• Command parsing (basic structure) (command.test.ts).
• Environment checks (server.test.ts).
• Basic error handling (server.test.ts).
• WhatsApp ID normalization (whatsapp.test.ts).
• Group sync operations (group-sync.test.ts).
• Needed: Tests for ensureUserExists integration, isGroupActive integration, CommandService logic, ResponseQueue processing (mocking API), TaskService operations.
• Tests mostly pass; currently 1 failing test: “Database > Table Schemas > response_queue table should have required columns”.

🧑‍💻 Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feature/implement-user-validation)
3. Add/update tests for new functionality
4. Ensure tests pass (bun test)
5. Submit a pull request

📚 Documentation

For detailed API documentation and architecture decisions, see the docs/ directory (if created).