feat(fase2): add Flow models, Flow Engine setup, update Docker Compose

- Add Flow and FlowSession SQLAlchemy models for chatbot flows
- Add TriggerType enum (welcome, keyword, fallback, event, manual)
- Setup flow-engine service with FastAPI structure
- Add flow-engine to docker-compose.yml

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docker-compose.yml

@@ -81,6 +81,25 @@ services:
     networks:
       - wac_network
 
+  flow-engine:
+    build:
+      context: ./services/flow-engine
+      dockerfile: Dockerfile
+    container_name: wac_flow_engine
+    restart: unless-stopped
+    environment:
+      DATABASE_URL: postgresql://${DB_USER:-whatsapp_admin}:${DB_PASSWORD}@postgres:5432/${DB_NAME:-whatsapp_central}
+      REDIS_URL: redis://redis:6379
+      API_GATEWAY_URL: http://api-gateway:8000
+      WHATSAPP_CORE_URL: http://whatsapp-core:3001
+    depends_on:
+      postgres:
+        condition: service_healthy
+      redis:
+        condition: service_healthy
+    networks:
+      - wac_network
+
   frontend:
     build:
       context: ./frontend

services/api-gateway/app/models/__init__.py

@@ -1,4 +1,5 @@
 from app.models.user import User
 from app.models.whatsapp import WhatsAppAccount, Contact, Conversation, Message
+from app.models.flow import Flow, FlowSession, TriggerType
 
-__all__ = ["User", "WhatsAppAccount", "Contact", "Conversation", "Message"]
+__all__ = ["User", "WhatsAppAccount", "Contact", "Conversation", "Message", "Flow", "FlowSession", "TriggerType"]

services/api-gateway/app/models/flow.py

@@ -0,0 +1,44 @@
+import uuid
+from datetime import datetime
+from sqlalchemy import Column, String, Boolean, DateTime, Text, Integer, Enum as SQLEnum
+from sqlalchemy.dialects.postgresql import UUID, JSONB
+import enum
+from app.core.database import Base
+
+
+class TriggerType(str, enum.Enum):
+    WELCOME = "welcome"
+    KEYWORD = "keyword"
+    FALLBACK = "fallback"
+    EVENT = "event"
+    MANUAL = "manual"
+
+
+class Flow(Base):
+    __tablename__ = "flows"
+
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    name = Column(String(100), nullable=False)
+    description = Column(Text, nullable=True)
+    trigger_type = Column(SQLEnum(TriggerType), nullable=False)
+    trigger_value = Column(String(255), nullable=True)
+    nodes = Column(JSONB, default=list)
+    edges = Column(JSONB, default=list)
+    variables = Column(JSONB, default=dict)
+    is_active = Column(Boolean, default=False, nullable=False)
+    version = Column(Integer, default=1, nullable=False)
+    created_at = Column(DateTime, default=datetime.utcnow, nullable=False)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow, nullable=False)
+
+
+class FlowSession(Base):
+    __tablename__ = "flow_sessions"
+
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    conversation_id = Column(UUID(as_uuid=True), nullable=False, index=True)
+    flow_id = Column(UUID(as_uuid=True), nullable=False)
+    current_node_id = Column(String(100), nullable=True)
+    variables = Column(JSONB, default=dict)
+    waiting_for_input = Column(Boolean, default=False)
+    created_at = Column(DateTime, default=datetime.utcnow, nullable=False)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow, nullable=False)

services/flow-engine/Dockerfile

@@ -0,0 +1,17 @@
+FROM python:3.11-slim
+
+WORKDIR /app
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    gcc \
+    libpq-dev \
+    && rm -rf /var/lib/apt/lists/*
+
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+COPY app ./app
+
+EXPOSE 8001
+
+CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8001"]

services/flow-engine/app/__init__.py

@@ -0,0 +1 @@
+# WhatsApp Centralizado - Flow Engine

services/flow-engine/app/config.py

@@ -0,0 +1,17 @@
+from pydantic_settings import BaseSettings
+from functools import lru_cache
+
+
+class Settings(BaseSettings):
+    DATABASE_URL: str = "postgresql://whatsapp_admin:password@localhost:5432/whatsapp_central"
+    REDIS_URL: str = "redis://localhost:6379"
+    API_GATEWAY_URL: str = "http://localhost:8000"
+    WHATSAPP_CORE_URL: str = "http://localhost:3001"
+
+    class Config:
+        env_file = ".env"
+
+
+@lru_cache
+def get_settings() -> Settings:
+    return Settings()

services/flow-engine/requirements.txt

@@ -0,0 +1,8 @@
+fastapi==0.115.6
+uvicorn[standard]==0.34.0
+sqlalchemy==2.0.36
+psycopg2-binary==2.9.10
+redis==5.2.1
+httpx==0.28.1
+pydantic==2.10.4
+pydantic-settings==2.7.1