Phase 1: Communications Module - Complete

Backend infrastructure:
- PostgreSQL models (users, channels, messages, DMs, files, artifacts)
- JWT authentication with password hashing
- Auth API (register, login, logout, get user)
- Channels API (create, list, join, leave)
- Messages API with @grimlock mention detection
- AI responds automatically when @mentioned
- Background task processing for AI responses

Database:
- SQLAlchemy ORM models
- Alembic ready for migrations
- PostgreSQL + Redis in docker-compose

Features working:
- User registration and login
- Create/join public channels
- Send messages in channels
- @grimlock triggers AI response with channel context
- Real-time ready (WebSocket next)

Next: WebSocket for real-time updates, frontend interface

backend/core/models.py

@@ -0,0 +1,146 @@
+"""
+Database Models - SQLAlchemy ORM
+"""
+
+from sqlalchemy import Column, Integer, String, Text, Boolean, DateTime, ForeignKey, Enum, Table
+from sqlalchemy.orm import relationship, declarative_base
+from sqlalchemy.sql import func
+from datetime import datetime
+import enum
+
+Base = declarative_base()
+
+# Association tables for many-to-many relationships
+channel_members = Table(
+    'channel_members',
+    Base.metadata,
+    Column('channel_id', Integer, ForeignKey('channels.id', ondelete='CASCADE'), primary_key=True),
+    Column('user_id', Integer, ForeignKey('users.id', ondelete='CASCADE'), primary_key=True),
+    Column('joined_at', DateTime, default=func.now())
+)
+
+class UserRole(str, enum.Enum):
+    ENGINEER = "engineer"
+    BD = "bd"
+    ADMIN = "admin"
+    EXEC = "exec"
+
+class ChannelType(str, enum.Enum):
+    PUBLIC = "public"
+    PRIVATE = "private"
+
+class User(Base):
+    __tablename__ = "users"
+    
+    id = Column(Integer, primary_key=True, index=True)
+    email = Column(String(255), unique=True, index=True, nullable=False)
+    name = Column(String(255), nullable=False)
+    password_hash = Column(String(255), nullable=False)
+    role = Column(Enum(UserRole), default=UserRole.ENGINEER, nullable=False)
+    is_active = Column(Boolean, default=True, nullable=False)
+    is_online = Column(Boolean, default=False, nullable=False)
+    last_seen = Column(DateTime, default=func.now())
+    created_at = Column(DateTime, default=func.now())
+    updated_at = Column(DateTime, default=func.now(), onupdate=func.now())
+    
+    # Relationships
+    messages = relationship("Message", back_populates="user", cascade="all, delete-orphan")
+    sent_dms = relationship("DirectMessage", foreign_keys="DirectMessage.sender_id", back_populates="sender")
+    received_dms = relationship("DirectMessage", foreign_keys="DirectMessage.recipient_id", back_populates="recipient")
+    channels = relationship("Channel", secondary=channel_members, back_populates="members")
+    files = relationship("File", back_populates="uploaded_by_user")
+    
+    def __repr__(self):
+        return f"<User {self.email}>"
+
+class Channel(Base):
+    __tablename__ = "channels"
+    
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String(100), unique=True, index=True, nullable=False)
+    description = Column(Text)
+    type = Column(Enum(ChannelType), default=ChannelType.PUBLIC, nullable=False)
+    created_by = Column(Integer, ForeignKey('users.id', ondelete='SET NULL'))
+    created_at = Column(DateTime, default=func.now())
+    
+    # Relationships
+    messages = relationship("Message", back_populates="channel", cascade="all, delete-orphan")
+    members = relationship("User", secondary=channel_members, back_populates="channels")
+    
+    def __repr__(self):
+        return f"<Channel #{self.name}>"
+
+class Message(Base):
+    __tablename__ = "messages"
+    
+    id = Column(Integer, primary_key=True, index=True)
+    channel_id = Column(Integer, ForeignKey('channels.id', ondelete='CASCADE'), nullable=False)
+    user_id = Column(Integer, ForeignKey('users.id', ondelete='SET NULL'), nullable=True)  # NULL if AI
+    content = Column(Text, nullable=False)
+    is_ai_message = Column(Boolean, default=False, nullable=False)
+    reply_to_message_id = Column(Integer, ForeignKey('messages.id', ondelete='SET NULL'), nullable=True)
+    created_at = Column(DateTime, default=func.now())
+    edited_at = Column(DateTime, nullable=True)
+    
+    # Relationships
+    channel = relationship("Channel", back_populates="messages")
+    user = relationship("User", back_populates="messages")
+    replies = relationship("Message", remote_side=[id], backref="parent_message")
+    artifacts = relationship("Artifact", back_populates="message", cascade="all, delete-orphan")
+    
+    def __repr__(self):
+        return f"<Message {self.id} in #{self.channel.name if self.channel else 'Unknown'}>"
+
+class DirectMessage(Base):
+    __tablename__ = "direct_messages"
+    
+    id = Column(Integer, primary_key=True, index=True)
+    sender_id = Column(Integer, ForeignKey('users.id', ondelete='CASCADE'), nullable=False)
+    recipient_id = Column(Integer, ForeignKey('users.id', ondelete='CASCADE'), nullable=False)
+    content = Column(Text, nullable=False)
+    is_ai_message = Column(Boolean, default=False, nullable=False)
+    read_at = Column(DateTime, nullable=True)
+    created_at = Column(DateTime, default=func.now())
+    edited_at = Column(DateTime, nullable=True)
+    
+    # Relationships
+    sender = relationship("User", foreign_keys=[sender_id], back_populates="sent_dms")
+    recipient = relationship("User", foreign_keys=[recipient_id], back_populates="received_dms")
+    
+    def __repr__(self):
+        return f"<DM from {self.sender_id} to {self.recipient_id}>"
+
+class File(Base):
+    __tablename__ = "files"
+    
+    id = Column(Integer, primary_key=True, index=True)
+    filename = Column(String(255), nullable=False)
+    original_filename = Column(String(255), nullable=False)
+    file_path = Column(String(500), nullable=False)
+    file_size = Column(Integer, nullable=False)  # bytes
+    mime_type = Column(String(100), nullable=False)
+    uploaded_by = Column(Integer, ForeignKey('users.id', ondelete='SET NULL'))
+    channel_id = Column(Integer, ForeignKey('channels.id', ondelete='CASCADE'), nullable=True)
+    created_at = Column(DateTime, default=func.now())
+    
+    # Relationships
+    uploaded_by_user = relationship("User", back_populates="files")
+    
+    def __repr__(self):
+        return f"<File {self.original_filename}>"
+
+class Artifact(Base):
+    __tablename__ = "artifacts"
+    
+    id = Column(Integer, primary_key=True, index=True)
+    message_id = Column(Integer, ForeignKey('messages.id', ondelete='CASCADE'), nullable=False)
+    filename = Column(String(255), nullable=False)
+    file_path = Column(String(500), nullable=False)
+    file_type = Column(String(50), nullable=False)  # pdf, csv, docx, etc.
+    created_at = Column(DateTime, default=func.now())
+    
+    # Relationships
+    message = relationship("Message", back_populates="artifacts")
+    
+    def __repr__(self):
+        return f"<Artifact {self.filename}>"