"""
Chat models for the application.
"""

from datetime import datetime
from app.database.db import db

class Chat(db.Model):
    """Chat model representing a chat session."""
    
    __tablename__ = 'chats'
    
    id = db.Column(db.Integer, primary_key=True)
    title = db.Column(db.String(100), nullable=True)
    is_team_chat = db.Column(db.Boolean, default=False)
    model_name = db.Column(db.String(50), nullable=False)
    created_at = db.Column(db.DateTime, default=datetime.utcnow)
    updated_at = db.Column(db.DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
    
    # Foreign keys
    user_id = db.Column(db.Integer, db.ForeignKey('users.id'), nullable=False)
    
    # Relationships
    messages = db.relationship('Message', backref='chat', lazy='dynamic', cascade='all, delete-orphan')
    team_members = db.relationship('TeamChatMember', backref='chat', lazy='dynamic', cascade='all, delete-orphan')
    
    def __repr__(self):
        return f'<Chat {self.id}: {self.title or "Untitled"}>'


class Message(db.Model):
    """Message model representing a single message in a chat."""
    
    __tablename__ = 'messages'
    
    id = db.Column(db.Integer, primary_key=True)
    content = db.Column(db.Text, nullable=False)
    is_user_message = db.Column(db.Boolean, default=True)
    created_at = db.Column(db.DateTime, default=datetime.utcnow)
    
    # Foreign keys
    chat_id = db.Column(db.Integer, db.ForeignKey('chats.id'), nullable=False)
    user_id = db.Column(db.Integer, db.ForeignKey('users.id'), nullable=True)
    
    def __repr__(self):
        return f'<Message {self.id}: {self.content[:20]}...>'


class TeamChatMember(db.Model):
    """Model representing a member of a team chat."""
    
    __tablename__ = 'team_chat_members'
    
    id = db.Column(db.Integer, primary_key=True)
    joined_at = db.Column(db.DateTime, default=datetime.utcnow)
    
    # Foreign keys
    chat_id = db.Column(db.Integer, db.ForeignKey('chats.id'), nullable=False)
    user_id = db.Column(db.Integer, db.ForeignKey('users.id'), nullable=False)
    
    # Ensure a user can only be added to a team chat once
    __table_args__ = (
        db.UniqueConstraint('chat_id', 'user_id', name='uq_team_chat_member'),
    )
    
    def __repr__(self):
        return f'<TeamChatMember chat_id={self.chat_id}, user_id={self.user_id}>'