"""
Database models and connection for Neon PostgreSQL.
"""

import os
from datetime import datetime
from sqlalchemy import create_engine, Column, String, Text, DateTime, ForeignKey, JSON
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker, relationship
from sqlalchemy.dialects.postgresql import UUID
import uuid

# Get database URL from environment
DATABASE_URL = os.getenv("DATABASE_URL")

# Create SQLAlchemy engine
engine = create_engine(DATABASE_URL) if DATABASE_URL else None
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine) if engine else None

Base = declarative_base()

# Models
class Conversation(Base):
    __tablename__ = "conversations"
    
    id = Column(String, primary_key=True, default=lambda: str(uuid.uuid4()))
    user_id = Column(String, nullable=False, index=True)  # Clerk user ID
    title = Column(String, nullable=False)
    created_at = Column(DateTime, default=datetime.utcnow)
    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
    summary = Column(Text, nullable=True)  # Short summary of the conversation
    
    # Relationship
    messages = relationship("Message", back_populates="conversation", cascade="all, delete-orphan")

class Message(Base):
    __tablename__ = "messages"
    
    id = Column(String, primary_key=True, default=lambda: str(uuid.uuid4()))
    conversation_id = Column(String, ForeignKey("conversations.id", ondelete="CASCADE"), nullable=False)
    role = Column(String, nullable=False)  # 'user' or 'assistant'
    content = Column(Text, nullable=False)
    thoughts = Column(JSON, nullable=True)  # Store agent thoughts
    created_at = Column(DateTime, default=datetime.utcnow)
    
    # Relationship
    conversation = relationship("Conversation", back_populates="messages")

# Database initialization
def init_db():
    """Create all tables in the database."""
    if engine:
        Base.metadata.create_all(bind=engine)
        print("✅ Database tables created successfully")
    else:
        print("⚠️  DATABASE_URL not configured")

def get_db():
    """Get database session."""
    if SessionLocal:
        db = SessionLocal()
        try:
            yield db
        finally:
            db.close()
    else:
        yield None