"""
Message model for storing individual chat messages
"""

from sqlalchemy import Column, String, Text, Integer, DateTime, JSON, ForeignKey, CheckConstraint
from sqlalchemy.dialects.postgresql import UUID
from sqlalchemy.orm import relationship
from sqlalchemy.sql import func
import uuid

from app.database import Base


class Message(Base):
    """
    Message model representing a single message in a conversation
    """

    __tablename__ = "messages"

    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4, index=True)
    conversation_id = Column(
        UUID(as_uuid=True),
        ForeignKey("conversations.id", ondelete="CASCADE"),
        nullable=False,
        index=True
    )

    # OpenAI Responses API response_id
    openai_response_id = Column(String(255), index=True)

    # Message content
    role = Column(String(50), nullable=False)  # user, assistant, system
    content = Column(Text, nullable=False)

    # Token count for this message
    token_count = Column(Integer, default=0)

    # Timestamp
    created_at = Column(DateTime(timezone=True), server_default=func.now(), nullable=False, index=True)

    # JSON field for metadata (file_search_results, etc.)
    meta_data = Column(JSON, default=dict, nullable=False)

    # Relationships
    conversation = relationship("Conversation", back_populates="messages")
    token_usage_records = relationship("TokenUsage", back_populates="message")

    # Constraints
    __table_args__ = (
        CheckConstraint(
            "role IN ('user', 'assistant', 'system')",
            name="check_message_role"
        ),
    )

    def __repr__(self):
        return f"<Message {self.id} - {self.role}>"