"""Chat models."""
from sqlalchemy import ForeignKey, JSON, String, Text
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.models.base import Base, TimestampMixin, UUIDMixin


class ChatSession(Base, UUIDMixin, TimestampMixin):
    """Chat session."""

    __tablename__ = "chat_sessions"

    user_id: Mapped[str | None] = mapped_column(
        ForeignKey("users.id", ondelete="CASCADE"), nullable=True, index=True
    )
    title: Mapped[str | None] = mapped_column(String(256), default="")
    skill_id: Mapped[str | None] = mapped_column(
        ForeignKey("skills.id", ondelete="SET NULL"), nullable=True
    )
    context_window: Mapped[int] = mapped_column(default=10, nullable=False)

    messages: Mapped[list["ChatMessage"]] = relationship(
        "ChatMessage", back_populates="session", cascade="all, delete-orphan"
    )


class ChatMessage(Base, UUIDMixin, TimestampMixin):
    """Chat message."""

    __tablename__ = "chat_messages"

    session_id: Mapped[str] = mapped_column(
        ForeignKey("chat_sessions.id", ondelete="CASCADE"), nullable=False, index=True
    )
    role: Mapped[str] = mapped_column(String(32), nullable=False, index=True)  # user / assistant / tool
    content: Mapped[str | None] = mapped_column(Text, default="")
    tool_calls: Mapped[list] = mapped_column(JSON, default=list, nullable=False)
    tool_results: Mapped[list] = mapped_column(JSON, default=list, nullable=False)
    references: Mapped[list] = mapped_column(JSON, default=list, nullable=False)
    token_usage: Mapped[dict | None] = mapped_column(JSON, nullable=True)

    session: Mapped["ChatSession"] = relationship("ChatSession", back_populates="messages")