"""
Database models for conversations.

Following core-api patterns: SQLAlchemy 2.0 with async support.
"""
from datetime import datetime
from uuid import UUID, uuid4

from sqlalchemy import ForeignKey, String, Text
from sqlalchemy.orm import Mapped, mapped_column, relationship

from src.db.models import Base


class Conversation(Base):
    """
    A conversation session with an agent.

    Tracks message history, token usage, and metadata.
    """
    __tablename__ = "conversations"

    id: Mapped[UUID] = mapped_column(primary_key=True, default=uuid4)
    user_id: Mapped[str] = mapped_column(String(255), index=True)
    agent_type: Mapped[str] = mapped_column(String(50), default="explore", insert_default="explore")
    title: Mapped[str | None] = mapped_column(String(255), nullable=True, default=None)
    working_dir: Mapped[str] = mapped_column(String(1024), default=".", insert_default=".")
    total_tokens: Mapped[int] = mapped_column(default=0, insert_default=0)
    created_at: Mapped[datetime] = mapped_column(default=datetime.utcnow)
    updated_at: Mapped[datetime | None] = mapped_column(
        default=datetime.utcnow,
        onupdate=datetime.utcnow,
        nullable=True
    )

    # Relationships
    messages: Mapped[list["Message"]] = relationship(
        back_populates="conversation",
        cascade="all, delete-orphan",
        order_by="Message.created_at",
    )

    def __repr__(self) -> str:
        return f"<Conversation {self.id} agent={self.agent_type}>"


class Message(Base):
    """
    A single message in a conversation.

    Tracks role, content, token count, and summarization state.
    """
    __tablename__ = "messages"

    id: Mapped[UUID] = mapped_column(primary_key=True, default=uuid4)
    conversation_id: Mapped[UUID] = mapped_column(
        ForeignKey("conversations.id", ondelete="CASCADE"),
        index=True
    )
    role: Mapped[str] = mapped_column(String(20))  # user, assistant, system, summary
    content: Mapped[str] = mapped_column(Text)
    token_count: Mapped[int] = mapped_column(default=0, insert_default=0)
    is_summary: Mapped[bool] = mapped_column(default=False, insert_default=False)
    summarizes_up_to: Mapped[UUID | None] = mapped_column(nullable=True, default=None)
    created_at: Mapped[datetime] = mapped_column(default=datetime.utcnow)

    # Relationships
    conversation: Mapped["Conversation"] = relationship(back_populates="messages")

    def __repr__(self) -> str:
        preview = self.content[:30] + "..." if len(self.content) > 30 else self.content
        return f"<Message {self.role}: {preview}>"