"""SQLModel database models."""

from enum import Enum
from sqlmodel import SQLModel, Field, Relationship
from datetime import datetime, timezone
from typing import Optional, List


class MessageRole(str, Enum):
    """Enum for chat message roles."""
    USER = "user"
    ASSISTANT = "assistant"


class Task(SQLModel, table=True):
    """Task database model with user ownership."""

    __tablename__ = "tasks"

    id: Optional[int] = Field(default=None, primary_key=True)
    user_id: str = Field(index=True, nullable=False)
    title: str = Field(max_length=200, nullable=False)
    description: Optional[str] = Field(default=None)
    completed: bool = Field(default=False, index=True)
    created_at: Optional[datetime] = Field(
        default_factory=lambda: datetime.now(timezone.utc).replace(tzinfo=None)
    )
    updated_at: Optional[datetime] = Field(
        default_factory=lambda: datetime.now(timezone.utc).replace(tzinfo=None)
    )


class Conversation(SQLModel, table=True):
    """Conversation model for chat sessions."""

    __tablename__ = "conversations"

    id: Optional[int] = Field(default=None, primary_key=True)
    user_id: str = Field(index=True, nullable=False)
    created_at: Optional[datetime] = Field(
        default_factory=lambda: datetime.now(timezone.utc).replace(tzinfo=None)
    )
    updated_at: Optional[datetime] = Field(
        default_factory=lambda: datetime.now(timezone.utc).replace(tzinfo=None)
    )

    # Relationship to messages
    messages: List["Message"] = Relationship(back_populates="conversation")


class Message(SQLModel, table=True):
    """Message model for individual chat messages."""

    __tablename__ = "messages"

    id: Optional[int] = Field(default=None, primary_key=True)
    conversation_id: int = Field(foreign_key="conversations.id", index=True, nullable=False)
    user_id: str = Field(index=True, nullable=False)
    role: MessageRole = Field(nullable=False)
    content: str = Field(nullable=False)
    created_at: Optional[datetime] = Field(
        default_factory=lambda: datetime.now(timezone.utc).replace(tzinfo=None),
        index=True
    )

    # Relationship back to conversation
    conversation: Optional[Conversation] = Relationship(back_populates="messages")