"""create conversations table

Revision ID: 002_create_conversations
Revises: 001_create_users
Create Date: 2026-04-16

"""
from __future__ import annotations

from typing import Sequence, Union

import sqlalchemy as sa
from alembic import op
from sqlalchemy.dialects import postgresql

revision: str = "002_create_conversations"
down_revision: Union[str, None] = "001_create_users"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    op.create_table(
        "conversations",
        sa.Column(
            "id",
            postgresql.UUID(as_uuid=True),
            primary_key=True,
            server_default=sa.text("gen_random_uuid()"),
        ),
        sa.Column(
            "user_id",
            postgresql.UUID(as_uuid=True),
            sa.ForeignKey("users.id", ondelete="CASCADE"),
            nullable=False,
        ),
        sa.Column("title", sa.String(length=500), nullable=True),
        sa.Column(
            "model_tag",
            sa.String(length=100),
            nullable=True,
            server_default=sa.text("'default'"),
        ),
        sa.Column(
            "created_at",
            sa.TIMESTAMP(timezone=True),
            server_default=sa.text("NOW()"),
        ),
        sa.Column(
            "updated_at",
            sa.TIMESTAMP(timezone=True),
            server_default=sa.text("NOW()"),
        ),
    )
    op.create_index(
        "idx_conversations_user",
        "conversations",
        ["user_id", sa.text("updated_at DESC")],
    )


def downgrade() -> None:
    op.drop_index("idx_conversations_user", table_name="conversations")
    op.drop_table("conversations")