"""add_messages_visibility_mask

Revision ID: 20260319_0003
Revises: 202603190002
Create Date: 2026-03-19 18:10:00

"""

from typing import Sequence

from alembic import op
import sqlalchemy as sa


# revision identifiers, used by Alembic.
revision: str = "20260319_0003"
down_revision: str | Sequence[str] | None = "202603190002"
branch_labels: str | Sequence[str] | None = None
depends_on: str | Sequence[str] | None = None


def upgrade() -> None:
    op.add_column(
        "messages",
        sa.Column(
            "visibility_mask",
            sa.BigInteger(),
            nullable=False,
            server_default=sa.text("0"),
        ),
    )
    op.create_index(
        "ix_messages_session_seq_visibility",
        "messages",
        ["session_id", "seq", "visibility_mask"],
        unique=False,
    )
    op.execute("UPDATE messages SET visibility_mask = 1 WHERE visibility_mask = 0")


def downgrade() -> None:
    op.drop_index("ix_messages_session_seq_visibility", table_name="messages")
    op.drop_column("messages", "visibility_mask")