"""add grouped_id to messages (Telegram album/media-group key)

Revision ID: 0003
Revises: 0002
Create Date: 2026-05-05

"""
from typing import Sequence, Union

import sqlalchemy as sa
from alembic import op

revision: str = "0003"
down_revision: Union[str, None] = "0002"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    op.add_column("messages", sa.Column("grouped_id", sa.BigInteger(), nullable=True))
    op.create_index(
        "ix_messages_grouped_id", "messages", ["channel_id", "grouped_id"]
    )
    # Backfill grouped_id from the stored raw JSONB for existing rows so that
    # albums saved before this migration are grouped retroactively.
    op.execute(
        """
        UPDATE messages
        SET grouped_id = (raw->>'grouped_id')::bigint
        WHERE grouped_id IS NULL
          AND raw IS NOT NULL
          AND raw->>'grouped_id' IS NOT NULL
        """
    )


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