"""Add byte_offset and byte_length to musehub_mpack_index for range-GET reads.

Enables O(object_size) byte-range S3 GETs instead of downloading the full
mpack to extract a single object.  NULL on existing rows — code falls back
to full-mpack download when columns are absent.

Revision ID: 0067
Revises: 0066
"""
from __future__ import annotations

import sqlalchemy as sa
from alembic import op

revision: str = "0067"
down_revision: str = "0066"
branch_labels = None
depends_on = None


def upgrade() -> None:
    op.add_column(
        "musehub_mpack_index",
        sa.Column("byte_offset", sa.BigInteger(), nullable=True),
    )
    op.add_column(
        "musehub_mpack_index",
        sa.Column("byte_length", sa.Integer(), nullable=True),
    )


def downgrade() -> None:
    op.drop_column("musehub_mpack_index", "byte_length")
    op.drop_column("musehub_mpack_index", "byte_offset")