"""Protected thumbnails (US06-03).

Revision ID: 0013_protected_thumbnails
Revises: 0012_archive_plans
Create Date: 2026-08-16

A protected thumbnail is the durable comparison preview of an asset whose
original has left active storage. It is evidence rather than cache, so the LRU
quota must not evict it: the archive medium may be offline when it is needed.
"""

import sqlalchemy as sa
from alembic import op

revision = "0013_protected_thumbnails"
down_revision = "0012_archive_plans"
branch_labels = None
depends_on = None


def upgrade() -> None:
    op.add_column(
        "thumbnails",
        sa.Column("protected", sa.Boolean(), nullable=False, server_default=sa.false()),
    )


def downgrade() -> None:
    op.drop_column("thumbnails", "protected")