"""Restore plans and archive divergence (US06-04).

Revision ID: 0014_restore_plans
Revises: 0013_protected_thumbnails
Create Date: 2026-08-16

Restore reuses the archive plan and journal tables: the crash-safe question is the
same one in the opposite direction (copy, verify, publish, register), so the rows
gain a ``direction`` instead of a parallel pair of tables. ``archive_divergent_at``
records the moment an archived copy was proven to hold bytes that are not the ones
the database recorded — a restore must never silently accept a different file.
"""

import sqlalchemy as sa
from alembic import op

revision = "0014_restore_plans"
down_revision = "0013_protected_thumbnails"
branch_labels = None
depends_on = None


def upgrade() -> None:
    for table in ("archive_plans", "archive_operations"):
        op.add_column(
            table,
            sa.Column("direction", sa.String(), nullable=False, server_default="archive"),
        )
    op.add_column(
        "assets", sa.Column("archive_divergent_at", sa.DateTime(timezone=True), nullable=True)
    )


def downgrade() -> None:
    op.drop_column("assets", "archive_divergent_at")
    for table in ("archive_plans", "archive_operations"):
        op.drop_column(table, "direction")