"""Phase 7: replace musehub_snapshots.manifest blob with normalized musehub_snapshot_entries table.

Revision ID: 0013
Revises: 0012
"""

from alembic import op
import sqlalchemy as sa

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


def upgrade() -> None:
    # ── musehub_snapshot_entries ──────────────────────────────────────────────
    op.create_table(
        "musehub_snapshot_entries",
        sa.Column("snapshot_id", sa.String(128), primary_key=True),
        sa.Column("path", sa.String(1024), primary_key=True),
        sa.Column("object_id", sa.String(128), nullable=False),
        sa.Column("size_bytes", sa.Integer(), nullable=False, server_default="0"),
        sa.ForeignKeyConstraint(
            ["snapshot_id"],
            ["musehub_snapshots.snapshot_id"],
            ondelete="CASCADE",
        ),
    )
    op.create_index(
        "ix_musehub_snapshot_entries_snapshot_id",
        "musehub_snapshot_entries",
        ["snapshot_id"],
    )
    op.create_index(
        "ix_musehub_snapshot_entries_object_id",
        "musehub_snapshot_entries",
        ["object_id"],
    )

    # ── drop the manifest JSON blob ───────────────────────────────────────────
    # All existing manifests are {} (empty) — the wire_push bug meant they were
    # never populated — so there is no data to migrate.
    op.drop_column("musehub_snapshots", "manifest")


def downgrade() -> None:
    op.add_column(
        "musehub_snapshots",
        sa.Column("manifest", sa.JSON(), nullable=False, server_default="{}"),
    )
    op.drop_index(
        "ix_musehub_snapshot_entries_object_id",
        table_name="musehub_snapshot_entries",
    )
    op.drop_index(
        "ix_musehub_snapshot_entries_snapshot_id",
        table_name="musehub_snapshot_entries",
    )
    op.drop_table("musehub_snapshot_entries")