"""widen alembic_version.version_num to 255

Revision ID: 20251107_123000_widen_alembic_version
Revises: 20251107_121500_labels_stickers
Create Date: 2025-11-07T12:30:00.000000
"""
from alembic import op
import sqlalchemy as sa

# revision identifiers, used by Alembic.
revision = "20251107_123000_widen_alembic_version"
down_revision = "20251107_121500_labels_stickers"
branch_labels = None
depends_on = None


def upgrade() -> None:
    """Increase the size of alembic_version.version_num to 255."""

    # Most projects use Postgres; this raw SQL is explicit and works reliably.
    # Widening requires no USING clause on Postgres, but we'll be explicit for clarity.
    op.execute(
        "ALTER TABLE alembic_version "
        "ALTER COLUMN version_num TYPE VARCHAR(255)"
    )

    # If you need cross-dialect support later, you could add dialect checks
    # and use batch_alter_table for SQLite. For your Postgres setup, this is sufficient.


def downgrade() -> None:
    """Shrink alembic_version.version_num back to 32.

    On Postgres, shrinking can fail if any row exceeds 32 chars.
    We proactively truncate to 32 to guarantee a clean downgrade.
    """
    # Truncate any too-long values to fit back into VARCHAR(32)
    op.execute(
        "UPDATE alembic_version SET version_num = LEFT(version_num, 32)"
    )
    op.execute(
        "ALTER TABLE alembic_version "
        "ALTER COLUMN version_num TYPE VARCHAR(32)"
    )