"""proxy leasing columns

Revision ID: abe00f7f8f72
Revises: 175f03f1c9f7
Create Date: 2025‑05‑05 18:12:44
"""

from alembic import op
import sqlalchemy as sa
from sqlalchemy import inspect

# revision identifiers, used by Alembic.
revision = "abe00f7f8f72"
down_revision = "175f03f1c9f7"
branch_labels = None
depends_on = None


def _has_column(bind, table: str, column: str) -> bool:
    insp = inspect(bind)
    return column in {c["name"] for c in insp.get_columns(table)}


def upgrade() -> None:
    bind = op.get_bind()

    # add only the columns that are missing
    add_in_use     = not _has_column(bind, "proxies", "in_use")
    add_last_fail  = not _has_column(bind, "proxies", "last_fail")

    if add_in_use or add_last_fail:
        with op.batch_alter_table("proxies") as batch:
            if add_in_use:
                batch.add_column(sa.Column("in_use", sa.Integer(), server_default="0"))
            if add_last_fail:
                batch.add_column(sa.Column("last_fail", sa.DateTime()))


def downgrade() -> None:
    # downgrade assumes the columns exist, so drop them only if present
    bind = op.get_bind()

    drop_in_use    = _has_column(bind, "proxies", "in_use")
    drop_last_fail = _has_column(bind, "proxies", "last_fail")

    if drop_in_use or drop_last_fail:
        with op.batch_alter_table("proxies") as batch:
            if drop_last_fail:
                batch.drop_column("last_fail")
            if drop_in_use:
                batch.drop_column("in_use")