"""Add marathon cover fields (cover_path and cover_url)

Revision ID: 019_add_marathon_cover
Revises: 018_seed_static_content
Create Date: 2024-12-21

"""
from typing import Sequence, Union

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


# revision identifiers, used by Alembic.
revision: str = '019_add_marathon_cover'
down_revision: Union[str, None] = '018_seed_static_content'
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def column_exists(table_name: str, column_name: str) -> bool:
    bind = op.get_bind()
    inspector = inspect(bind)
    columns = [col['name'] for col in inspector.get_columns(table_name)]
    return column_name in columns


def upgrade() -> None:
    # cover_path - путь к файлу в S3 хранилище
    if not column_exists('marathons', 'cover_path'):
        op.add_column('marathons', sa.Column('cover_path', sa.String(500), nullable=True))

    # cover_url - API URL для доступа к обложке
    if not column_exists('marathons', 'cover_url'):
        op.add_column('marathons', sa.Column('cover_url', sa.String(500), nullable=True))


def downgrade() -> None:
    if column_exists('marathons', 'cover_url'):
        op.drop_column('marathons', 'cover_url')
    if column_exists('marathons', 'cover_path'):
        op.drop_column('marathons', 'cover_path')