"""Add bonus assignment disputes support

Revision ID: 021_add_bonus_disputes
Revises: 020_add_game_types
Create Date: 2024-12-29

"""
from typing import Sequence, Union

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


# revision identifiers, used by Alembic.
revision: str = '021_add_bonus_disputes'
down_revision: Union[str, None] = '020_add_game_types'
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 constraint_exists(table_name: str, constraint_name: str) -> bool:
    bind = op.get_bind()
    inspector = inspect(bind)
    constraints = inspector.get_unique_constraints(table_name)
    return any(c['name'] == constraint_name for c in constraints)


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

    # Add bonus_assignment_id column to disputes
    if not column_exists('disputes', 'bonus_assignment_id'):
        op.add_column('disputes', sa.Column(
            'bonus_assignment_id',
            sa.Integer(),
            nullable=True
        ))
        op.create_foreign_key(
            'fk_disputes_bonus_assignment_id',
            'disputes',
            'bonus_assignments',
            ['bonus_assignment_id'],
            ['id'],
            ondelete='CASCADE'
        )
        op.create_index('ix_disputes_bonus_assignment_id', 'disputes', ['bonus_assignment_id'])

    # Drop the unique index on assignment_id first (required before making nullable)
    if bind.dialect.name != 'sqlite':
        try:
            op.drop_index('ix_disputes_assignment_id', 'disputes')
        except Exception:
            pass  # Index might not exist

    # Make assignment_id nullable (PostgreSQL only, SQLite doesn't support ALTER COLUMN)
    if bind.dialect.name != 'sqlite':
        op.alter_column('disputes', 'assignment_id', nullable=True)

    # Create a non-unique index on assignment_id
    try:
        op.create_index('ix_disputes_assignment_id_non_unique', 'disputes', ['assignment_id'])
    except Exception:
        pass  # Index might already exist


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

    # Remove non-unique index
    try:
        op.drop_index('ix_disputes_assignment_id_non_unique', table_name='disputes')
    except Exception:
        pass

    # Make assignment_id not nullable again
    if bind.dialect.name != 'sqlite':
        op.alter_column('disputes', 'assignment_id', nullable=False)

    # Recreate unique index
    try:
        op.create_index('ix_disputes_assignment_id', 'disputes', ['assignment_id'], unique=True)
    except Exception:
        pass

    # Remove foreign key, index and column
    if column_exists('disputes', 'bonus_assignment_id'):
        try:
            op.drop_constraint('fk_disputes_bonus_assignment_id', 'disputes', type_='foreignkey')
        except Exception:
            pass
        op.drop_index('ix_disputes_bonus_assignment_id', table_name='disputes')
        op.drop_column('disputes', 'bonus_assignment_id')