"""empty message

Revision ID: 7eaec0e12079
Revises: 43afc70a7016
Create Date: 2024-06-18 16:45:06.102210

"""
from alembic import op
import sqlalchemy as sa
from sqlalchemy import text
from spiffworkflow_backend.models.db import dialect_name


# revision identifiers, used by Alembic.
revision = '7eaec0e12079'
down_revision = '43afc70a7016'
branch_labels = None
depends_on = None

def delete_orphaned_future_tasks() -> None:
    # Ensure database connection
    conn = op.get_bind()

    dialect = dialect_name()

    if dialect == "mysql":
        delete_query = text("""
            DELETE future_task FROM future_task
            LEFT JOIN task ON future_task.guid = task.guid
            WHERE task.guid IS NULL;
        """)
    elif dialect == "postgresql":
        delete_query = text("""
            DELETE FROM future_task
            USING task
            WHERE future_task.guid = task.guid
            AND task.guid IS NULL;
        """)
    elif dialect == "sqlite":
        delete_query = text("""
            DELETE FROM future_task
            WHERE guid NOT IN (
                SELECT guid FROM task
            );
        """)
    else:
        raise ValueError(f"Unsupported database dialect: {dialect}")

    # Execute the delete query
    conn.execute(delete_query)


def upgrade() -> None:
    delete_orphaned_future_tasks()
    with op.batch_alter_table('future_task', schema=None) as batch_op:
        batch_op.create_foreign_key('future_task_task_guid_fk', 'task', ['guid'], ['guid'], ondelete='CASCADE')


def downgrade() -> None:
    # ### commands auto generated by Alembic - please adjust! ###
    with op.batch_alter_table('future_task', schema=None) as batch_op:
        batch_op.drop_constraint('future_task_task_guid_fk', type_='foreignkey')

    # ### end Alembic commands ###