from alembic import op
from alembic.operations.ops import CreatePrimaryKeyOp, CreateForeignKeyOp
import sqlalchemy as sa

def upgrade():

    conn = op.get_bind()
    ctx = op.get_context()
    existing_metadata = sa.schema.MetaData()
    target_metadata = ctx.opts['target_metadata']

    # Rename table.
    new_name = 'new_table_name'
    op.rename_table('old_table_name', new_name)

    # Drop PK and FKs reflected from existing table.
    existing_table = sa.Table(new_name, existing_metadata, autoload_with=conn)
    op.drop_constraint(existing_table.primary_key.name, new_name)
    for c in existing_table.foreign_key_constraints:
        op.drop_constraint(c.name, new_name)

    # Recreate PK and FKs according to naming convention and current class name.
    target_table = sa.Table(new_name, target_metadata)
    op.invoke(CreatePrimaryKeyOp.from_constraint(target_table.primary_key))
    for c in target_table.foreign_key_constraints:
        op.invoke(CreateForeignKeyOp.from_constraint(c))