In a saucepan, place mustard seeds in oil and cook until they pop. Add whole cloves, star anise, and curry leaves. Cook until fragrant (about 1 minute). Next, add grapes, raisins, allepo pepper and pomegranate seeds. Stir ingredients to mix, then add grape juice and vinegar. Cover and simmer slowly over low heat until grapes soften, but hold their shape. Finish with the pine nuts and salt to taste.