import act4e_interfaces as I


class SolCurrencyOptimization(I.CurrencyOptimization):
    def compute_optimal_conversion(
        self,
        available: I.SemiCategory[I.RichObject[str], I.RichMorphism[I.CurrencyExchanger]],
        source: str,
        amount: float,
        target: str,
    ) -> I.OptimalSolution:
        source, target = available.get_object(source), available.get_object(target)

        results = {}
        for l in range(available.objects().size() + 1):
            paths = available.hom(source, target, l)
            for p in paths.elements():
                # Allow to go through exchanges only once
                names = p.label.split(";")
                if any([names.count(n) > 1 for n in names]):
                    continue

                rate, commission = p.mordata.rate, p.mordata.commission
                res = amount * rate - commission
                results[res] = p

        final = max(results.keys())
        path = results[final].label.split(";")
        return I.OptimalSolution(path, final)