#include <xrpl/beast/unit_test.h>
#include <xrpl/protocol/TER.h>

#include <tuple>
#include <type_traits>

namespace xrpl {

struct TER_test : public beast::unit_test::suite
{
    void
    testTransResultInfo()
    {
        for (auto i = -400; i < 400; ++i)
        {
            TER t = TER::fromInt(i);
            auto inRange = isTelLocal(t) || isTemMalformed(t) ||
                isTefFailure(t) || isTerRetry(t) || isTesSuccess(t) ||
                isTecClaim(t);

            std::string token, text;
            auto good = transResultInfo(t, token, text);
            BEAST_EXPECT(inRange || !good);
            BEAST_EXPECT(transToken(t) == (good ? token : "-"));
            BEAST_EXPECT(transHuman(t) == (good ? text : "-"));

            auto code = transCode(token);
            BEAST_EXPECT(good == !!code);
            BEAST_EXPECT(!code || *code == t);
        }
    }

    // Helper template that makes sure two types are not convertible or
    // assignable if not the same.
    // o I1 one tuple index.
    // o I2 other tuple index.
    // o Tup is expected to be a tuple.
    // It's a functor, rather than a function template, since a class template
    // can be a template argument without being full specified.
    template <std::size_t I1, std::size_t I2>
    class NotConvertible
    {
    public:
        template <typename Tup>
        void
        operator()(Tup const& tup, beast::unit_test::suite&) const
        {
            // Entries in the tuple should not be convertible or assignable
            // unless they are the same types.
            using To_t = std::decay_t<decltype(std::get<I1>(tup))>;
            using From_t = std::decay_t<decltype(std::get<I2>(tup))>;
            static_assert(
                std::is_same<From_t, To_t>::value ==
                    std::is_convertible<From_t, To_t>::value,
                "Convert err");
            static_assert(
                std::is_same<To_t, From_t>::value ==
                    std::is_constructible<To_t, From_t>::value,
                "Construct err");
            static_assert(
                std::is_same<To_t, From_t>::value ==
                    std::is_assignable<To_t&, From_t const&>::value,
                "Assign err");

            // Assignment or conversion from integer to type should never work.
            static_assert(
                !std::is_convertible<int, To_t>::value, "Convert err");
            static_assert(
                !std::is_constructible<To_t, int>::value, "Construct err");
            static_assert(
                !std::is_assignable<To_t&, int const&>::value, "Assign err");
        }
    };

    // Fast iteration over the tuple.
    template <
        std::size_t I1,
        std::size_t I2,
        template <std::size_t, std::size_t>
        class Func,
        typename Tup>
    std::enable_if_t<I1 != 0>
    testIterate(Tup const& tup, beast::unit_test::suite& s)
    {
        Func<I1, I2> func;
        func(tup, s);
        testIterate<I1 - 1, I2, Func>(tup, s);
    }

    // Slow iteration over the tuple.
    template <
        std::size_t I1,
        std::size_t I2,
        template <std::size_t, std::size_t>
        class Func,
        typename Tup>
    std::enable_if_t<I1 == 0 && I2 != 0>
    testIterate(Tup const& tup, beast::unit_test::suite& s)
    {
        Func<I1, I2> func;
        func(tup, s);
        testIterate<std::tuple_size<Tup>::value - 1, I2 - 1, Func>(tup, s);
    }

    // Finish iteration over the tuple.
    template <
        std::size_t I1,
        std::size_t I2,
        template <std::size_t, std::size_t>
        class Func,
        typename Tup>
    std::enable_if_t<I1 == 0 && I2 == 0>
    testIterate(Tup const& tup, beast::unit_test::suite& s)
    {
        Func<I1, I2> func;
        func(tup, s);
    }

    void
    testConversion()
    {
        // Verify that valid conversions are valid and invalid conversions
        // are not valid.

        // Examples of each kind of enum.
        static auto const terEnums = std::make_tuple(
            telLOCAL_ERROR,
            temMALFORMED,
            tefFAILURE,
            terRETRY,
            tesSUCCESS,
            tecCLAIM);
        static int const hiIndex{
            std::tuple_size<decltype(terEnums)>::value - 1};

        // Verify that enums cannot be converted to other enum types.
        testIterate<hiIndex, hiIndex, NotConvertible>(terEnums, *this);

        // Lambda that verifies assignability and convertibility.
        auto isConvertable = [](auto from, auto to) {
            using From_t = std::decay_t<decltype(from)>;
            using To_t = std::decay_t<decltype(to)>;
            static_assert(
                std::is_convertible<From_t, To_t>::value, "Convert err");
            static_assert(
                std::is_constructible<To_t, From_t>::value, "Construct err");
            static_assert(
                std::is_assignable<To_t&, From_t const&>::value, "Assign err");
        };

        // Verify the right types convert to NotTEC.
        NotTEC const notTec;
        isConvertable(telLOCAL_ERROR, notTec);
        isConvertable(temMALFORMED, notTec);
        isConvertable(tefFAILURE, notTec);
        isConvertable(terRETRY, notTec);
        isConvertable(tesSUCCESS, notTec);
        isConvertable(notTec, notTec);

        // Lambda that verifies types and not assignable or convertible.
        auto notConvertible = [](auto from, auto to) {
            using To_t = std::decay_t<decltype(to)>;
            using From_t = std::decay_t<decltype(from)>;
            static_assert(
                !std::is_convertible<From_t, To_t>::value, "Convert err");
            static_assert(
                !std::is_constructible<To_t, From_t>::value, "Construct err");
            static_assert(
                !std::is_assignable<To_t&, From_t const&>::value, "Assign err");
        };

        // Verify types that shouldn't convert to NotTEC.
        TER const ter;
        notConvertible(tecCLAIM, notTec);
        notConvertible(ter, notTec);
        notConvertible(4, notTec);

        // Verify the right types convert to TER.
        isConvertable(telLOCAL_ERROR, ter);
        isConvertable(temMALFORMED, ter);
        isConvertable(tefFAILURE, ter);
        isConvertable(terRETRY, ter);
        isConvertable(tesSUCCESS, ter);
        isConvertable(tecCLAIM, ter);
        isConvertable(notTec, ter);
        isConvertable(ter, ter);

        // Verify that you can't convert from int to ter.
        notConvertible(4, ter);
    }

    // Helper template that makes sure two types are comparable.  Also
    // verifies that one of the types does not compare to int.
    // o I1 one tuple index.
    // o I2 other tuple index.
    // o Tup is expected to be a tuple.
    // It's a functor, rather than a function template, since a class template
    // can be a template argument without being full specified.
    template <std::size_t I1, std::size_t I2>
    class CheckComparable
    {
    public:
        template <typename Tup>
        void
        operator()(Tup const& tup, beast::unit_test::suite& s) const
        {
            // All entries in the tuple should be comparable one to the other.
            auto const lhs = std::get<I1>(tup);
            auto const rhs = std::get<I2>(tup);

            static_assert(
                std::is_same<decltype(operator==(lhs, rhs)), bool>::value,
                "== err");

            static_assert(
                std::is_same<decltype(operator!=(lhs, rhs)), bool>::value,
                "!= err");

            static_assert(
                std::is_same<decltype(operator<(lhs, rhs)), bool>::value,
                "< err");

            static_assert(
                std::is_same<decltype(operator<=(lhs, rhs)), bool>::value,
                "<= err");

            static_assert(
                std::is_same<decltype(operator>(lhs, rhs)), bool>::value,
                "> err");

            static_assert(
                std::is_same<decltype(operator>=(lhs, rhs)), bool>::value,
                ">= err");

            // Make sure a sampling of TER types exhibit the expected behavior
            // for all comparison operators.
            s.expect((lhs == rhs) == (TERtoInt(lhs) == TERtoInt(rhs)));
            s.expect((lhs != rhs) == (TERtoInt(lhs) != TERtoInt(rhs)));
            s.expect((lhs < rhs) == (TERtoInt(lhs) < TERtoInt(rhs)));
            s.expect((lhs <= rhs) == (TERtoInt(lhs) <= TERtoInt(rhs)));
            s.expect((lhs > rhs) == (TERtoInt(lhs) > TERtoInt(rhs)));
            s.expect((lhs >= rhs) == (TERtoInt(lhs) >= TERtoInt(rhs)));
        }
    };

    void
    testComparison()
    {
        // All of the TER-related types should be comparable.

        // Examples of all the types we expect to successfully compare.
        static auto const ters = std::make_tuple(
            telLOCAL_ERROR,
            temMALFORMED,
            tefFAILURE,
            terRETRY,
            tesSUCCESS,
            tecCLAIM,
            NotTEC{telLOCAL_ERROR},
            TER{tecCLAIM});
        static int const hiIndex{std::tuple_size<decltype(ters)>::value - 1};

        // Verify that all types in the ters tuple can be compared with all
        // the other types in ters.
        testIterate<hiIndex, hiIndex, CheckComparable>(ters, *this);
    }

    void
    run() override
    {
        testTransResultInfo();
        testConversion();
        testComparison();
    }
};

BEAST_DEFINE_TESTSUITE(TER, protocol, xrpl);

}  // namespace xrpl