#include <gtest/gtest.h>
#include <m5_utility/stl/expected.hpp>

struct no_throw {
    no_throw(std::string i) : i(i)
    {
    }
    std::string i;
};
struct canthrow_move {
    canthrow_move(std::string i) : i(i)
    {
    }
    canthrow_move(canthrow_move const &) = default;
    canthrow_move(canthrow_move &&other) noexcept(false) : i(other.i)
    {
    }
    canthrow_move &operator=(canthrow_move &&) = default;
    std::string i;
};

bool should_throw = false;

#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED
struct willthrow_move {
    willthrow_move(std::string i) : i(i)
    {
    }
    willthrow_move(willthrow_move const &) = default;
    willthrow_move(willthrow_move &&other) : i(other.i)
    {
        if (should_throw) throw 0;
    }
    willthrow_move &operator=(willthrow_move &&) = default;
    std::string i;
};
#endif  // TL_EXPECTED_EXCEPTIONS_ENABLED

static_assert(m5::stl::detail::is_swappable<no_throw>::value, "");

template <class T1, class T2>
void swap_test()
{
    std::string s1 = "abcdefghijklmnopqrstuvwxyz";
    std::string s2 = "zyxwvutsrqponmlkjihgfedcba";

    m5::stl::expected<T1, T2> a{s1};
    m5::stl::expected<T1, T2> b{s2};
    swap(a, b);
    EXPECT_TRUE(a->i == s2);
    EXPECT_TRUE(b->i == s1);

    a = s1;
    b = m5::stl::unexpected<T2>(s2);
    swap(a, b);
    EXPECT_TRUE(a.error().i == s2);
    EXPECT_TRUE(b->i == s1);

    a = m5::stl::unexpected<T2>(s1);
    b = s2;
    swap(a, b);
    EXPECT_TRUE(a->i == s2);
    EXPECT_TRUE(b.error().i == s1);

    a = m5::stl::unexpected<T2>(s1);
    b = m5::stl::unexpected<T2>(s2);
    swap(a, b);
    EXPECT_TRUE(a.error().i == s2);
    EXPECT_TRUE(b.error().i == s1);

    a = s1;
    b = s2;
    a.swap(b);
    EXPECT_TRUE(a->i == s2);
    EXPECT_TRUE(b->i == s1);

    a = s1;
    b = m5::stl::unexpected<T2>(s2);
    a.swap(b);
    EXPECT_TRUE(a.error().i == s2);
    EXPECT_TRUE(b->i == s1);

    a = m5::stl::unexpected<T2>(s1);
    b = s2;
    a.swap(b);
    EXPECT_TRUE(a->i == s2);
    EXPECT_TRUE(b.error().i == s1);

    a = m5::stl::unexpected<T2>(s1);
    b = m5::stl::unexpected<T2>(s2);
    a.swap(b);
    EXPECT_TRUE(a.error().i == s2);
    EXPECT_TRUE(b.error().i == s1);
}

#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED
TEST(Expected, swap)
{
    {
        SCOPED_TRACE("no_throw no-throw");
        swap_test<no_throw, no_throw>();
    }
    {
        SCOPED_TRACE("no_throw canthrow");
        swap_test<no_throw, canthrow_move>();
    }
    {
        SCOPED_TRACE("canthrow no_throw");
        swap_test<canthrow_move, no_throw>();
    }

    std::string s1 = "abcdefghijklmnopqrstuvwxyz";
    std::string s2 = "zyxwvutsrqponmlkjihgfedcbaxxx";
    m5::stl::expected<no_throw, willthrow_move> a{s1};
    m5::stl::expected<no_throw, willthrow_move> b{m5::stl::unexpect, s2};
    should_throw = 1;

#ifdef _MSC_VER
    // this seems to break catch on GCC and Clang
    EXPECT_TRUE_THROWS(swap(a, b));
#endif

    EXPECT_TRUE(a->i == s1);
    EXPECT_TRUE(b.error().i == s2);
}
#endif  // TL_EXPECTED_EXCEPTIONS_ENABLED