#include <gtest/gtest.h>

#include "dpf.hpp"

#include <cstdint>
#include <limits>
#include <random>

TEST(ConstrainedCmp, LemmaAdjacentPairs)
{
    // |x0 − x1| = 1 ⇒ local_ccmp = 1{x0 < x1}.
    EXPECT_EQ(dpf::local_ccmp(0, 1), 1u);
    EXPECT_EQ(dpf::local_ccmp(1, 0), 0u);
    EXPECT_EQ(dpf::local_ccmp(2, 3), 1u);
    EXPECT_EQ(dpf::local_ccmp(3, 2), 0u);
    EXPECT_EQ(dpf::local_ccmp(100, 101), 1u);
    EXPECT_EQ(dpf::local_ccmp(101, 100), 0u);
    // Control-bit pairs used by arith leaf open (t0 ⊕ t1 = 1).
    EXPECT_EQ(dpf::local_ccmp(0, 1), 1u);  // g = t1
    EXPECT_EQ(dpf::local_ccmp(1, 0), 0u);  // g = t1
}

TEST(ConstrainedCmp, RandomAdjacentBatch)
{
    std::mt19937_64 rng{0xC0FFEEULL};
    std::uniform_int_distribution<std::uint64_t> dist(0, (1ull << 40) - 2);
    for (int i = 0; i < 256; ++i)
    {
        const std::uint64_t a = dist(rng);
        const std::uint64_t b = a + 1;
        EXPECT_EQ(dpf::local_ccmp(a, b), 1u) << a << " < " << b;
        EXPECT_EQ(dpf::local_ccmp(b, a), 0u) << b << " > " << a;
        EXPECT_EQ(dpf::local_ccmp_int(a, b), 1u);
        EXPECT_EQ(dpf::local_ccmp_int(b, a), 0u);
    }
}

TEST(ConstrainedCmp, PartyTermsMatchTheAndInputs)
{
    uint8_t z0 = 9, z1 = 9, l = 9;
    dpf::detail::ccmp_party_terms(0b10, 0, z0, z1, l);
    EXPECT_EQ(l, 0u);
    EXPECT_EQ(z0, 1u);
    EXPECT_EQ(z1, 1u);
    dpf::detail::ccmp_party_terms(0b11, 1, z0, z1, l);
    EXPECT_EQ(l, 1u);
    EXPECT_EQ(z0, 1u);
    EXPECT_EQ(z1, static_cast<uint8_t>(1u ^ 1u ^ 1u));
}

TEST(ConstrainedCmp, AdjacentAtTheTopOfUint64)
{
    const std::uint64_t top = std::numeric_limits<std::uint64_t>::max();
    EXPECT_EQ(dpf::local_ccmp(top - 1, top), 1u);
    EXPECT_EQ(dpf::local_ccmp(top, top - 1), 0u);
}

TEST(ConstrainedCmp, ProtocolHook)
{
    dpf::detail::urandom_pad_rng pads{};
    dpf::local_cw_protocol<dpf::detail::urandom_pad_rng> proto{pads};
    EXPECT_EQ(proto.open_ccmp(0, 1), 1u);
    EXPECT_EQ(proto.open_ccmp(1, 0), 0u);
}