#include <gtest/gtest.h>
#include <web_server/src/H264_Encoder.hpp>
#include <chrono>
#include <cstddef>
#include <cstdint>
#include <optional>
#include <vector>

namespace aethera::web {
namespace {
std::vector<std::byte> test_pattern(std::uint32_t width,
                                    std::uint32_t height) {
    std::vector<std::byte> result(
        static_cast<std::size_t>(width) * height * 4U);
    for (std::uint32_t y = 0; y < height; ++y) {
        for (std::uint32_t x = 0; x < width; ++x) {
            const auto offset =
                (static_cast<std::size_t>(y) * width + x) * 4U;
            result[offset] =
                std::byte{static_cast<std::uint8_t>(x)};
            result[offset + 1U] =
                std::byte{static_cast<std::uint8_t>(y)};
            result[offset + 2U] =
                std::byte{static_cast<std::uint8_t>(x ^ y)};
            result[offset + 3U] = std::byte{255};
        }
    }
    return result;
}
}

TEST(H264_Encoder, Rejects_Invalid_Input_Before_FFmpeg) {
    H264_Encoder encoder(30.0);
    const auto pixels = test_pattern(320, 180);
    EXPECT_THROW(static_cast<void>(encoder.encode(
                     pixels, 319, 180, Video_Pixel_Layout::rgba,
                     1, std::chrono::microseconds{33'333})),
                 std::invalid_argument);
    EXPECT_THROW(static_cast<void>(encoder.encode(
                     std::span<const std::byte>{pixels}.first(
                         pixels.size() - 1U),
                     320, 180, Video_Pixel_Layout::rgba,
                     1, std::chrono::microseconds{33'333})),
                 std::invalid_argument);
}

TEST(H264_Encoder, Libx264_Produces_Ordered_Annex_B_Access_Units) {
    /* 四个 720x420 Plot 组成的一行真实 Gallery 图集。 */
    constexpr std::uint32_t width{2'880};
    constexpr std::uint32_t height{420};
    H264_Encoder encoder(30.0);
    auto pixels = test_pattern(width, height);
    std::optional<Encoded_Video_Frame> first;
    std::uint64_t produced{};
    for (std::uint64_t sequence = 1; sequence <= 4; ++sequence) {
        pixels[0] = std::byte{static_cast<std::uint8_t>(sequence)};
        auto encoded = encoder.encode(
            pixels, width, height, Video_Pixel_Layout::rgba, sequence,
            std::chrono::microseconds{
                static_cast<std::int64_t>(sequence * 33'333)});
        if (!encoded) continue;
        if (!first) first = encoded;
        EXPECT_EQ(encoded->sequence, sequence);
        EXPECT_EQ(encoded->backend, Video_Encoder_Backend::libx264);
        EXPECT_FALSE(encoded->annex_b.empty());
        ++produced;
    }
    ASSERT_TRUE(first);
    EXPECT_TRUE(first->key_frame);
    ASSERT_GE(first->annex_b.size(), 4U);
    EXPECT_EQ(first->annex_b[0], std::byte{0});
    EXPECT_EQ(first->annex_b[1], std::byte{0});
    EXPECT_TRUE(first->annex_b[2] == std::byte{1} ||
        (first->annex_b[2] == std::byte{0} &&
         first->annex_b[3] == std::byte{1}));
    EXPECT_EQ(produced, 4U);
    EXPECT_EQ(video_encoder_backend_name(first->backend), "libx264");
    EXPECT_EQ(h264_profile_level_id(), "640033");
}
}