// XYParser API 单元测试文件
// 测试 XYParser 库的核心功能，包括解析器创建、错误处理、帧解析等

#include <gtest/gtest.h>
#include "../XYParserApi.h"

#include <algorithm>
#include <array>
#include <cstddef>
#include <cstdint>
#include <cmath>
#include <string>
#include <vector>

// 匿名命名空间，包含测试辅助代码
namespace {

/// ParserGuard 类：RAII 封装，确保解析器资源自动释放
/// 当对象生命周期结束时自动调用 XYParser_DestroyParser 释放资源
class ParserGuard {
public:
    /// 构造函数，接管解析器句柄的所有权
    /// @param handle XYParser 解析器句柄
    explicit ParserGuard(XYParserHandle handle) : handle_(handle) {}

    /// 析构函数，自动释放解析器资源
    ~ParserGuard()
    {
        if (handle_ != nullptr) {
            XYParser_DestroyParser(handle_);
        }
    }

    /// 获取解析器句柄
    /// @return XYParser 解析器句柄
    XYParserHandle get() const
    {
        return handle_;
    }

private:
    XYParserHandle handle_; ///< 解析器句柄
};

/// 构建最小帧数据的辅助函数
/// 生成符合 XYParser 协议格式的测试帧数据
/// @param channel_count 通道数量
/// @param frame_index 帧索引，小端写入标签区前 4 字节
/// @return 包含完整帧数据的字节向量
std::vector<std::uint8_t> BuildMinimalFrame(std::uint8_t channel_count,
                                            std::uint32_t frame_index,
                                            std::array<std::uint8_t, 6> reserved = {})
{
    constexpr std::size_t kSamplesPerFrame = 5;  ///< 每帧采样数
    constexpr std::uint8_t kHeader = 0xAA;       ///< 帧头标记
    constexpr std::uint8_t kTail = 0x55;         ///< 帧尾标记
    constexpr std::size_t kTagLen = 25;          ///< 标签长度

    // 计算帧结构大小
    const std::size_t sample_bytes = static_cast<std::size_t>(channel_count) * 3 + 2;
    const std::uint16_t payload_length = static_cast<std::uint16_t>(sample_bytes * kSamplesPerFrame);
    const std::size_t frame_size = 1 + kTagLen + payload_length + 2;

    std::vector<std::uint8_t> frame(frame_size, 0);
    std::size_t offset = 0;

    // 写入帧头
    frame[offset++] = kHeader;

    // 写入标签数据中的帧索引（小端序）
    frame[offset++] = static_cast<std::uint8_t>(frame_index & 0xFF);
    frame[offset++] = static_cast<std::uint8_t>((frame_index >> 8) & 0xFF);
    frame[offset++] = static_cast<std::uint8_t>((frame_index >> 16) & 0xFF);
    frame[offset++] = static_cast<std::uint8_t>((frame_index >> 24) & 0xFF);

    // 写入负载长度（大端序）
    frame[offset++] = static_cast<std::uint8_t>((payload_length >> 8) & 0xFF);
    frame[offset++] = static_cast<std::uint8_t>(payload_length & 0xFF);

    // 写入电池电量和通道数
    frame[offset++] = 95;
    frame[offset++] = channel_count;

    // 写入姿态、生理量和保留字段
    offset += 2 + 2 + 2 + 2 + 2;
    for (std::uint8_t value : reserved) {
        frame[offset++] = value;
    }

    // 写入采样数据
    for (std::size_t sample = 0; sample < kSamplesPerFrame; ++sample) {
        for (std::size_t channel = 0; channel < channel_count; ++channel) {
            frame[offset++] = 0x00;
            frame[offset++] = 0x00;
            frame[offset++] = static_cast<std::uint8_t>(sample + channel + 1);
        }
        // 每个采样后的额外字节
        frame[offset++] = 0x00;
        frame[offset++] = 0x00;
    }

    // 写入帧尾
    frame[offset++] = 0x00;
    frame[offset++] = kTail;
    frame[offset++] = kTail;

    return frame;
}

/// 为现有调用点保留默认 frame_index=1 的便捷重载
std::vector<std::uint8_t> BuildMinimalFrame(std::uint8_t channel_count)
{
    return BuildMinimalFrame(channel_count, 1U);
}

void WriteSigned24(std::vector<std::uint8_t>& frame, std::size_t& offset, int raw_value)
{
    constexpr int kMinSigned24 = -8388608;
    constexpr int kMaxSigned24 = 8388607;
    raw_value = std::max(kMinSigned24, std::min(kMaxSigned24, raw_value));
    std::uint32_t encoded = 0;
    if (raw_value < 0) {
        encoded = static_cast<std::uint32_t>((1 << 24) + raw_value);
    } else {
        encoded = static_cast<std::uint32_t>(raw_value);
    }

    frame[offset++] = static_cast<std::uint8_t>((encoded >> 16) & 0xFF);
    frame[offset++] = static_cast<std::uint8_t>((encoded >> 8) & 0xFF);
    frame[offset++] = static_cast<std::uint8_t>(encoded & 0xFF);
}

std::vector<std::uint8_t> BuildFrameWithRawSamples(
    std::uint8_t channel_count,
    std::uint32_t frame_index,
    const std::array<std::array<int, XYPARSER_MAX_CHANNELS>, XYPARSER_SAMPLES_PER_FRAME>& raw_samples,
    std::array<std::uint8_t, 6> reserved = {})
{
    constexpr std::uint8_t kHeader = 0xAA;
    constexpr std::uint8_t kTail = 0x55;
    constexpr std::size_t kTagLen = 25;

    const std::size_t sample_bytes = static_cast<std::size_t>(channel_count) * 3 + 2;
    const std::uint16_t payload_length = static_cast<std::uint16_t>(sample_bytes * XYPARSER_SAMPLES_PER_FRAME);
    const std::size_t frame_size = 1 + kTagLen + payload_length + 2;

    std::vector<std::uint8_t> frame(frame_size, 0);
    std::size_t offset = 0;
    frame[offset++] = kHeader;
    frame[offset++] = static_cast<std::uint8_t>(frame_index & 0xFF);
    frame[offset++] = static_cast<std::uint8_t>((frame_index >> 8) & 0xFF);
    frame[offset++] = static_cast<std::uint8_t>((frame_index >> 16) & 0xFF);
    frame[offset++] = static_cast<std::uint8_t>((frame_index >> 24) & 0xFF);
    frame[offset++] = static_cast<std::uint8_t>((payload_length >> 8) & 0xFF);
    frame[offset++] = static_cast<std::uint8_t>(payload_length & 0xFF);
    frame[offset++] = 95;
    frame[offset++] = channel_count;
    offset += 2 + 2 + 2 + 2 + 2;
    for (std::uint8_t value : reserved) {
        frame[offset++] = value;
    }

    for (std::size_t sample = 0; sample < XYPARSER_SAMPLES_PER_FRAME; ++sample) {
        for (std::size_t channel = 0; channel < channel_count; ++channel) {
            WriteSigned24(frame, offset, raw_samples[sample][channel]);
        }
        frame[offset++] = 0x00;
        frame[offset++] = 0x00;
    }

    frame[offset++] = 0x00;
    frame[offset++] = kTail;
    frame[offset++] = kTail;
    return frame;
}

int BuildSineRawValue(int sample_index, int sample_rate, double frequency_hz, double amplitude)
{
    const double angle = 2.0 * 3.14159265358979323846 * frequency_hz *
                         static_cast<double>(sample_index) / static_cast<double>(sample_rate);
    return static_cast<int>(std::lround(std::sin(angle) * amplitude));
}

int BuildCombinedSineRawValue(int sample_index,
                              int sample_rate,
                              double primary_frequency_hz,
                              double primary_amplitude,
                              double secondary_frequency_hz = 0.0,
                              double secondary_amplitude = 0.0)
{
    return BuildSineRawValue(sample_index, sample_rate, primary_frequency_hz, primary_amplitude) +
           BuildSineRawValue(sample_index, sample_rate, secondary_frequency_hz, secondary_amplitude);
}

std::vector<double> BuildAlgorithmDataForSingleChannel(int sample_rate,
                                                       double primary_frequency_hz,
                                                       double primary_amplitude,
                                                       double secondary_frequency_hz = 0.0,
                                                       double secondary_amplitude = 0.0)
{
    std::vector<double> algorithm_data(
        static_cast<std::size_t>(sample_rate * XYPARSER_FRAME_DATA_COLUMN_COUNT), 0.0);
    for (int sample = 0; sample < sample_rate; ++sample) {
        const std::size_t sample_offset = static_cast<std::size_t>(sample) * XYPARSER_FRAME_DATA_COLUMN_COUNT;
        algorithm_data[sample_offset] = static_cast<double>(BuildCombinedSineRawValue(sample,
                                                                                      sample_rate,
                                                                                      primary_frequency_hz,
                                                                                      primary_amplitude,
                                                                                      secondary_frequency_hz,
                                                                                      secondary_amplitude));
    }
    return algorithm_data;
}

std::vector<double> BuildAlgorithmDataForTwoChannels(int sample_rate,
                                                     double channel0_frequency_hz,
                                                     double channel0_amplitude,
                                                     double channel1_frequency_hz,
                                                     double channel1_amplitude)
{
    std::vector<double> algorithm_data(
        static_cast<std::size_t>(sample_rate * XYPARSER_FRAME_DATA_COLUMN_COUNT), 0.0);
    for (int sample = 0; sample < sample_rate; ++sample) {
        const std::size_t sample_offset = static_cast<std::size_t>(sample) * XYPARSER_FRAME_DATA_COLUMN_COUNT;
        algorithm_data[sample_offset] = static_cast<double>(
            BuildSineRawValue(sample, sample_rate, channel0_frequency_hz, channel0_amplitude));
        algorithm_data[sample_offset + 1] = static_cast<double>(
            BuildSineRawValue(sample, sample_rate, channel1_frequency_hz, channel1_amplitude));
    }
    return algorithm_data;
}

std::vector<std::vector<std::uint8_t>> BuildFrameSequenceForSingleChannel(std::uint8_t channel_count,
                                                                          int sample_rate,
                                                                          double primary_frequency_hz,
                                                                          double primary_amplitude,
                                                                          double secondary_frequency_hz = 0.0,
                                                                          double secondary_amplitude = 0.0)
{
    const int frame_count = sample_rate / static_cast<int>(XYPARSER_SAMPLES_PER_FRAME);
    std::vector<std::vector<std::uint8_t>> frames;
    frames.reserve(static_cast<std::size_t>(frame_count));

    for (int frame_index = 0; frame_index < frame_count; ++frame_index) {
        std::array<std::array<int, XYPARSER_MAX_CHANNELS>, XYPARSER_SAMPLES_PER_FRAME> raw_samples{};
        for (int sample_offset = 0; sample_offset < static_cast<int>(XYPARSER_SAMPLES_PER_FRAME); ++sample_offset) {
            const int sample_index = frame_index * static_cast<int>(XYPARSER_SAMPLES_PER_FRAME) + sample_offset;
            raw_samples[static_cast<std::size_t>(sample_offset)][0] =
                BuildCombinedSineRawValue(sample_index,
                                          sample_rate,
                                          primary_frequency_hz,
                                          primary_amplitude,
                                          secondary_frequency_hz,
                                          secondary_amplitude);
        }
        frames.push_back(BuildFrameWithRawSamples(
            channel_count, static_cast<std::uint32_t>(frame_index + 1), raw_samples));
    }

    return frames;
}

std::vector<std::vector<std::uint8_t>> BuildFrameSequenceForTwoChannels(std::uint8_t channel_count,
                                                                        int sample_rate,
                                                                        double channel0_frequency_hz,
                                                                        double channel0_amplitude,
                                                                        double channel1_frequency_hz,
                                                                        double channel1_amplitude)
{
    const int frame_count = sample_rate / static_cast<int>(XYPARSER_SAMPLES_PER_FRAME);
    std::vector<std::vector<std::uint8_t>> frames;
    frames.reserve(static_cast<std::size_t>(frame_count));

    for (int frame_index = 0; frame_index < frame_count; ++frame_index) {
        std::array<std::array<int, XYPARSER_MAX_CHANNELS>, XYPARSER_SAMPLES_PER_FRAME> raw_samples{};
        for (int sample_offset = 0; sample_offset < static_cast<int>(XYPARSER_SAMPLES_PER_FRAME); ++sample_offset) {
            const int sample_index = frame_index * static_cast<int>(XYPARSER_SAMPLES_PER_FRAME) + sample_offset;
            raw_samples[static_cast<std::size_t>(sample_offset)][0] =
                BuildSineRawValue(sample_index, sample_rate, channel0_frequency_hz, channel0_amplitude);
            raw_samples[static_cast<std::size_t>(sample_offset)][1] =
                BuildSineRawValue(sample_index, sample_rate, channel1_frequency_hz, channel1_amplitude);
        }
        frames.push_back(BuildFrameWithRawSamples(
            channel_count, static_cast<std::uint32_t>(frame_index + 1), raw_samples));
    }

    return frames;
}

int FindFrequencyIndex(const XYParserWelchSummary& summary, double target_frequency_hz)
{
    for (std::uint32_t index = 0; index < summary.frequency_count; ++index) {
        if (std::abs(summary.frequencies[index] - target_frequency_hz) < 1e-9) {
            return static_cast<int>(index);
        }
    }
    return -1;
}

int FindPeakPsdIndex(const XYParserWelchSummary& summary, XYParserLeadChannelNumber lead)
{
    if (summary.frequency_count == 0) {
        return -1;
    }

    const std::size_t lead_index = static_cast<std::size_t>(lead);
    std::uint32_t peak_index = 0;
    double peak_value = summary.psd_values[lead_index][0];
    for (std::uint32_t index = 1; index < summary.frequency_count; ++index) {
        if (summary.psd_values[lead_index][index] > peak_value) {
            peak_value = summary.psd_values[lead_index][index];
            peak_index = index;
        }
    }
    return static_cast<int>(peak_index);
}

double ExpectedBinCenteredHanningPeakPsd(double peak_amplitude_uv)
{
    // For a 1-second window where sample_rate == n_per_seg, the periodic Hann window used by
    // the implementation yields a one-sided PSD peak of A^2 / 3 for a bin-centered sine wave.
    return (peak_amplitude_uv * peak_amplitude_uv) / 3.0;
}

std::uint16_t MeasureLeadImpedanceForMixedSine(std::uint8_t channel_count,
                                               XYParserLeadChannelNumber lead,
                                               int sample_rate,
                                               double primary_frequency_hz,
                                               double primary_amplitude,
                                               double secondary_frequency_hz,
                                               double secondary_amplitude);

std::uint16_t MeasureLeadImpedanceForSine(std::uint8_t channel_count,
                                          XYParserLeadChannelNumber lead,
                                          int sample_rate,
                                          double frequency_hz,
                                          double amplitude)
{
    return MeasureLeadImpedanceForMixedSine(
        channel_count, lead, sample_rate, frequency_hz, amplitude, 0.0, 0.0);
}

std::uint16_t MeasureLeadImpedanceForMixedSine(std::uint8_t channel_count,
                                               XYParserLeadChannelNumber lead,
                                               int sample_rate,
                                               double primary_frequency_hz,
                                               double primary_amplitude,
                                               double secondary_frequency_hz,
                                               double secondary_amplitude)
{
    ParserGuard parser(XYParser_CreateParser(channel_count));
    if (parser.get() == nullptr) {
        ADD_FAILURE() << "failed to create parser";
        return 0;
    }

    XYParser_SetBypassChecksum(parser.get(), 1);
    XYParser_SetSampleRate(parser.get(), sample_rate);
    XYParser_SetImpedanceDetection(parser.get(), 1);

    const auto frames = BuildFrameSequenceForSingleChannel(channel_count,
                                                           sample_rate,
                                                           primary_frequency_hz,
                                                           primary_amplitude,
                                                           secondary_frequency_hz,
                                                           secondary_amplitude);
    std::array<XYParserFrameSummary, 1> summaries{};
    for (const auto& frame : frames) {
        if (XYParser_Feed(parser.get(),
                          frame.data(),
                          frame.size(),
                          summaries.data(),
                          static_cast<int>(summaries.size())) != 1) {
            ADD_FAILURE() << "failed to feed frame for impedance measurement";
            return 0;
        }
    }

    std::array<XYParserImpedanceSummary, 1> impedance{};
    if (XYParser_ReadImpedance(parser.get(), impedance.data(), static_cast<int>(impedance.size())) != 1) {
        ADD_FAILURE() << "failed to read impedance summary";
        return 0;
    }

    return impedance[0].impedance_values[static_cast<std::size_t>(lead)];
}

} // namespace

/// 测试：创建解析器时拒绝不支持的通道数
TEST(XYParserApiTests, CreateParserRejectsUnsupportedChannelCount)
{
    // 7 通道是不支持的配置，应返回 nullptr
    EXPECT_EQ(XYParser_CreateParser(7), nullptr);
}

/// 测试：对空解析器句柄调用 GetLastError 应返回正确错误信息
TEST(XYParserApiTests, GetLastErrorReturnsMessageForNullParser)
{
    // 传入 nullptr 应返回 "invalid parser handle"
    EXPECT_EQ(std::string(XYParser_GetLastError(nullptr)), std::string("invalid parser handle"));
}

TEST(XYParserApiTests, Serialize8ChImpedanceOpenCommandMatchesWirelessEegPacket)
{
    constexpr std::size_t kCommandSize = 7;
    std::array<std::uint8_t, kCommandSize> command{};
    const int command_size = XYParser_Serialize8ChImpedanceCommand(1, command.data(), command.size());

    ASSERT_EQ(command_size, static_cast<int>(kCommandSize));
    const std::array<std::uint8_t, kCommandSize> expected = {
        0xAA, 0x00, 0x01, 0xA1, 0xA1, 0x55, 0x55};
    EXPECT_EQ(command, expected);
}

TEST(XYParserApiTests, Serialize8ChImpedanceCloseCommandMatchesWirelessEegPacket)
{
    constexpr std::size_t kCommandSize = 7;
    std::array<std::uint8_t, kCommandSize> command{};
    const int command_size = XYParser_Serialize8ChImpedanceCommand(0, command.data(), command.size());

    ASSERT_EQ(command_size, static_cast<int>(kCommandSize));
    const std::array<std::uint8_t, kCommandSize> expected = {
        0xAA, 0x00, 0x01, 0xA0, 0xA0, 0x55, 0x55};
    EXPECT_EQ(command, expected);
}

TEST(XYParserApiTests, Serialize8ChImpedanceCommandRejectsSmallBuffer)
{
    std::array<std::uint8_t, 6> command{};
    EXPECT_EQ(XYParser_Serialize8ChImpedanceCommand(1, command.data(), command.size()), 0);
}

TEST(XYParserApiTests, Get8ChImpedanceCommandSizeMatchesSerializedLength)
{
    EXPECT_EQ(XYParser_Get8ChImpedanceCommandSize(), static_cast<std::size_t>(7));
}

TEST(XYParserApiTests, SerializeTriggerCommandMatchesWirelessEegPacket)
{
    std::array<std::uint8_t, 8> command{};
    const int command_size = XYParser_SerializeTriggerCommand(
        XYPARSER_TRIGGER_TRAIN_0,
        command.data(),
        command.size());

    ASSERT_EQ(command_size, static_cast<int>(XYParser_GetTriggerCommandSize()));
    const std::array<std::uint8_t, 7> expected = {0xAA, 0x00, 0x00, 0xBB, 0xBB, 0x55, 0x55};
    EXPECT_TRUE(std::equal(expected.begin(), expected.end(), command.begin()));
}

TEST(XYParserApiTests, SerializeTrain1TriggerCommandMatchesWirelessEegPacket)
{
    std::array<std::uint8_t, 8> command{};
    const int command_size = XYParser_SerializeTriggerCommand(
        XYPARSER_TRIGGER_TRAIN_1,
        command.data(),
        command.size());

    ASSERT_EQ(command_size, static_cast<int>(XYParser_GetTriggerCommandSize()));
    const std::array<std::uint8_t, 7> expected = {0xAA, 0x00, 0x00, 0xBC, 0xBC, 0x55, 0x55};
    EXPECT_TRUE(std::equal(expected.begin(), expected.end(), command.begin()));
}

TEST(XYParserApiTests, SerializeTriggerCommandRejectsUnsupportedTriggerType)
{
    std::array<std::uint8_t, 8> command{};
    EXPECT_EQ(XYParser_SerializeTriggerCommand(0xAA, command.data(), command.size()), 0);
}

TEST(XYParserApiTests, SerializeTriggerCommandRejectsSmallBuffer)
{
    std::array<std::uint8_t, 6> command{};
    EXPECT_EQ(XYParser_SerializeTriggerCommand(XYPARSER_TRIGGER_TRAIN_1, command.data(), command.size()), 0);
}

TEST(XYParserApiTests, GetAlgorithmDataValueCountMatchesFrameLayout)
{
    EXPECT_EQ(XYParser_GetAlgorithmDataValueCount(),
              static_cast<std::size_t>(XYPARSER_FRAME_ALGORITHM_VALUE_COUNT));
}

TEST(XYParserApiTests, GetLeadMapCountReturnsExpectedCounts)
{
    EXPECT_EQ(XYParser_GetLeadMapCount(8), 8);
    EXPECT_EQ(XYParser_GetLeadMapCount(64), 64);
    EXPECT_EQ(XYParser_GetLeadMapCount(7), 0);
}

TEST(XYParserApiTests, GetLeadMapReturnsExpected8ChannelSubset)
{
    std::array<XYParserLeadChannelNumber, 8> leads{};
    const int count = XYParser_GetLeadMap(8, leads.data(), static_cast<int>(leads.size()));

    ASSERT_EQ(count, 8);
    const std::array<XYParserLeadChannelNumber, 8> expected = {
        LeadChannel_PO5, LeadChannel_POZ, LeadChannel_PO6, LeadChannel_PO7,
        LeadChannel_O1, LeadChannel_OZ, LeadChannel_O2, LeadChannel_PO8};
    EXPECT_EQ(leads, expected);
}

TEST(XYParserApiTests, GetLeadMapReturnsExpected64ChannelOrder)
{
    std::array<XYParserLeadChannelNumber, 64> leads{};
    const int count = XYParser_GetLeadMap(64, leads.data(), static_cast<int>(leads.size()));

    ASSERT_EQ(count, 64);
    EXPECT_EQ(leads.front(), LeadChannel_FP1);
    EXPECT_EQ(leads[1], LeadChannel_FP2);
    EXPECT_EQ(leads[13], LeadChannel_PO5);
    EXPECT_EQ(leads[55], LeadChannel_PO7);
    EXPECT_EQ(leads.back(), LeadChannel_F1);
}

TEST(XYParserApiTests, GetLeadMapRejectsUnsupportedChannelCountOrSmallBuffer)
{
    std::array<XYParserLeadChannelNumber, 7> small_buffer{};
    EXPECT_EQ(XYParser_GetLeadMap(8, small_buffer.data(), static_cast<int>(small_buffer.size())), 0);
    EXPECT_EQ(XYParser_GetLeadMap(7, nullptr, 0), 0);
}

TEST(XYParserApiTests, Convert8ChFramesTo64ChMapsKnownLeadsAndPadsOthersWithZero)
{
    std::array<XYParserFrameSummary, 2> input{};
    input[0].frame_index = 7U;
    input[0].channel_count = 8U;
    input[0].battery = 88U;
    input[0].sample_count = 5U;
    input[0].impedance_enabled = 1U;
    input[0].current_gain = 24U;
    input[0].current_sample_rate_hz = 1000U;
    input[0].cap_type = 7U;
    input[0].gnd_detached = 1U;
    input[0].sample_trigger_types[0] = 0xB2;
    input[0].sample_trigger_indices[0] = 3U;
    input[0].channel_values_uv[0][0] = 11.0;
    input[0].channel_values_uv[0][1] = 12.0;
    input[0].channel_values_uv[0][2] = 13.0;
    input[0].channel_values_uv[0][3] = 14.0;
    input[0].channel_values_uv[0][4] = 15.0;
    input[0].channel_values_uv[0][5] = 16.0;
    input[0].channel_values_uv[0][6] = 17.0;
    input[0].channel_values_uv[0][7] = 18.0;

    input[1].frame_index = 8U;
    input[1].channel_count = 8U;
    input[1].battery = 77U;
    input[1].sample_count = 5U;
    input[1].channel_values_uv[1][0] = 21.0;

    std::array<XYParserFrameSummary, 2> output{};
    ASSERT_EQ(XYParser_Convert8ChFramesTo64Ch(input.data(), static_cast<int>(input.size()), output.data(), static_cast<int>(output.size())), 2);
    EXPECT_EQ(output[0].frame_index, 7U);
    EXPECT_EQ(output[0].channel_count, 64U);
    EXPECT_EQ(output[0].battery, 88U);
    EXPECT_EQ(output[0].sample_count, 5U);
    EXPECT_EQ(output[0].impedance_enabled, 1U);
    EXPECT_EQ(output[0].current_gain, 24U);
    EXPECT_EQ(output[0].current_sample_rate_hz, 1000U);
    EXPECT_EQ(output[0].cap_type, 7U);
    EXPECT_EQ(output[0].gnd_detached, 1U);
    EXPECT_EQ(output[0].sample_trigger_types[0], 0xB2);
    EXPECT_EQ(output[0].sample_trigger_indices[0], 3U);
    EXPECT_DOUBLE_EQ(output[0].channel_values_uv[0][LeadChannel_PO5], 11.0);
    EXPECT_DOUBLE_EQ(output[0].channel_values_uv[0][LeadChannel_POZ], 12.0);
    EXPECT_DOUBLE_EQ(output[0].channel_values_uv[0][LeadChannel_PO6], 13.0);
    EXPECT_DOUBLE_EQ(output[0].channel_values_uv[0][LeadChannel_PO7], 14.0);
    EXPECT_DOUBLE_EQ(output[0].channel_values_uv[0][LeadChannel_O1], 15.0);
    EXPECT_DOUBLE_EQ(output[0].channel_values_uv[0][LeadChannel_OZ], 16.0);
    EXPECT_DOUBLE_EQ(output[0].channel_values_uv[0][LeadChannel_O2], 17.0);
    EXPECT_DOUBLE_EQ(output[0].channel_values_uv[0][LeadChannel_PO8], 18.0);
    EXPECT_DOUBLE_EQ(output[0].channel_values_uv[0][LeadChannel_FP1], 0.0);
    EXPECT_DOUBLE_EQ(output[0].channel_values_uv[0][LeadChannel_CZ], 0.0);
    EXPECT_EQ(output[1].frame_index, 8U);
    EXPECT_EQ(output[1].channel_count, 64U);
    EXPECT_DOUBLE_EQ(output[1].channel_values_uv[1][LeadChannel_PO5], 21.0);
}

TEST(XYParserApiTests, Convert8ChFramesTo64ChRejectsInvalidArgumentsAndStopsAtNon8ChannelInput)
{
    std::array<XYParserFrameSummary, 2> input{};
    input[0].channel_count = 8U;
    input[1].channel_count = 64U;
    std::array<XYParserFrameSummary, 2> output{};

    EXPECT_EQ(XYParser_Convert8ChFramesTo64Ch(nullptr, 1, output.data(), static_cast<int>(output.size())), 0);
    EXPECT_EQ(XYParser_Convert8ChFramesTo64Ch(input.data(), 1, nullptr, static_cast<int>(output.size())), 0);
    EXPECT_EQ(XYParser_Convert8ChFramesTo64Ch(input.data(), 0, output.data(), static_cast<int>(output.size())), 0);
    EXPECT_EQ(XYParser_Convert8ChFramesTo64Ch(input.data(), static_cast<int>(input.size()), output.data(), static_cast<int>(output.size())), 1);
    EXPECT_EQ(output[0].channel_count, 64U);
}

TEST(XYParserApiTests, ConvertSampleFramesToAlgorithmDataAppendsTriggerColumnsPerSample)
{
    constexpr std::size_t kFrameValueCount = XYPARSER_FRAME_ALGORITHM_VALUE_COUNT;
    XYParserFrameSummary input{};
    input.channel_count = 64U;
    input.sample_count = 5U;
    input.channel_values_uv[0][0] = 101.0;
    input.channel_values_uv[0][63] = 164.0;
    input.sample_trigger_types[0] = 0xA5;
    input.sample_trigger_indices[0] = 9U;
    input.channel_values_uv[1][10] = 210.0;
    input.sample_trigger_types[1] = 0x7F;
    input.sample_trigger_indices[1] = 5U;
    input.channel_values_uv[4][3] = 403.0;
    input.sample_trigger_types[4] = 0xB2;
    input.sample_trigger_indices[4] = 11U;

    std::array<double, kFrameValueCount> output{};
    ASSERT_EQ(XYParser_ConvertSampleFramesToAlgorithmData(&input, output.data()), 1);

    const std::size_t sample0 = 0;
    const std::size_t sample1 = XYPARSER_FRAME_DATA_COLUMN_COUNT;
    const std::size_t sample4 = 4 * XYPARSER_FRAME_DATA_COLUMN_COUNT;

    EXPECT_DOUBLE_EQ(output[sample0 + 0], 101.0);
    EXPECT_DOUBLE_EQ(output[sample0 + 63], 164.0);
    EXPECT_DOUBLE_EQ(output[sample0 + XYPARSER_FRAME_DATA_TRIGGER_TYPE_INDEX], 165.0);
    EXPECT_DOUBLE_EQ(output[sample0 + XYPARSER_FRAME_DATA_TRIGGER_INDEX_INDEX], 9.0);
    EXPECT_DOUBLE_EQ(output[sample4 + 3], 403.0);
    EXPECT_DOUBLE_EQ(output[sample4 + XYPARSER_FRAME_DATA_TRIGGER_TYPE_INDEX], 178.0);
    EXPECT_DOUBLE_EQ(output[sample4 + XYPARSER_FRAME_DATA_TRIGGER_INDEX_INDEX], 11.0);
    EXPECT_DOUBLE_EQ(output[sample1 + 10], 210.0);
    EXPECT_DOUBLE_EQ(output[sample1 + XYPARSER_FRAME_DATA_TRIGGER_TYPE_INDEX], 127.0);
    EXPECT_DOUBLE_EQ(output[sample1 + XYPARSER_FRAME_DATA_TRIGGER_INDEX_INDEX], 5.0);
}

TEST(XYParserApiTests, ConvertSampleFramesToAlgorithmDataRejectsInvalidArgumentsAndNon64ChannelInput)
{
    constexpr std::size_t kFrameValueCount = XYPARSER_FRAME_ALGORITHM_VALUE_COUNT;
    XYParserFrameSummary input{};
    input.channel_count = 8U;
    std::array<double, kFrameValueCount> output{};

    EXPECT_EQ(XYParser_ConvertSampleFramesToAlgorithmData(nullptr, output.data()), 0);
    EXPECT_EQ(XYParser_ConvertSampleFramesToAlgorithmData(&input, nullptr), 0);
    EXPECT_EQ(XYParser_ConvertSampleFramesToAlgorithmData(&input, output.data()), 0);
    EXPECT_DOUBLE_EQ(output[XYPARSER_FRAME_DATA_TRIGGER_TYPE_INDEX], 0.0);
}

TEST(XYParserApiTests, FeedAlgorithmDataCachesSamplesBuildsFramesAndFlushesTailSamples)
{
    ParserGuard parser(XYParser_CreateParser(64));
    ASSERT_NE(parser.get(), nullptr);

    constexpr int kTotalSamples = 7;
    constexpr int kColumnCount = XYPARSER_FRAME_DATA_COLUMN_COUNT;
    std::array<double, static_cast<std::size_t>(kTotalSamples) * kColumnCount> input_data{};
    for (int sample_index = 0; sample_index < kTotalSamples; ++sample_index) {
        const std::size_t row_offset = static_cast<std::size_t>(sample_index) * kColumnCount;
        input_data[row_offset + 0] = 1000.0 + sample_index;
        input_data[row_offset + 10] = 2000.0 + sample_index;
        input_data[row_offset + 63] = 3000.0 + sample_index;
        input_data[row_offset + XYPARSER_FRAME_DATA_TRIGGER_TYPE_INDEX] = 10.0 + sample_index;
        input_data[row_offset + XYPARSER_FRAME_DATA_TRIGGER_INDEX_INDEX] = 20.0 + sample_index;
    }
    const std::uint8_t* input_bytes = reinterpret_cast<const std::uint8_t*>(input_data.data());
    const std::size_t first_chunk_size = 3 * static_cast<std::size_t>(kColumnCount) * sizeof(double) + sizeof(double);
    const std::size_t second_chunk_size = sizeof(input_data) - first_chunk_size;

    std::array<XYParserFrameSummary, 1> summaries{};
    EXPECT_EQ(XYParser_FeedAlgorithmData(
                  parser.get(),
                  input_bytes,
                  first_chunk_size,
                  summaries.data(),
                  static_cast<int>(summaries.size())),
              0);

    ASSERT_EQ(XYParser_FeedAlgorithmData(
                  parser.get(),
                  input_bytes + first_chunk_size,
                  second_chunk_size,
                  summaries.data(),
                  static_cast<int>(summaries.size())),
              1);
    EXPECT_EQ(summaries[0].frame_index, 1U);
    EXPECT_EQ(summaries[0].channel_count, 64U);
    EXPECT_EQ(summaries[0].sample_count, 5U);
    EXPECT_DOUBLE_EQ(summaries[0].channel_values_uv[0][0], 1000.0);
    EXPECT_DOUBLE_EQ(summaries[0].channel_values_uv[2][10], 2002.0);
    EXPECT_DOUBLE_EQ(summaries[0].channel_values_uv[4][63], 3004.0);
    EXPECT_EQ(summaries[0].sample_trigger_types[0], 10U);
    EXPECT_EQ(summaries[0].sample_trigger_indices[4], 24U);

    XYParserFrameSummary tail_summary{};
    ASSERT_EQ(XYParser_FlushAlgorithmData(parser.get(), &tail_summary), 1);
    EXPECT_EQ(tail_summary.frame_index, 2U);
    EXPECT_EQ(tail_summary.channel_count, 64U);
    EXPECT_EQ(tail_summary.sample_count, 2U);
    EXPECT_DOUBLE_EQ(tail_summary.channel_values_uv[0][0], 1005.0);
    EXPECT_DOUBLE_EQ(tail_summary.channel_values_uv[1][63], 3006.0);
    EXPECT_EQ(tail_summary.sample_trigger_types[0], 15U);
    EXPECT_EQ(tail_summary.sample_trigger_indices[1], 26U);
    EXPECT_DOUBLE_EQ(tail_summary.channel_values_uv[2][0], 0.0);
    EXPECT_EQ(tail_summary.sample_trigger_types[2], 0U);

    XYParser_ResetAlgorithmDataCache(parser.get());
    EXPECT_EQ(XYParser_FlushAlgorithmData(parser.get(), &tail_summary), 0);
}

TEST(XYParserApiTests, GetLeadNameReturnsExpectedNames)
{
    EXPECT_EQ(std::string(XYParser_GetLeadName(LeadChannel_FP1)), "FP1");
    EXPECT_EQ(std::string(XYParser_GetLeadName(LeadChannel_PO5)), "PO5");
    EXPECT_EQ(std::string(XYParser_GetLeadName(LeadChannel_OZ)), "OZ");
    EXPECT_EQ(std::string(XYParser_GetLeadName(LeadChannel_GND)), "GND");
}

TEST(XYParserApiTests, GetLeadNameCovers8ChannelSubsetNames)
{
    EXPECT_EQ(std::string(XYParser_GetLeadName(LeadChannel_POZ)), "POZ");
    EXPECT_EQ(std::string(XYParser_GetLeadName(LeadChannel_PO6)), "PO6");
    EXPECT_EQ(std::string(XYParser_GetLeadName(LeadChannel_PO7)), "PO7");
    EXPECT_EQ(std::string(XYParser_GetLeadName(LeadChannel_PO8)), "PO8");
    EXPECT_EQ(std::string(XYParser_GetLeadName(LeadChannel_O1)), "O1");
    EXPECT_EQ(std::string(XYParser_GetLeadName(LeadChannel_O2)), "O2");
}

TEST(XYParserApiTests, GetLeadNameReturnsEmptyStringForInvalidLead)
{
    EXPECT_EQ(std::string(XYParser_GetLeadName(static_cast<XYParserLeadChannelNumber>(255))), "");
}

TEST(XYParserApiTests, GetWelchBandNameReturnsExpectedNames)
{
    EXPECT_EQ(std::string(XYParser_GetWelchBandName(0)), "delta");
    EXPECT_EQ(std::string(XYParser_GetWelchBandName(1)), "theta");
    EXPECT_EQ(std::string(XYParser_GetWelchBandName(2)), "alpha");
    EXPECT_EQ(std::string(XYParser_GetWelchBandName(3)), "beta");
    EXPECT_EQ(std::string(XYParser_GetWelchBandName(4)), "gamma");
}

TEST(XYParserApiTests, GetWelchBandNameReturnsEmptyStringForInvalidIndex)
{
    EXPECT_EQ(std::string(XYParser_GetWelchBandName(-1)), "");
    EXPECT_EQ(std::string(XYParser_GetWelchBandName(XYPARSER_WELCH_BAND_COUNT)), "");
}

TEST(XYParserApiTests, GetWelchBandRangeReturnsExpectedRanges)
{
    double low_hz = 0.0;
    double high_hz = 0.0;

    ASSERT_EQ(XYParser_GetWelchBandRange(0, &low_hz, &high_hz), 1);
    EXPECT_DOUBLE_EQ(low_hz, 0.5);
    EXPECT_DOUBLE_EQ(high_hz, 4.0);

    ASSERT_EQ(XYParser_GetWelchBandRange(4, &low_hz, &high_hz), 1);
    EXPECT_DOUBLE_EQ(low_hz, 30.0);
    EXPECT_DOUBLE_EQ(high_hz, 50.0);
}

TEST(XYParserApiTests, GetWelchBandRangeRejectsInvalidArguments)
{
    double low_hz = 0.0;
    double high_hz = 0.0;

    EXPECT_EQ(XYParser_GetWelchBandRange(-1, &low_hz, &high_hz), 0);
    EXPECT_EQ(XYParser_GetWelchBandRange(XYPARSER_WELCH_BAND_COUNT, &low_hz, &high_hz), 0);
    EXPECT_EQ(XYParser_GetWelchBandRange(0, nullptr, &high_hz), 0);
    EXPECT_EQ(XYParser_GetWelchBandRange(0, &low_hz, nullptr), 0);
}

TEST(XYParserApiTests, SetImpedanceDetectionSwitchesParserGainBetween24And6)
{
    ParserGuard parser(XYParser_CreateParser(8));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetAdcParams(parser.get(), 4.5, 6.0);
    XYParser_SetBypassChecksum(parser.get(), 1);

    const std::vector<std::uint8_t> frame1 = BuildMinimalFrame(8, 1U);
    const std::vector<std::uint8_t> frame2 = BuildMinimalFrame(8, 2U);
    const std::vector<std::uint8_t> frame3 = BuildMinimalFrame(8, 3U);
    std::array<XYParserFrameSummary, 1> summaries{};

    ASSERT_EQ(XYParser_Feed(parser.get(), frame1.data(), frame1.size(), summaries.data(), static_cast<int>(summaries.size())), 1);
    const double gain6_value_before = summaries[0].channel_values_uv[0][0];

    XYParser_SetImpedanceDetection(parser.get(), 1);
    ASSERT_EQ(XYParser_Feed(parser.get(), frame2.data(), frame2.size(), summaries.data(), static_cast<int>(summaries.size())), 1);
    const double gain24_value = summaries[0].channel_values_uv[0][0];

    XYParser_SetImpedanceDetection(parser.get(), 0);
    ASSERT_EQ(XYParser_Feed(parser.get(), frame3.data(), frame3.size(), summaries.data(), static_cast<int>(summaries.size())), 1);
    const double gain6_value_after = summaries[0].channel_values_uv[0][0];

    EXPECT_NEAR(gain24_value * 4.0, gain6_value_before, 1e-9);
    EXPECT_NEAR(gain6_value_after, gain6_value_before, 1e-9);
}

TEST(XYParserApiTests, ImpedanceReturnsOneResultAfterOneSecondFor8Channels)
{
    ParserGuard parser(XYParser_CreateParser(8));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetBypassChecksum(parser.get(), 1);
    XYParser_SetSampleRate(parser.get(), 10);
    XYParser_SetImpedanceDetection(parser.get(), 1);

    std::array<std::array<int, XYPARSER_MAX_CHANNELS>, XYPARSER_SAMPLES_PER_FRAME> raw_samples1{};
    std::array<std::array<int, XYPARSER_MAX_CHANNELS>, XYPARSER_SAMPLES_PER_FRAME> raw_samples2{};
    for (int sample = 0; sample < 10; ++sample) {
        const int raw_value = BuildSineRawValue(sample, 10, 2.0, 1000000.0);
        if (sample < static_cast<int>(XYPARSER_SAMPLES_PER_FRAME)) {
            raw_samples1[static_cast<std::size_t>(sample)][0] = raw_value;
        } else {
            raw_samples2[static_cast<std::size_t>(sample - XYPARSER_SAMPLES_PER_FRAME)][0] = raw_value;
        }
    }

    const std::vector<std::uint8_t> frame1 = BuildFrameWithRawSamples(8, 1U, raw_samples1);
    const std::vector<std::uint8_t> frame2 = BuildFrameWithRawSamples(8, 2U, raw_samples2);
    std::array<XYParserFrameSummary, 2> summaries{};
    std::array<XYParserImpedanceSummary, 2> impedance{};

    EXPECT_EQ(XYParser_Feed(parser.get(), frame1.data(), frame1.size(), summaries.data(), static_cast<int>(summaries.size())), 1);
    EXPECT_EQ(XYParser_ReadImpedance(parser.get(), impedance.data(), static_cast<int>(impedance.size())), 0);

    EXPECT_EQ(XYParser_Feed(parser.get(), frame2.data(), frame2.size(), summaries.data(), static_cast<int>(summaries.size())), 1);
    ASSERT_EQ(XYParser_ReadImpedance(parser.get(), impedance.data(), static_cast<int>(impedance.size())), 1);
    EXPECT_EQ(impedance[0].channel_count, 8);
    EXPECT_EQ(impedance[0].sample_rate, 10U);
    EXPECT_EQ(impedance[0].window_sample_count, 10U);
    EXPECT_GT(impedance[0].impedance_values[LeadChannel_PO5], 0);
    EXPECT_EQ(impedance[0].impedance_values[LeadChannel_FP1], 0);
}

TEST(XYParserApiTests, ReadImpedanceConsumesQueuedResults)
{
    ParserGuard parser(XYParser_CreateParser(8));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetBypassChecksum(parser.get(), 1);
    XYParser_SetSampleRate(parser.get(), 10);
    XYParser_SetImpedanceDetection(parser.get(), 1);

    std::array<std::array<int, XYPARSER_MAX_CHANNELS>, XYPARSER_SAMPLES_PER_FRAME> raw_samples1{};
    std::array<std::array<int, XYPARSER_MAX_CHANNELS>, XYPARSER_SAMPLES_PER_FRAME> raw_samples2{};
    for (int sample = 0; sample < 10; ++sample) {
        const int raw_value = BuildSineRawValue(sample, 10, 2.0, 1000000.0);
        if (sample < static_cast<int>(XYPARSER_SAMPLES_PER_FRAME)) {
            raw_samples1[static_cast<std::size_t>(sample)][0] = raw_value;
        } else {
            raw_samples2[static_cast<std::size_t>(sample - XYPARSER_SAMPLES_PER_FRAME)][0] = raw_value;
        }
    }

    const std::vector<std::uint8_t> frame1 = BuildFrameWithRawSamples(8, 1U, raw_samples1);
    const std::vector<std::uint8_t> frame2 = BuildFrameWithRawSamples(8, 2U, raw_samples2);
    std::array<XYParserFrameSummary, 1> summaries{};
    std::array<XYParserImpedanceSummary, 1> impedance{};

    ASSERT_EQ(XYParser_Feed(parser.get(), frame1.data(), frame1.size(), summaries.data(), static_cast<int>(summaries.size())), 1);
    ASSERT_EQ(XYParser_Feed(parser.get(), frame2.data(), frame2.size(), summaries.data(), static_cast<int>(summaries.size())), 1);

    ASSERT_EQ(XYParser_ReadImpedance(parser.get(), impedance.data(), static_cast<int>(impedance.size())), 1);
    EXPECT_GT(impedance[0].impedance_values[LeadChannel_PO5], 0);
    EXPECT_EQ(XYParser_ReadImpedance(parser.get(), impedance.data(), static_cast<int>(impedance.size())), 0);
}

TEST(XYParserApiTests, ImpedanceUsesUnifiedLeadIndexesFor64Channels)
{
    ParserGuard parser(XYParser_CreateParser(64));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetBypassChecksum(parser.get(), 1);
    XYParser_SetSampleRate(parser.get(), 10);
    XYParser_SetImpedanceDetection(parser.get(), 1);

    std::array<std::array<int, XYPARSER_MAX_CHANNELS>, XYPARSER_SAMPLES_PER_FRAME> raw_samples1{};
    std::array<std::array<int, XYPARSER_MAX_CHANNELS>, XYPARSER_SAMPLES_PER_FRAME> raw_samples2{};
    for (int sample = 0; sample < 10; ++sample) {
        const int raw_value = BuildSineRawValue(sample, 10, 3.0, 1000000.0);
        if (sample < static_cast<int>(XYPARSER_SAMPLES_PER_FRAME)) {
            raw_samples1[static_cast<std::size_t>(sample)][0] = raw_value;
        } else {
            raw_samples2[static_cast<std::size_t>(sample - XYPARSER_SAMPLES_PER_FRAME)][0] = raw_value;
        }
    }

    const std::vector<std::uint8_t> frame1 = BuildFrameWithRawSamples(64, 1U, raw_samples1);
    const std::vector<std::uint8_t> frame2 = BuildFrameWithRawSamples(64, 2U, raw_samples2);
    std::array<XYParserFrameSummary, 2> summaries{};
    std::array<XYParserImpedanceSummary, 2> impedance{};

    EXPECT_EQ(XYParser_Feed(parser.get(), frame1.data(), frame1.size(), summaries.data(), static_cast<int>(summaries.size())), 1);
    EXPECT_EQ(XYParser_Feed(parser.get(), frame2.data(), frame2.size(), summaries.data(), static_cast<int>(summaries.size())), 1);
    ASSERT_EQ(XYParser_ReadImpedance(parser.get(), impedance.data(), static_cast<int>(impedance.size())), 1);
    EXPECT_EQ(impedance[0].channel_count, 64);
    EXPECT_GT(impedance[0].impedance_values[LeadChannel_FP1], 0);
    EXPECT_EQ(impedance[0].impedance_values[LeadChannel_FP2], 0);
}

TEST(XYParserApiTests, ImpedanceSeparatesDifferentChannelLeadsFor64Channels)
{
    ParserGuard parser(XYParser_CreateParser(64));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetBypassChecksum(parser.get(), 1);
    XYParser_SetSampleRate(parser.get(), 10);
    XYParser_SetImpedanceDetection(parser.get(), 1);

    const auto frames = BuildFrameSequenceForTwoChannels(64, 10, 3.0, 1000000.0, 2.0, 250000.0);
    ASSERT_EQ(frames.size(), 2U);

    std::array<XYParserFrameSummary, 1> summaries{};
    std::array<XYParserImpedanceSummary, 1> impedance{};
    for (const auto& frame : frames) {
        ASSERT_EQ(XYParser_Feed(parser.get(),
                                frame.data(),
                                frame.size(),
                                summaries.data(),
                                static_cast<int>(summaries.size())),
                  1);
    }

    ASSERT_EQ(XYParser_ReadImpedance(parser.get(), impedance.data(), static_cast<int>(impedance.size())), 1);
    EXPECT_GT(impedance[0].impedance_values[LeadChannel_FP1], 0);
    EXPECT_GT(impedance[0].impedance_values[LeadChannel_FP2], 0);
    EXPECT_GT(impedance[0].impedance_values[LeadChannel_FP1], impedance[0].impedance_values[LeadChannel_FP2]);
    EXPECT_EQ(impedance[0].impedance_values[LeadChannel_PO6], 0);
}

TEST(XYParserApiTests, ImpedanceDisableClearsHalfWindow)
{
    ParserGuard parser(XYParser_CreateParser(64));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetBypassChecksum(parser.get(), 1);
    XYParser_SetSampleRate(parser.get(), 10);
    XYParser_SetImpedanceDetection(parser.get(), 1);

    const auto full_frames = BuildFrameSequenceForSingleChannel(64, 10, 3.0, 1000000.0);
    ASSERT_EQ(full_frames.size(), 2U);

    std::array<XYParserFrameSummary, 1> summaries{};
    std::array<XYParserImpedanceSummary, 1> impedance{};

    ASSERT_EQ(XYParser_Feed(parser.get(),
                            full_frames[0].data(),
                            full_frames[0].size(),
                            summaries.data(),
                            static_cast<int>(summaries.size())),
              1);
    EXPECT_EQ(XYParser_ReadImpedance(parser.get(), impedance.data(), static_cast<int>(impedance.size())), 0);

    XYParser_SetImpedanceDetection(parser.get(), 0);
    XYParser_SetImpedanceDetection(parser.get(), 1);

    ASSERT_EQ(XYParser_Feed(parser.get(),
                            full_frames[0].data(),
                            full_frames[0].size(),
                            summaries.data(),
                            static_cast<int>(summaries.size())),
              1);
    EXPECT_EQ(XYParser_ReadImpedance(parser.get(), impedance.data(), static_cast<int>(impedance.size())), 0);

    ASSERT_EQ(XYParser_Feed(parser.get(),
                            full_frames[1].data(),
                            full_frames[1].size(),
                            summaries.data(),
                            static_cast<int>(summaries.size())),
              1);
    ASSERT_EQ(XYParser_ReadImpedance(parser.get(), impedance.data(), static_cast<int>(impedance.size())), 1);
    EXPECT_GT(impedance[0].impedance_values[LeadChannel_FP1], 0);
}

TEST(XYParserApiTests, ImpedanceSampleRateChangeClearsHalfWindow)
{
    ParserGuard parser(XYParser_CreateParser(64));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetBypassChecksum(parser.get(), 1);
    XYParser_SetSampleRate(parser.get(), 10);
    XYParser_SetImpedanceDetection(parser.get(), 1);

    const auto frames_10hz_window = BuildFrameSequenceForSingleChannel(64, 10, 3.0, 1000000.0);
    ASSERT_EQ(frames_10hz_window.size(), 2U);

    std::array<XYParserFrameSummary, 1> summaries{};
    std::array<XYParserImpedanceSummary, 1> impedance{};

    ASSERT_EQ(XYParser_Feed(parser.get(),
                            frames_10hz_window[0].data(),
                            frames_10hz_window[0].size(),
                            summaries.data(),
                            static_cast<int>(summaries.size())),
              1);
    EXPECT_EQ(XYParser_ReadImpedance(parser.get(), impedance.data(), static_cast<int>(impedance.size())), 0);

    XYParser_SetSampleRate(parser.get(), 20);

    const auto frames_20hz_window = BuildFrameSequenceForSingleChannel(64, 20, 3.0, 1000000.0);
    ASSERT_EQ(frames_20hz_window.size(), 4U);

    for (const auto& frame : frames_20hz_window) {
        ASSERT_EQ(XYParser_Feed(parser.get(),
                                frame.data(),
                                frame.size(),
                                summaries.data(),
                                static_cast<int>(summaries.size())),
                  1);
    }

    ASSERT_EQ(XYParser_ReadImpedance(parser.get(), impedance.data(), static_cast<int>(impedance.size())), 1);
    EXPECT_EQ(impedance[0].sample_rate, 20U);
    EXPECT_EQ(impedance[0].window_sample_count, 20U);
    EXPECT_GT(impedance[0].impedance_values[LeadChannel_FP1], 0);
}

TEST(XYParserApiTests, ImpedanceSuppresses50HzLineNoiseFor64Channels)
{
    constexpr int kSampleRate = 200;
    constexpr double kAmplitude = 1000000.0;

    const std::uint16_t signal_10hz = MeasureLeadImpedanceForSine(
        64, LeadChannel_FP1, kSampleRate, 10.0, kAmplitude);
    const std::uint16_t line_noise_50hz = MeasureLeadImpedanceForSine(
        64, LeadChannel_FP1, kSampleRate, 50.0, kAmplitude);

    EXPECT_GT(signal_10hz, 0);
    EXPECT_LT(line_noise_50hz, signal_10hz);
}

TEST(XYParserApiTests, ImpedanceSuppressesFrequenciesAround50HzAnd100HzFor64Channels)
{
    constexpr int kSampleRate = 200;
    constexpr double kAmplitude = 1000000.0;

    const std::uint16_t signal_10hz = MeasureLeadImpedanceForSine(
        64, LeadChannel_FP1, kSampleRate, 10.0, kAmplitude);
    const std::uint16_t signal_49hz = MeasureLeadImpedanceForSine(
        64, LeadChannel_FP1, kSampleRate, 49.0, kAmplitude);
    const std::uint16_t signal_50hz = MeasureLeadImpedanceForSine(
        64, LeadChannel_FP1, kSampleRate, 50.0, kAmplitude);
    const std::uint16_t signal_51hz = MeasureLeadImpedanceForSine(
        64, LeadChannel_FP1, kSampleRate, 51.0, kAmplitude);
    const std::uint16_t signal_100hz = MeasureLeadImpedanceForSine(
        64, LeadChannel_FP1, kSampleRate, 100.0, kAmplitude);

    ASSERT_GT(signal_10hz, 0);
    EXPECT_LT(signal_49hz, signal_10hz);
    EXPECT_LT(signal_50hz, signal_10hz);
    EXPECT_LT(signal_51hz, signal_10hz);
    EXPECT_LT(signal_100hz, signal_10hz);
}

TEST(XYParserApiTests, ImpedancePreserves10HzSignalWhenMixedWithStrong50HzLineNoise)
{
    constexpr int kSampleRate = 200;
    constexpr double kSignalAmplitude = 1000000.0;
    constexpr double kLineNoiseAmplitude = 3000000.0;

    const std::uint16_t signal_10hz = MeasureLeadImpedanceForSine(
        64, LeadChannel_FP1, kSampleRate, 10.0, kSignalAmplitude);
    const std::uint16_t line_noise_50hz = MeasureLeadImpedanceForSine(
        64, LeadChannel_FP1, kSampleRate, 50.0, kLineNoiseAmplitude);
    const std::uint16_t mixed_signal = MeasureLeadImpedanceForMixedSine(
        64, LeadChannel_FP1, kSampleRate, 10.0, kSignalAmplitude, 50.0, kLineNoiseAmplitude);

    ASSERT_GT(signal_10hz, 0);
    EXPECT_LT(line_noise_50hz, signal_10hz);
    EXPECT_GT(mixed_signal, line_noise_50hz);
    EXPECT_NEAR(static_cast<double>(mixed_signal),
                static_cast<double>(signal_10hz),
                std::max(1.0, static_cast<double>(signal_10hz) * 0.2));
}

TEST(XYParserApiTests, ImpedancePreserves10HzSignalWhenMixedWithStrong49To51HzLineNoise)
{
    constexpr int kSampleRate = 200;
    constexpr double kSignalAmplitude = 1000000.0;
    constexpr double kLineNoiseAmplitude = 3000000.0;

    const std::uint16_t signal_10hz = MeasureLeadImpedanceForSine(
        64, LeadChannel_FP1, kSampleRate, 10.0, kSignalAmplitude);
    ASSERT_GT(signal_10hz, 0);

    for (double line_noise_hz : {49.0, 50.0, 51.0}) {
        const std::uint16_t pure_line_noise = MeasureLeadImpedanceForSine(
            64, LeadChannel_FP1, kSampleRate, line_noise_hz, kLineNoiseAmplitude);
        const std::uint16_t mixed_signal = MeasureLeadImpedanceForMixedSine(
            64,
            LeadChannel_FP1,
            kSampleRate,
            10.0,
            kSignalAmplitude,
            line_noise_hz,
            kLineNoiseAmplitude);

        EXPECT_LT(pure_line_noise, signal_10hz) << "line noise hz=" << line_noise_hz;
        EXPECT_GT(mixed_signal, pure_line_noise) << "line noise hz=" << line_noise_hz;
        EXPECT_NEAR(static_cast<double>(mixed_signal),
                    static_cast<double>(signal_10hz),
                    std::max(1.0, static_cast<double>(signal_10hz) * 0.2))
            << "line noise hz=" << line_noise_hz;
    }
}

TEST(XYParserApiTests, WelchReturnsOneResultAfterOneSecondFromAlgorithmData)
{
    ParserGuard parser(XYParser_CreateParser(64));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetSampleRate(parser.get(), 10);
    XYParser_SetWelchDetection(parser.get(), 1);

    std::vector<double> algorithm_data(static_cast<std::size_t>(10 * XYPARSER_FRAME_DATA_COLUMN_COUNT), 0.0);
    for (int sample = 0; sample < 10; ++sample) {
        const std::size_t sample_offset = static_cast<std::size_t>(sample) * XYPARSER_FRAME_DATA_COLUMN_COUNT;
        algorithm_data[sample_offset] = static_cast<double>(BuildSineRawValue(sample, 10, 2.0, 1000000.0));
    }

    std::array<XYParserWelchSummary, 2> welch{};

    EXPECT_EQ(XYParser_FeedAlgorithmData(
                  parser.get(),
                  reinterpret_cast<const std::uint8_t*>(algorithm_data.data()),
                  algorithm_data.size() * sizeof(double),
                  nullptr,
                  0),
              0);
    ASSERT_EQ(XYParser_ReadWelch(parser.get(), welch.data(), static_cast<int>(welch.size())), 1);
    EXPECT_EQ(welch[0].ok, 1);
    EXPECT_EQ(welch[0].channel_count, 64);
    EXPECT_EQ(welch[0].sample_rate, 10U);
    EXPECT_EQ(welch[0].window_sample_count, 10U);
    EXPECT_GT(welch[0].frequency_count, 0U);
    EXPECT_DOUBLE_EQ(welch[0].frequencies[0], 1.0);
    EXPECT_GT(welch[0].psd_values[LeadChannel_FP1][0], 0.0);
    EXPECT_EQ(welch[0].psd_values[LeadChannel_FP2][0], 0.0);
    EXPECT_GT(welch[0].band_values[0][LeadChannel_FP1], 0.0);
}

TEST(XYParserApiTests, WelchDetects50HzPeakFromAlgorithmData)
{
    ParserGuard parser(XYParser_CreateParser(64));
    ASSERT_NE(parser.get(), nullptr);

    constexpr int kSampleRate = 200;
    XYParser_SetSampleRate(parser.get(), kSampleRate);
    XYParser_SetWelchDetection(parser.get(), 1);

    const std::vector<double> algorithm_data = BuildAlgorithmDataForSingleChannel(
        kSampleRate, 50.0, 1000000.0, 10.0, 100000.0);

    std::array<XYParserWelchSummary, 1> welch{};
    EXPECT_EQ(XYParser_FeedAlgorithmData(
                  parser.get(),
                  reinterpret_cast<const std::uint8_t*>(algorithm_data.data()),
                  algorithm_data.size() * sizeof(double),
                  nullptr,
                  0),
              0);

    ASSERT_EQ(XYParser_ReadWelch(parser.get(), welch.data(), static_cast<int>(welch.size())), 1);
    ASSERT_EQ(welch[0].ok, 1);

    const int frequency_10hz_index = FindFrequencyIndex(welch[0], 10.0);
    const int frequency_50hz_index = FindFrequencyIndex(welch[0], 50.0);
    const int peak_index = FindPeakPsdIndex(welch[0], LeadChannel_FP1);

    ASSERT_GE(frequency_10hz_index, 0);
    ASSERT_GE(frequency_50hz_index, 0);
    ASSERT_GE(peak_index, 0);

    EXPECT_DOUBLE_EQ(welch[0].frequencies[static_cast<std::size_t>(peak_index)], 50.0);
    EXPECT_GT(welch[0].psd_values[LeadChannel_FP1][static_cast<std::size_t>(frequency_50hz_index)],
              welch[0].psd_values[LeadChannel_FP1][static_cast<std::size_t>(frequency_10hz_index)]);
    EXPECT_GT(welch[0].band_values[4][LeadChannel_FP1], welch[0].band_values[2][LeadChannel_FP1]);
}

TEST(XYParserApiTests, WelchDetects49HzPeakFromAlgorithmData)
{
    ParserGuard parser(XYParser_CreateParser(64));
    ASSERT_NE(parser.get(), nullptr);

    constexpr int kSampleRate = 200;
    XYParser_SetSampleRate(parser.get(), kSampleRate);
    XYParser_SetWelchDetection(parser.get(), 1);

    const std::vector<double> algorithm_data = BuildAlgorithmDataForSingleChannel(
        kSampleRate, 49.0, 1000000.0, 10.0, 100000.0);

    std::array<XYParserWelchSummary, 1> welch{};
    EXPECT_EQ(XYParser_FeedAlgorithmData(
                  parser.get(),
                  reinterpret_cast<const std::uint8_t*>(algorithm_data.data()),
                  algorithm_data.size() * sizeof(double),
                  nullptr,
                  0),
              0);

    ASSERT_EQ(XYParser_ReadWelch(parser.get(), welch.data(), static_cast<int>(welch.size())), 1);
    ASSERT_EQ(welch[0].ok, 1);

    const int frequency_10hz_index = FindFrequencyIndex(welch[0], 10.0);
    const int frequency_49hz_index = FindFrequencyIndex(welch[0], 49.0);
    const int peak_index = FindPeakPsdIndex(welch[0], LeadChannel_FP1);

    ASSERT_GE(frequency_10hz_index, 0);
    ASSERT_GE(frequency_49hz_index, 0);
    ASSERT_GE(peak_index, 0);

    EXPECT_DOUBLE_EQ(welch[0].frequencies[static_cast<std::size_t>(peak_index)], 49.0);
    EXPECT_GT(welch[0].psd_values[LeadChannel_FP1][static_cast<std::size_t>(frequency_49hz_index)],
              welch[0].psd_values[LeadChannel_FP1][static_cast<std::size_t>(frequency_10hz_index)]);
    EXPECT_GT(welch[0].band_values[4][LeadChannel_FP1], welch[0].band_values[2][LeadChannel_FP1]);
}

TEST(XYParserApiTests, WelchReportedFrequenciesDoNotExceed50Hz)
{
    ParserGuard parser(XYParser_CreateParser(64));
    ASSERT_NE(parser.get(), nullptr);

    constexpr int kSampleRate = 200;
    XYParser_SetSampleRate(parser.get(), kSampleRate);
    XYParser_SetWelchDetection(parser.get(), 1);

    const std::vector<double> algorithm_data = BuildAlgorithmDataForSingleChannel(
        kSampleRate, 51.0, 1000000.0, 100.0, 500000.0);

    std::array<XYParserWelchSummary, 1> welch{};
    EXPECT_EQ(XYParser_FeedAlgorithmData(
                  parser.get(),
                  reinterpret_cast<const std::uint8_t*>(algorithm_data.data()),
                  algorithm_data.size() * sizeof(double),
                  nullptr,
                  0),
              0);

    ASSERT_EQ(XYParser_ReadWelch(parser.get(), welch.data(), static_cast<int>(welch.size())), 1);
    ASSERT_EQ(welch[0].ok, 1);
    ASSERT_GT(welch[0].frequency_count, 0U);

    EXPECT_LE(welch[0].frequencies[welch[0].frequency_count - 1], 50.0);
    EXPECT_EQ(FindFrequencyIndex(welch[0], 51.0), -1);
    EXPECT_EQ(FindFrequencyIndex(welch[0], 100.0), -1);
}

TEST(XYParserApiTests, WelchDetects49And50HzPeakWhenMixedWith10Hz)
{
    constexpr int kSampleRate = 200;

    for (double line_noise_hz : {49.0, 50.0}) {
        ParserGuard parser(XYParser_CreateParser(64));
        ASSERT_NE(parser.get(), nullptr);

        XYParser_SetSampleRate(parser.get(), kSampleRate);
        XYParser_SetWelchDetection(parser.get(), 1);

        const std::vector<double> algorithm_data = BuildAlgorithmDataForSingleChannel(
            kSampleRate, line_noise_hz, 1000000.0, 10.0, 100000.0);

        std::array<XYParserWelchSummary, 1> welch{};
        EXPECT_EQ(XYParser_FeedAlgorithmData(
                      parser.get(),
                      reinterpret_cast<const std::uint8_t*>(algorithm_data.data()),
                      algorithm_data.size() * sizeof(double),
                      nullptr,
                      0),
                  0);

        ASSERT_EQ(XYParser_ReadWelch(parser.get(), welch.data(), static_cast<int>(welch.size())), 1);
        ASSERT_EQ(welch[0].ok, 1);

        const int frequency_10hz_index = FindFrequencyIndex(welch[0], 10.0);
        const int line_noise_index = FindFrequencyIndex(welch[0], line_noise_hz);
        const int peak_index = FindPeakPsdIndex(welch[0], LeadChannel_FP1);

        ASSERT_GE(frequency_10hz_index, 0) << "line noise hz=" << line_noise_hz;
        ASSERT_GE(line_noise_index, 0) << "line noise hz=" << line_noise_hz;
        ASSERT_GE(peak_index, 0) << "line noise hz=" << line_noise_hz;

        EXPECT_DOUBLE_EQ(welch[0].frequencies[static_cast<std::size_t>(peak_index)], line_noise_hz)
            << "line noise hz=" << line_noise_hz;
        EXPECT_GT(welch[0].psd_values[LeadChannel_FP1][static_cast<std::size_t>(line_noise_index)],
                  welch[0].psd_values[LeadChannel_FP1][static_cast<std::size_t>(frequency_10hz_index)])
            << "line noise hz=" << line_noise_hz;
        EXPECT_GT(welch[0].band_values[4][LeadChannel_FP1], welch[0].band_values[2][LeadChannel_FP1])
            << "line noise hz=" << line_noise_hz;
    }
}

TEST(XYParserApiTests, WelchDoesNotReport51HzButGammaBandRisesWhenMixedWith10Hz)
{
    ParserGuard parser(XYParser_CreateParser(64));
    ASSERT_NE(parser.get(), nullptr);

    constexpr int kSampleRate = 200;
    XYParser_SetSampleRate(parser.get(), kSampleRate);
    XYParser_SetWelchDetection(parser.get(), 1);

    const std::vector<double> algorithm_data = BuildAlgorithmDataForSingleChannel(
        kSampleRate, 51.0, 1000000.0, 10.0, 100000.0);

    std::array<XYParserWelchSummary, 1> welch{};
    EXPECT_EQ(XYParser_FeedAlgorithmData(
                  parser.get(),
                  reinterpret_cast<const std::uint8_t*>(algorithm_data.data()),
                  algorithm_data.size() * sizeof(double),
                  nullptr,
                  0),
              0);

    ASSERT_EQ(XYParser_ReadWelch(parser.get(), welch.data(), static_cast<int>(welch.size())), 1);
    ASSERT_EQ(welch[0].ok, 1);

    const int frequency_10hz_index = FindFrequencyIndex(welch[0], 10.0);
    const int frequency_50hz_index = FindFrequencyIndex(welch[0], 50.0);

    ASSERT_GE(frequency_10hz_index, 0);
    ASSERT_GE(frequency_50hz_index, 0);

    EXPECT_EQ(FindFrequencyIndex(welch[0], 51.0), -1);
    EXPECT_GT(welch[0].band_values[4][LeadChannel_FP1], welch[0].band_values[2][LeadChannel_FP1]);
    EXPECT_GT(welch[0].psd_values[LeadChannel_FP1][static_cast<std::size_t>(frequency_50hz_index)],
              welch[0].psd_values[LeadChannel_FP1][static_cast<std::size_t>(frequency_10hz_index)]);
}

TEST(XYParserApiTests, WelchDoesNotReport100HzOrPolluteLowFrequencyBands)
{
    ParserGuard parser(XYParser_CreateParser(64));
    ASSERT_NE(parser.get(), nullptr);

    constexpr int kSampleRate = 200;
    XYParser_SetSampleRate(parser.get(), kSampleRate);
    XYParser_SetWelchDetection(parser.get(), 1);

    const std::vector<double> algorithm_data = BuildAlgorithmDataForSingleChannel(
        kSampleRate, 100.0, 1000000.0, 10.0, 100000.0);

    std::array<XYParserWelchSummary, 1> welch{};
    EXPECT_EQ(XYParser_FeedAlgorithmData(
                  parser.get(),
                  reinterpret_cast<const std::uint8_t*>(algorithm_data.data()),
                  algorithm_data.size() * sizeof(double),
                  nullptr,
                  0),
              0);

    ASSERT_EQ(XYParser_ReadWelch(parser.get(), welch.data(), static_cast<int>(welch.size())), 1);
    ASSERT_EQ(welch[0].ok, 1);

    const int frequency_10hz_index = FindFrequencyIndex(welch[0], 10.0);
    const int frequency_50hz_index = FindFrequencyIndex(welch[0], 50.0);

    ASSERT_GE(frequency_10hz_index, 0);
    ASSERT_GE(frequency_50hz_index, 0);

    EXPECT_EQ(FindFrequencyIndex(welch[0], 100.0), -1);
    EXPECT_LE(welch[0].frequencies[welch[0].frequency_count - 1], 50.0);
    EXPECT_GT(welch[0].psd_values[LeadChannel_FP1][static_cast<std::size_t>(frequency_10hz_index)], 0.0);
    EXPECT_LT(welch[0].psd_values[LeadChannel_FP1][static_cast<std::size_t>(frequency_50hz_index)],
              welch[0].psd_values[LeadChannel_FP1][static_cast<std::size_t>(frequency_10hz_index)]);
    EXPECT_GT(welch[0].band_values[2][LeadChannel_FP1], welch[0].band_values[0][LeadChannel_FP1]);
    EXPECT_GT(welch[0].band_values[2][LeadChannel_FP1], welch[0].band_values[1][LeadChannel_FP1]);
}

TEST(XYParserApiTests, WelchResetClearsHalfWindowAfterDisableEnable)
{
    ParserGuard parser(XYParser_CreateParser(64));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetSampleRate(parser.get(), 10);
    XYParser_SetWelchDetection(parser.get(), 1);

    const std::vector<double> full_data = BuildAlgorithmDataForSingleChannel(10, 2.0, 1000000.0);
    const std::size_t half_row_count =
        static_cast<std::size_t>(XYPARSER_SAMPLES_PER_FRAME) * XYPARSER_FRAME_DATA_COLUMN_COUNT;
    const std::vector<double> first_half(full_data.begin(), full_data.begin() + static_cast<std::ptrdiff_t>(half_row_count));
    const std::vector<double> second_half(full_data.begin() + static_cast<std::ptrdiff_t>(half_row_count), full_data.end());

    std::array<XYParserWelchSummary, 1> welch{};

    EXPECT_EQ(XYParser_FeedAlgorithmData(
                  parser.get(),
                  reinterpret_cast<const std::uint8_t*>(first_half.data()),
                  first_half.size() * sizeof(double),
                  nullptr,
                  0),
              0);
    EXPECT_EQ(XYParser_ReadWelch(parser.get(), welch.data(), static_cast<int>(welch.size())), 0);

    XYParser_SetWelchDetection(parser.get(), 0);
    XYParser_SetWelchDetection(parser.get(), 1);

    EXPECT_EQ(XYParser_FeedAlgorithmData(
                  parser.get(),
                  reinterpret_cast<const std::uint8_t*>(first_half.data()),
                  first_half.size() * sizeof(double),
                  nullptr,
                  0),
              0);
    EXPECT_EQ(XYParser_ReadWelch(parser.get(), welch.data(), static_cast<int>(welch.size())), 0);

    EXPECT_EQ(XYParser_FeedAlgorithmData(
                  parser.get(),
                  reinterpret_cast<const std::uint8_t*>(second_half.data()),
                  second_half.size() * sizeof(double),
                  nullptr,
                  0),
              0);
    ASSERT_EQ(XYParser_ReadWelch(parser.get(), welch.data(), static_cast<int>(welch.size())), 1);
    EXPECT_EQ(welch[0].ok, 1);
}

TEST(XYParserApiTests, WelchSeparatesDifferentChannelPeaks)
{
    ParserGuard parser(XYParser_CreateParser(64));
    ASSERT_NE(parser.get(), nullptr);

    constexpr int kSampleRate = 200;
    XYParser_SetSampleRate(parser.get(), kSampleRate);
    XYParser_SetWelchDetection(parser.get(), 1);

    const std::vector<double> algorithm_data = BuildAlgorithmDataForTwoChannels(
        kSampleRate, 10.0, 1000000.0, 20.0, 1000000.0);

    std::array<XYParserWelchSummary, 1> welch{};
    EXPECT_EQ(XYParser_FeedAlgorithmData(
                  parser.get(),
                  reinterpret_cast<const std::uint8_t*>(algorithm_data.data()),
                  algorithm_data.size() * sizeof(double),
                  nullptr,
                  0),
              0);

    ASSERT_EQ(XYParser_ReadWelch(parser.get(), welch.data(), static_cast<int>(welch.size())), 1);
    ASSERT_EQ(welch[0].ok, 1);

    const int fp1_peak_index = FindPeakPsdIndex(welch[0], LeadChannel_FP1);
    const int fp2_peak_index = FindPeakPsdIndex(welch[0], LeadChannel_FP2);
    const int frequency_10hz_index = FindFrequencyIndex(welch[0], 10.0);
    const int frequency_20hz_index = FindFrequencyIndex(welch[0], 20.0);

    ASSERT_GE(fp1_peak_index, 0);
    ASSERT_GE(fp2_peak_index, 0);
    ASSERT_GE(frequency_10hz_index, 0);
    ASSERT_GE(frequency_20hz_index, 0);

    EXPECT_DOUBLE_EQ(welch[0].frequencies[static_cast<std::size_t>(fp1_peak_index)], 10.0);
    EXPECT_DOUBLE_EQ(welch[0].frequencies[static_cast<std::size_t>(fp2_peak_index)], 20.0);
    EXPECT_GT(welch[0].psd_values[LeadChannel_FP1][static_cast<std::size_t>(frequency_10hz_index)],
              welch[0].psd_values[LeadChannel_FP1][static_cast<std::size_t>(frequency_20hz_index)]);
    EXPECT_GT(welch[0].psd_values[LeadChannel_FP2][static_cast<std::size_t>(frequency_20hz_index)],
              welch[0].psd_values[LeadChannel_FP2][static_cast<std::size_t>(frequency_10hz_index)]);
}

TEST(XYParserApiTests, WelchPsdIncreasesWithSignalAmplitude)
{
    ParserGuard low_amplitude_parser(XYParser_CreateParser(64));
    ParserGuard high_amplitude_parser(XYParser_CreateParser(64));
    ASSERT_NE(low_amplitude_parser.get(), nullptr);
    ASSERT_NE(high_amplitude_parser.get(), nullptr);

    constexpr int kSampleRate = 200;
    XYParser_SetSampleRate(low_amplitude_parser.get(), kSampleRate);
    XYParser_SetWelchDetection(low_amplitude_parser.get(), 1);
    XYParser_SetSampleRate(high_amplitude_parser.get(), kSampleRate);
    XYParser_SetWelchDetection(high_amplitude_parser.get(), 1);

    const std::vector<double> low_amplitude_data = BuildAlgorithmDataForSingleChannel(
        kSampleRate, 10.0, 100000.0);
    const std::vector<double> high_amplitude_data = BuildAlgorithmDataForSingleChannel(
        kSampleRate, 10.0, 1000000.0);

    std::array<XYParserWelchSummary, 1> low_welch{};
    std::array<XYParserWelchSummary, 1> high_welch{};

    EXPECT_EQ(XYParser_FeedAlgorithmData(
                  low_amplitude_parser.get(),
                  reinterpret_cast<const std::uint8_t*>(low_amplitude_data.data()),
                  low_amplitude_data.size() * sizeof(double),
                  nullptr,
                  0),
              0);
    EXPECT_EQ(XYParser_FeedAlgorithmData(
                  high_amplitude_parser.get(),
                  reinterpret_cast<const std::uint8_t*>(high_amplitude_data.data()),
                  high_amplitude_data.size() * sizeof(double),
                  nullptr,
                  0),
              0);

    ASSERT_EQ(XYParser_ReadWelch(low_amplitude_parser.get(), low_welch.data(), static_cast<int>(low_welch.size())), 1);
    ASSERT_EQ(XYParser_ReadWelch(high_amplitude_parser.get(), high_welch.data(), static_cast<int>(high_welch.size())), 1);

    const int low_frequency_10hz_index = FindFrequencyIndex(low_welch[0], 10.0);
    const int high_frequency_10hz_index = FindFrequencyIndex(high_welch[0], 10.0);
    ASSERT_GE(low_frequency_10hz_index, 0);
    ASSERT_GE(high_frequency_10hz_index, 0);

    EXPECT_GT(high_welch[0].psd_values[LeadChannel_FP1][static_cast<std::size_t>(high_frequency_10hz_index)],
              low_welch[0].psd_values[LeadChannel_FP1][static_cast<std::size_t>(low_frequency_10hz_index)]);
    EXPECT_GT(high_welch[0].band_values[2][LeadChannel_FP1],
              low_welch[0].band_values[2][LeadChannel_FP1]);
}

TEST(XYParserApiTests, WelchAbsolutePsdMatches10HzSineAt100UvPeakToPeak)
{
    ParserGuard parser(XYParser_CreateParser(64));
    ASSERT_NE(parser.get(), nullptr);

    constexpr int kSampleRate = 250;
    constexpr double kFrequencyHz = 10.0;
    constexpr double kPeakToPeakUv = 100.0;
    constexpr double kPeakAmplitudeUv = kPeakToPeakUv / 2.0;
    constexpr double kExpectedPeakPsd = 833.3333333333334;

    XYParser_SetSampleRate(parser.get(), kSampleRate);
    XYParser_SetWelchDetection(parser.get(), 1);

    const std::vector<double> algorithm_data =
        BuildAlgorithmDataForSingleChannel(kSampleRate, kFrequencyHz, kPeakAmplitudeUv);

    std::array<XYParserWelchSummary, 1> welch{};
    EXPECT_EQ(XYParser_FeedAlgorithmData(
                  parser.get(),
                  reinterpret_cast<const std::uint8_t*>(algorithm_data.data()),
                  algorithm_data.size() * sizeof(double),
                  nullptr,
                  0),
              0);

    ASSERT_EQ(XYParser_ReadWelch(parser.get(), welch.data(), static_cast<int>(welch.size())), 1);
    ASSERT_EQ(welch[0].ok, 1);

    const int peak_index = FindPeakPsdIndex(welch[0], LeadChannel_FP1);
    const int frequency_10hz_index = FindFrequencyIndex(welch[0], kFrequencyHz);
    ASSERT_GE(peak_index, 0);
    ASSERT_GE(frequency_10hz_index, 0);

    EXPECT_DOUBLE_EQ(welch[0].frequencies[static_cast<std::size_t>(peak_index)], kFrequencyHz);
    EXPECT_DOUBLE_EQ(welch[0].frequencies[static_cast<std::size_t>(frequency_10hz_index)], kFrequencyHz);

    const double peak_psd = welch[0].psd_values[LeadChannel_FP1][static_cast<std::size_t>(frequency_10hz_index)];
    EXPECT_NEAR(peak_psd,
                ExpectedBinCenteredHanningPeakPsd(kPeakAmplitudeUv),
                kExpectedPeakPsd * 0.1);
    EXPECT_GT(welch[0].band_values[2][LeadChannel_FP1], welch[0].band_values[4][LeadChannel_FP1]);
}

TEST(XYParserApiTests, ReadWelchConsumesQueuedResults)
{
    ParserGuard parser(XYParser_CreateParser(64));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetSampleRate(parser.get(), 10);
    XYParser_SetWelchDetection(parser.get(), 1);

    const std::vector<double> algorithm_data = BuildAlgorithmDataForSingleChannel(10, 2.0, 1000000.0);
    std::array<XYParserWelchSummary, 1> welch{};

    EXPECT_EQ(XYParser_FeedAlgorithmData(
                  parser.get(),
                  reinterpret_cast<const std::uint8_t*>(algorithm_data.data()),
                  algorithm_data.size() * sizeof(double),
                  nullptr,
                  0),
              0);

    ASSERT_EQ(XYParser_ReadWelch(parser.get(), welch.data(), static_cast<int>(welch.size())), 1);
    EXPECT_EQ(welch[0].ok, 1);
    EXPECT_EQ(XYParser_ReadWelch(parser.get(), welch.data(), static_cast<int>(welch.size())), 0);
}

TEST(XYParserApiTests, Convert8ChTo64ChAlgorithmDataMatchesDirect64Ch)
{
    ParserGuard parser8(XYParser_CreateParser(8));
    ParserGuard parser64(XYParser_CreateParser(64));
    ASSERT_NE(parser8.get(), nullptr);
    ASSERT_NE(parser64.get(), nullptr);

    XYParser_SetBypassChecksum(parser8.get(), 1);
    XYParser_SetBypassChecksum(parser64.get(), 1);

    std::array<XYParserLeadChannelNumber, 8> leads8{};
    std::array<XYParserLeadChannelNumber, 64> leads64{};
    ASSERT_EQ(XYParser_GetLeadMap(8, leads8.data(), static_cast<int>(leads8.size())), 8);
    ASSERT_EQ(XYParser_GetLeadMap(64, leads64.data(), static_cast<int>(leads64.size())), 64);

    std::array<std::array<int, XYPARSER_MAX_CHANNELS>, XYPARSER_SAMPLES_PER_FRAME> raw_samples8{};
    std::array<std::array<int, XYPARSER_MAX_CHANNELS>, XYPARSER_SAMPLES_PER_FRAME> raw_samples64{};
    for (std::size_t sample_index = 0; sample_index < XYPARSER_SAMPLES_PER_FRAME; ++sample_index) {
        for (std::size_t channel_index = 0; channel_index < leads8.size(); ++channel_index) {
            const int raw_value = static_cast<int>((sample_index + 1) * 1000 + static_cast<int>(channel_index) * 100);
            raw_samples8[sample_index][channel_index] = raw_value;

            for (std::size_t raw64_index = 0; raw64_index < leads64.size(); ++raw64_index) {
                if (leads64[raw64_index] == leads8[channel_index]) {
                    raw_samples64[sample_index][raw64_index] = raw_value;
                    break;
                }
            }
        }
    }

    const std::vector<std::uint8_t> frame8 = BuildFrameWithRawSamples(8, 1U, raw_samples8);
    const std::vector<std::uint8_t> frame64 = BuildFrameWithRawSamples(64, 1U, raw_samples64);

    std::array<XYParserFrameSummary, 1> summaries8{};
    std::array<XYParserFrameSummary, 1> summaries64{};
    std::array<XYParserFrameSummary, 1> converted64{};

    ASSERT_EQ(XYParser_Feed(parser8.get(), frame8.data(), frame8.size(), summaries8.data(), static_cast<int>(summaries8.size())), 1);
    ASSERT_EQ(XYParser_Feed(parser64.get(), frame64.data(), frame64.size(), summaries64.data(), static_cast<int>(summaries64.size())), 1);
    ASSERT_EQ(XYParser_Convert8ChFramesTo64Ch(summaries8.data(), 1, converted64.data(), 1), 1);

    std::vector<double> converted_algorithm_data(XYPARSER_FRAME_ALGORITHM_VALUE_COUNT, 0.0);
    std::vector<double> direct_algorithm_data(XYPARSER_FRAME_ALGORITHM_VALUE_COUNT, 0.0);
    ASSERT_EQ(XYParser_ConvertSampleFramesToAlgorithmData(&converted64[0], converted_algorithm_data.data()), 1);
    ASSERT_EQ(XYParser_ConvertSampleFramesToAlgorithmData(&summaries64[0], direct_algorithm_data.data()), 1);

    for (std::size_t i = 0; i < converted_algorithm_data.size(); ++i) {
        EXPECT_DOUBLE_EQ(converted_algorithm_data[i], direct_algorithm_data[i]) << "index=" << i;
    }
}

TEST(XYParserApiTests, WelchFrameFeedDoesNotProduceResults)
{
    ParserGuard parser(XYParser_CreateParser(64));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetBypassChecksum(parser.get(), 1);
    XYParser_SetSampleRate(parser.get(), 10);
    XYParser_SetWelchDetection(parser.get(), 1);

    std::array<std::array<int, XYPARSER_MAX_CHANNELS>, XYPARSER_SAMPLES_PER_FRAME> raw_samples1{};
    std::array<std::array<int, XYPARSER_MAX_CHANNELS>, XYPARSER_SAMPLES_PER_FRAME> raw_samples2{};
    for (int sample = 0; sample < 10; ++sample) {
        const int raw_value = BuildSineRawValue(sample, 10, 2.0, 1000000.0);
        if (sample < static_cast<int>(XYPARSER_SAMPLES_PER_FRAME)) {
            raw_samples1[static_cast<std::size_t>(sample)][0] = raw_value;
        } else {
            raw_samples2[static_cast<std::size_t>(sample - XYPARSER_SAMPLES_PER_FRAME)][0] = raw_value;
        }
    }

    const std::vector<std::uint8_t> frame1 = BuildFrameWithRawSamples(64, 1U, raw_samples1);
    const std::vector<std::uint8_t> frame2 = BuildFrameWithRawSamples(64, 2U, raw_samples2);
    std::array<XYParserFrameSummary, 2> summaries{};
    std::array<XYParserWelchSummary, 1> welch{};

    EXPECT_EQ(XYParser_Feed(parser.get(), frame1.data(), frame1.size(), summaries.data(), static_cast<int>(summaries.size())), 1);
    EXPECT_EQ(XYParser_Feed(parser.get(), frame2.data(), frame2.size(), summaries.data(), static_cast<int>(summaries.size())), 1);
    EXPECT_EQ(XYParser_ReadWelch(parser.get(), welch.data(), static_cast<int>(welch.size())), 0);
}

TEST(XYParserApiTests, WelchDisabledDoesNotProduceResultsFromAlgorithmData)
{
    ParserGuard parser(XYParser_CreateParser(64));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetSampleRate(parser.get(), 10);

    std::vector<double> algorithm_data(static_cast<std::size_t>(10 * XYPARSER_FRAME_DATA_COLUMN_COUNT), 0.0);
    for (int sample = 0; sample < 10; ++sample) {
        const std::size_t sample_offset = static_cast<std::size_t>(sample) * XYPARSER_FRAME_DATA_COLUMN_COUNT;
        algorithm_data[sample_offset] = static_cast<double>(BuildSineRawValue(sample, 10, 2.0, 1000000.0));
    }

    std::array<XYParserWelchSummary, 1> welch{};
    EXPECT_EQ(XYParser_FeedAlgorithmData(
                  parser.get(),
                  reinterpret_cast<const std::uint8_t*>(algorithm_data.data()),
                  algorithm_data.size() * sizeof(double),
                  nullptr,
                  0),
              0);
    EXPECT_EQ(XYParser_ReadWelch(parser.get(), welch.data(), static_cast<int>(welch.size())), 0);
}

/// 测试：Feed 函数能正确解析完整的 8 通道帧
TEST(XYParserApiTests, FeedParsesAComplete8ChannelFrame)
{
    // 创建 8 通道解析器
    ParserGuard parser(XYParser_CreateParser(8));
    ASSERT_NE(parser.get(), nullptr);

    // 设置 ADC 参数和校验和绕过标志
    XYParser_SetAdcParams(parser.get(), 4.5, 6.0);
    XYParser_SetBypassChecksum(parser.get(), 1);

    // 构建测试帧并解析
    const std::vector<std::uint8_t> bytes = BuildMinimalFrame(8);
    std::array<XYParserFrameSummary, 1> summaries{};

    const int frame_count = XYParser_Feed(
        parser.get(),
        bytes.data(),
        bytes.size(),
        summaries.data(),
        static_cast<int>(summaries.size()));

    // 验证解析结果
    ASSERT_EQ(frame_count, 1);                             // 应解析出 1 帧
    EXPECT_EQ(summaries[0].frame_index, 1U);               // 帧索引应为 1
    EXPECT_EQ(summaries[0].channel_count, 8U);             // 通道数应为 8
    EXPECT_EQ(summaries[0].battery, 95U);                  // 电池电量应为 95
    EXPECT_EQ(summaries[0].sample_count, 5U);              // 采样数应为 5
    EXPECT_GT(summaries[0].channel_values_uv[0][0], 0.0);  // 通道值应大于 0
    EXPECT_EQ(summaries[0].sample_trigger_types[0], 0U);   // 触发类型应为 0
    EXPECT_EQ(summaries[0].sample_trigger_indices[0], 0U); // 触发索引应为 0
}

TEST(XYParserApiTests, FeedParsesReservedMetadataInto8ChannelSummary)
{
    ParserGuard parser(XYParser_CreateParser(8));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetBypassChecksum(parser.get(), 1);

    const std::array<std::uint8_t, 6> reserved = {0x01, 24, 2, 9, 1, 0x5A};
    const std::vector<std::uint8_t> bytes = BuildMinimalFrame(8, 1U, reserved);
    std::array<XYParserFrameSummary, 1> summaries{};

    ASSERT_EQ(XYParser_Feed(
                  parser.get(),
                  bytes.data(),
                  bytes.size(),
                  summaries.data(),
                  static_cast<int>(summaries.size())),
              1);
    EXPECT_EQ(summaries[0].impedance_enabled, 1U);
    EXPECT_EQ(summaries[0].current_gain, 24U);
    EXPECT_EQ(summaries[0].current_sample_rate_hz, 1000U);
    EXPECT_EQ(summaries[0].cap_type, 9U);
    EXPECT_EQ(summaries[0].gnd_detached, 1U);
}

/// 测试：Feed 函数能缓冲部分数据直到完整帧可用
TEST(XYParserApiTests, FeedBuffersPartialDataUntilAFullFrameIsAvailable)
{
    // 创建 8 通道解析器
    ParserGuard parser(XYParser_CreateParser(8));
    ASSERT_NE(parser.get(), nullptr);

    // 设置校验和绕过标志
    XYParser_SetBypassChecksum(parser.get(), 1);

    // 构建测试帧并分成两部分
    const std::vector<std::uint8_t> bytes = BuildMinimalFrame(8);
    const std::size_t split_index = bytes.size() / 2;
    std::array<XYParserFrameSummary, 1> summaries{};

    // 第一次 Feed：传入前半部分数据
    const int first_result = XYParser_Feed(
        parser.get(),
        bytes.data(),
        split_index,
        summaries.data(),
        static_cast<int>(summaries.size()));
    EXPECT_EQ(first_result, 0);  // 数据不完整，不应解析出帧

    // 第二次 Feed：传入后半部分数据
    const int second_result = XYParser_Feed(
        parser.get(),
        bytes.data() + split_index,
        bytes.size() - split_index,
        summaries.data(),
        static_cast<int>(summaries.size()));
    ASSERT_EQ(second_result, 1);         // 数据完整，应解析出 1 帧
    EXPECT_EQ(summaries[0].frame_index, 1U);  // 帧索引应为 1
}

// ============================================================================
// 解析器创建测试
// ============================================================================

/// 测试：成功创建 8 通道解析器
TEST(XYParserApiTests, CreateParserSucceedsFor8Channels)
{
    ParserGuard parser(XYParser_CreateParser(8));
    EXPECT_NE(parser.get(), nullptr);
}

/// 测试：成功创建 64 通道解析器
TEST(XYParserApiTests, CreateParserSucceedsFor64Channels)
{
    ParserGuard parser(XYParser_CreateParser(64));
    EXPECT_NE(parser.get(), nullptr);
}

/// 测试：创建 0 通道解析器应失败
TEST(XYParserApiTests, CreateParserRejectsZeroChannels)
{
    EXPECT_EQ(XYParser_CreateParser(0), nullptr);
}

/// 测试：创建不支持的通道数（如 100）应失败
TEST(XYParserApiTests, CreateParserRejectsExcessiveChannels)
{
    EXPECT_EQ(XYParser_CreateParser(100), nullptr);
}

// ============================================================================
// 参数设置函数测试
// ============================================================================

/// 测试：设置正常的 ADC 参数
TEST(XYParserApiTests, SetAdcParamsAcceptsValidValues)
{
    ParserGuard parser(XYParser_CreateParser(8));
    ASSERT_NE(parser.get(), nullptr);

    // 不应崩溃
    EXPECT_NO_THROW(XYParser_SetAdcParams(parser.get(), 4.5, 6.0));
}

/// 测试：设置边界值的 ADC 参数
TEST(XYParserApiTests, SetAdcParamsAcceptsBoundaryValues)
{
    ParserGuard parser(XYParser_CreateParser(8));
    ASSERT_NE(parser.get(), nullptr);

    // 测试零值
    EXPECT_NO_THROW(XYParser_SetAdcParams(parser.get(), 0.0, 0.0));
    // 测试较大值
    EXPECT_NO_THROW(XYParser_SetAdcParams(parser.get(), 100.0, 1000.0));
}

/// 测试：对空句柄调用 SetAdcParams
TEST(XYParserApiTests, SetAdcParamsOnNullHandle)
{
    // 不应崩溃
    EXPECT_NO_THROW(XYParser_SetAdcParams(nullptr, 4.5, 6.0));
}

/// 测试：关闭校验和绕过
TEST(XYParserApiTests, SetBypassChecksumOff)
{
    ParserGuard parser(XYParser_CreateParser(8));
    ASSERT_NE(parser.get(), nullptr);

    EXPECT_NO_THROW(XYParser_SetBypassChecksum(parser.get(), 0));
}

/// 测试：对空句柄调用 SetBypassChecksum
TEST(XYParserApiTests, SetBypassChecksumOnNullHandle)
{
    EXPECT_NO_THROW(XYParser_SetBypassChecksum(nullptr, 1));
}

// ============================================================================
// 64 导控制协议序列化测试
// ============================================================================

/// 测试：64 导开启阻抗命令序列化与 WirelessEEG 协议保持一致
TEST(XYParserApiTests, Serialize64ImpedanceOpenCommandMatchesWirelessEegProtocol)
{
    std::array<std::uint8_t, 32> buffer{};
    const int size = XYParser_Serialize64ImpedanceCommand(1, buffer.data(), buffer.size());

    ASSERT_EQ(size, static_cast<int>(XYParser_Get64ImpedanceCommandSize()));

    const std::vector<std::uint8_t> expected = {
        0xAA, 0x01, 0x00, 0x07,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x01, 0x09, 0x55, 0x55
    };
    EXPECT_TRUE(std::equal(expected.begin(), expected.end(), buffer.begin()));
}

/// 测试：64 导增益和采样率命令序列化与 WirelessEEG 协议保持一致
TEST(XYParserApiTests, Serialize64GainAndSampleRateCommandMatchesWirelessEegProtocol)
{
    std::array<std::uint8_t, 32> buffer{};
    const int size = XYParser_Serialize64GainSampleRateCommand(24, 1000, buffer.data(), buffer.size());

    ASSERT_EQ(size, static_cast<int>(XYParser_Get64GainSampleRateCommandSize()));

    const std::vector<std::uint8_t> expected = {
        0xAA, 0x02, 0x00, 0x08,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x18, 0x02, 0x24, 0x55, 0x55
    };
    EXPECT_TRUE(std::equal(expected.begin(), expected.end(), buffer.begin()));
}

/// 测试：64 导增益和采样率命令拒绝非法采样率
TEST(XYParserApiTests, Serialize64GainAndSampleRateCommandRejectsUnsupportedSampleRate)
{
    std::array<std::uint8_t, 32> buffer{};
    EXPECT_EQ(XYParser_Serialize64GainSampleRateCommand(24, 256, buffer.data(), buffer.size()), 0);
}

/// 测试：64 导阻抗命令在输出缓冲区不足时返回失败
TEST(XYParserApiTests, Serialize64ImpedanceCommandRejectsSmallBuffer)
{
    std::array<std::uint8_t, 4> buffer{};
    EXPECT_EQ(XYParser_Serialize64ImpedanceCommand(1, buffer.data(), buffer.size()), 0);
}

// ============================================================================
// Feed 函数帧解析测试
// ============================================================================

/// 测试：传入空数据
TEST(XYParserApiTests, FeedParsesEmptyData)
{
    ParserGuard parser(XYParser_CreateParser(8));
    ASSERT_NE(parser.get(), nullptr);

    std::array<XYParserFrameSummary, 10> summaries{};
    const int result = XYParser_Feed(
        parser.get(),
        nullptr,
        0,
        summaries.data(),
        static_cast<int>(summaries.size()));

    EXPECT_EQ(result, 0);
}

/// 测试：只传入帧头数据
TEST(XYParserApiTests, FeedParsesOnlyHeader)
{
    ParserGuard parser(XYParser_CreateParser(8));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetBypassChecksum(parser.get(), 1);

    // 只发送帧头
    const std::vector<std::uint8_t> header_only = {0xAA, 0x01, 0x00, 0x00, 0x00};
    std::array<XYParserFrameSummary, 10> summaries{};

    const int result = XYParser_Feed(
        parser.get(),
        header_only.data(),
        header_only.size(),
        summaries.data(),
        static_cast<int>(summaries.size()));

    EXPECT_EQ(result, 0);  // 数据不完整，不应解析出帧
}

/// 测试：解析完整的 64 通道帧
TEST(XYParserApiTests, FeedParses64ChannelFrame)
{
    ParserGuard parser(XYParser_CreateParser(64));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetAdcParams(parser.get(), 4.5, 6.0);
    XYParser_SetBypassChecksum(parser.get(), 1);

    const std::vector<std::uint8_t> bytes = BuildMinimalFrame(64);
    std::array<XYParserFrameSummary, 1> summaries{};

    const int frame_count = XYParser_Feed(
        parser.get(),
        bytes.data(),
        bytes.size(),
        summaries.data(),
        static_cast<int>(summaries.size()));

    ASSERT_EQ(frame_count, 1);
    EXPECT_EQ(summaries[0].channel_count, 64U);
}

TEST(XYParserApiTests, FeedParsesReservedMetadataInto64ChannelSummary)
{
    ParserGuard parser(XYParser_CreateParser(64));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetBypassChecksum(parser.get(), 1);

    const std::array<std::uint8_t, 6> reserved = {0x00, 6, 1, 4, 0, 0x00};
    const std::vector<std::uint8_t> bytes = BuildMinimalFrame(64, 1U, reserved);
    std::array<XYParserFrameSummary, 1> summaries{};

    ASSERT_EQ(XYParser_Feed(
                  parser.get(),
                  bytes.data(),
                  bytes.size(),
                  summaries.data(),
                  static_cast<int>(summaries.size())),
              1);
    EXPECT_EQ(summaries[0].impedance_enabled, 0U);
    EXPECT_EQ(summaries[0].current_gain, 6U);
    EXPECT_EQ(summaries[0].current_sample_rate_hz, 500U);
    EXPECT_EQ(summaries[0].cap_type, 4U);
    EXPECT_EQ(summaries[0].gnd_detached, 0U);
}

/// 测试：连续解析多个帧
TEST(XYParserApiTests, FeedParsesMultipleFrames)
{
    ParserGuard parser(XYParser_CreateParser(8));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetBypassChecksum(parser.get(), 1);

    // 构建两个连续的帧
    const std::vector<std::uint8_t> frame1 = BuildMinimalFrame(8, 1U);
    const std::vector<std::uint8_t> frame2 = BuildMinimalFrame(8, 2U);

    std::vector<std::uint8_t> combined(frame1);
    combined.insert(combined.end(), frame2.begin(), frame2.end());

    std::array<XYParserFrameSummary, 10> summaries{};
    const int frame_count = XYParser_Feed(
        parser.get(),
        combined.data(),
        combined.size(),
        summaries.data(),
        static_cast<int>(summaries.size()));

    EXPECT_EQ(frame_count, 2);
    EXPECT_EQ(summaries[0].frame_index, 1U);
    EXPECT_EQ(summaries[1].frame_index, 2U);
}

/// 测试：帧索引递增
TEST(XYParserApiTests, FeedIncrementsFrameIndex)
{
    ParserGuard parser(XYParser_CreateParser(8));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetBypassChecksum(parser.get(), 1);

    // 连续发送多个帧
    std::array<XYParserFrameSummary, 10> summaries{};
    int total_frames = 0;

    for (int i = 0; i < 3; ++i) {
        const std::vector<std::uint8_t> frame = BuildMinimalFrame(8, static_cast<std::uint32_t>(i + 1));
        const int count = XYParser_Feed(
            parser.get(),
            frame.data(),
            frame.size(),
            summaries.data() + total_frames,
            static_cast<int>(summaries.size()) - total_frames);
        total_frames += count;
    }

    EXPECT_EQ(total_frames, 3);
    for (int i = 0; i < 3; ++i) {
        EXPECT_EQ(summaries[i].frame_index, static_cast<std::uint32_t>(i + 1));
    }
}

/// 测试：电池电量字段解析
TEST(XYParserApiTests, FeedParsesBatteryValue)
{
    ParserGuard parser(XYParser_CreateParser(8));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetBypassChecksum(parser.get(), 1);

    const std::vector<std::uint8_t> bytes = BuildMinimalFrame(8);
    std::array<XYParserFrameSummary, 1> summaries{};

    XYParser_Feed(
        parser.get(),
        bytes.data(),
        bytes.size(),
        summaries.data(),
        static_cast<int>(summaries.size()));

    EXPECT_EQ(summaries[0].battery, 95U);  // BuildMinimalFrame 中设置的电池电量
}

// ============================================================================
// 帧数据边界测试
// ============================================================================

/// 测试：跨多次 Feed 的不完整帧
TEST(XYParserApiTests, FeedHandlesIncompleteFrameAcrossMultipleFeeds)
{
    ParserGuard parser(XYParser_CreateParser(8));
    ASSERT_NE(parser.get(), nullptr);

    XYParser_SetBypassChecksum(parser.get(), 1);

    const std::vector<std::uint8_t> bytes = BuildMinimalFrame(8);
    std::array<XYParserFrameSummary, 1> summaries{};

    // 分成 3 次发送
    const std::size_t part1_size = bytes.size() / 3;
    const std::size_t part2_size = bytes.size() / 3;

    EXPECT_EQ(XYParser_Feed(parser.get(), bytes.data(), part1_size,
        summaries.data(), static_cast<int>(summaries.size())), 0);

    EXPECT_EQ(XYParser_Feed(parser.get(), bytes.data() + part1_size, part2_size,
        summaries.data(), static_cast<int>(summaries.size())), 0);

    const int result = XYParser_Feed(
        parser.get(),
        bytes.data() + part1_size + part2_size,
        bytes.size() - part1_size - part2_size,
        summaries.data(),
        static_cast<int>(summaries.size()));

    ASSERT_EQ(result, 1);
    EXPECT_EQ(summaries[0].frame_index, 1U);
}

// ============================================================================
// 销毁和错误处理测试
// ============================================================================

/// 测试：销毁空句柄
TEST(XYParserApiTests, DestroyParserAcceptsNullHandle)
{
    EXPECT_NO_THROW(XYParser_DestroyParser(nullptr));
}

/// 测试：连续创建和销毁
TEST(XYParserApiTests, CreateAndDestroyMultipleParsers)
{
    for (int i = 0; i < 10; ++i) {
        ParserGuard parser(XYParser_CreateParser(8));
        EXPECT_NE(parser.get(), nullptr);
    }
    // 析构时自动销毁所有解析器
}

/// 测试：GetLastError 在正常操作后
TEST(XYParserApiTests, GetLastErrorAfterSuccessfulCreate)
{
    ParserGuard parser(XYParser_CreateParser(8));
    ASSERT_NE(parser.get(), nullptr);

    // 正常操作后，错误信息应为空（空字符串）,不能是 nullptr
    const char* error = XYParser_GetLastError(parser.get());
    EXPECT_TRUE(std::string(error).empty());
}