// ================================================================================================
// Audio Backend - 音频格式转换测试
// ================================================================================================

#include <gtest/gtest.h>
#include "engine/audio_buffer.h"
#include "simd/audio_processing.h"
#include "tests/common/test_fixtures.h"
#include "tests/common/test_utils.h"
#include <vector>
#include <limits>

using namespace audio_backend;
using namespace audio_backend::engine;
using namespace audio_backend::simd;

// 音频格式转换测试固定装置
class AudioFormatConversionTest : public test::AudioEngineTest {
protected:
    void SetUp() override {
        test::AudioEngineTest::SetUp();
        
        // 设置最大值常量
        int16_max_ = std::numeric_limits<int16_t>::max();
        int32_max_ = std::numeric_limits<int32_t>::max();
        
        // 准备测试数据
        setup_test_data();
    }
    
    void TearDown() override {
        test::AudioEngineTest::TearDown();
    }
    
    // 准备各种格式的测试数据
    void setup_test_data() {
        // 创建测试样本（包含正负值和特殊值）
        float_samples_ = {
            0.0f, 0.5f, -0.5f, 1.0f, -1.0f,
            0.25f, -0.25f, 0.75f, -0.75f,
            0.1f, -0.1f, 0.01f, -0.01f,
            0.99f, -0.99f, 0.999f, -0.999f
        };
        
        // 从float生成对应的int16数据
        int16_samples_.resize(float_samples_.size());
        for (size_t i = 0; i < float_samples_.size(); ++i) {
            int16_samples_[i] = static_cast<int16_t>(float_samples_[i] * int16_max_);
        }
        
        // 从float生成对应的int24数据（存储在int32中）
        int32_samples_.resize(float_samples_.size());
        for (size_t i = 0; i < float_samples_.size(); ++i) {
            int32_samples_[i] = static_cast<int32_t>(float_samples_[i] * 8388607.0f); // 2^23 - 1
        }
    }
    
protected:
    std::vector<float> float_samples_;
    std::vector<int16_t> int16_samples_;
    std::vector<int32_t> int32_samples_;
    
    int16_t int16_max_;
    int32_t int32_max_;
};

// 测试FLOAT32 -> INT16转换
TEST_F(AudioFormatConversionTest, FloatToInt16Conversion) {
    // 创建输出缓冲区
    std::vector<int16_t> output(float_samples_.size());
    
    // 转换
    convert_float_to_int16(float_samples_.data(), output.data(), float_samples_.size());
    
    // 验证
    for (size_t i = 0; i < float_samples_.size(); ++i) {
        int16_t expected = static_cast<int16_t>(float_samples_[i] * int16_max_);
        EXPECT_NEAR(output[i], expected, 1) << "at index " << i; // 允许±1的误差
    }
    
    // 测试特殊情况: 大于1.0的值应该被限幅为最大值
    float large_value = 1.5f;
    int16_t clipped_output;
    convert_float_to_int16(&large_value, &clipped_output, 1);
    EXPECT_EQ(clipped_output, int16_max_);
    
    // 测试特殊情况: 小于-1.0的值应该被限幅为最小值
    float small_value = -1.5f;
    convert_float_to_int16(&small_value, &clipped_output, 1);
    EXPECT_EQ(clipped_output, -int16_max_ - 1); // -32768
}

// 测试INT16 -> FLOAT32转换
TEST_F(AudioFormatConversionTest, Int16ToFloatConversion) {
    // 创建输出缓冲区
    std::vector<float> output(int16_samples_.size());
    
    // 转换
    convert_int16_to_float(int16_samples_.data(), output.data(), int16_samples_.size());
    
    // 验证
    for (size_t i = 0; i < int16_samples_.size(); ++i) {
        float expected = static_cast<float>(int16_samples_[i]) / int16_max_;
        EXPECT_NEAR(output[i], expected, 1.0f / int16_max_) << "at index " << i;
    }
    
    // 测试特殊情况: 最大值应该转换为接近1.0
    int16_t max_value = int16_max_;
    float max_output;
    convert_int16_to_float(&max_value, &max_output, 1);
    EXPECT_NEAR(max_output, 1.0f, 1.0f / int16_max_);
    
    // 测试特殊情况: 最小值应该转换为接近-1.0
    int16_t min_value = -int16_max_ - 1; // -32768
    float min_output;
    convert_int16_to_float(&min_value, &min_output, 1);
    EXPECT_NEAR(min_output, -1.0f, 1.0f / int16_max_);
}

// 测试FLOAT32 -> INT32转换
TEST_F(AudioFormatConversionTest, FloatToInt32Conversion) {
    // 创建输出缓冲区
    std::vector<int32_t> output(float_samples_.size());
    
    // 转换
    convert_float_to_int32(float_samples_.data(), output.data(), float_samples_.size());
    
    // 验证
    for (size_t i = 0; i < float_samples_.size(); ++i) {
        int32_t expected = static_cast<int32_t>(float_samples_[i] * int32_max_);
        // int32转换精度较高，但仍允许小的误差
        EXPECT_NEAR(output[i], expected, 256) << "at index " << i;
    }
    
    // 测试特殊情况: 大于1.0的值应该被限幅
    float large_value = 1.5f;
    int32_t clipped_output;
    convert_float_to_int32(&large_value, &clipped_output, 1);
    EXPECT_EQ(clipped_output, int32_max_);
}

// 测试INT32 -> FLOAT32转换
TEST_F(AudioFormatConversionTest, Int32ToFloatConversion) {
    // 创建输出缓冲区
    std::vector<float> output(int32_samples_.size());
    
    // 转换
    convert_int32_to_float(int32_samples_.data(), output.data(), int32_samples_.size());
    
    // 验证
    for (size_t i = 0; i < int32_samples_.size(); ++i) {
        float expected = static_cast<float>(int32_samples_[i]) / 8388607.0f; // 2^23 - 1 (24位有效位)
        EXPECT_NEAR(output[i], expected, 1.0f / 8388607.0f) << "at index " << i;
    }
}

// 测试FLOAT32 -> INT24转换
TEST_F(AudioFormatConversionTest, FloatToInt24Conversion) {
    // 创建输出缓冲区 (INT24存储在INT32中)
    std::vector<int32_t> output(float_samples_.size());
    
    // 转换
    convert_float_to_int24(float_samples_.data(), output.data(), float_samples_.size());
    
    // 验证
    for (size_t i = 0; i < float_samples_.size(); ++i) {
        int32_t expected = static_cast<int32_t>(float_samples_[i] * 8388607.0f); // 2^23 - 1
        // 确保值在24位范围内
        expected &= 0x00FFFFFF;
        if (expected & 0x00800000) {  // 负值处理
            expected |= 0xFF000000;
        }
        
        // 24位转换允许小的误差
        EXPECT_NEAR(output[i], expected, 2) << "at index " << i;
    }
}

// 测试INT24 -> FLOAT32转换
TEST_F(AudioFormatConversionTest, Int24ToFloatConversion) {
    // 准备24位整数样本（在int32中存储）
    std::vector<int32_t> int24_samples(float_samples_.size());
    for (size_t i = 0; i < float_samples_.size(); ++i) {
        int24_samples[i] = static_cast<int32_t>(float_samples_[i] * 8388607.0f) & 0x00FFFFFF;
        if (int24_samples[i] & 0x00800000) {  // 负值处理
            int24_samples[i] |= 0xFF000000;
        }
    }
    
    // 创建输出缓冲区
    std::vector<float> output(int24_samples.size());
    
    // 转换
    convert_int24_to_float(int24_samples.data(), output.data(), int24_samples.size());
    
    // 验证
    for (size_t i = 0; i < int24_samples.size(); ++i) {
        float expected = static_cast<float>(int24_samples[i]) / 8388607.0f; // 2^23 - 1
        EXPECT_NEAR(output[i], expected, 1.0f / 8388607.0f) << "at index " << i;
    }
}

// 测试FLOAT32 -> FLOAT64转换
TEST_F(AudioFormatConversionTest, FloatToDoubleConversion) {
    // 创建输出缓冲区
    std::vector<double> output(float_samples_.size());
    
    // 转换
    convert_float_to_double(float_samples_.data(), output.data(), float_samples_.size());
    
    // 验证
    for (size_t i = 0; i < float_samples_.size(); ++i) {
        double expected = static_cast<double>(float_samples_[i]);
        EXPECT_DOUBLE_EQ(output[i], expected) << "at index " << i;
    }
}

// 测试FLOAT64 -> FLOAT32转换
TEST_F(AudioFormatConversionTest, DoubleToFloatConversion) {
    // 准备双精度浮点样本
    std::vector<double> double_samples(float_samples_.size());
    for (size_t i = 0; i < float_samples_.size(); ++i) {
        double_samples[i] = static_cast<double>(float_samples_[i]);
    }
    
    // 创建输出缓冲区
    std::vector<float> output(double_samples.size());
    
    // 转换
    convert_double_to_float(double_samples.data(), output.data(), double_samples.size());
    
    // 验证
    for (size_t i = 0; i < double_samples.size(); ++i) {
        float expected = static_cast<float>(double_samples[i]);
        EXPECT_FLOAT_EQ(output[i], expected) << "at index " << i;
    }
}

// 测试INT16 -> INT32转换
TEST_F(AudioFormatConversionTest, Int16ToInt32Conversion) {
    // 创建输出缓冲区
    std::vector<int32_t> output(int16_samples_.size());
    
    // 转换
    convert_int16_to_int32(int16_samples_.data(), output.data(), int16_samples_.size());
    
    // 验证 (16位转32位应该是左移16位)
    for (size_t i = 0; i < int16_samples_.size(); ++i) {
        int32_t expected = static_cast<int32_t>(int16_samples_[i]) << 16;
        EXPECT_EQ(output[i], expected) << "at index " << i;
    }
}

// 测试INT32 -> INT16转换
TEST_F(AudioFormatConversionTest, Int32ToInt16Conversion) {
    // 创建输出缓冲区
    std::vector<int16_t> output(int32_samples_.size());
    
    // 转换
    convert_int32_to_int16(int32_samples_.data(), output.data(), int32_samples_.size());
    
    // 验证 (32位转16位应该是右移16位，可能会有截断)
    for (size_t i = 0; i < int32_samples_.size(); ++i) {
        int16_t expected = static_cast<int16_t>(int32_samples_[i] >> 8); // 从24位转16位
        EXPECT_NEAR(output[i], expected, 1) << "at index " << i;
    }
}

int main(int argc, char** argv) {
    ::testing::InitGoogleTest(&argc, argv);
    return RUN_ALL_TESTS();
}