// ================================================================================================
// Audio Backend - 环形缓冲区测试
// ================================================================================================

#include <gtest/gtest.h>
#include "engine/audio_buffer.h"
#include "tests/common/test_fixtures.h"
#include "tests/common/test_utils.h"
#include <thread>
#include <atomic>
#include <vector>

using namespace audio_backend;
using namespace audio_backend::engine;

// 环形缓冲区测试固定装置
class RingBufferTest : public test::BaseTest {
protected:
    void SetUp() override {
        test::BaseTest::SetUp();
    }
    
    void TearDown() override {
        test::BaseTest::TearDown();
    }
    
    // 测试不同类型的环形缓冲区
    template<typename T>
    void test_basic_operations(size_t capacity) {
        RingBuffer<T> buffer(capacity);
        
        // 初始状态
        EXPECT_EQ(buffer.capacity(), capacity);
        EXPECT_EQ(buffer.available(), 0);
        EXPECT_EQ(buffer.space(), capacity);
        EXPECT_TRUE(buffer.empty());
        EXPECT_FALSE(buffer.full());
    }
    
    template<typename T>
    void test_single_element_operations(size_t capacity, const std::vector<T>& test_data) {
        RingBuffer<T> buffer(capacity);
        
        // 推入和弹出单个元素
        for (const T& value : test_data) {
            EXPECT_TRUE(buffer.write(&value, 1));
            EXPECT_EQ(buffer.available(), 1);
            
            T output;
            EXPECT_TRUE(buffer.read(&output, 1));
            EXPECT_EQ(buffer.available(), 0);
            EXPECT_EQ(output, value);
        }
    }
    
    template<typename T>
    void test_batch_operations(size_t capacity, const std::vector<T>& test_data) {
        RingBuffer<T> buffer(capacity);
        
        // 批量写入
        size_t batch_size = std::min(test_data.size(), capacity);
        size_t written = buffer.write(test_data.data(), batch_size);
        EXPECT_EQ(written, batch_size);
        EXPECT_EQ(buffer.available(), batch_size);
        
        // 批量读取
        std::vector<T> output(batch_size);
        size_t read = buffer.read(output.data(), batch_size);
        EXPECT_EQ(read, batch_size);
        EXPECT_EQ(buffer.available(), 0);
        
        for (size_t i = 0; i < batch_size; ++i) {
            EXPECT_EQ(output[i], test_data[i]);
        }
    }
    
    template<typename T>
    void test_wrap_around(size_t capacity, const std::vector<T>& test_data) {
        RingBuffer<T> buffer(capacity);
        
        // 填充一半
        size_t half = capacity / 2;
        EXPECT_EQ(buffer.write(test_data.data(), half), half);
        
        // 读取一半
        std::vector<T> output(half);
        EXPECT_EQ(buffer.read(output.data(), half), half);
        
        // 现在写入超过一半，测试环绕
        size_t to_write = std::min(test_data.size(), capacity - half + half);
        EXPECT_EQ(buffer.write(test_data.data(), to_write), to_write);
        
        // 读取全部
        output.resize(to_write);
        EXPECT_EQ(buffer.read(output.data(), to_write), to_write);
        
        for (size_t i = 0; i < to_write; ++i) {
            EXPECT_EQ(output[i], test_data[i]);
        }
    }
};

// 测试基本的Float类型RingBuffer操作
TEST_F(RingBufferTest, FloatBasicOperations) {
    test_basic_operations<float>(1024);
}

// 测试基本的Int16类型RingBuffer操作
TEST_F(RingBufferTest, Int16BasicOperations) {
    test_basic_operations<int16_t>(1024);
}

// 测试单元素Float操作
TEST_F(RingBufferTest, FloatSingleElementOperations) {
    std::vector<float> test_data = {0.1f, 0.2f, 0.3f, 0.4f, 0.5f};
    test_single_element_operations<float>(16, test_data);
}

// 测试单元素Int16操作
TEST_F(RingBufferTest, Int16SingleElementOperations) {
    std::vector<int16_t> test_data = {100, 200, 300, 400, 500};
    test_single_element_operations<int16_t>(16, test_data);
}

// 测试批量Float操作
TEST_F(RingBufferTest, FloatBatchOperations) {
    std::vector<float> test_data(128);
    for (size_t i = 0; i < test_data.size(); ++i) {
        test_data[i] = static_cast<float>(i) / 100.0f;
    }
    test_batch_operations<float>(256, test_data);
}

// 测试批量Int16操作
TEST_F(RingBufferTest, Int16BatchOperations) {
    std::vector<int16_t> test_data(128);
    for (size_t i = 0; i < test_data.size(); ++i) {
        test_data[i] = static_cast<int16_t>(i * 10);
    }
    test_batch_operations<int16_t>(256, test_data);
}

// 测试环绕逻辑
TEST_F(RingBufferTest, FloatWrapAround) {
    std::vector<float> test_data(256);
    for (size_t i = 0; i < test_data.size(); ++i) {
        test_data[i] = static_cast<float>(i) / 100.0f;
    }
    test_wrap_around<float>(128, test_data);
}

// 测试环绕逻辑
TEST_F(RingBufferTest, Int16WrapAround) {
    std::vector<int16_t> test_data(256);
    for (size_t i = 0; i < test_data.size(); ++i) {
        test_data[i] = static_cast<int16_t>(i * 10);
    }
    test_wrap_around<int16_t>(128, test_data);
}

// 测试缓冲区容量边界
TEST_F(RingBufferTest, CapacityBoundaries) {
    // 零容量
    RingBuffer<float> zero_buffer(0);
    EXPECT_EQ(zero_buffer.capacity(), 0);
    EXPECT_TRUE(zero_buffer.empty());
    EXPECT_TRUE(zero_buffer.full());  // 零容量缓冲区应该同时是空的和满的
    
    float value = 1.0f;
    EXPECT_EQ(zero_buffer.write(&value, 1), 0);  // 无法写入
    
    // 最小容量
    RingBuffer<float> min_buffer(1);
    EXPECT_EQ(min_buffer.capacity(), 1);
    EXPECT_TRUE(min_buffer.empty());
    EXPECT_FALSE(min_buffer.full());
    
    // 写入一个元素，缓冲区应该是满的
    EXPECT_EQ(min_buffer.write(&value, 1), 1);
    EXPECT_FALSE(min_buffer.empty());
    EXPECT_TRUE(min_buffer.full());
    
    // 再写入应该失败
    EXPECT_EQ(min_buffer.write(&value, 1), 0);
}

// 测试清空操作
TEST_F(RingBufferTest, ClearOperation) {
    RingBuffer<float> buffer(128);
    
    // 填充一些数据
    std::vector<float> test_data(64);
    for (size_t i = 0; i < test_data.size(); ++i) {
        test_data[i] = static_cast<float>(i) / 100.0f;
    }
    
    EXPECT_EQ(buffer.write(test_data.data(), test_data.size()), test_data.size());
    EXPECT_EQ(buffer.available(), test_data.size());
    
    // 清空
    buffer.clear();
    EXPECT_EQ(buffer.available(), 0);
    EXPECT_EQ(buffer.space(), buffer.capacity());
    EXPECT_TRUE(buffer.empty());
    EXPECT_FALSE(buffer.full());
}

// 测试尝试写入超过容量
TEST_F(RingBufferTest, WriteBeyondCapacity) {
    const size_t capacity = 128;
    RingBuffer<float> buffer(capacity);
    
    std::vector<float> test_data(capacity * 2);  // 两倍容量
    for (size_t i = 0; i < test_data.size(); ++i) {
        test_data[i] = static_cast<float>(i) / 100.0f;
    }
    
    // 应该只写入容量大小
    size_t written = buffer.write(test_data.data(), test_data.size());
    EXPECT_EQ(written, capacity);
    EXPECT_EQ(buffer.available(), capacity);
    EXPECT_TRUE(buffer.full());
}

// 测试并发安全性
TEST_F(RingBufferTest, ConcurrentAccess) {
    const size_t capacity = 1024;
    const size_t iterations = 1000;
    
    RingBuffer<int> buffer(capacity);
    std::atomic<bool> done(false);
    std::atomic<size_t> producer_count(0);
    std::atomic<size_t> consumer_count(0);
    
    // 生产者线程
    auto producer = [&]() {
        for (size_t i = 0; i < iterations; ++i) {
            int value = static_cast<int>(i);
            if (buffer.write(&value, 1) == 1) {
                producer_count++;
            }
        }
    };
    
    // 消费者线程
    auto consumer = [&]() {
        while (!done || buffer.available() > 0) {
            int value;
            if (buffer.read(&value, 1) == 1) {
                consumer_count++;
            } else {
                // 给生产者一些时间
                std::this_thread::yield();
            }
        }
    };
    
    // 启动线程
    std::thread producer_thread(producer);
    std::thread consumer_thread(consumer);
    
    // 等待生产者完成
    producer_thread.join();
    done = true;
    
    // 等待消费者完成
    consumer_thread.join();
    
    // 验证所有数据都被正确处理
    EXPECT_EQ(producer_count.load(), iterations);
    EXPECT_EQ(consumer_count.load(), iterations);
    EXPECT_TRUE(buffer.empty());
}

// 测试调整大小
TEST_F(RingBufferTest, Resize) {
    RingBuffer<float> buffer(128);
    
    // 填充一些数据
    std::vector<float> test_data(64);
    for (size_t i = 0; i < test_data.size(); ++i) {
        test_data[i] = static_cast<float>(i) / 100.0f;
    }
    
    EXPECT_EQ(buffer.write(test_data.data(), test_data.size()), test_data.size());
    
    // 调整大小（会清空缓冲区）
    buffer.resize(256);
    EXPECT_EQ(buffer.capacity(), 256);
    EXPECT_EQ(buffer.available(), 0);
    EXPECT_EQ(buffer.space(), 256);
    
    // 再次写入
    EXPECT_EQ(buffer.write(test_data.data(), test_data.size()), test_data.size());
    EXPECT_EQ(buffer.available(), test_data.size());
    
    // 调整到更小（会清空缓冲区）
    buffer.resize(32);
    EXPECT_EQ(buffer.capacity(), 32);
    EXPECT_EQ(buffer.available(), 0);
    EXPECT_EQ(buffer.space(), 32);
}

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