// ================================================================================================
// Audio Backend - 前端通信接口示例
// ================================================================================================
// 描述: 演示前端通信模块的使用方法
// 功能: 引擎连接、设备管理、网络发现、音频传输
// ================================================================================================

#include "audio_backend/frontend.h"
#include <iostream>
#include <string>
#include <thread>
#include <chrono>
#include <atomic>
#include <csignal>

using namespace audio_backend;
using namespace audio_backend::frontend;

// 全局退出标志
std::atomic<bool> g_running{true};

// 信号处理器
void signal_handler(int signal) {
    std::cout << "接收到信号: " << signal << ", 准备退出..." << std::endl;
    g_running = false;
}

// 事件监听器
class DemoEventListener : public IFrontendEventListener {
public:
    void on_frontend_event(FrontendEvent event, const std::string& data) override {
        std::cout << "[事件] ";
        switch (event) {
            case FrontendEvent::EngineConnected:
                std::cout << "引擎已连接";
                break;
            case FrontendEvent::EngineDisconnected:
                std::cout << "引擎已断开";
                break;
            case FrontendEvent::DeviceAdded:
                std::cout << "设备已添加";
                break;
            case FrontendEvent::DeviceRemoved:
                std::cout << "设备已移除";
                break;
            case FrontendEvent::NetworkServiceFound:
                std::cout << "发现网络服务";
                break;
            case FrontendEvent::NetworkServiceLost:
                std::cout << "丢失网络服务";
                break;
            case FrontendEvent::AudioStreamStarted:
                std::cout << "音频流已开始";
                break;
            case FrontendEvent::AudioStreamStopped:
                std::cout << "音频流已停止";
                break;
            case FrontendEvent::ConfigurationChanged:
                std::cout << "配置已更改";
                break;
            default:
                std::cout << "未知事件";
                break;
        }
        if (!data.empty()) {
            std::cout << ": " << data;
        }
        std::cout << std::endl;
    }
    
    void on_audio_device_changed(const std::string& device_id, bool added) override {
        std::cout << "[设备] " << (added ? "添加" : "移除") << " 设备: " << device_id << std::endl;
    }
    
    void on_audio_stream_data(const engine::AudioBuffer& buffer) override {
        // 在实际应用中处理收到的音频数据
        std::cout << "[音频] 收到音频数据: " 
                  << buffer.frames() << " 帧, " 
                  << buffer.channels() << " 声道" << std::endl;
    }
    
    void on_network_service_discovered(const std::string& service_name, 
                                      const std::string& address, 
                                      uint16_t port) override {
        std::cout << "[发现] 服务: " << service_name 
                  << " 地址: " << address 
                  << " 端口: " << port << std::endl;
    }
    
    void on_frontend_error(common::ErrorCode error, const std::string& message) override {
        std::cout << "[错误] 代码: " << static_cast<int>(error) 
                  << " 消息: " << message << std::endl;
    }
};

// ================================================================================================
// 本地音频引擎连接示例
// ================================================================================================
void local_engine_demo() {
    std::cout << "\n=== 本地音频引擎连接示例 ===\n" << std::endl;
    
    // 创建前端管理器
    auto frontend = create_frontend_manager("demo_frontend");
    if (!frontend) {
        std::cerr << "无法创建前端管理器" << std::endl;
        return;
    }
    
    // 添加事件监听器
    auto listener = std::make_shared<DemoEventListener>();
    frontend->add_event_listener(listener);
    
    // 初始化前端
    auto result = frontend->initialize();
    if (result != common::ErrorCode::SUCCESS) {
        std::cerr << "前端初始化失败: " << static_cast<int>(result) << std::endl;
        return;
    }
    std::cout << "前端初始化成功" << std::endl;
    
    // 连接到音频引擎
    std::cout << "连接到本地音频引擎..." << std::endl;
    result = frontend->connect_to_engine("tcp://localhost:5555");
    if (result != common::ErrorCode::SUCCESS) {
        std::cerr << "无法连接到音频引擎: " << static_cast<int>(result) << std::endl;
        std::cout << "请确保音频引擎正在运行，继续演示其他功能..." << std::endl;
    } else {
        std::cout << "成功连接到音频引擎" << std::endl;
    }
    
    // 获取音频设备
    std::cout << "\n获取音频设备列表..." << std::endl;
    auto devices = frontend->get_audio_devices();
    if (devices.empty()) {
        std::cout << "未找到音频设备" << std::endl;
    } else {
        std::cout << "找到 " << devices.size() << " 个音频设备:" << std::endl;
        for (const auto& device : devices) {
            std::cout << " - " << device.name 
                      << " (ID: " << device.id << ")"
                      << " [" << (device.is_input ? "输入" : "") 
                      << (device.is_output ? "输出" : "") << "]"
                      << (device.is_default ? " 默认" : "") << std::endl;
        }
        
        // 如果找到默认输出设备，设置它
        for (const auto& device : devices) {
            if (device.is_output && device.is_default) {
                std::cout << "\n设置默认输出设备: " << device.name << std::endl;
                frontend->set_output_device(device.id);
                break;
            }
        }
    }
    
    // 启动音频流（在实际环境中可能会开始播放声音）
    std::cout << "\n尝试启动音频..." << std::endl;
    result = frontend->start_audio_stream();
    if (result != common::ErrorCode::SUCCESS) {
        std::cerr << "无法启动音频流: " << static_cast<int>(result) << std::endl;
    } else {
        std::cout << "音频流已启动" << std::endl;
        
        // 保持音频流一小段时间
        std::cout << "音频流运行中..." << std::endl;
        std::this_thread::sleep_for(std::chrono::seconds(2));
        
        std::cout << "停止音频流..." << std::endl;
        frontend->stop_audio_stream();
    }
    
    // 断开音频引擎
    std::cout << "\n断开音频引擎..." << std::endl;
    frontend->disconnect_from_engine();
    
    // 关闭前端
    std::cout << "关闭前端..." << std::endl;
    frontend->shutdown();
    
    std::cout << "本地音频引擎示例完成" << std::endl;
}

// ================================================================================================
// 网络服务发现示例
// ================================================================================================
void network_discovery_demo() {
    std::cout << "\n=== 网络服务发现示例 ===\n" << std::endl;
    
    // 创建前端管理器
    auto frontend = create_frontend_manager("discovery_demo");
    if (!frontend) {
        std::cerr << "无法创建前端管理器" << std::endl;
        return;
    }
    
    // 添加事件监听器
    auto listener = std::make_shared<DemoEventListener>();
    frontend->add_event_listener(listener);
    
    // 初始化前端
    auto result = frontend->initialize();
    if (result != common::ErrorCode::SUCCESS) {
        std::cerr << "前端初始化失败: " << static_cast<int>(result) << std::endl;
        return;
    }
    
    // 启动网络发现
    std::cout << "启动网络服务发现..." << std::endl;
    result = frontend->start_network_discovery();
    if (result != common::ErrorCode::SUCCESS) {
        std::cerr << "无法启动网络发现: " << static_cast<int>(result) << std::endl;
        frontend->shutdown();
        return;
    }
    
    // 等待并显示发现的服务
    std::cout << "搜索网络音频服务 (5秒)..." << std::endl;
    std::this_thread::sleep_for(std::chrono::seconds(5));
    
    auto services = frontend->get_discovered_services();
    if (services.empty()) {
        std::cout << "未找到网络音频服务" << std::endl;
    } else {
        std::cout << "找到 " << services.size() << " 个网络音频服务:" << std::endl;
        for (const auto& service : services) {
            std::cout << " - " << service.service_name 
                      << " (类型: " << service.service_type << ")"
                      << " 地址: " << service.address
                      << " 端口: " << service.port << std::endl;
        }
        
        // 如果发现了服务，尝试连接第一个服务
        if (!services.empty()) {
            const auto& first_service = services[0];
            std::cout << "\n尝试连接到服务: " << first_service.service_name << std::endl;
            
            result = frontend->connect_to_network_service(first_service.service_id);
            if (result != common::ErrorCode::SUCCESS) {
                std::cerr << "无法连接到服务: " << static_cast<int>(result) << std::endl;
            } else {
                std::cout << "成功连接到服务" << std::endl;
                
                // 在实际应用中，此处可以开始音频流传输
                // frontend->start_network_audio_stream(...);
                
                std::cout << "断开服务连接..." << std::endl;
                frontend->disconnect_from_network_service(first_service.service_id);
            }
        }
    }
    
    // 停止网络发现
    std::cout << "\n停止网络发现..." << std::endl;
    frontend->stop_network_discovery();
    
    // 关闭前端
    frontend->shutdown();
    
    std::cout << "网络服务发现示例完成" << std::endl;
}

// ================================================================================================
// 音频流传输示例
// ================================================================================================
void audio_streaming_demo() {
    std::cout << "\n=== 音频流传输示例 ===\n" << std::endl;
    
    // 创建音频流发送器
    auto sender_config = network::create_balanced_config();
    auto sender = network::create_audio_stream_sender(sender_config);
    if (!sender) {
        std::cerr << "无法创建音频流发送器" << std::endl;
        return;
    }
    
    // 创建音频流接收器
    auto receiver_config = network::create_balanced_config();
    auto receiver = network::create_audio_stream_receiver(receiver_config);
    if (!receiver) {
        std::cerr << "无法创建音频流接收器" << std::endl;
        return;
    }
    
    // 创建UDP传输
    auto transport_config = network::transport_factory::get_recommended_udp_config();
    transport_config.local_port = 12345;  // 发送端端口
    auto transport = network::transport_factory::create_udp_transport();
    if (!transport) {
        std::cerr << "无法创建UDP传输" << std::endl;
        return;
    }
    
    // 初始化传输
    if (transport->initialize(transport_config) != common::ErrorCode::SUCCESS) {
        std::cerr << "无法初始化UDP传输" << std::endl;
        return;
    }
    
    // 绑定到本地端口
    network::NetworkEndpoint local_endpoint("127.0.0.1", 12345, network::TransportProtocol::UDP);
    if (transport->bind(local_endpoint) != common::ErrorCode::SUCCESS) {
        std::cerr << "无法绑定到本地端口" << std::endl;
        return;
    }
    
    // 接收器的传输（在实际应用中，这会在不同机器上）
    auto receiver_transport = network::transport_factory::create_udp_transport();
    transport_config.local_port = 12346;  // 接收端端口
    receiver_transport->initialize(transport_config);
    network::NetworkEndpoint receiver_endpoint("127.0.0.1", 12346, network::TransportProtocol::UDP);
    receiver_transport->bind(receiver_endpoint);
    
    // 初始化发送器和接收器
    sender->initialize(transport);
    receiver->initialize(receiver_transport);
    
    std::cout << "音频流传输已设置，实际应用中会传输音频数据" << std::endl;
    std::cout << "发送器 -> 127.0.0.1:12345" << std::endl;
    std::cout << "接收器 <- 127.0.0.1:12346" << std::endl;
    
    // 在实际应用中，此处会有一个循环发送音频数据
    /*
    // 示例代码（不会执行）
    engine::AudioConfig config;
    config.sample_rate = 48000;
    config.channels = 2;
    config.format = engine::AudioFormat::FLOAT32;
    config.frames_per_buffer = 480;  // 10ms @ 48kHz
    
    engine::AudioBuffer buffer(config);
    
    while (running) {
        // 获取音频数据到buffer
        sender->send_audio(buffer);
        std::this_thread::sleep_for(std::chrono::milliseconds(10));
    }
    */
    
    // 关闭发送器和接收器
    std::cout << "\n关闭音频流..." << std::endl;
    sender->shutdown();
    receiver->shutdown();
    transport->shutdown();
    receiver_transport->shutdown();
    
    std::cout << "音频流传输示例成" << std::endl;
}

// ================================================================================================
// 编解码示例
// ================================================================================================
void codec_demo() {
    std::cout << "\n=== 音频编解码示例 ===\n" << std::endl;
    
    // 创建Opus编解码器
    codec::CodecConfig opus_config;
    opus_config.codec_type = codec::CodecType::OPUS;
    opus_config.sample_rate = 48000;
    opus_config.channels = 2;
    opus_config.bitrate = 128000;  // 128 kbps
    
    auto encoder = codec::create_codec(opus_config);
    if (!encoder) {
        std::cerr << "无法创建Opus编解码器" << std::endl;
        return;
    }
    
    // 初始化编码器
    encoder->initialize();
    
    // 创建测试音频缓冲区
    engine::AudioConfig audio_config;
    audio_config.sample_rate = 48000;
    audio_config.channels = 2;
    audio_config.format = engine::AudioFormat::FLOAT32;
    audio_config.frames_per_buffer = 960;  // 20ms @ 48kHz
    
    engine::AudioBuffer test_buffer(audio_config);
    
    // 生成正弦波测试数据
    float* data = test_buffer.interleaved_data<float>();
    for (uint32_t i = 0; i < test_buffer.frames(); i++) {
        for (uint16_t c = 0; c < test_buffer.channels(); c++) {
            // 生成一个440Hz的正弦波
            float sample = std::sin(2.0f * 3.14159f * 440.0f * i / 48000.0f);
            data[i * test_buffer.channels() + c] = sample * 0.5f;  // 半音量
        }
    }
    
    // 编码测试数据
    std::vector<uint8_t> encoded_data;
    auto result = encoder->encode(test_buffer, encoded_data);
    if (result != common::ErrorCode::SUCCESS) {
        std::cerr << "编码失败: " << static_cast<int>(result) << std::endl;
        encoder->shutdown();
        return;
    }
    
    std::cout << "音频编码结果:" << std::endl;
    std::cout << " - 原始大小: " << test_buffer.size_bytes() << " 字节" << std::endl;
    std::cout << " - 编码大小: " << encoded_data.size() << " 字节" << std::endl;
    std::cout << " - 压缩率: " << (100.0 * encoded_data.size() / test_buffer.size_bytes()) << "%" << std::endl;
    
    // 解码测试数据
    engine::AudioBuffer decoded_buffer;
    result = encoder->decode(encoded_data, decoded_buffer);
    if (result != common::ErrorCode::SUCCESS) {
        std::cerr << "解码失败: " << static_cast<int>(result) << std::endl;
        encoder->shutdown();
        return;
    }
    
    std::cout << "音频解码结果:" << std::endl;
    std::cout << " - 解码后大小: " << decoded_buffer.size_bytes() << " 字节" << std::endl;
    std::cout << " - 帧数: " << decoded_buffer.frames() << std::endl;
    std::cout << " - 声道数: " << decoded_buffer.channels() << std::endl;
    
    // 关闭编解码器
    encoder->shutdown();
    
    std::cout << "音频编解码示例完成" << std::endl;
}

// ================================================================================================
// 主函数
// ================================================================================================
int main() {
    std::cout << "====================================\n";
    std::cout << "Audio Backend 前端通信示例\n";
    std::cout << "====================================\n";
    
    // 设置信号处理
    std::signal(SIGINT, signal_handler);  // Ctrl+C
    std::signal(SIGTERM, signal_handler);  // 终止信号
    
    try {
        // 初始化前端系统
        frontend::initialize_frontend();
        
        // 运行各个示例
        local_engine_demo();
        network_discovery_demo();
        audio_streaming_demo();
        codec_demo();
        
        // 关闭前端系统
        frontend::shutdown_frontend();
        
        std::cout << "\n====================================\n";
        std::cout << "演示完成\n";
        std::cout << "====================================\n";
        
    } catch (const std::exception& e) {
        std::cerr << "演示过程中发生错误: " << e.what() << "\n";
        return 1;
    }
    
    return 0;
}