// ================================================================================================
// Audio Backend - 测试模拟对象实现
// ================================================================================================

#include "mock_objects.h"
#include <random>
#include <chrono>
#include <cmath>

namespace audio_backend {
namespace test {

//===================================================================================================
// ResourceLimiter 实现
//===================================================================================================
struct ResourceLimiter::Impl {
    size_t memory_limit = std::numeric_limits<size_t>::max();
    float cpu_limit = 100.0f;
    size_t io_limit = std::numeric_limits<size_t>::max();
    size_t network_limit = std::numeric_limits<size_t>::max();
    
    ResourceUsage current_usage;
    std::mt19937 rng{static_cast<unsigned int>(std::chrono::steady_clock::now().time_since_epoch().count())};
};

ResourceLimiter::ResourceLimiter() : pimpl_(std::make_unique<Impl>()) {}
ResourceLimiter::~ResourceLimiter() = default;

void ResourceLimiter::set_memory_limit(size_t bytes) {
    pimpl_->memory_limit = bytes;
}

void ResourceLimiter::set_cpu_limit(float percentage) {
    pimpl_->cpu_limit = std::clamp(percentage, 0.0f, 100.0f);
}

void ResourceLimiter::set_io_limit(size_t bytes_per_sec) {
    pimpl_->io_limit = bytes_per_sec;
}

void ResourceLimiter::set_network_limit(size_t bytes_per_sec) {
    pimpl_->network_limit = bytes_per_sec;
}

void ResourceLimiter::reset_limits() {
    pimpl_->memory_limit = std::numeric_limits<size_t>::max();
    pimpl_->cpu_limit = 100.0f;
    pimpl_->io_limit = std::numeric_limits<size_t>::max();
    pimpl_->network_limit = std::numeric_limits<size_t>::max();
}

ResourceUsage ResourceLimiter::get_current_usage() const {
    // 模拟随机资源使用
    std::uniform_real_distribution<float> cpu_dist(0.0f, pimpl_->cpu_limit * 1.2f);
    std::uniform_int_distribution<size_t> memory_dist(0, pimpl_->memory_limit);
    std::uniform_int_distribution<size_t> io_dist(0, pimpl_->io_limit);
    std::uniform_int_distribution<size_t> network_dist(0, pimpl_->network_limit);
    
    ResourceUsage usage;
    usage.memory_usage_bytes = memory_dist(pimpl_->rng);
    usage.cpu_usage_percent = cpu_dist(pimpl_->rng);
    usage.io_bytes_per_sec = io_dist(pimpl_->rng);
    usage.network_bytes_per_sec = network_dist(pimpl_->rng);
    
    return usage;
}

bool ResourceLimiter::is_limit_reached(ResourceType type) const {
    auto usage = get_current_usage();
    switch (type) {
        case ResourceType::Memory:
            return usage.memory_usage_bytes >= pimpl_->memory_limit;
        case ResourceType::CPU:
            return usage.cpu_usage_percent >= pimpl_->cpu_limit;
        case ResourceType::IO:
            return usage.io_bytes_per_sec >= pimpl_->io_limit;
        case ResourceType::Network:
            return usage.network_bytes_per_sec >= pimpl_->network_limit;
        default:
            return false;
    }
}

//===================================================================================================
// ErrorInjector 实现
//===================================================================================================
struct ErrorInjector::Impl {
    std::map<std::string, std::map<std::string, ErrorCallback>> registered_errors;
    float error_probability = 0.0f;
    std::mt19937 rng{static_cast<unsigned int>(std::chrono::steady_clock::now().time_since_epoch().count())};
};

ErrorInjector::ErrorInjector() : pimpl_(std::make_unique<Impl>()) {}
ErrorInjector::~ErrorInjector() = default;

void ErrorInjector::register_error(const std::string& component, const std::string& operation, ErrorCallback callback) {
    pimpl_->registered_errors[component][operation] = std::move(callback);
}

bool ErrorInjector::inject_error(const std::string& component, const std::string& operation) {
    auto comp_it = pimpl_->registered_errors.find(component);
    if (comp_it != pimpl_->registered_errors.end()) {
        auto op_it = comp_it->second.find(operation);
        if (op_it != comp_it->second.end()) {
            op_it->second();
            return true;
        }
    }
    return false;
}

bool ErrorInjector::inject_random_error() {
    std::uniform_real_distribution<float> dist(0.0f, 1.0f);
    if (dist(pimpl_->rng) < pimpl_->error_probability) {
        // 随机选择一个错误注入
        if (pimpl_->registered_errors.empty()) {
            return false;
        }
        
        std::vector<std::pair<std::string, std::string>> error_keys;
        for (const auto& comp : pimpl_->registered_errors) {
            for (const auto& op : comp.second) {
                error_keys.emplace_back(comp.first, op.first);
            }
        }
        
        if (error_keys.empty()) {
            return false;
        }
        
        std::uniform_int_distribution<size_t> key_dist(0, error_keys.size() - 1);
        auto selected = error_keys[key_dist(pimpl_->rng)];
        return inject_error(selected.first, selected.second);
    }
    return false;
}

void ErrorInjector::set_error_probability(float probability) {
    pimpl_->error_probability = std::clamp(probability, 0.0f, 1.0f);
}

void ErrorInjector::reset() {
    pimpl_->registered_errors.clear();
    pimpl_->error_probability = 0.0f;
}

//===================================================================================================
// MockAudioGenerator 实现
//===================================================================================================
struct MockAudioGenerator::Impl {
    int sample_rate;
    int channels;
    SignalType type = SignalType::Sine;
    float frequency = 440.0f;
    float amplitude = 0.5f;
    float phase = 0.0f;
    float phase_increment = 0.0f;
    
    std::mt19937 rng{static_cast<unsigned int>(std::chrono::steady_clock::now().time_since_epoch().count())};
    
    Impl(int sr, int ch) : sample_rate(sr), channels(ch) {
        update_phase_increment();
    }
    
    void update_phase_increment() {
        phase_increment = 2.0f * M_PI * frequency / static_cast<float>(sample_rate);
    }
    
    float generate_sample() {
        float sample = 0.0f;
        
        switch (type) {
            case SignalType::Sine:
                sample = amplitude * std::sin(phase);
                break;
                
            case SignalType::Square:
                sample = amplitude * (std::sin(phase) >= 0.0f ? 1.0f : -1.0f);
                break;
                
            case SignalType::Triangle:
                sample = amplitude * (2.0f / M_PI) * std::asin(std::sin(phase));
                break;
                
            case SignalType::Sawtooth: {
                float normalized_phase = std::fmod(phase, 2.0f * M_PI) / (2.0f * M_PI);
                sample = amplitude * (2.0f * normalized_phase - 1.0f);
                break;
            }
                
            case SignalType::Noise: {
                std::uniform_real_distribution<float> dist(-amplitude, amplitude);
                sample = dist(rng);
                break;
            }
                
            case SignalType::Silence:
            default:
                sample = 0.0f;
                break;
        }
        
        // 更新相位
        phase += phase_increment;
        if (phase > 2.0f * M_PI) {
            phase -= 2.0f * M_PI;
        }
        
        return sample;
    }
};

MockAudioGenerator::MockAudioGenerator(int sample_rate, int channels) 
    : pimpl_(std::make_unique<Impl>(sample_rate, channels)) {}

MockAudioGenerator::~MockAudioGenerator() = default;

void MockAudioGenerator::set_signal_type(SignalType type) {
    pimpl_->type = type;
}

void MockAudioGenerator::set_frequency(float frequency_hz) {
    pimpl_->frequency = frequency_hz;
    pimpl_->update_phase_increment();
}

void MockAudioGenerator::set_amplitude(float amplitude) {
    pimpl_->amplitude = amplitude;
}

void MockAudioGenerator::set_phase(float phase_radians) {
    pimpl_->phase = phase_radians;
}

void MockAudioGenerator::generate(float* buffer, size_t frames) {
    for (size_t i = 0; i < frames; ++i) {
        float sample = pimpl_->generate_sample();
        for (int ch = 0; ch < pimpl_->channels; ++ch) {
            buffer[i * pimpl_->channels + ch] = sample;
        }
    }
}

void MockAudioGenerator::reset() {
    pimpl_->phase = 0.0f;
}

} // namespace test
} // namespace audio_backend