#include "utils_packet_queue.h"
#include "../base/logger.h"
#include <algorithm>
#include <shared_mutex>

namespace av {
namespace utils {

using namespace av;

PacketQueue::PacketQueue(const PacketQueueConfig& config)
    : config_(config) {
    Logger::instance().debugf("PacketQueue created with max size: {}, max bytes: {}", 
                 config_.maxSize, config_.maxBytes);
}

PacketQueue::~PacketQueue() {
    shutdown_ = true;
    notEmpty_.notify_all();
    notFull_.notify_all();
    clear();
    Logger::instance().debug("PacketQueue destroyed");
}

ErrorCode PacketQueue::enqueue(std::unique_ptr<PacketQueueItem> item) {
    if (!item) {
        return ErrorCode::INVALID_PARAMS;
    }
    
    if (shutdown_) {
        return ErrorCode::INVALID_STATE;
    }
    
    // 检查流过滤
    if (!isStreamAllowed(item->streamIndex)) {
        Logger::instance().debugf("Packet dropped - stream {} not allowed", item->streamIndex);
        return ErrorCode::SUCCESS;
    }
    
    std::unique_lock<std::mutex> lock(queueMutex_);
    
    // 检查是否需要丢包
    if (shouldDropPacket(*item)) {
        if (dropCallback_) {
            dropCallback_(*item, "Smart packet drop");
        }
        
        std::lock_guard<std::mutex> statsLock(statsMutex_);
        stats_.totalDropped++;
        
        Logger::instance().debug("Packet dropped by smart drop policy");
        return ErrorCode::SUCCESS;
    }
    
    // 检查队列是否已满
    size_t currentSize = config_.priorityQueue ? priorityQueue_.size() : normalQueue_.size();
    size_t currentBytes = totalBytes_.load();
    
    bool queueFull = (currentSize >= config_.maxSize) || (currentBytes >= config_.maxBytes);
    
    if (blocking_ && queueFull) {
        if (config_.dropOnFull) {
            // 根据策略丢弃包
            if (config_.dropOldest) {
                dropOldestPacket();
            } else if (config_.dropNonKeyPackets && !item->isKeyPacket) {
                dropNonKeyPackets();
            } else {
                if (dropCallback_) {
                    dropCallback_(*item, "Queue full - drop newest");
                }
                
                std::lock_guard<std::mutex> statsLock(statsMutex_);
                stats_.totalDropped++;
                
                Logger::instance().debug("Packet dropped - queue full");
                return ErrorCode::SUCCESS;
            }
        } else {
            // 等待队列有空间
            if (!notFull_.wait_for(lock, std::chrono::milliseconds(config_.timeoutMs),
                                  [this, currentSize, currentBytes] { 
                                      size_t newSize = config_.priorityQueue ? priorityQueue_.size() : normalQueue_.size();
                                      size_t newBytes = totalBytes_.load();
                                      return (newSize < config_.maxSize && newBytes < config_.maxBytes) || shutdown_; 
                                  })) {
                Logger::instance().warning("Enqueue timeout");
                return ErrorCode::TIMEOUT;
            }
            
            if (shutdown_) {
                return ErrorCode::INVALID_STATE;
            }
        }
    }
    
    // 更新字节计数
    if (item->packet) {
        totalBytes_ += item->packet->size;
    }
    
    // 在move之前保存item的引用，用于后续的统计和回调
    const PacketQueueItem& itemRef = *item;
    
    // 添加到队列
    if (config_.priorityQueue) {
        enqueueToPriorityQueue(std::move(item));
    } else {
        enqueueToNormalQueue(std::move(item));
    }
    
    // 更新统计信息
    if (config_.enableStats) {
        updateStats(itemRef, true);
    }
    
    // 通知等待的消费者
    notEmpty_.notify_one();
    
    // 回调
    if (enqueueCallback_) {
        enqueueCallback_(itemRef);
    }
    
    return ErrorCode::SUCCESS;
}

std::unique_ptr<PacketQueueItem> PacketQueue::dequeue() {
    return dequeue(config_.timeoutMs);
}

std::unique_ptr<PacketQueueItem> PacketQueue::dequeue(int timeoutMs) {
    std::unique_lock<std::mutex> lock(queueMutex_);
    
    // 等待队列有数据
    if (blocking_) {
        bool hasData = config_.priorityQueue ? !priorityQueue_.empty() : !normalQueue_.empty();
        
        if (!hasData) {
            if (!notEmpty_.wait_for(lock, std::chrono::milliseconds(timeoutMs),
                                   [this] { 
                                       bool hasData = config_.priorityQueue ? !priorityQueue_.empty() : !normalQueue_.empty();
                                       return hasData || shutdown_; 
                                   })) {
                return nullptr; // 超时
            }
            
            if (shutdown_) {
                return nullptr;
            }
        }
    }
    
    // 检查队列是否为空
    bool isEmpty = config_.priorityQueue ? priorityQueue_.empty() : normalQueue_.empty();
    if (isEmpty) {
        return nullptr;
    }
    
    // 取出包
    std::unique_ptr<PacketQueueItem> item;
    if (config_.priorityQueue) {
        item = dequeueFromPriorityQueue();
    } else {
        item = dequeueFromNormalQueue();
    }
    
    if (!item) {
        return nullptr;
    }
    
    // 更新字节计数
    if (item->packet) {
        totalBytes_ -= item->packet->size;
    }
    
    // 更新统计信息
    if (config_.enableStats) {
        updateStats(*item, false);
    }
    
    // 通知等待的生产者
    notFull_.notify_one();
    
    // 回调
    if (dequeueCallback_) {
        dequeueCallback_(*item);
    }
    
    return item;
}

ErrorCode PacketQueue::enqueue(AVPacket* packet, int streamIndex, int priority) {
    if (!packet) {
        return ErrorCode::INVALID_PARAMS;
    }
    
    auto item = std::make_unique<PacketQueueItem>(packet, streamIndex, priority);
    return enqueue(std::move(item));
}

AVPacket* PacketQueue::dequeuePacket() {
    auto item = dequeue();
    if (item) {
        AVPacket* packet = item->packet;
        item->packet = nullptr; // 转移所有权
        return packet;
    }
    return nullptr;
}

AVPacket* PacketQueue::dequeuePacket(int timeoutMs) {
    auto item = dequeue(timeoutMs);
    if (item) {
        AVPacket* packet = item->packet;
        item->packet = nullptr; // 转移所有权
        return packet;
    }
    return nullptr;
}

ErrorCode PacketQueue::enqueueWithPriority(AVPacket* packet, int priority, int streamIndex) {
    if (!packet) {
        return ErrorCode::INVALID_PARAMS;
    }
    
    auto item = std::make_unique<PacketQueueItem>(packet, streamIndex, priority);
    return enqueue(std::move(item));
}

std::unique_ptr<PacketQueueItem> PacketQueue::dequeueHighestPriority() {
    if (!config_.priorityQueue) {
        Logger::instance().warning("Priority queue not enabled");
        return dequeue();
    }
    
    return dequeue();
}

void PacketQueue::clear() {
    std::lock_guard<std::mutex> lock(queueMutex_);
    
    // 清空普通队列
    while (!normalQueue_.empty()) {
        normalQueue_.pop();
    }
    
    // 清空优先级队列
    while (!priorityQueue_.empty()) {
        priorityQueue_.pop();
    }
    
    totalBytes_ = 0;
    Logger::instance().debug("Packet queue cleared");
}

void PacketQueue::flush() {
    clear();
    notEmpty_.notify_all();
    notFull_.notify_all();
}

void PacketQueue::setMaxSize(size_t maxSize) {
    std::lock_guard<std::mutex> lock(queueMutex_);
    config_.maxSize = maxSize;
    
    // 如果当前队列大小超过新的最大值，丢弃多余的包
    size_t currentSize = config_.priorityQueue ? priorityQueue_.size() : normalQueue_.size();
    while (currentSize > maxSize) {
        if (config_.dropOldest) {
            dropOldestPacket();
        } else {
            break;
        }
        currentSize = config_.priorityQueue ? priorityQueue_.size() : normalQueue_.size();
    }
    
    Logger::instance().debugf("Packet queue max size set to: {}", maxSize);
}

void PacketQueue::setMaxBytes(size_t maxBytes) {
    config_.maxBytes = maxBytes;
    Logger::instance().debugf("Packet queue max bytes set to: {}", maxBytes);
}

void PacketQueue::setDropPolicy(bool dropOnFull, bool dropOldest) {
    config_.dropOnFull = dropOnFull;
    config_.dropOldest = dropOldest;
    Logger::instance().debugf("Drop policy set: dropOnFull={}, dropOldest={}", dropOnFull, dropOldest);
}

void PacketQueue::enablePriorityQueue(bool enable) {
    std::lock_guard<std::mutex> lock(queueMutex_);
    
    if (config_.priorityQueue == enable) {
        return;
    }
    
    // 如果要切换队列类型，需要迁移数据
    if (enable) {
        // 从普通队列迁移到优先级队列
        while (!normalQueue_.empty()) {
            auto item = std::move(normalQueue_.front());
            normalQueue_.pop();
            priorityQueue_.push(std::move(item));
        }
    } else {
        // 从优先级队列迁移到普通队列
        std::vector<std::unique_ptr<PacketQueueItem>> tempItems;
        while (!priorityQueue_.empty()) {
            tempItems.push_back(std::move(const_cast<std::unique_ptr<PacketQueueItem>&>(priorityQueue_.top())));
            priorityQueue_.pop();
        }
        
        // 按时间戳排序后加入普通队列
        std::sort(tempItems.begin(), tempItems.end(),
                 [](const std::unique_ptr<PacketQueueItem>& a, const std::unique_ptr<PacketQueueItem>& b) {
                     return a->dts < b->dts;
                 });
        
        for (auto& item : tempItems) {
            normalQueue_.push(std::move(item));
        }
    }
    
    config_.priorityQueue = enable;
    Logger::instance().debugf("Priority queue {}", enable ? "enabled" : "disabled");
}

size_t PacketQueue::size() const {
    std::lock_guard<std::mutex> lock(queueMutex_);
    return config_.priorityQueue ? priorityQueue_.size() : normalQueue_.size();
}

size_t PacketQueue::bytes() const {
    return totalBytes_.load();
}

bool PacketQueue::empty() const {
    std::lock_guard<std::mutex> lock(queueMutex_);
    return config_.priorityQueue ? priorityQueue_.empty() : normalQueue_.empty();
}

bool PacketQueue::full() const {
    std::lock_guard<std::mutex> lock(queueMutex_);
    size_t currentSize = config_.priorityQueue ? priorityQueue_.size() : normalQueue_.size();
    return currentSize >= config_.maxSize;
}

bool PacketQueue::fullByBytes() const {
    return totalBytes_.load() >= config_.maxBytes;
}

size_t PacketQueue::capacity() const {
    return config_.maxSize;
}

size_t PacketQueue::capacityBytes() const {
    return config_.maxBytes;
}

PacketQueueStats PacketQueue::getStats() const {
    std::lock_guard<std::mutex> lock(statsMutex_);
    PacketQueueStats stats = stats_;
    stats.currentSize = size();
    stats.totalBytes = bytes();
    return stats;
}

void PacketQueue::resetStats() {
    std::lock_guard<std::mutex> lock(statsMutex_);
    stats_ = PacketQueueStats();
    Logger::instance().debug("Packet queue stats reset");
}

void PacketQueue::enablePacketDrop(bool enable, double maxLatency, int dropRatio) {
    config_.enablePacketDrop = enable;
    config_.maxLatency = maxLatency;
    config_.dropRatio = dropRatio;
    
    Logger::instance().debugf("Packet drop enabled: {}, maxLatency: {}ms, dropRatio: {}", 
                 enable, maxLatency, dropRatio);
}

void PacketQueue::setPacketDropCallback(std::function<bool(const PacketQueueItem&)> callback) {
    packetDropCallback_ = callback;
}

void PacketQueue::setBlocking(bool blocking) {
    blocking_ = blocking;
    if (!blocking) {
        notEmpty_.notify_all();
        notFull_.notify_all();
    }
    Logger::instance().debugf("Packet queue blocking mode: {}", blocking);
}

void PacketQueue::wakeup() {
    notEmpty_.notify_all();
    notFull_.notify_all();
}

void PacketQueue::setStreamFilter(const std::vector<int>& allowedStreams) {
    std::lock_guard<std::mutex> lock(streamFilterMutex_);
    allowedStreams_ = allowedStreams;
    hasStreamFilter_ = !allowedStreams.empty();
    Logger::instance().debugf("Stream filter set with {} allowed streams", allowedStreams.size());
}

void PacketQueue::clearStreamFilter() {
    std::lock_guard<std::mutex> lock(streamFilterMutex_);
    allowedStreams_.clear();
    hasStreamFilter_ = false;
    Logger::instance().debug("Stream filter cleared");
}

// 内部方法实现
bool PacketQueue::shouldDropPacket(const PacketQueueItem& item) const {
    if (!config_.enablePacketDrop) {
        return false;
    }
    
    // 自定义丢包回调
    if (packetDropCallback_ && packetDropCallback_(item)) {
        return true;
    }
    
    // 基于延迟的丢包
    if (shouldDropByLatency(item)) {
        return true;
    }
    
    // 基于比例的丢包
    if (shouldDropByRatio()) {
        return true;
    }
    
    // 基于大小的丢包
    if (shouldDropBySize()) {
        return true;
    }
    
    return false;
}

void PacketQueue::dropOldestPacket() {
    if (config_.priorityQueue) {
        if (!priorityQueue_.empty()) {
            auto& oldestItem = const_cast<std::unique_ptr<PacketQueueItem>&>(priorityQueue_.top());
            
            if (dropCallback_) {
                dropCallback_(*oldestItem, "Drop oldest packet");
            }
            
            if (oldestItem->packet) {
                totalBytes_ -= oldestItem->packet->size;
            }
            
            priorityQueue_.pop();
            
            std::lock_guard<std::mutex> statsLock(statsMutex_);
            stats_.totalDropped++;
            
            Logger::instance().debug("Dropped oldest packet from priority queue");
        }
    } else {
        if (!normalQueue_.empty()) {
            auto& oldestItem = normalQueue_.front();
            
            if (dropCallback_) {
                dropCallback_(*oldestItem, "Drop oldest packet");
            }
            
            if (oldestItem->packet) {
                totalBytes_ -= oldestItem->packet->size;
            }
            
            normalQueue_.pop();
            
            std::lock_guard<std::mutex> statsLock(statsMutex_);
            stats_.totalDropped++;
            
            Logger::instance().debug("Dropped oldest packet from normal queue");
        }
    }
}

void PacketQueue::dropNewestPacket() {
    // 这个方法在enqueue时调用，不需要实际操作队列
}

void PacketQueue::dropLargestPacket() {
    // 找到最大的包并丢弃
    // 这里简化实现，直接丢弃最旧的包
    dropOldestPacket();
}

void PacketQueue::dropNonKeyPackets() {
    std::vector<std::unique_ptr<PacketQueueItem>> keyPackets;
    
    if (config_.priorityQueue) {
        while (!priorityQueue_.empty()) {
            auto item = std::move(const_cast<std::unique_ptr<PacketQueueItem>&>(priorityQueue_.top()));
            priorityQueue_.pop();
            
            if (item->isKeyPacket) {
                keyPackets.push_back(std::move(item));
            } else {
                if (dropCallback_) {
                    dropCallback_(*item, "Drop non-key packet");
                }
                
                if (item->packet) {
                    totalBytes_ -= item->packet->size;
                }
                
                std::lock_guard<std::mutex> statsLock(statsMutex_);
                stats_.totalDropped++;
            }
        }
        
        // 重新加入关键包
        for (auto& item : keyPackets) {
            priorityQueue_.push(std::move(item));
        }
    } else {
        while (!normalQueue_.empty()) {
            auto item = std::move(normalQueue_.front());
            normalQueue_.pop();
            
            if (item->isKeyPacket) {
                keyPackets.push_back(std::move(item));
            } else {
                if (dropCallback_) {
                    dropCallback_(*item, "Drop non-key packet");
                }
                
                if (item->packet) {
                    totalBytes_ -= item->packet->size;
                }
                
                std::lock_guard<std::mutex> statsLock(statsMutex_);
                stats_.totalDropped++;
            }
        }
        
        // 重新加入关键包
        for (auto& item : keyPackets) {
            normalQueue_.push(std::move(item));
        }
    }
    
    Logger::instance().debugf("Dropped non-key packets, kept {} key packets", keyPackets.size());
}

void PacketQueue::updateStats(const PacketQueueItem& item, bool isEnqueue) {
    std::lock_guard<std::mutex> lock(statsMutex_);
    
    if (isEnqueue) {
        stats_.totalEnqueued++;
        size_t currentSize = config_.priorityQueue ? priorityQueue_.size() : normalQueue_.size();
        stats_.maxSize = std::max(stats_.maxSize, currentSize);
        
        if (item.packet) {
            stats_.totalBytes += item.packet->size;
            
            // 更新平均包大小
            if (stats_.totalEnqueued == 1) {
                stats_.averagePacketSize = item.packet->size;
            } else {
                stats_.averagePacketSize = (stats_.averagePacketSize * (stats_.totalEnqueued - 1) + item.packet->size) / stats_.totalEnqueued;
            }
        }
    } else {
        stats_.totalDequeued++;
        
        // 计算等待时间
        double waitTime = calculateWaitTime(item);
        if (waitTime > 0) {
            // 更新平均等待时间
            if (stats_.totalDequeued == 1) {
                stats_.averageWaitTime = waitTime;
            } else {
                stats_.averageWaitTime = (stats_.averageWaitTime * (stats_.totalDequeued - 1) + waitTime) / stats_.totalDequeued;
            }
            
            stats_.maxWaitTime = std::max(stats_.maxWaitTime, waitTime);
        }
    }
    
    stats_.lastUpdateTime = std::chrono::steady_clock::now();
}

double PacketQueue::calculateWaitTime(const PacketQueueItem& item) const {
    auto now = std::chrono::steady_clock::now();
    auto duration = std::chrono::duration_cast<std::chrono::microseconds>(now - item.enqueueTime);
    return duration.count() / 1000.0; // 转换为毫秒
}

bool PacketQueue::isStreamAllowed(int streamIndex) const {
    if (!hasStreamFilter_) {
        return true;
    }
    
    std::lock_guard<std::mutex> lock(streamFilterMutex_);
    return std::find(allowedStreams_.begin(), allowedStreams_.end(), streamIndex) != allowedStreams_.end();
}

bool PacketQueue::shouldDropByLatency(const PacketQueueItem& item) const {
    double waitTime = calculateWaitTime(item);
    return waitTime > config_.maxLatency;
}

bool PacketQueue::shouldDropByRatio() const {
    if (config_.dropRatio <= 1) {
        return false;
    }
    
    uint64_t count = packetCounter_.fetch_add(1);
    return (count % config_.dropRatio) == 0;
}

bool PacketQueue::shouldDropBySize() const {
    return totalBytes_.load() > config_.maxBytes;
}

void PacketQueue::enqueueToNormalQueue(std::unique_ptr<PacketQueueItem> item) {
    normalQueue_.push(std::move(item));
}

void PacketQueue::enqueueToPriorityQueue(std::unique_ptr<PacketQueueItem> item) {
    priorityQueue_.push(std::move(item));
}

std::unique_ptr<PacketQueueItem> PacketQueue::dequeueFromNormalQueue() {
    if (normalQueue_.empty()) {
        return nullptr;
    }
    
    auto item = std::move(normalQueue_.front());
    normalQueue_.pop();
    return item;
}

std::unique_ptr<PacketQueueItem> PacketQueue::dequeueFromPriorityQueue() {
    if (priorityQueue_.empty()) {
        return nullptr;
    }
    
    auto item = std::move(const_cast<std::unique_ptr<PacketQueueItem>&>(priorityQueue_.top()));
    priorityQueue_.pop();
    return item;
}

// 多流包队列实现
MultiStreamPacketQueue::MultiStreamPacketQueue(const PacketQueueConfig& config)
    : defaultConfig_(config) {
    Logger::instance().debug("MultiStreamPacketQueue created");
}

MultiStreamPacketQueue::~MultiStreamPacketQueue() {
    clear();
    Logger::instance().debug("MultiStreamPacketQueue destroyed");
}

ErrorCode MultiStreamPacketQueue::addStream(int streamIndex, const PacketQueueConfig& config) {
    std::unique_lock<std::shared_mutex> lock(streamsMutex_);
    
    if (streamQueues_.find(streamIndex) != streamQueues_.end()) {
        Logger::instance().warningf("Stream {} already exists", streamIndex);
        return ErrorCode::ALREADY_EXISTS;
    }
    
    streamQueues_[streamIndex] = std::make_unique<PacketQueue>(config);
    Logger::instance().debugf("Added stream: {}", streamIndex);
    
    return ErrorCode::SUCCESS;
}

ErrorCode MultiStreamPacketQueue::removeStream(int streamIndex) {
    std::unique_lock<std::shared_mutex> lock(streamsMutex_);
    
    auto it = streamQueues_.find(streamIndex);
    if (it == streamQueues_.end()) {
        Logger::instance().warningf("Stream {} not found", streamIndex);
        return ErrorCode::NOT_FOUND;
    }
    
    streamQueues_.erase(it);
    Logger::instance().debugf("Removed stream: {}", streamIndex);
    
    return ErrorCode::SUCCESS;
}

bool MultiStreamPacketQueue::hasStream(int streamIndex) const {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    return streamQueues_.find(streamIndex) != streamQueues_.end();
}

std::vector<int> MultiStreamPacketQueue::getStreamIndices() const {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    std::vector<int> indices;
    for (const auto& pair : streamQueues_) {
        indices.push_back(pair.first);
    }
    
    return indices;
}

ErrorCode MultiStreamPacketQueue::enqueue(AVPacket* packet, int streamIndex) {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    auto it = streamQueues_.find(streamIndex);
    if (it == streamQueues_.end()) {
        // 自动创建流队列
        lock.unlock();
        addStream(streamIndex, defaultConfig_);
        lock.lock();
        
        it = streamQueues_.find(streamIndex);
        if (it == streamQueues_.end()) {
            return ErrorCode::NOT_FOUND;
        }
    }
    
    return it->second->enqueue(packet, streamIndex);
}

AVPacket* MultiStreamPacketQueue::dequeue(int streamIndex) {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    auto it = streamQueues_.find(streamIndex);
    if (it == streamQueues_.end()) {
        return nullptr;
    }
    
    return it->second->dequeuePacket();
}

AVPacket* MultiStreamPacketQueue::dequeue(int streamIndex, int timeoutMs) {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    auto it = streamQueues_.find(streamIndex);
    if (it == streamQueues_.end()) {
        return nullptr;
    }
    
    return it->second->dequeuePacket(timeoutMs);
}

ErrorCode MultiStreamPacketQueue::enqueueToAll(AVPacket* packet) {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    ErrorCode result = ErrorCode::SUCCESS;
    for (const auto& pair : streamQueues_) {
        // 为每个流创建包的副本
        AVPacket* packetCopy = av_packet_alloc();
        if (!packetCopy) {
            result = ErrorCode::MEMORY_ALLOC_FAILED;
            continue;
        }
        
        if (av_packet_ref(packetCopy, packet) < 0) {
            av_packet_free(&packetCopy);
            result = ErrorCode::COPY_FAILED;
            continue;
        }
        
        ErrorCode enqueueResult = pair.second->enqueue(packetCopy, pair.first);
        if (enqueueResult != ErrorCode::SUCCESS) {
            av_packet_free(&packetCopy);
            result = enqueueResult;
        }
    }
    
    return result;
}

std::vector<AVPacket*> MultiStreamPacketQueue::dequeueFromAll() {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    std::vector<AVPacket*> packets;
    for (const auto& pair : streamQueues_) {
        AVPacket* packet = pair.second->dequeuePacket();
        packets.push_back(packet); // 可能为nullptr
    }
    
    return packets;
}

AVPacket* MultiStreamPacketQueue::dequeueSynchronized() {
    std::lock_guard<std::mutex> lock(syncMutex_);
    
    // 从同步队列中取出时间戳最小的包
    if (!syncQueue_.empty()) {
        SyncItem item = syncQueue_.top();
        syncQueue_.pop();
        return item.packet;
    }
    
    // 如果同步队列为空，从各个流队列中取包并排序
    std::vector<SyncItem> items;
    
    {
        std::shared_lock<std::shared_mutex> streamLock(streamsMutex_);
        for (const auto& pair : streamQueues_) {
            AVPacket* packet = pair.second->dequeuePacket(10); // 短超时
            if (packet) {
                SyncItem item;
                item.packet = packet;
                item.streamIndex = pair.first;
                item.timestamp = (packet->dts != AV_NOPTS_VALUE) ? packet->dts : packet->pts;
                items.push_back(item);
            }
        }
    }
    
    if (items.empty()) {
        return nullptr;
    }
    
    // 按时间戳排序
    std::sort(items.begin(), items.end(), [](const SyncItem& a, const SyncItem& b) {
        return a.timestamp < b.timestamp;
    });
    
    // 返回时间戳最小的包
    AVPacket* result = items[0].packet;
    
    // 将其余包放入同步队列
    for (size_t i = 1; i < items.size(); ++i) {
        syncQueue_.push(items[i]);
    }
    
    return result;
}

std::vector<AVPacket*> MultiStreamPacketQueue::dequeueSynchronizedBatch(size_t maxCount) {
    std::vector<AVPacket*> packets;
    
    for (size_t i = 0; i < maxCount; ++i) {
        AVPacket* packet = dequeueSynchronized();
        if (!packet) {
            break;
        }
        packets.push_back(packet);
    }
    
    return packets;
}

void MultiStreamPacketQueue::clear() {
    std::unique_lock<std::shared_mutex> lock(streamsMutex_);
    
    for (auto& pair : streamQueues_) {
        pair.second->clear();
    }
    
    // 清空同步队列
    std::lock_guard<std::mutex> syncLock(syncMutex_);
    while (!syncQueue_.empty()) {
        SyncItem item = syncQueue_.top();
        syncQueue_.pop();
        if (item.packet) {
            av_packet_free(&item.packet);
        }
    }
    
    Logger::instance().debug("All stream queues cleared");
}

void MultiStreamPacketQueue::clearStream(int streamIndex) {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    auto it = streamQueues_.find(streamIndex);
    if (it != streamQueues_.end()) {
        it->second->clear();
        Logger::instance().debugf("Stream {} queue cleared", streamIndex);
    }
}

void MultiStreamPacketQueue::flush() {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    for (auto& pair : streamQueues_) {
        pair.second->flush();
    }
    
    Logger::instance().debug("All stream queues flushed");
}

void MultiStreamPacketQueue::flushStream(int streamIndex) {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    auto it = streamQueues_.find(streamIndex);
    if (it != streamQueues_.end()) {
        it->second->flush();
        Logger::instance().debugf("Stream {} queue flushed", streamIndex);
    }
}

size_t MultiStreamPacketQueue::size() const {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    size_t totalSize = 0;
    for (const auto& pair : streamQueues_) {
        totalSize += pair.second->size();
    }
    
    return totalSize;
}

size_t MultiStreamPacketQueue::size(int streamIndex) const {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    auto it = streamQueues_.find(streamIndex);
    if (it != streamQueues_.end()) {
        return it->second->size();
    }
    
    return 0;
}

size_t MultiStreamPacketQueue::bytes() const {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    size_t totalBytes = 0;
    for (const auto& pair : streamQueues_) {
        totalBytes += pair.second->bytes();
    }
    
    return totalBytes;
}

size_t MultiStreamPacketQueue::bytes(int streamIndex) const {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    auto it = streamQueues_.find(streamIndex);
    if (it != streamQueues_.end()) {
        return it->second->bytes();
    }
    
    return 0;
}

bool MultiStreamPacketQueue::empty() const {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    for (const auto& pair : streamQueues_) {
        if (!pair.second->empty()) {
            return false;
        }
    }
    
    return true;
}

bool MultiStreamPacketQueue::empty(int streamIndex) const {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    auto it = streamQueues_.find(streamIndex);
    if (it != streamQueues_.end()) {
        return it->second->empty();
    }
    
    return true;
}

std::map<int, PacketQueueStats> MultiStreamPacketQueue::getAllStats() const {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    std::map<int, PacketQueueStats> allStats;
    for (const auto& pair : streamQueues_) {
        allStats[pair.first] = pair.second->getStats();
    }
    
    return allStats;
}

PacketQueueStats MultiStreamPacketQueue::getStats(int streamIndex) const {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    auto it = streamQueues_.find(streamIndex);
    if (it != streamQueues_.end()) {
        return it->second->getStats();
    }
    
    return PacketQueueStats();
}

void MultiStreamPacketQueue::resetStats() {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    for (auto& pair : streamQueues_) {
        pair.second->resetStats();
    }
    
    Logger::instance().debug("All stream queue stats reset");
}

void MultiStreamPacketQueue::resetStats(int streamIndex) {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    auto it = streamQueues_.find(streamIndex);
    if (it != streamQueues_.end()) {
        it->second->resetStats();
        Logger::instance().debugf("Stream {} queue stats reset", streamIndex);
    }
}

void MultiStreamPacketQueue::setBlocking(bool blocking) {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    for (auto& pair : streamQueues_) {
        pair.second->setBlocking(blocking);
    }
    
    Logger::instance().debugf("All stream queues blocking mode: {}", blocking);
}

void MultiStreamPacketQueue::wakeupAll() {
    std::shared_lock<std::shared_mutex> lock(streamsMutex_);
    
    for (auto& pair : streamQueues_) {
        pair.second->wakeup();
    }
}

// 工厂类实现
std::unique_ptr<PacketQueue> PacketQueueFactory::createStandardQueue(size_t maxSize) {
    PacketQueueConfig config;
    config.maxSize = maxSize;
    config.dropOnFull = true;
    config.dropOldest = true;
    config.timeoutMs = 1000;
    config.enableStats = true;
    
    return std::make_unique<PacketQueue>(config);
}

std::unique_ptr<PacketQueue> PacketQueueFactory::createLowLatencyQueue(size_t maxSize) {
    PacketQueueConfig config;
    config.maxSize = maxSize;
    config.dropOnFull = true;
    config.dropOldest = true;
    config.timeoutMs = 100;
    config.enableStats = true;
    config.enablePacketDrop = true;
    config.maxLatency = 100.0;
    config.dropRatio = 3;
    
    return std::make_unique<PacketQueue>(config);
}

std::unique_ptr<PacketQueue> PacketQueueFactory::createHighCapacityQueue(size_t maxSize) {
    PacketQueueConfig config;
    config.maxSize = maxSize;
    config.maxBytes = 200 * 1024 * 1024; // 200MB
    config.dropOnFull = false; // 不丢包，等待
    config.dropOldest = true;
    config.timeoutMs = 5000;
    config.enableStats = true;
    config.enablePacketDrop = false;
    
    return std::make_unique<PacketQueue>(config);
}

std::unique_ptr<PacketQueue> PacketQueueFactory::createRealtimeQueue(size_t maxSize, double maxLatency) {
    PacketQueueConfig config;
    config.maxSize = maxSize;
    config.dropOnFull = true;
    config.dropOldest = true;
    config.timeoutMs = 50;
    config.enableStats = true;
    config.enablePacketDrop = true;
    config.maxLatency = maxLatency;
    config.dropRatio = 2;
    config.dropNonKeyPackets = true;
    
    return std::make_unique<PacketQueue>(config);
}

std::unique_ptr<PacketQueue> PacketQueueFactory::createPriorityQueue(size_t maxSize) {
    PacketQueueConfig config;
    config.maxSize = maxSize;
    config.priorityQueue = true;
    config.dropOnFull = true;
    config.dropOldest = true;
    config.timeoutMs = 1000;
    config.enableStats = true;
    
    return std::make_unique<PacketQueue>(config);
}

std::unique_ptr<MultiStreamPacketQueue> PacketQueueFactory::createMultiStreamQueue(const PacketQueueConfig& config) {
    return std::make_unique<MultiStreamPacketQueue>(config);
}

} // namespace utils
} // namespace av