// rtsp_manager.cpp
#include "rtmp_manager.hpp"
#include "logger.hpp"
#include <chrono>
#include <thread>
#include <iostream>
#include <algorithm>
#include <utility> // for move
#include <memory>

std::unordered_map<std::string, std::unique_ptr<RTMPManager::StreamContext>> RTMPManager::streams;
std::mutex RTMPManager::streams_mutex;
RTMPManager::StreamCallback RTMPManager::status_callback = nullptr;

static inline std::string stream_type_suffix(StreamType type)
{
    return (type == StreamType::MAIN) ? "_main" : "_sub";
}

std::string RTMPManager::make_stream_key(const std::string &cam_name, StreamType type)
{
    return cam_name + stream_type_suffix(type);
}

void RTMPManager::init()
{
    gst_init(nullptr, nullptr);
    LOG_INFO("[RTMP] GStreamer initialized.");

    // 启动 stop_worker_thread
    stop_thread_running.store(true);
    stop_thread = std::thread([]
                              {
        while (stop_thread_running.load())
        {
            std::unique_ptr<StreamContext> ctx;
            {
                std::unique_lock<std::mutex> lock(RTMPManager::stop_queue_mutex);
                RTMPManager::stop_cv.wait(lock, []{
                    return !RTMPManager::stop_queue.empty() || !RTMPManager::stop_thread_running.load();
                });
                if (!RTMPManager::stop_queue.empty())
                {
                    ctx = std::move(RTMPManager::stop_queue.front());
                    RTMPManager::stop_queue.pop();
                }
            }
            if (ctx && ctx->thread.joinable())
            {
                ctx->thread.join();
                LOG_INFO("[RTMP] Stream thread joined asynchronously");
            }
        } });
}

void RTMPManager::set_status_callback(StreamCallback cb)
{
    status_callback = std::move(cb);
}

void RTMPManager::update_status(const std::string &key, const StreamStatus &status)
{
    {
        std::lock_guard<std::mutex> lock(streams_mutex);
        auto it = streams.find(key);
        if (it != streams.end())
            it->second->status = status;
    }
    if (status_callback)
        status_callback(key, status);
}

GstElement *RTMPManager::create_pipeline(const Camera &cam, StreamType type)
{
    int width = cam.width;
    int height = cam.height;
    int fps = cam.fps;
    int bitrate = cam.bitrate;

    if (type == StreamType::SUB)
    {
        width = std::max(160, width / 2);
        height = std::max(120, height / 2);
        fps = std::max(10, fps / 2);
        bitrate = std::max(300000, bitrate / 2);
    }

    std::string stream_name = cam.name + stream_type_suffix(type);
    std::string pipeline_str =
        "v4l2src device=" + cam.device +
        " ! video/x-raw,format=NV12,width=" + std::to_string(width) +
        ",height=" + std::to_string(height) +
        ",framerate=" + std::to_string(fps) +
        "/1 ! queue max-size-buffers=1 leaky=downstream "
        "! mpph264enc bps=" +
        std::to_string(bitrate) +
        " gop=" + std::to_string(fps) +
        " ! h264parse ! flvmux streamable=true name=mux "
        "! rtmpsink location=\"rtmp://127.0.0.1/live/" +
        stream_name + " live=1\" sync=false";

    LOG_INFO("[RTMP] Creating pipeline for '" + stream_name + "': " + pipeline_str);

    GError *error = nullptr;
    GstElement *pipeline = gst_parse_launch(pipeline_str.c_str(), &error);
    if (error)
    {
        LOG_ERROR("[RTMP] Pipeline parse error: " + std::string(error->message));
        g_error_free(error);
        return nullptr;
    }
    return pipeline;
}

void RTMPManager::stream_loop(Camera cam, StreamType type)
{
    const std::string key = make_stream_key(cam.name, type);
    LOG_INFO("[RTMP] Stream loop started for " + key);

    const int MAX_RETRIES = 5;
    int retry_count = 0;

    while (true)
    {
        {
            std::lock_guard<std::mutex> lock(streams_mutex);
            auto it = streams.find(key);
            if (it == streams.end() || !it->second->running.load())
                break;
        }

        GstElement *pipeline = create_pipeline(cam, type);
        if (!pipeline)
        {
            update_status(key, {false, StreamResult::PIPELINE_ERROR, "Failed to create pipeline"});
            std::this_thread::sleep_for(std::chrono::seconds(3));
            if (++retry_count > MAX_RETRIES)
                break;
            continue;
        }

        GstBus *bus = gst_element_get_bus(pipeline);
        gst_element_set_state(pipeline, GST_STATE_PLAYING);
        update_status(key, {true, StreamResult::OK, ""});
        LOG_INFO("[RTMP] " + key + " is streaming.");

        bool stop_flag = false;
        GstMessage *msg = nullptr;

        while (true)
        {
            msg = gst_bus_timed_pop_filtered(
                bus, GST_CLOCK_TIME_NONE,
                static_cast<GstMessageType>(GST_MESSAGE_ERROR | GST_MESSAGE_EOS));

            {
                std::lock_guard<std::mutex> lock(streams_mutex);
                auto it = streams.find(key);
                if (it == streams.end() || !it->second->running.load())
                {
                    stop_flag = true;
                    break;
                }
            }

            if (!msg)
                continue;

            if (GST_MESSAGE_TYPE(msg) == GST_MESSAGE_ERROR)
            {
                GError *err = nullptr;
                gchar *debug = nullptr;
                gst_message_parse_error(msg, &err, &debug);
                std::string err_msg = err ? err->message : "Unknown GStreamer error";
                LOG_ERROR("[RTMP] Error in " + key + ": " + err_msg);
                update_status(key, {false, StreamResult::CONNECTION_FAIL, err_msg});
                if (err)
                    g_error_free(err);
                if (debug)
                    g_free(debug);
                stop_flag = true;
            }
            else if (GST_MESSAGE_TYPE(msg) == GST_MESSAGE_EOS)
            {
                LOG_WARN("[RTMP] EOS on " + key);
                update_status(key, {false, StreamResult::EOS_RECEIVED, "EOS"});
                stop_flag = true;
            }

            gst_message_unref(msg);
            if (stop_flag)
                break;
        }

        gst_element_set_state(pipeline, GST_STATE_NULL);
        if (bus)
            gst_object_unref(bus);
        gst_object_unref(pipeline);

        if (!stop_flag)
            break;

        if (++retry_count > MAX_RETRIES)
        {
            LOG_ERROR("[RTMP] " + key + " reached max retries. Giving up.");
            break;
        }

        LOG_WARN("[RTMP] Reconnecting " + key + " in 3s...");
        std::this_thread::sleep_for(std::chrono::seconds(3));
    }

    update_status(key, {false, StreamResult::UNKNOWN, "Stream loop exited"});
    LOG_INFO("[RTMP] Stream loop ended for " + key);
}

void RTMPManager::start_camera(const Camera &cam, StreamType type)
{
    std::string key = make_stream_key(cam.name, type);
    {
        std::lock_guard<std::mutex> lock(streams_mutex);
        auto it = streams.find(key);
        if (it != streams.end() && it->second->running.load())
        {
            LOG_WARN("[RTMP] " + key + " already streaming.");
            return;
        }

        // create a new context on heap and keep a unique_ptr in map
        auto ctx = std::make_unique<StreamContext>();
        ctx->running.store(true);
        ctx->status = {true, StreamResult::OK, ""};

        // start thread after moving unique_ptr into map (to avoid racing)
        // insert placeholder first to reserve key, then start thread
        streams.emplace(key, std::move(ctx));
    }

    // actually start thread outside the lock (we need to get pointer again)
    {
        std::lock_guard<std::mutex> lock(streams_mutex);
        auto it = streams.find(key);
        if (it != streams.end())
        {
            // start the thread that runs stream_loop; capture cam and type by value
            it->second->thread = std::thread([cam, type]()
                                             { stream_loop(cam, type); });
        }
    }

    LOG_INFO("[RTMP] start_camera requested for " + key);
}

void RTMPManager::stop_camera(const std::string &cam_name, StreamType type)
{
    std::string key = make_stream_key(cam_name, type);
    std::unique_ptr<StreamContext> taken_ctx;

    {
        std::lock_guard<std::mutex> lock(streams_mutex);
        auto it = streams.find(key);
        if (it == streams.end())
        {
            LOG_WARN("[RTMP] " + key + " not found.");
            return;
        }

        it->second->running.store(false);
        taken_ctx = std::move(it->second);
        streams.erase(it);
    }

    // 异步加入 stop 队列，由 stop_worker_thread join
    if (taken_ctx)
    {
        {
            std::lock_guard<std::mutex> lock(stop_queue_mutex);
            stop_queue.push(std::move(taken_ctx));
        }
        stop_cv.notify_one();
    }

    update_status(key, {false, StreamResult::OK, "Stopped manually"});
    LOG_INFO("[RTMP] stop_camera queued for async stop: " + key);
}

void RTMPManager::stop_all()
{
    std::vector<std::unique_ptr<StreamContext>> taken;
    std::vector<std::string> keys;

    {
        std::lock_guard<std::mutex> lock(streams_mutex);
        for (auto &kv : streams)
        {
            keys.push_back(kv.first);
            kv.second->running.store(false);
        }
        // move all contexts out
        for (auto &k : keys)
        {
            auto it = streams.find(k);
            if (it != streams.end())
                taken.push_back(std::move(it->second));
            streams.erase(k);
        }
    }

    // join threads
    for (size_t i = 0; i < taken.size(); ++i)
    {
        if (taken[i] && taken[i]->thread.joinable())
            taken[i]->thread.join();
    }

    LOG_INFO("[RTMP] stop_all completed.");
}

bool RTMPManager::is_streaming(const std::string &cam_name, StreamType type)
{
    std::lock_guard<std::mutex> lock(streams_mutex);
    auto key = make_stream_key(cam_name, type);
    auto it = streams.find(key);
    return it != streams.end() && it->second->running.load();
}

bool RTMPManager::is_any_streaming()
{
    std::lock_guard<std::mutex> lock(streams_mutex);
    for (auto &kv : streams)
        if (kv.second->running.load())
            return true;
    return false;
}

std::string RTMPManager::get_stream_url(const std::string &cam_name, StreamType type)
{
    return "rtmp://127.0.0.1/live/" + make_stream_key(cam_name, type);
}