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

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

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.");
}

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, height = cam.height, fps = cam.fps, 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::publish_stream_status(const std::string &cam_name, StreamType type, const std::string &seqNo, bool ok, const std::string &reason)
{
    // 找 camera index
    int cam_index = -1;
    Camera *cam_ptr = nullptr;
    for (size_t i = 0; i < g_app_config.cameras.size(); ++i)
    {
        if (g_app_config.cameras[i].name == cam_name)
        {
            cam_index = static_cast<int>(i);
            cam_ptr = &g_app_config.cameras[i];
            break;
        }
    }

    nlohmann::json ch_resp;
    ch_resp["loc"] = cam_index;
    ch_resp["url"] = ok && cam_ptr ? get_stream_url(cam_ptr->name, type) : "";
    ch_resp["result"] = ok ? 0 : 1;
    ch_resp["reason"] = reason;

    nlohmann::json reply;
    reply["type"] = "response";
    reply["seqNo"] = seqNo;
    reply["data"] = nlohmann::json::array({ch_resp});

    mqtt_client->publish(g_app_config.mqtt.topics.video_down, reply.dump());
}

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

    const int MAX_RETRIES = 3;
    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)
        {
            std::string reason = "Failed to create pipeline (device unavailable or resolution unsupported)";
            update_status(key, {false, StreamResult::PIPELINE_ERROR, reason});
            publish_stream_status(cam.name, type, seqNo, false, reason);
            if (++retry_count > MAX_RETRIES)
                break;
            std::this_thread::sleep_for(std::chrono::seconds(1));
            continue;
        }

        GstBus *bus = gst_element_get_bus(pipeline);
        gst_element_set_state(pipeline, GST_STATE_PLAYING);

        bool first_frame_received = false;
        bool stop_flag = false;

        const int FIRST_FRAME_TIMEOUT_SEC = 5; // 等待第一帧最大秒数
        auto first_frame_start = std::chrono::steady_clock::now();

        while (!stop_flag)
        {
            GstMessage *msg = gst_bus_timed_pop_filtered(
                bus, 100 * GST_MSECOND,
                static_cast<GstMessageType>(GST_MESSAGE_ERROR | GST_MESSAGE_EOS | GST_MESSAGE_STATE_CHANGED));

            {
                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 (!first_frame_received)
            {
                auto elapsed = std::chrono::steady_clock::now() - first_frame_start;
                if (std::chrono::duration_cast<std::chrono::seconds>(elapsed).count() > FIRST_FRAME_TIMEOUT_SEC)
                {
                    std::string reason = "No frames received within timeout";
                    LOG_WARN("[RTMP] " + key + ": " + reason);
                    update_status(key, {false, StreamResult::TIMEOUT, reason});
                    publish_stream_status(cam.name, type, seqNo, false, reason);
                    stop_flag = true;
                }
            }

            if (!msg)
                continue;

            switch (GST_MESSAGE_TYPE(msg))
            {
            case 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});
                publish_stream_status(cam.name, type, seqNo, false, err_msg);
                if (err)
                    g_error_free(err);
                if (debug)
                    g_free(debug);
                stop_flag = true;
                break;
            }
            case GST_MESSAGE_EOS:
                LOG_WARN("[RTMP] EOS on " + key);
                update_status(key, {false, StreamResult::EOS_RECEIVED, "EOS"});
                publish_stream_status(cam.name, type, seqNo, false, "EOS received");
                stop_flag = true;
                break;
            case GST_MESSAGE_STATE_CHANGED:
            {
                GstState old_state, new_state;
                gst_message_parse_state_changed(msg, &old_state, &new_state, nullptr);
                if (GST_MESSAGE_SRC(msg) == GST_OBJECT(pipeline) && new_state == GST_STATE_PLAYING && !first_frame_received)
                {
                    first_frame_received = true;
                    LOG_INFO("[RTMP] First frame received for " + key);
                    update_status(key, {true, StreamResult::OK, ""});
                    publish_stream_status(cam.name, type, seqNo, true, "Streaming OK");
                }
                break;
            }
            }

            gst_message_unref(msg);
        }

        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;
        }

        std::this_thread::sleep_for(std::chrono::seconds(1));
    }

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

// 修改 start_camera，新增 seqNo 参数
void RTMPManager::start_camera(const Camera &cam, StreamType type, const std::string &seqNo)
{
    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.");
        // 上报已经在请求状态
        publish_stream_status(cam.name, type, seqNo, false, "Already streaming");
        return;
    }

    auto ctx = std::make_unique<StreamContext>();
    ctx->running.store(true);
    ctx->thread = std::thread([cam, type, seqNo]()
                              {
                                  stream_loop(cam, type, seqNo); // stream_loop 内部处理 MQTT 上报
                              });

    streams[key] = std::move(ctx);
    LOG_INFO("[RTMP] start_camera requested for " + key);
}

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

    {
        std::lock_guard<std::mutex> lock(streams_mutex);
        auto it = streams.find(key);
        if (it == streams.end())
        {
            LOG_WARN("[RTMP] " + key + " not found.");
            // 上报停止失败（未找到）
            publish_stream_status(cam_name, type, seqNo, false, "Stream not found");
            return;
        }

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

    if (ctx->thread.joinable())
        ctx->thread.join();

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

    // MQTT 上报手动停止成功
    publish_stream_status(cam_name, type, seqNo, true, "Stopped manually");
}

void RTMPManager::stop_all()
{
    std::vector<std::unique_ptr<StreamContext>> ctxs;

    {
        std::lock_guard<std::mutex> lock(streams_mutex);
        for (auto &kv : streams)
            kv.second->running.store(false);
        for (auto &kv : streams)
            ctxs.push_back(std::move(kv.second));
        streams.clear();
    }

    for (auto &ctx : ctxs)
        if (ctx->thread.joinable())
            ctx->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 it = streams.find(make_stream_key(cam_name, type));
    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);
}