// rtmp_manager.cpp
#include "rtmp_manager.hpp"

#include <chrono>
#include <iostream>
#include <thread>

#include "logger.hpp"

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

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;
}

int get_camera_index(const std::string &name)
{
    for (size_t i = 0; i < g_app_config.cameras.size(); ++i)
        if (g_app_config.cameras[i].name == name) return static_cast<int>(i);
    return -1;
}

// Start camera, return result info (不再 publish)
RTMPManager::StreamResultInfo RTMPManager::start_camera(const Camera &cam, StreamType type)
{
    StreamResultInfo res;
    res.loc = get_camera_index(cam.name);
    res.url = get_stream_url(cam.name, type);

    std::string key = make_stream_key(cam.name, type);
    auto ctx = std::make_unique<StreamContext>();
    StreamContext *ctx_ptr = ctx.get();

    {
        std::lock_guard<std::mutex> lock(streams_mutex);
        auto it = streams.find(key);
        if (it != streams.end() && it->second->running.load())
        {
            res.result = 0;
            res.reason = "Already streaming";
            return res;
        }

        ctx->running.store(true);
        streams[key] = std::move(ctx);
    }

    std::future<StreamResultInfo> fut = ctx_ptr->start_result.get_future();

    ctx_ptr->thread = std::thread([cam, type, ctx_ptr]() { RTMPManager::stream_loop(cam, type, ctx_ptr); });

    if (fut.wait_for(std::chrono::seconds(5)) == std::future_status::ready)
    {
        res = fut.get();
    }
    else
    {
        res.result = 1;
        res.reason = "Start timeout";
    }

    return res;
}

// Stop camera, return result info (不再 publish)
RTMPManager::StreamResultInfo RTMPManager::stop_camera(const std::string &cam_name, StreamType type)
{
    StreamResultInfo res;
    res.loc = get_camera_index(cam_name);
    res.url = get_stream_url(cam_name, type);

    std::unique_ptr<StreamContext> ctx;
    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())
        {
            res.result = 0;
            res.reason = "Not streaming";
            return res;
        }

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

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

    res.result = 0;
    res.reason = "Stopped manually";
    return res;
}

void RTMPManager::stream_loop(Camera cam, StreamType type, StreamContext *ctx)
{
    constexpr int FIRST_FRAME_TIMEOUT_SEC = 5;

    StreamResultInfo res;
    res.loc = get_camera_index(cam.name);
    res.url = get_stream_url(cam.name, type);

    std::string key = make_stream_key(cam.name, type);
    LOG_INFO("[RTMP] Stream loop started for " + key);

    GstElement *pipeline = create_pipeline(cam, type);
    if (!pipeline)
    {
        res.result = 1;
        res.reason = "Failed to create pipeline";
        ctx->start_result.set_value(res);
        return;
    }

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

    bool first_frame_received = false;
    auto start_time = std::chrono::steady_clock::now();

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

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

        // 超时未收到第一帧
        if (!first_frame_received)
        {
            auto elapsed = std::chrono::steady_clock::now() - start_time;
            if (std::chrono::duration_cast<std::chrono::seconds>(elapsed).count() > FIRST_FRAME_TIMEOUT_SEC)
            {
                res.result = 1;
                res.reason = "No frames received within timeout";
                ctx->start_result.set_value(res);
                break;
            }
        }

        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";
                res.result = 1;
                res.reason = "Pipeline error: " + err_msg;
                ctx->start_result.set_value(res);
                if (err) g_error_free(err);
                if (debug) g_free(debug);
                break;
            }
            case GST_MESSAGE_EOS:
                res.result = 1;
                res.reason = "EOS received";
                ctx->start_result.set_value(res);
                break;
            case GST_MESSAGE_STATE_CHANGED:
                // pipeline 播放状态变化，不算成功
                break;
            case GST_MESSAGE_ELEMENT:
                if (!first_frame_received)
                {
                    first_frame_received = true;
                    res.result = 0;
                    res.reason = "First frame received, started OK";
                    ctx->start_result.set_value(res);
                }
                break;
            default:
                break;
        }

        gst_message_unref(msg);
    }

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

    // 清理 streams
    {
        std::lock_guard<std::mutex> lock(streams_mutex);
        streams.erase(key);
    }

    LOG_INFO("[RTMP] Stream loop ended for " + key);
}

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;
}

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.");
}