#include <gtest/gtest.h>
#include <mcp/core/runtime/Gallery_Plots.hpp>
#include <render_common.hpp>
#include <web_server/src/media/Gallery_Video_Stream.hpp>
#include <array>
#include <atomic>
#include <chrono>
#include <ranges>
#include <stdexcept>
#include <string>

namespace aethera::web::media {
namespace {

using Clock = std::chrono::steady_clock;

void corun_until_or_throw(std::string_view operation,
                          const std::function<bool()>& completed) {
    std::string failure;
    Task_Graph coordinator{"gallery.video.test.await"};
    coordinator.add("await", [&] {
        const auto deadline = Clock::now() + std::chrono::seconds{10};
        Task_Graph::corun_until([&] {
            if (completed()) return true;
            if (Clock::now() < deadline) return false;
            failure = std::string{operation} + " timed out";
            return true;
        });
    });
    aethera::detail::run_taskflow(coordinator);
    if (!failure.empty()) throw std::runtime_error(failure);
}

void configure_manual_pixel_delivery(const std::shared_ptr<Plot>& plot) {
    ASSERT_TRUE(plot);
    ASSERT_TRUE(plot->write_prop(
        "frame-analysis", "pacing_mode", "manual").value(
            "success", false));
    ASSERT_TRUE(plot->write_prop(
        "frame-analysis", "pixel_delivery_enabled", true).value(
            "success", false));
    ASSERT_NO_THROW(corun_until_or_throw("manual Plot policy", [&] {
        const auto diagnostics = plot->diagnostics();
        const auto& configuration = diagnostics.at("frame_policy").at(
            "configuration");
        return configuration.at("mode") == "manual" &&
            configuration.at("pixel_delivery_enabled").get<bool>();
    }));
}

void schedule_manual_frame(const std::shared_ptr<Plot>& plot,
                           std::uint64_t correlation_sequence) {
    const auto now = Clock::now();
    plot->schedule_render(Plot_Render_Tick{
        .issued_at = now,
        .sequence = correlation_sequence,
        .time_milliseconds =
            std::chrono::duration<double, std::milli>(
                now.time_since_epoch()).count(),
        .width = 720,
        .height = 420,
        .source = Frame_Request_Source::immediate
    });
}

TEST(Gallery_Video_Stream,
     Encodes_Each_Plots_Independent_Policy_Frames_Without_Grouping) {
    const auto definitions = gallery_plot_definitions();
    const auto found = std::ranges::find_if(
        definitions, [](const Plot_Definition& definition) {
            return definition.dimension == Plot_Dimension::two_d;
        });
    ASSERT_NE(found, definitions.end());
    auto plot_a = found->create();
    auto plot_b = found->create();
    configure_manual_pixel_delivery(plot_a);
    configure_manual_pixel_delivery(plot_b);

    auto stream = Gallery_Video_Stream::create({
        {"plot-a", plot_a}, {"plot-b", plot_b}});
    ASSERT_TRUE(stream);
    constexpr std::size_t frame_count{5};
    std::array<std::atomic_uint64_t, frame_count> sequences{};
    std::atomic_size_t received{};
    const auto subscription = stream->subscribe(
        "gallery-video-test",
        [&](Gallery_Stream_Frame frame) {
            if (!frame.video) return;
            const auto index = received.fetch_add(
                1, std::memory_order_acq_rel);
            if (index < sequences.size())
                sequences[index].store(
                    frame.video->sequence, std::memory_order_release);
        },
        [] { return true; },
        [] { return nlohmann::json::object(); });

    const std::array<std::shared_ptr<Plot>, frame_count> schedule{
        plot_a, plot_a, plot_b, plot_a, plot_b};
    for (std::size_t index = 0; index < schedule.size(); ++index) {
        schedule_manual_frame(schedule[index], index + 1U);
        ASSERT_NO_THROW(corun_until_or_throw("encoded Plot frame", [&] {
            return received.load(std::memory_order_acquire) > index;
        }));
    }

    EXPECT_EQ(received.load(std::memory_order_acquire), frame_count);
    for (std::size_t index = 0; index < frame_count; ++index)
        EXPECT_EQ(sequences[index].load(std::memory_order_acquire),
                  index + 1U);
    const auto diagnostics = stream->diagnostics();
    EXPECT_EQ(diagnostics.at("received_frame_count"), frame_count);
    EXPECT_EQ(diagnostics.at("processed_frame_count"), frame_count);
    EXPECT_EQ(diagnostics.at("encoded_frame_count"), frame_count);
    EXPECT_EQ(diagnostics.at("pending_frame_count"), 0U);

    stream->unsubscribe(subscription);
    stream->shutdown();
}

}
}