#include "Plot.hpp"
#include "Renderable_Adapter.hpp"
#include <asio/co_spawn.hpp>
#include <asio/error_code.hpp>
#include <asio/experimental/concurrent_channel.hpp>
#include <asio/post.hpp>
#include <asio/redirect_error.hpp>
#include <asio/strand.hpp>
#include <asio/use_awaitable.hpp>
#include <render_2D/plottable/Plottables.hpp>
#include <render_3D/Render_3D.hpp>
#include <magic_enum/magic_enum.hpp>
#include <algorithm>
#include <array>
#include <cmath>
#include <deque>
#include <memory>
#include <mutex>
#include <numbers>
#include <stdexcept>
#include <tuple>
#include <unordered_map>
#include <utility>
#include <variant>
#include <vector>
namespace aethera::web {
namespace {
using namespace render_2d;
using namespace render_3d;
using Scene_2D = Impl<Render_Scene_2D>;
using Scene_3D = Impl<Render_Scene_3D>;
using Frequency_Axis_Object = Impl<Frequency_Axis>;
using Numeric_Axis_Object = Impl<Numeric_Axis>;
using Time_Axis_Object = Impl<Time_Axis>;
using Selection_Object = Impl<Selection_Rectangle_Overlay>;
constexpr std::uint16_t frame_protocol_version{4};
enum class Frame_Pacing_Mode : std::uint32_t {
    manual,
    fixed_rate,
    minimum_latency,
    maximum_rate
};
struct Frame_Pacing_Properties {
    Frame_Pacing_Mode mode{Frame_Pacing_Mode::fixed_rate}; /* 控制后继 render 请求节奏的策略。 */
    double fixed_rate_fps{30.0}; /* 固定频率策略的目标帧率，单位为 FPS。 */
    double minimum_latency_headroom{1.25}; /* 最低延迟策略相对 P95 生成耗时的安全系数。 */
};
class Frame_Policy final {
public:
    [[nodiscard]] Frame_Pacing_Properties snapshot() const;
    [[nodiscard]] nlohmann::json schema() const;
    [[nodiscard]] nlohmann::json write_prop(std::string_view key, const nlohmann::json& value);
private:
    mutable std::mutex mutex; /* 保护异步帧发布与 HTTP 属性编辑读取。 */
    Frame_Pacing_Properties pacing{}; /* 可编辑帧调度属性的唯一权威来源。 */
};
std::string_view pacing_mode_name(Frame_Pacing_Mode mode) {
    switch (mode) {
    case Frame_Pacing_Mode::manual: return "manual";
    case Frame_Pacing_Mode::fixed_rate: return "fixed_rate";
    case Frame_Pacing_Mode::minimum_latency: return "minimum_latency";
    case Frame_Pacing_Mode::maximum_rate: return "maximum_rate";
    }
    throw std::logic_error("unknown frame pacing mode");
}
std::optional<Frame_Pacing_Mode> parse_pacing_mode(std::string_view value) {
    if (value == "manual") return Frame_Pacing_Mode::manual;
    if (value == "fixed_rate") return Frame_Pacing_Mode::fixed_rate;
    if (value == "minimum_latency") return Frame_Pacing_Mode::minimum_latency;
    if (value == "maximum_rate") return Frame_Pacing_Mode::maximum_rate;
    return std::nullopt;
}
Frame_Pacing_Properties Frame_Policy::snapshot() const {
    std::lock_guard lock(mutex);
    return pacing;
}
nlohmann::json Frame_Policy::schema() const {
    std::lock_guard lock(mutex);
    nlohmann::json fields = nlohmann::json::array();
    fields.push_back({{"key", "pacing_mode"}, {"label", "帧刷新策略"}, {"editor", "select"}, {"editable", true}, {"description", "选择浏览器如何安排下一次 render 调用。"}, {"technical_description", "Controls client-side render cadence using end-to-end samples computed by the browser."}, {"value", pacing_mode_name(pacing.mode)}, {"options", nlohmann::json::array({{{"value", "manual"}, {"label", "手动刷新"}}, {{"value", "fixed_rate"}, {"label", "固定频率"}}, {{"value", "minimum_latency"}, {"label", "最低延迟"}}, {{"value", "maximum_rate"}, {"label", "最高频率"}}})}});
    fields.push_back({{"key", "fixed_rate_fps"}, {"label", "固定目标帧率"}, {"editor", "number"}, {"editable", true}, {"description", "固定频率策略下每秒发起的 render 次数。"}, {"technical_description", "Target render request rate used by fixed_rate pacing, in frames per second."}, {"value", pacing.fixed_rate_fps}});
    fields.push_back({{"key", "minimum_latency_headroom"}, {"label", "最低延迟余量"}, {"editor", "number"}, {"editable", true}, {"description", "最低延迟策略使用的浏览器端 P95 端到端耗时安全系数。"}, {"technical_description", "Multiplier applied to browser-computed P95 request-to-pixel latency before scheduling the next render request."}, {"value", pacing.minimum_latency_headroom}});
    return {{"id", "frame-runtime"}, {"label", "帧策略与诊断"}, {"kind", "runtime"}, {"fields", std::move(fields)}, {"state", nlohmann::json::object()}};
}
nlohmann::json Frame_Policy::write_prop(std::string_view key, const nlohmann::json& value) {
    std::lock_guard lock(mutex);
    if (key == "pacing_mode") {
        if (!value.is_string()) return {{"success", false}, {"error", "pacing_mode requires a string"}};
        const auto parsed = parse_pacing_mode(value.get_ref<const std::string&>());
        if (!parsed) return {{"success", false}, {"error", "unknown frame pacing mode"}};
        pacing.mode = *parsed;
        return {{"success", true}, {"component", "frame-runtime"}, {"key", key}, {"value", pacing_mode_name(pacing.mode)}};
    }
    if (key == "fixed_rate_fps") {
        if (!value.is_number()) return {{"success", false}, {"error", "fixed_rate_fps requires a number"}};
        const double next = value.get<double>();
        if (!std::isfinite(next) || next < 0.1 || next > 240.0) return {{"success", false}, {"error", "fixed_rate_fps must be between 0.1 and 240"}};
        pacing.fixed_rate_fps = next;
        return {{"success", true}, {"component", "frame-runtime"}, {"key", key}, {"value", pacing.fixed_rate_fps}};
    }
    if (key == "minimum_latency_headroom") {
        if (!value.is_number()) return {{"success", false}, {"error", "minimum_latency_headroom requires a number"}};
        const double next = value.get<double>();
        if (!std::isfinite(next) || next < 1.0 || next > 4.0) return {{"success", false}, {"error", "minimum_latency_headroom must be between 1 and 4"}};
        pacing.minimum_latency_headroom = next;
        return {{"success", true}, {"component", "frame-runtime"}, {"key", key}, {"value", pacing.minimum_latency_headroom}};
    }
    return {{"success", false}, {"error", "unknown frame runtime property"}};
}
nlohmann::json frame_metadata(Render_Frame& frame, std::uint32_t width, std::uint32_t height, std::size_t byte_length, const Frame_Pacing_Properties& pacing) {
    nlohmann::json markers = nlohmann::json::object();
    for (const auto& point : frame.trace_points()) markers[std::string(magic_enum::enum_name(point.marker))] = point.elapsed_ns;
    nlohmann::json measurements = nlohmann::json::object();
    for (const auto& value : frame.trace_values()) measurements[std::string(magic_enum::enum_name(value.measurement))] = value.value_ns;
    const auto identity = frame.identity();
    return {
        {"kind", "frame_metadata"}, {"protocol", "aethera.frame"}, {"version", frame_protocol_version},
        {"sequence", identity.sequence}, {"correlation_id", identity.correlation_id},
        {"created_time_unix_ms", static_cast<double>(frame.created_time_unix_ns()) / 1'000'000.0},
        {"pixel", {{"width", width}, {"height", height}, {"format", "rgba8"}, {"byte_length", byte_length}}},
        {"pacing", {{"mode", pacing_mode_name(pacing.mode)}, {"fixed_rate_fps", pacing.fixed_rate_fps}, {"minimum_latency_headroom", pacing.minimum_latency_headroom}}},
        {"trace", {{"clock", "steady_elapsed_ns"}, {"markers", std::move(markers)}, {"measurements", std::move(measurements)}}}
    };
}
std::shared_ptr<const Plot_Frame_Message> encode_frame(Frame_2D* frame, const Frame_Pacing_Properties& pacing) {
    frame->mark(Frame_Trace_Marker::websocket_publish_started);
    const Image_View image = frame->image();
    std::string output;
    output.reserve(static_cast<std::size_t>(image.width) * image.height * 4);
    for (int y = 0; y < image.height; ++y) {
        const auto* row = reinterpret_cast<const std::uint8_t*>(
            image.data + static_cast<std::ptrdiff_t>(y) * image.stride);
        for (int x = 0; x < image.width; ++x) {
            const auto* pixel = row + x * 4;
            output.push_back(static_cast<char>(pixel[2]));
            output.push_back(static_cast<char>(pixel[1]));
            output.push_back(static_cast<char>(pixel[0]));
            output.push_back(static_cast<char>(pixel[3]));
        }
    }
    frame->mark(Frame_Trace_Marker::websocket_publish_finished);
    auto message = std::make_shared<Plot_Frame_Message>();
    message->pixels = std::move(output);
    message->metadata = frame_metadata(*frame, static_cast<std::uint32_t>(image.width), static_cast<std::uint32_t>(image.height), message->pixels.size(), pacing).dump();
    return message;
}
std::shared_ptr<const Plot_Frame_Message> encode_frame(Frame_3D* frame, const Frame_Pacing_Properties& pacing) {
    frame->mark(Frame_Trace_Marker::websocket_publish_started);
    const auto pixels = frame->pixels();
    auto message = std::make_shared<Plot_Frame_Message>();
    message->pixels.assign(reinterpret_cast<const char*>(pixels.data()), pixels.size());
    frame->mark(Frame_Trace_Marker::websocket_publish_finished);
    const auto extent = frame->extent();
    message->metadata = frame_metadata(*frame, extent.width, extent.height, message->pixels.size(), pacing).dump();
    return message;
}
struct Schema_Query {
    Plot::Json_Handler handler;
};
struct Frame_Submission {
    const void* owner{}; /* 只向发起 render 的 WebSocket 连接返回完成帧。 */
    Plot_Frame_Request request{}; /* 浏览器帧请求及关联标识。 */
};
struct Prop_Write {
    std::string component;
    std::string key;
    nlohmann::json value;
    Plot::Json_Handler handler;
};
using Plot_Input = std::variant<Frame_Submission, Schema_Query, Prop_Write>;
template <typename... Owned_Objects>
class Scene_View_Model final : public Plot::Scene_View {
public:
    Scene_View_Model(std::vector<std::unique_ptr<detail::Renderable_Descriptor>> value_descriptors,
                     std::function<void(const Plot_Frame_Request&)> value_update,
                     Owned_Objects... owned_objects) : descriptors(std::move(value_descriptors)),
                                                       update_scene(std::move(value_update)),
                                                       objects(std::move(owned_objects)...) {}
    nlohmann::json schema() const override {
        nlohmann::json components = nlohmann::json::array();
        for (const auto& descriptor : descriptors) components.push_back(descriptor->schema());
        return {{"protocol", "aethera.plot.inspector"}, {"version", 2}, {"components", std::move(components)}};
    }
    nlohmann::json write_prop(std::string_view component, std::string_view key, const nlohmann::json& value) override {
        const auto found = std::ranges::find_if(descriptors, [&](const auto& item) {
            return item->id() == component;
        });
        if (found == descriptors.end()) return {{"success", false}, {"error", "unknown component"}};
        auto result = (*found)->write_prop(key, value);
        result["component"] = component;
        return result;
    }
    void update(const Plot_Frame_Request& request) override {
        update_scene(request);
    }
private:
    std::vector<std::unique_ptr<detail::Renderable_Descriptor>> descriptors;
    std::function<void(const Plot_Frame_Request&)> update_scene;
    std::tuple<Owned_Objects...> objects;
};
template <auto Member, structive::Fixed_String Key, structive::Fixed_String Description>
using Prop_Field = detail::Prop_Field<Member, Key, Description>;
template <typename Definition, auto Member, structive::Fixed_String Key, structive::Fixed_String Description>
using State_Field = detail::State_Field<typename Definition::Base_Tag, Member, Key, Description>;
template <typename Object, typename... Fields>
std::unique_ptr<detail::Renderable_Descriptor> make_renderable_component(
    std::string id, std::string label, std::string kind, Object& object) {
    using Definition = typename Object::Attached_Object;
    using Tag = typename Definition::Base_Tag;
    using State = typename Definition::State;
    using Adapter = detail::Renderable_Adapter<Object, Fields...,
                                               detail::State_Field<Tag, &State::prepare_dirty, "prepare_dirty", "Whether source changes require the prepare stage to run again.">,
                                               detail::State_Field<Tag, &State::paint_dirty, "paint_dirty", "Whether prepared visual data requires the paint stage to run again.">,
                                               detail::State_Field<Tag, &State::prepare_executed, "prepare_executed", "Whether the prepare stage executed during the latest scene cycle.">,
                                               detail::State_Field<Tag, &State::paint_executed, "paint_executed", "Whether the paint stage executed during the latest scene cycle.">,
                                               detail::State_Field<Tag, &State::prepare_graph_rebuilt, "prepare_graph_rebuilt", "Whether the prepare task graph was rebuilt during the latest cycle.">,
                                               detail::State_Field<Tag, &State::paint_graph_rebuilt, "paint_graph_rebuilt", "Whether the paint task graph was rebuilt during the latest cycle.">,
                                               detail::State_Field<Tag, &State::prepare_task_count, "prepare_task_count", "Number of tasks in the current prepare execution graph.">,
                                               detail::State_Field<Tag, &State::paint_task_count, "paint_task_count", "Number of tasks in the current paint execution graph.">,
                                               detail::State_Field<Tag, &State::prepare_execution_time_ns, "prepare_execution_time_ns", "Measured prepare-stage execution time in nanoseconds.">,
                                               detail::State_Field<Tag, &State::paint_execution_time_ns, "paint_execution_time_ns", "Measured paint-stage execution time in nanoseconds.">>;
    return detail::make_renderable_descriptor(std::move(id), std::move(label), std::move(kind), Adapter{object});
}
template <typename Scene_Object>
std::unique_ptr<detail::Renderable_Descriptor> make_scene_component(Scene_Object& scene) {
    using Definition = typename Scene_Object::Attached_Object;
    using Prop = typename Definition::Prop;
    using Adapter = detail::Renderable_Adapter<Scene_Object,
                                               detail::Prop_Field<&Prop::viewport, "viewport", "Final scene viewport in physical pixels.">,
                                               detail::Prop_Field<&Prop::background, "background", "Scene clear color.">,
                                               detail::Prop_Field<&Prop::view_active, "view_active", "Whether the scene publishes rendered frames.">,
                                               detail::State_Field<Scene::Base_Tag, &Scene::State::taskflow_rebuilt, "taskflow_rebuilt", "Whether the scene task graph was rebuilt.">,
                                               detail::State_Field<Scene::Base_Tag, &Scene::State::renderable_count, "renderable_count", "Number of renderables attached to the scene.">,
                                               detail::State_Field<Scene::Base_Tag, &Scene::State::taskflow_task_count, "taskflow_task_count", "Number of tasks in the scene graph.">,
                                               detail::State_Field<Scene::Base_Tag, &Scene::State::taskflow_dependency_count, "taskflow_dependency_count", "Number of graph dependencies.">,
                                               detail::State_Field<Scene::Base_Tag, &Scene::State::taskflow_max_predecessors, "taskflow_max_predecessors", "Maximum direct predecessors of a task.">,
                                               detail::State_Field<Scene::Base_Tag, &Scene::State::taskflow_max_successors, "taskflow_max_successors", "Maximum direct successors of a task.">,
                                               detail::State_Field<Scene::Base_Tag, &Scene::State::taskflow_execution_time_ns, "taskflow_execution_time_ns", "Scene graph execution time in nanoseconds.">>;
    return detail::make_renderable_descriptor("scene", "场景", "scene", Adapter{scene});
}
template <>
std::unique_ptr<detail::Renderable_Descriptor> make_scene_component<Scene_3D>(Scene_3D& scene) {
    using Adapter = detail::Renderable_Adapter<Scene_3D,
                                               detail::Prop_Field<&Render_Scene_3D::Prop::clear_color, "clear_color", "Linear scene clear color.">,
                                               detail::Prop_Field<&Render_Scene_3D::Prop::view_active, "view_active", "Whether the scene publishes rendered frames.">,
                                               detail::State_Field<Scene::Base_Tag, &Scene::State::taskflow_rebuilt, "taskflow_rebuilt", "Whether the scene task graph was rebuilt.">,
                                               detail::State_Field<Scene::Base_Tag, &Scene::State::renderable_count, "renderable_count", "Number of renderables attached to the scene.">,
                                               detail::State_Field<Scene::Base_Tag, &Scene::State::taskflow_task_count, "taskflow_task_count", "Number of tasks in the scene graph.">,
                                               detail::State_Field<Scene::Base_Tag, &Scene::State::taskflow_dependency_count, "taskflow_dependency_count", "Number of graph dependencies.">,
                                               detail::State_Field<Scene::Base_Tag, &Scene::State::taskflow_max_predecessors, "taskflow_max_predecessors", "Maximum direct predecessors of a task.">,
                                               detail::State_Field<Scene::Base_Tag, &Scene::State::taskflow_max_successors, "taskflow_max_successors", "Maximum direct successors of a task.">,
                                               detail::State_Field<Scene::Base_Tag, &Scene::State::taskflow_execution_time_ns, "taskflow_execution_time_ns", "Scene graph execution time in nanoseconds.">>;
    return detail::make_renderable_descriptor("scene", "场景", "scene", Adapter{scene});
}
template <typename Axis_Object>
std::unique_ptr<detail::Renderable_Descriptor> make_axis_component(
    std::string id, std::string label, Axis_Object& axis) {
    return make_renderable_component<Axis_Object,
                                     Prop_Field<&Abs_Axis::Prop::position, "position", "Axis origin in viewport pixels.">,
                                     Prop_Field<&Abs_Axis::Prop::pixel_length, "pixel_length", "Signed axis length in pixels.">,
                                     Prop_Field<&Abs_Axis::Prop::orientation, "orientation", "Axis orientation.">,
                                     Prop_Field<&Abs_Axis::Prop::tick_length, "tick_length", "Major tick length.">,
                                     Prop_Field<&Abs_Axis::Prop::sub_tick_length, "sub_tick_length", "Minor tick length.">,
                                     Prop_Field<&Abs_Axis::Prop::axis_pen, "axis_pen", "Axis line and tick style.">,
                                     Prop_Field<&Abs_Axis::Prop::unit_text, "unit_text", "Axis unit label.">,
                                     Prop_Field<&Abs_Axis::Prop::unit_text_font, "unit_text_font", "Axis label font.">,
                                     Prop_Field<&Abs_Axis::Prop::unit_text_pen, "unit_text_pen", "Axis label foreground.">,
                                     Prop_Field<&Abs_Axis::Prop::unit_text_background_brush, "unit_text_background_brush", "Axis label background.">,
                                     Prop_Field<&Abs_Axis::Prop::label_rotation_degrees, "label_rotation_degrees", "Tick label rotation.">,
                                     Prop_Field<&Numeric_Axis::Prop::coordinate_range, "coordinate_range", "Visible coordinate range.">,
                                     Prop_Field<&Numeric_Axis::Prop::precision, "precision", "Maximum decimal precision.">,
                                     Prop_Field<&Numeric_Axis::Prop::locale, "locale", "Numeric label locale.">,
                                     Prop_Field<&Numeric_Axis::Prop::wheel_enabled, "wheel_enabled", "Allows wheel zoom.">,
                                     Prop_Field<&Numeric_Axis::Prop::drag_enabled, "drag_enabled", "Allows pointer drag panning.">>(
        std::move(id), std::move(label), "axis", axis);
}
template <>
std::unique_ptr<detail::Renderable_Descriptor> make_axis_component<Time_Axis_Object>(
    std::string id, std::string label, Time_Axis_Object& axis) {
    return make_renderable_component<Time_Axis_Object,
                                     Prop_Field<&Abs_Axis::Prop::position, "position", "Axis origin in viewport pixels.">,
                                     Prop_Field<&Abs_Axis::Prop::pixel_length, "pixel_length", "Signed axis length in pixels.">,
                                     Prop_Field<&Abs_Axis::Prop::orientation, "orientation", "Axis orientation.">,
                                     Prop_Field<&Abs_Axis::Prop::tick_length, "tick_length", "Major tick length.">,
                                     Prop_Field<&Abs_Axis::Prop::sub_tick_length, "sub_tick_length", "Minor tick length.">,
                                     Prop_Field<&Abs_Axis::Prop::axis_pen, "axis_pen", "Axis line and tick style.">,
                                     Prop_Field<&Abs_Axis::Prop::unit_text, "unit_text", "Axis unit label.">,
                                     Prop_Field<&Abs_Axis::Prop::unit_text_font, "unit_text_font", "Axis label font.">,
                                     Prop_Field<&Abs_Axis::Prop::unit_text_pen, "unit_text_pen", "Axis label foreground.">,
                                     Prop_Field<&Abs_Axis::Prop::unit_text_background_brush, "unit_text_background_brush", "Axis label background.">,
                                     Prop_Field<&Abs_Axis::Prop::label_rotation_degrees, "label_rotation_degrees", "Tick label rotation.">,
                                     Prop_Field<&Time_Axis::Prop::visible_count, "visible_count", "Maximum visible time samples.">,
                                     Prop_Field<&Time_Axis::Prop::tick_label_spacing_px, "tick_label_spacing_px", "Spacing between time labels.">,
                                     Prop_Field<&Time_Axis::Prop::estimated_label_width_px, "estimated_label_width_px", "Estimated time label width.">,
                                     Prop_Field<&Time_Axis::Prop::format, "format", "Time label format.">,
                                     Prop_Field<&Time_Axis::Prop::newest_at_start, "newest_at_start", "Places the newest time at the range origin.">,
                                     State_Field<Time_Axis, &Time_Axis::State::next_tick, "next_tick", "Next allocated time tick.">,
                                     State_Field<Time_Axis, &Time_Axis::State::samples, "samples", "Published time sample window.">>(
        std::move(id), std::move(label), "axis", axis);
}
template <typename... Fields, typename Object, typename... Owned_Objects>
std::unique_ptr<Plot::Scene_View> make_scene_view(
    Object& object,
    Scene_2D& scene,
    std::function<void(const Plot_Frame_Request&)> update,
    Owned_Objects&&... owned_objects) {
    using Definition = typename Object::Attached_Object;
    using Tag = typename Definition::Base_Tag;
    using State = typename Definition::State;
    std::vector<std::unique_ptr<detail::Renderable_Descriptor>> components;
    components.push_back(make_scene_component(scene));
    components.push_back(make_renderable_component<Object, Fields...>("plot", "主绘图组件", "renderable", object));
    std::size_t axis_index{};
    const auto append_owned = [&](const auto& owned) {
        using Owned = std::remove_cvref_t<decltype(owned)>;
        if constexpr (std::same_as<typename Owned::element_type, Frequency_Axis_Object>
            || std::same_as<typename Owned::element_type, Numeric_Axis_Object>
            || std::same_as<typename Owned::element_type, Time_Axis_Object>) {
            const auto id = axis_index++ == 0 ? "axis-x" : "axis-y";
            components.push_back(make_axis_component(id, id == std::string_view{"axis-x"} ? "横向坐标轴" : "纵向坐标轴", *owned));
        }
        else if constexpr (std::same_as<typename Owned::element_type, Selection_Object> && !std::same_as<Object, Selection_Object>) {
            components.push_back(make_renderable_component<Selection_Object,
                                                           Prop_Field<&Selection_Rectangle_Overlay::Prop::label_font, "label_font", "Font used for labels attached to selected regions.">,
                                                           Prop_Field<&Selection_Rectangle_Overlay::Prop::label_pen, "label_pen", "Pen used to draw selected-region label text.">,
                                                           Prop_Field<&Selection_Rectangle_Overlay::Prop::selection_brush, "selection_brush", "Brush used to fill selected rectangular regions.">,
                                                           Prop_Field<&Selection_Rectangle_Overlay::Prop::selection_border_pen, "selection_border_pen", "Pen used to draw selected-region borders.">,
                                                           Prop_Field<&Selection_Rectangle_Overlay::Prop::selected_regions, "selected_regions", "Collection of selected rectangles expressed in axis coordinates.">,
                                                           State_Field<Selection_Rectangle_Overlay, &Selection_Rectangle_Overlay::State::selected_region_count, "selected_region_count", "Number of rectangular regions currently selected.">>("selection", "矩形选区", "overlay", *owned));
        }
    };
    (append_owned(owned_objects), ...);
    return std::make_unique<Scene_View_Model<std::remove_cvref_t<Owned_Objects>...>>(
        std::move(components),
        std::move(update),
        std::forward<Owned_Objects>(owned_objects)...);
}
std::unique_ptr<Frequency_Axis_Object> make_frequency_axis() {
    auto result = Frequency_Axis_Object::Builder{}
                  .set(&Abs_Axis::Prop::orientation, Axis_Orientation::horizontal)
                  .set(&Abs_Axis::Prop::position, Point_F{64.0, 370.0})
                  .set(&Abs_Axis::Prop::pixel_length, 620.0)
                  .set(&Numeric_Axis::Prop::coordinate_range, Axis_Range{0.0, 100.0})
                  .build();
    if (!result) throw std::logic_error("frequency axis dependency graph is invalid");
    return std::move(result).value();
}
std::unique_ptr<Numeric_Axis_Object> make_numeric_axis(
    Axis_Orientation orientation, Point_F position, Axis_Pixel_Length length,
    Axis_Range range) {
    auto result = Numeric_Axis_Object::Builder{}
                  .set(&Abs_Axis::Prop::orientation, orientation)
                  .set(&Abs_Axis::Prop::position, position)
                  .set(&Abs_Axis::Prop::pixel_length, length)
                  .set(&Numeric_Axis::Prop::coordinate_range, range)
                  .build();
    if (!result) throw std::logic_error("numeric axis dependency graph is invalid");
    return std::move(result).value();
}
std::unique_ptr<Time_Axis_Object> make_time_axis(
    Axis_Orientation orientation, Point_F position, Axis_Pixel_Length length) {
    auto result = Time_Axis_Object::Builder{}
                  .set(&Abs_Axis::Prop::orientation, orientation)
                  .set(&Abs_Axis::Prop::position, position)
                  .set(&Abs_Axis::Prop::pixel_length, length)
                  .build();
    if (!result) throw std::logic_error("time axis dependency graph is invalid");
    return std::move(result).value();
}
template <Axis_Object Horizontal_Axis, Axis_Object Vertical_Axis>
std::unique_ptr<Selection_Object> selection_overlay(Horizontal_Axis* horizontal_axis, Vertical_Axis* vertical_axis) {
    auto result = Selection_Object::Builder(horizontal_axis, vertical_axis).build();
    if (!result) throw std::logic_error("selection overlay axes form an invalid dependency graph");
    return std::move(result).value();
}
template <Renderable_Object Plot_Object>
void place_selection_over(Scene_2D* scene, Selection_Object* selection, Plot_Object* plot) {
    const auto result = scene->template edit_dependency_graph<Paint_Tag>([&](auto& paint) {
        paint.add_dependency(selection, plot);
    });
    if (!result) throw std::logic_error("selection overlay paint order is invalid");
}
template <typename... Axes>
void resize_axes(Scene_2D* scene, Size viewport, Axes*... axes) {
    const Size previous_viewport = scene->template read_prop<Render_Scene_2D::Base_Tag>().viewport;
    if (previous_viewport == viewport || previous_viewport.empty()) return;
    const auto resize_axis = [&](auto* axis) {
        const auto layout = axis->template read_prop<Abs_Axis::Base_Tag>();
        const double horizontal_scale = static_cast<double>(viewport.width) / previous_viewport.width;
        const double vertical_scale = static_cast<double>(viewport.height) / previous_viewport.height;
        axis->template set<&Abs_Axis::Prop::position>(Point_F{
            layout.position.x * horizontal_scale,
            layout.position.y * vertical_scale
        });
        axis->template set<&Abs_Axis::Prop::pixel_length>(layout.pixel_length *
            (layout.orientation == Axis_Orientation::horizontal ? horizontal_scale : vertical_scale));
    };
    (resize_axis(axes), ...);
}
template <typename Scene_Object>
void dispatch_plot_input(Scene_Object& scene, const Plot_Input_Event& input) {
    const auto dispatch = [&](auto event) {
        scene.dispatch_event(std::move(event));
    };
    const auto apply_pointer = [&](auto& event) {
        event.position = input.position;
        event.global_position = input.global_position;
        event.button = input.button;
        event.buttons = input.buttons;
        event.modifiers = input.modifiers;
    };
    switch (input.type) {
    case Event_Type::pointer_move:
    case Event_Type::pointer_press:
    case Event_Type::pointer_release: {
        auto event = std::make_unique<Basic_Pointer_Event<Point_F>>(input.type);
        apply_pointer(*event);
        dispatch(std::move(event));
        break;
    }
    case Event_Type::wheel: {
        auto event = std::make_unique<Basic_Wheel_Event<Point_F>>();
        apply_pointer(*event);
        event->pixel_delta_x = input.pixel_delta_x;
        event->pixel_delta_y = input.pixel_delta_y;
        event->angle_delta_x = input.angle_delta_x;
        event->angle_delta_y = input.angle_delta_y;
        dispatch(std::move(event));
        break;
    }
    case Event_Type::key_press:
    case Event_Type::key_release: {
        auto event = std::make_unique<Key_Event>(input.type);
        event->key = input.key;
        event->native_key = input.native_key;
        event->modifiers = input.modifiers;
        event->auto_repeat = input.auto_repeat;
        dispatch(std::move(event));
        break;
    }
    default: {
        dispatch(std::make_unique<Event>(input.type));
        break;
    }
    }
}
}
std::shared_ptr<Plot> make_axes_plot(asio::any_io_executor executor) {
    constexpr Size canvas{720, 420};
    auto frequency = make_frequency_axis();
    frequency->template set<&Abs_Axis::Prop::unit_text>("Hz");
    auto numeric = make_numeric_axis(
        Axis_Orientation::vertical, {64.0, 370.0}, -320.0, {-100.0, 0.0});
    numeric->template set<&Abs_Axis::Prop::unit_text>("dB");
    auto time = make_time_axis(
        Axis_Orientation::horizontal, {64.0, 190.0}, 620.0);
    time->template set<&Abs_Axis::Prop::unit_text>("Time");
    auto scene = *Scene_2D::Builder{}
                  .set(&Render_Scene_2D::Prop::viewport, canvas)
                  .set(&Render_Scene_2D::Prop::background, Color{7, 13, 24, 255})
                  .set(&Render_Scene_2D::Prop::view_active, true)
                  .build();
    const auto topology = scene->template edit_dependency_graph<Prepare_Data_Tag, Paint_Tag>([&](auto& prepare, auto& paint) {
        prepare.add(frequency.get());
        prepare.add(numeric.get());
        prepare.add(time.get());
        paint.add(frequency.get());
        paint.add(numeric.get());
        paint.add(time.get());
    });
    if (!topology) throw std::logic_error("axis gallery topology is invalid");
    auto update = [scene = scene.get(), frequency = frequency.get(), numeric = numeric.get(), time = time.get()](const Plot_Frame_Request& event) {
        resize_axes(scene, {static_cast<int>(event.width), static_cast<int>(event.height)}, frequency, numeric, time);
        constexpr double day_milliseconds = 86'400'000.0;
        time->append_time(Time_Of_Day{
            static_cast<std::int64_t>(
                std::fmod(std::max(0.0, event.time_milliseconds), day_milliseconds))
        });
    };
    std::vector<std::unique_ptr<detail::Renderable_Descriptor>> components;
    components.push_back(make_scene_component(*scene));
    components.push_back(make_axis_component("axis-frequency", "频率轴", *frequency));
    components.push_back(make_axis_component("axis-value", "数值轴", *numeric));
    components.push_back(make_axis_component("axis-time", "时间轴", *time));
    auto view = std::make_unique<Scene_View_Model<decltype(frequency), decltype(numeric), decltype(time)>>(
        std::move(components), std::move(update), std::move(frequency), std::move(numeric), std::move(time));
    return std::make_shared<Plot>(std::move(executor), std::move(scene), std::move(view));
}
std::shared_ptr<Plot> make_spectrum_plot(asio::any_io_executor executor) {
    constexpr Size canvas{720, 420};
    auto frequency = make_frequency_axis();
    auto vertical = make_numeric_axis(Axis_Orientation::vertical, {64.0, 370.0}, -320.0, {-110.0, 0.0});
    auto spectrum = *Impl<Spectrum>::Builder(frequency.get(), vertical.get())
                     .set(&Spectrum::Prop::frequency_range, Axis_Range{0.0, 100.0})
                     .set(&Spectrum::Prop::max_hold_visible, true)
                     .build();
    auto selection = selection_overlay(frequency.get(), vertical.get());
    auto scene = *Scene_2D::Builder()
                  .set(&Render_Scene_2D::Prop::viewport, canvas)
                  .set(&Render_Scene_2D::Prop::background, Color{7, 13, 24, 255})
                  .set(&Render_Scene_2D::Prop::view_active, true)
                  .add_renderable(selection.get())
                  .build();
    place_selection_over(scene.get(), selection.get(), spectrum.get());
    auto update = [scene = scene.get(), raw = spectrum.get(), frequency = frequency.get(), vertical = vertical.get()](const Plot_Frame_Request& event) {
        resize_axes(scene, {static_cast<int>(event.width), static_cast<int>(event.height)}, frequency, vertical);
        std::array<double, 256> samples{};
        for (std::size_t i = 0; i < samples.size(); ++i) {
            const double x = static_cast<double>(i) / samples.size();
            samples[i] = -92.0 + 54.0 * std::exp(-180.0 * std::pow(x - 0.28 - 0.03 * std::sin(event.time_milliseconds * 0.001), 2.0))
            + 42.0 * std::exp(-260.0 * std::pow(x - 0.68, 2.0))
            + 2.5 * std::sin(i * 0.31 + event.time_milliseconds * 0.004);
        }
        raw->update_samples(samples);
    };
    auto view = make_scene_view<
        Prop_Field<&Spectrum::Prop::center_frequency, "center_frequency", "Frequency placed at the visual center of the spectrum axis.">,
        Prop_Field<&Spectrum::Prop::partition_count, "partition_count", "Number of partitions used to prepare and render spectrum samples.">,
        Prop_Field<&Spectrum::Prop::max_hold_visible, "max_hold_visible", "Shows the accumulated maximum-hold spectrum curve when enabled.">,
        Prop_Field<&Spectrum::Prop::min_hold_visible, "min_hold_visible", "Shows the accumulated minimum-hold spectrum curve when enabled.">,
        Prop_Field<&Spectrum::Prop::max_marker_visible, "max_marker_visible", "Displays the marker attached to the strongest visible sample.">,
        Prop_Field<&Spectrum::Prop::min_marker_visible, "min_marker_visible", "Displays the marker attached to the weakest visible sample.">,
        Prop_Field<&Spectrum::Prop::sweep_region_visible, "sweep_region_visible", "Highlights the configured sweep-frequency interval on the plot.">,
        Prop_Field<&Spectrum::Prop::visible_range_only, "visible_range_only", "Restricts sample preparation to the frequency range currently visible on the axis.">,
        Prop_Field<&Spectrum::Prop::frequency_range, "frequency_range", "Maps the complete input sample span onto frequency coordinates.">,
        Prop_Field<&Spectrum::Prop::sweep_frequency_range, "sweep_frequency_range", "Defines the frequency interval rendered as the sweep region.">,
        Prop_Field<&Spectrum::Prop::partition_mode, "partition_mode", "Selects how samples are divided between preparation tasks.">,
        Prop_Field<&Spectrum::Prop::interpolation_mode, "interpolation_mode", "Selects the interpolation algorithm used between adjacent spectrum samples.">,
        Prop_Field<&Spectrum::Prop::max_brush, "max_brush", "Fill brush used for the maximum-hold area.">,
        Prop_Field<&Spectrum::Prop::current_brush, "current_brush", "Fill brush used for the current spectrum area.">,
        Prop_Field<&Spectrum::Prop::min_brush, "min_brush", "Fill brush used for the minimum-hold area.">,
        Prop_Field<&Spectrum::Prop::max_pen, "max_pen", "Stroke style used for the maximum-hold curve.">,
        Prop_Field<&Spectrum::Prop::current_pen, "current_pen", "Stroke style used for the current spectrum curve.">,
        Prop_Field<&Spectrum::Prop::min_pen, "min_pen", "Stroke style used for the minimum-hold curve.">,
        Prop_Field<&Spectrum::Prop::selected_marker_pen, "selected_marker_pen", "Stroke style used to emphasize the currently selected marker.">,
        Prop_Field<&Spectrum::Prop::marker_pen, "marker_pen", "Default stroke style used for unselected spectrum markers.">,
        Prop_Field<&Spectrum::Prop::middle_frequency_pen, "middle_frequency_pen", "Stroke style used for the center-frequency indicator.">,
        Prop_Field<&Spectrum::Prop::sweep_region_brush, "sweep_region_brush", "Fill brush used to highlight the sweep-frequency interval.">,
        Prop_Field<&Spectrum::Prop::custom_markers, "custom_markers", "User-defined marker positions and presentation data.">,
        Prop_Field<&Spectrum::Prop::selected_marker, "selected_marker", "Index of the custom marker currently selected for interaction.">,
        State_Field<Spectrum, &Spectrum::State::sample_count, "sample_count", "Number of input spectrum samples available in the latest update.">,
        State_Field<Spectrum, &Spectrum::State::rendered_point_count, "rendered_point_count", "Number of curve points emitted by the latest render preparation.">,
        State_Field<Spectrum, &Spectrum::State::selectable_marker_count, "selectable_marker_count", "Number of markers currently eligible for selection.">>(
        *spectrum, *scene, std::move(update), std::move(frequency), std::move(vertical), std::move(spectrum), std::move(selection));
    return std::make_shared<Plot>(std::move(executor), std::move(scene), std::move(view));
}
std::shared_ptr<Plot> make_frequency_trace_plot(asio::any_io_executor executor) {
    constexpr Size canvas{720, 420};
    auto time = make_time_axis(
        Axis_Orientation::horizontal, {64.0, 370.0}, 620.0);
    auto vertical = make_numeric_axis(
        Axis_Orientation::vertical, {64.0, 370.0}, -320.0, {-1.2, 1.2});
    auto trace = *Impl<Frequency_Trace>::Builder(time.get(), vertical.get()).build();
    auto selection = selection_overlay(time.get(), vertical.get());
    auto scene = *Scene_2D::Builder{}
                  .set(&Render_Scene_2D::Prop::viewport, canvas)
                  .set(&Render_Scene_2D::Prop::background, Color{7, 13, 24, 255})
                  .set(&Render_Scene_2D::Prop::view_active, true)
                  .add_renderable(trace.get())
                  .add_renderable(selection.get())
                  .build();
    place_selection_over(scene.get(), selection.get(), trace.get());
    auto update = [scene = scene.get(), raw = trace.get(), time = time.get(), vertical = vertical.get()](const Plot_Frame_Request& event) {
        resize_axes(scene, {static_cast<int>(event.width), static_cast<int>(event.height)}, time, vertical);
        constexpr double day_milliseconds = 86'400'000.0;
        const auto tick = time->append_time(Time_Of_Day{
            static_cast<std::int64_t>(
                std::fmod(std::max(0.0, event.time_milliseconds), day_milliseconds))
        });
        raw->append_sample(tick,
                           std::sin(event.time_milliseconds * 0.0025) * 0.8
                           + std::sin(event.time_milliseconds * 0.0007) * 0.2);
    };
    auto view = make_scene_view<
        Prop_Field<&Frequency_Trace::Prop::partition_count, "partition_count", "Number of partitions used to prepare the time-ordered trace.">,
        Prop_Field<&Frequency_Trace::Prop::pen, "pen", "Stroke style used to draw the frequency trace.">,
        Prop_Field<&Frequency_Trace::Prop::partition_mode, "partition_mode", "Selects how trace samples are divided between preparation tasks.">,
        Prop_Field<&Frequency_Trace::Prop::samples, "samples", "Complete time-ordered collection of frequency trace samples.">,
        State_Field<Frequency_Trace, &Frequency_Trace::State::sample_count, "sample_count", "Number of samples retained by the current trace.">,
        State_Field<Frequency_Trace, &Frequency_Trace::State::rendered_point_count, "rendered_point_count", "Number of points emitted for the latest trace frame.">>(
        *trace, *scene, std::move(update), std::move(time), std::move(vertical), std::move(trace), std::move(selection));
    return std::make_shared<Plot>(std::move(executor), std::move(scene), std::move(view));
}
std::shared_ptr<Plot> make_sweep_spectrum_plot(asio::any_io_executor executor) {
    constexpr Size canvas{720, 420};
    auto frequency = make_frequency_axis();
    auto vertical = make_numeric_axis(
        Axis_Orientation::vertical, {64.0, 370.0}, -320.0, {-110.0, 0.0});
    auto sweep = *Impl<Sweep_Spectrum>::Builder(frequency.get(), vertical.get())
                  .set(&Sweep_Spectrum::Prop::frequency_range, Axis_Range{0.0, 100.0})
                  .set(&Sweep_Spectrum::Prop::bins_per_block, std::size_t{8})
                  .set(&Sweep_Spectrum::Prop::block_count, std::size_t{64})
                  .build();
    auto selection = selection_overlay(frequency.get(), vertical.get());
    auto scene = *Scene_2D::Builder{}
                  .set(&Render_Scene_2D::Prop::viewport, canvas)
                  .set(&Render_Scene_2D::Prop::background, Color{7, 13, 24, 255})
                  .set(&Render_Scene_2D::Prop::view_active, true)
                  .add_renderable(sweep.get())
                  .add_renderable(selection.get())
                  .build();
    place_selection_over(scene.get(), selection.get(), sweep.get());
    auto update = [scene = scene.get(), raw = sweep.get(), frequency = frequency.get(), vertical = vertical.get()](const Plot_Frame_Request& event) {
        resize_axes(scene, {static_cast<int>(event.width), static_cast<int>(event.height)}, frequency, vertical);
        const auto& state = raw->template read_prop<Sweep_Spectrum::Base_Tag>();
        const std::size_t block_count = std::max<std::size_t>(1, state.block_count);
        const std::size_t bins_per_block = std::max<std::size_t>(1, state.bins_per_block);
        const std::size_t block_index = state.blocks.size() < block_count ? state.blocks.size() : state.next_block_index % block_count;
        std::vector<double> values(bins_per_block);
        for (std::size_t i = 0; i < values.size(); ++i) {
            const auto sweep_index = block_index * values.size() + i;
            values[i] = -90.0 + 35.0 * std::sin(sweep_index * 0.08 + event.time_milliseconds * 0.002);
        }
        raw->append_block(values);
    };
    auto view = make_scene_view<
        Prop_Field<&Sweep_Spectrum::Prop::bins_per_block, "bins_per_block", "Number of frequency bins stored in each incoming sweep block.">,
        Prop_Field<&Sweep_Spectrum::Prop::block_count, "block_count", "Number of blocks required to compose one complete sweep.">,
        Prop_Field<&Sweep_Spectrum::Prop::partition_count, "partition_count", "Number of partitions used during sweep preparation.">,
        Prop_Field<&Sweep_Spectrum::Prop::visible_range_only, "visible_range_only", "Restricts preparation to the frequency interval visible on the axis.">,
        Prop_Field<&Sweep_Spectrum::Prop::frequency_range, "frequency_range", "Maps the complete sweep span onto frequency coordinates.">,
        Prop_Field<&Sweep_Spectrum::Prop::partition_mode, "partition_mode", "Selects how sweep blocks are divided between preparation tasks.">,
        Prop_Field<&Sweep_Spectrum::Prop::pen, "pen", "Stroke style used for the completed sweep curve.">,
        Prop_Field<&Sweep_Spectrum::Prop::current_frequency_pen, "current_frequency_pen", "Stroke style used for the current sweep-frequency indicator.">,
        Prop_Field<&Sweep_Spectrum::Prop::interpolation_mode, "interpolation_mode", "Selects interpolation between adjacent sweep bins.">,
        Prop_Field<&Sweep_Spectrum::Prop::blocks, "blocks", "Latest data stored in each fixed frequency-segment slot.">,
        State_Field<Sweep_Spectrum, &Sweep_Spectrum::State::stored_block_count, "stored_block_count", "Number of frequency segments that currently contain data.">,
        State_Field<Sweep_Spectrum, &Sweep_Spectrum::State::stored_point_count, "stored_point_count", "Total number of points retained by the single composite sweep curve.">,
        State_Field<Sweep_Spectrum, &Sweep_Spectrum::State::rendered_point_count, "rendered_point_count", "Number of points emitted for the single composite sweep curve.">>(
        *sweep, *scene, std::move(update), std::move(frequency), std::move(vertical), std::move(sweep), std::move(selection));
    return std::make_shared<Plot>(std::move(executor), std::move(scene), std::move(view));
}
std::shared_ptr<Plot> make_afterglow_plot(asio::any_io_executor executor) {
    constexpr Size canvas{720, 420};
    auto frequency = make_frequency_axis();
    auto vertical = make_numeric_axis(
        Axis_Orientation::vertical, {64.0, 370.0}, -320.0, {-110.0, 0.0});
    auto afterglow = *Impl<Afterglow>::Builder(frequency.get(), vertical.get())
                      .set(&Afterglow::Prop::frequency_range, Axis_Range{0.0, 100.0})
                      .set(&Afterglow::Prop::power_range, Axis_Range{-110.0, 0.0})
                      .set(&Afterglow::Prop::power_point_size, 96)
                      .build();
    auto selection = selection_overlay(frequency.get(), vertical.get());
    auto scene = *Scene_2D::Builder{}
                  .set(&Render_Scene_2D::Prop::viewport, canvas)
                  .set(&Render_Scene_2D::Prop::background, Color{7, 13, 24, 255})
                  .set(&Render_Scene_2D::Prop::view_active, true)
                  .add_renderable(afterglow.get())
                  .add_renderable(selection.get())
                  .build();
    place_selection_over(scene.get(), selection.get(), afterglow.get());
    auto update = [scene = scene.get(), raw = afterglow.get(), frequency = frequency.get(), vertical = vertical.get()](const Plot_Frame_Request& event) {
        resize_axes(scene, {static_cast<int>(event.width), static_cast<int>(event.height)}, frequency, vertical);
        std::array<double, 192> values{};
        for (std::size_t i = 0; i < values.size(); ++i)
            values[i] = -95.0 + 62.0 * std::exp(-220.0 * std::pow(
                static_cast<double>(i) / values.size() - 0.5
                - 0.18 * std::sin(event.time_milliseconds * 0.0008), 2.0));
        raw->append_spectrum(values);
    };
    auto view = make_scene_view<
        Prop_Field<&Afterglow::Prop::frequency_point_size, "frequency_point_size", "Number of frequency cells allocated across each afterglow row.">,
        Prop_Field<&Afterglow::Prop::power_point_size, "power_point_size", "Number of power cells allocated along the vertical afterglow range.">,
        Prop_Field<&Afterglow::Prop::partition_count, "partition_count", "Number of partitions used to prepare afterglow history.">,
        Prop_Field<&Afterglow::Prop::interpolate, "interpolate", "Enables interpolation when mapping samples into the afterglow grid.">,
        Prop_Field<&Afterglow::Prop::attenuation_rate, "attenuation_rate", "Controls how quickly historical energy fades between updates.">,
        Prop_Field<&Afterglow::Prop::frequency_range, "frequency_range", "Maps input samples onto the afterglow frequency axis.">,
        Prop_Field<&Afterglow::Prop::power_range, "power_range", "Defines the minimum and maximum power represented by the color grid.">,
        Prop_Field<&Afterglow::Prop::partition_mode, "partition_mode", "Selects how afterglow cells are divided between preparation tasks.">,
        Prop_Field<&Afterglow::Prop::color_map, "color_map", "Maps accumulated energy values to rendered colors.">,
        Prop_Field<&Afterglow::Prop::spectra, "spectra", "Spectrum history currently retained for afterglow rendering.">,
        State_Field<Afterglow, &Afterglow::State::history_count, "history_count", "Number of spectrum frames retained in afterglow history.">,
        State_Field<Afterglow, &Afterglow::State::latest_spectrum_point_count, "latest_spectrum_point_count", "Number of samples in the most recently appended spectrum.">,
        State_Field<Afterglow, &Afterglow::State::rendered_cell_count, "rendered_cell_count", "Number of colored cells emitted for the latest frame.">>(
        *afterglow, *scene, std::move(update), std::move(frequency), std::move(vertical), std::move(afterglow), std::move(selection));
    return std::make_shared<Plot>(std::move(executor), std::move(scene), std::move(view));
}
std::shared_ptr<Plot> make_waterfall_plot(asio::any_io_executor executor) {
    constexpr Size canvas{720, 420};
    auto frequency = make_frequency_axis();
    auto time = make_time_axis(
        Axis_Orientation::vertical, {64.0, 370.0}, -320.0);
    auto waterfall = *Impl<Waterfall>::Builder(frequency.get(), time.get())
                      .set(&Waterfall::Prop::frequency_range, Axis_Range{0.0, 100.0})
                      .set(&Waterfall::Prop::power_range, Axis_Range{-110.0, 0.0})
                      .build();
    auto selection = selection_overlay(frequency.get(), time.get());
    auto scene = *Scene_2D::Builder{}
                  .set(&Render_Scene_2D::Prop::viewport, canvas)
                  .set(&Render_Scene_2D::Prop::background, Color{7, 13, 24, 255})
                  .set(&Render_Scene_2D::Prop::view_active, true)
                  .add_renderable(waterfall.get())
                  .add_renderable(selection.get())
                  .build();
    place_selection_over(scene.get(), selection.get(), waterfall.get());
    auto update = [scene = scene.get(), raw = waterfall.get(), frequency = frequency.get(), time = time.get()](const Plot_Frame_Request& event) {
        resize_axes(scene, {static_cast<int>(event.width), static_cast<int>(event.height)}, frequency, time);
        std::array<double, 192> values{};
        for (std::size_t i = 0; i < values.size(); ++i)
            values[i] = -100.0 + 70.0 * std::exp(-240.0 * std::pow(
                static_cast<double>(i) / values.size() - 0.5
                - 0.22 * std::sin(event.time_milliseconds * 0.0006), 2.0));
        constexpr double day_milliseconds = 86'400'000.0;
        const auto tick = time->append_time(Time_Of_Day{
            static_cast<std::int64_t>(
                std::fmod(std::max(0.0, event.time_milliseconds), day_milliseconds))
        });
        raw->append_row(tick, values);
    };
    auto view = make_scene_view<
        Prop_Field<&Waterfall::Prop::tooltip_enabled, "tooltip_enabled", "Enables value inspection tooltips over waterfall cells.">,
        Prop_Field<&Waterfall::Prop::tooltip_font, "tooltip_font", "Font used to render waterfall tooltip text.">,
        Prop_Field<&Waterfall::Prop::tooltip_text_pen, "tooltip_text_pen", "Pen used to draw tooltip text and its foreground color.">,
        Prop_Field<&Waterfall::Prop::tooltip_background_brush, "tooltip_background_brush", "Brush used to fill the tooltip background panel.">,
        Prop_Field<&Waterfall::Prop::frequency_bin_count, "frequency_bin_count", "Number of frequency bins expected in each waterfall row.">,
        Prop_Field<&Waterfall::Prop::partition_count, "partition_count", "Number of partitions used to prepare waterfall cells.">,
        Prop_Field<&Waterfall::Prop::visible_range_only, "visible_range_only", "Restricts preparation to frequencies visible on the current axis.">,
        Prop_Field<&Waterfall::Prop::frequency_range, "frequency_range", "Maps row samples onto waterfall frequency coordinates.">,
        Prop_Field<&Waterfall::Prop::power_range, "power_range", "Defines the power interval mapped through the waterfall color map.">,
        Prop_Field<&Waterfall::Prop::partition_mode, "partition_mode", "Selects how waterfall rows are divided between preparation tasks.">,
        Prop_Field<&Waterfall::Prop::interpolation_mode, "interpolation_mode", "Selects interpolation when samples are mapped to raster cells.">,
        Prop_Field<&Waterfall::Prop::color_map, "color_map", "Maps sample power values to waterfall colors.">,
        Prop_Field<&Waterfall::Prop::rows, "rows", "Time-ordered collection of spectrum rows retained by the waterfall.">,
        State_Field<Waterfall, &Waterfall::State::row_count, "row_count", "Number of waterfall rows currently retained.">,
        State_Field<Waterfall, &Waterfall::State::stored_point_count, "stored_point_count", "Total number of spectrum points retained across all rows.">,
        State_Field<Waterfall, &Waterfall::State::rendered_cell_count, "rendered_cell_count", "Number of raster cells emitted for the latest frame.">>(
        *waterfall, *scene, std::move(update), std::move(frequency), std::move(time), std::move(waterfall), std::move(selection));
    return std::make_shared<Plot>(std::move(executor), std::move(scene), std::move(view));
}
std::shared_ptr<Plot> make_constellation_plot(asio::any_io_executor executor) {
    constexpr Size canvas{720, 420};
    auto horizontal = make_numeric_axis(
        Axis_Orientation::horizontal, {64.0, 370.0}, 620.0, {-1.2, 1.2});
    auto vertical = make_numeric_axis(
        Axis_Orientation::vertical, {64.0, 370.0}, -320.0, {-1.2, 1.2});
    auto constellation = *Impl<Constellation_Diagram>::Builder(horizontal.get(), vertical.get())
                          .set(&Constellation_Diagram::Prop::i_range, Axis_Range{-1.2, 1.2})
                          .set(&Constellation_Diagram::Prop::q_range, Axis_Range{-1.2, 1.2})
                          .build();
    auto selection = selection_overlay(horizontal.get(), vertical.get());
    auto scene = *Scene_2D::Builder{}
                  .set(&Render_Scene_2D::Prop::viewport, canvas)
                  .set(&Render_Scene_2D::Prop::background, Color{7, 13, 24, 255})
                  .set(&Render_Scene_2D::Prop::view_active, true)
                  .add_renderable(constellation.get())
                  .add_renderable(selection.get())
                  .build();
    place_selection_over(scene.get(), selection.get(), constellation.get());
    auto update = [scene = scene.get(), raw = constellation.get(), horizontal = horizontal.get(), vertical = vertical.get()](const Plot_Frame_Request& event) {
        resize_axes(scene, {static_cast<int>(event.width), static_cast<int>(event.height)}, horizontal, vertical);
        const auto& state = raw->template read_prop<Constellation_Diagram::Base_Tag>();
        const int anchor_count = static_cast<int>(state.type);
        const double radius = std::min(state.i_range.size(), state.q_range.size()) * 0.4;
        const double phase = event.time_milliseconds * 0.001;
        for (int index = 0; index < anchor_count; ++index) {
            const double angle = state.phase_offset_radians
            + 2.0 * std::numbers::pi * static_cast<double>(index) / anchor_count;
            const double noise_i = 0.025 * std::sin(phase * 11.0 + index * 1.73)
            + 0.012 * std::cos(phase * 23.0 + index * 0.61);
            const double noise_q = 0.025 * std::cos(phase * 13.0 + index * 1.37)
            + 0.012 * std::sin(phase * 19.0 + index * 0.47);
            raw->append_point({
                state.i_range.center() + std::cos(angle) * radius + noise_i,
                state.q_range.center() + std::sin(angle) * radius + noise_q
            });
        }
    };
    auto view = make_scene_view<
        Prop_Field<&Constellation_Diagram::Prop::point_lifetime_ms, "point_lifetime_ms", "Time in milliseconds that an appended constellation point remains visible.">,
        Prop_Field<&Constellation_Diagram::Prop::type, "type", "Selects the modulation constellation used to generate reference anchors.">,
        Prop_Field<&Constellation_Diagram::Prop::phase_offset_radians, "phase_offset_radians", "Rotates constellation points and anchors by the specified phase angle.">,
        Prop_Field<&Constellation_Diagram::Prop::i_range, "i_range", "Defines the horizontal in-phase coordinate interval.">,
        Prop_Field<&Constellation_Diagram::Prop::q_range, "q_range", "Defines the vertical quadrature coordinate interval.">,
        Prop_Field<&Constellation_Diagram::Prop::point_color, "point_color", "Color used to render received I/Q samples.">,
        Prop_Field<&Constellation_Diagram::Prop::anchor_color, "anchor_color", "Color used to render ideal modulation anchors.">,
        Prop_Field<&Constellation_Diagram::Prop::points, "points", "Current time-stamped collection of received I/Q samples.">,
        State_Field<Constellation_Diagram, &Constellation_Diagram::State::point_count, "point_count", "Number of constellation samples currently retained.">>(
        *constellation, *scene, std::move(update), std::move(horizontal), std::move(vertical), std::move(constellation), std::move(selection));
    return std::make_shared<Plot>(std::move(executor), std::move(scene), std::move(view));
}
std::shared_ptr<Plot> make_selection_overlay_plot(asio::any_io_executor executor) {
    constexpr Size canvas{720, 420};
    auto horizontal = make_numeric_axis(
        Axis_Orientation::horizontal, {64.0, 370.0}, 620.0, {0.0, 100.0});
    auto vertical = make_numeric_axis(
        Axis_Orientation::vertical, {64.0, 370.0}, -320.0, {0.0, 100.0});
    auto selection = *Impl<Selection_Rectangle_Overlay>::Builder(horizontal.get(), vertical.get()).build();
    auto scene = *Scene_2D::Builder{}
                  .set(&Render_Scene_2D::Prop::viewport, canvas)
                  .set(&Render_Scene_2D::Prop::background, Color{7, 13, 24, 255})
                  .set(&Render_Scene_2D::Prop::view_active, true)
                  .add_renderable(selection.get())
                  .build();
    auto update = [scene = scene.get(), horizontal = horizontal.get(), vertical = vertical.get()](const Plot_Frame_Request& event) {
        resize_axes(scene, {static_cast<int>(event.width), static_cast<int>(event.height)}, horizontal, vertical);
    };
    auto view = make_scene_view<
        Prop_Field<&Selection_Rectangle_Overlay::Prop::label_font, "label_font", "Font used for labels attached to selected regions.">,
        Prop_Field<&Selection_Rectangle_Overlay::Prop::label_pen, "label_pen", "Pen used to draw selected-region label text.">,
        Prop_Field<&Selection_Rectangle_Overlay::Prop::selection_brush, "selection_brush", "Brush used to fill selected rectangular regions.">,
        Prop_Field<&Selection_Rectangle_Overlay::Prop::selection_border_pen, "selection_border_pen", "Pen used to draw selected-region borders.">,
        Prop_Field<&Selection_Rectangle_Overlay::Prop::selected_regions, "selected_regions", "Collection of selected rectangles expressed in axis coordinates.">,
        State_Field<Selection_Rectangle_Overlay,
                    &Selection_Rectangle_Overlay::State::selected_region_count,
                    "selected_region_count",
                    "Number of rectangular regions currently selected.">>(
        *selection, *scene, std::move(update), std::move(horizontal), std::move(vertical), std::move(selection));
    return std::make_shared<Plot>(std::move(executor), std::move(scene), std::move(view));
}
struct Plot::Private {
    using Scene = std::variant<std::unique_ptr<Scene_2D>, std::unique_ptr<Scene_3D>>;
    using Frame = std::variant<std::unique_ptr<Frame_2D>, std::unique_ptr<Frame_3D>>;
    struct Managed_Frame {
        const void* owner{}; /* 发起本帧的 WebSocket 连接身份。 */
        Plot_Frame_Request request{}; /* 创建本帧的浏览器请求及 viewport。 */
        Frame frame{}; /* Web 层唯一拥有并传给 Scene 的外部帧。 */
    };
    asio::strand<asio::any_io_executor> strand; /* 串行执行帧请求、属性写入和 Schema 查询。 */
    asio::experimental::concurrent_channel<void(asio::error_code, Plot_Input)> inputs; /* 不承载输入事件的异步命令通道。 */
    std::unique_ptr<Scene_View> view; /* 使用层数据推进及反射描述实现；拥有 Scene 引用的图元。 */
    Scene scene; /* 当前 Plot 唯一拥有的 2D 或 3D Scene；析构先于 view 所有图元。 */
    std::once_flag start_once; /* 保证回调与协程只安装一次。 */
    std::mutex handlers_mutex; /* 保护跨 Drogon 连接线程修改的订阅表。 */
    std::unordered_map<const void*, Frame_Handler> handlers; /* 以连接身份索引的完成帧订阅。 */
    std::uint64_t next_frame_sequence{1}; /* 下一外部帧使用的单调序号；只在 strand 访问。 */
    Frame_Policy frame_policy{}; /* 仅保存可编辑刷新策略，不保存衍生统计。 */
    std::optional<Managed_Frame> active_frame{}; /* 当前由 Scene/异步后端借用指针的外部帧。 */
    std::deque<const void*> pending_order{}; /* 按首次等待顺序保存连接身份，避免连接间饥饿。 */
    std::unordered_map<const void*, Managed_Frame> pending_frames{}; /* 每个连接只保留最新一个尚未提交 Scene 的外部帧。 */
    bool frame_in_flight{}; /* Scene 是否已有一次尚未完成回调的帧。 */
    template <typename Scene_Object>
    Private(asio::any_io_executor executor,
            std::unique_ptr<Scene_Object> value_scene,
            std::unique_ptr<Scene_View> value_view) : strand(asio::make_strand(std::move(executor))), inputs(strand, 32),
                                                      view(std::move(value_view)), scene(std::move(value_scene)) {}
    void publish(const void* owner, std::shared_ptr<const Plot_Frame_Message> frame) {
        Frame_Handler output;
        {
            std::lock_guard lock(handlers_mutex);
            const auto found = handlers.find(owner);
            if (found != handlers.end()) output = found->second;
        }
        if (output) output(std::move(frame));
    }
    [[nodiscard]] nlohmann::json schema() const;
    [[nodiscard]] Managed_Frame make_frame(Frame_Submission submission);
    void request_frame(Frame_Submission submission);
    void render_frame(Managed_Frame frame);
    void publish_completed_frame(Render_Frame* frame);
    void frame_completed();
};
nlohmann::json Plot::Private::schema() const {
    auto result = view->schema();
    result["components"].push_back(frame_policy.schema());
    return result;
}
Plot::Private::Managed_Frame Plot::Private::make_frame(Frame_Submission submission) {
    const Frame_Identity identity{next_frame_sequence++, submission.request.correlation_id};
    if (std::holds_alternative<std::unique_ptr<Scene_2D>>(scene)) return {submission.owner, std::move(submission.request), std::make_unique<Frame_2D>(identity)};
    return {submission.owner, std::move(submission.request), std::make_unique<Frame_3D>(identity)};
}
void Plot::Private::request_frame(Frame_Submission submission) {
    auto frame = make_frame(std::move(submission));
    if (frame_in_flight) {
        const auto found = pending_frames.find(frame.owner);
        if (found != pending_frames.end()) found->second = std::move(frame);
        else {
            const auto owner = frame.owner;
            pending_order.push_back(owner);
            pending_frames.emplace(owner, std::move(frame));
        }
        return;
    }
    render_frame(std::move(frame));
}
void Plot::Private::render_frame(Managed_Frame frame) {
    frame_in_flight = true;
    active_frame = std::move(frame);
    auto& request = active_frame->request;
    request.width = std::clamp(request.width, 160U, 1920U);
    request.height = std::clamp(request.height, 120U, 1080U);
    view->update(request);
    if (auto* scene_2d = std::get_if<std::unique_ptr<Scene_2D>>(&scene)) {
        (*scene_2d)->set<&Render_Scene_2D::Prop::viewport>(Size{static_cast<int>(request.width), static_cast<int>(request.height)});
        const auto result = (*scene_2d)->render(std::get<std::unique_ptr<Frame_2D>>(active_frame->frame).get());
        if (result != Render_Scene_2D::Render_Result::completed)
            asio::post(strand, [this] {
                frame_completed();
            });
        return;
    }
    auto& scene_3d = std::get<std::unique_ptr<Scene_3D>>(scene);
    scene_3d->set<&Render_Scene_3D::Prop::viewport>(Extent{request.width, request.height});
    const auto result = scene_3d->render(std::get<std::unique_ptr<Frame_3D>>(active_frame->frame).get());
    if (result != Render_Scene_3D::Render_Result::submitted)
        asio::post(strand, [this] {
            frame_completed();
        });
}
void Plot::Private::publish_completed_frame(Render_Frame* frame) {
    if (!active_frame) throw std::logic_error("frame callback has no externally owned active frame");
    const auto pacing = frame_policy.snapshot();
    if (auto* frame_2d = std::get_if<std::unique_ptr<Frame_2D>>(&active_frame->frame); frame_2d && frame_2d->get() == frame) publish(active_frame->owner, encode_frame(frame_2d->get(), pacing));
    else if (auto* frame_3d = std::get_if<std::unique_ptr<Frame_3D>>(&active_frame->frame); frame_3d && frame_3d->get() == frame) publish(active_frame->owner, encode_frame(frame_3d->get(), pacing));
    else throw std::logic_error("frame callback does not match the externally owned active frame");
    frame_completed();
}
void Plot::Private::frame_completed() {
    active_frame.reset();
    frame_in_flight = false;
    while (!pending_order.empty()) {
        const auto owner = pending_order.front();
        pending_order.pop_front();
        auto next = pending_frames.extract(owner);
        if (next.empty()) continue;
        render_frame(std::move(next.mapped()));
        return;
    }
}
Plot::Plot(asio::any_io_executor executor,
           std::unique_ptr<Scene_2D> scene,
           std::unique_ptr<Scene_View> view) : d(std::make_unique<Private>(std::move(executor), std::move(scene), std::move(view))) {}
Plot::Plot(asio::any_io_executor executor,
           std::unique_ptr<Scene_3D> scene,
           std::unique_ptr<Scene_View> view) : d(std::make_unique<Private>(std::move(executor), std::move(scene), std::move(view))) {}
Plot::~Plot() {
    d->inputs.close();
}
void Plot::ensure_started() {
    std::call_once(d->start_once, [this] {
        auto self = shared_from_this();
        if (auto* scene = std::get_if<std::unique_ptr<Scene_2D>>(&d->scene)) {
            (*scene)->set_frame_callback([weak = weak_from_this()](Frame_2D* frame) {
                if (auto owner = weak.lock()) {
                    frame->mark(Frame_Trace_Marker::callback_finished);
                    asio::post(owner->d->strand, [weak, frame] {
                        if (auto next_owner = weak.lock()) next_owner->d->publish_completed_frame(frame);
                    });
                }
            });
        }
        else {
            std::get<std::unique_ptr<Scene_3D>>(d->scene)->set_frame_callback(
                [weak = weak_from_this()](Frame_3D* frame) {
                    if (auto owner = weak.lock()) {
                        frame->mark(Frame_Trace_Marker::callback_finished);
                        asio::post(owner->d->strand, [weak, frame] {
                            if (auto next_owner = weak.lock()) next_owner->d->publish_completed_frame(frame);
                        });
                    }
                });
        }
        asio::co_spawn(d->strand, [self]() -> asio::awaitable<void> {
            for (;;) {
                asio::error_code error;
                auto input = co_await self->d->inputs.async_receive(
                    asio::redirect_error(asio::use_awaitable, error));
                if (error) co_return;
                if (auto* query = std::get_if<Schema_Query>(&input)) {
                    query->handler(self->d->schema());
                    continue;
                }
                if (auto* write = std::get_if<Prop_Write>(&input)) {
                    write->handler(write->component == "frame-runtime"
                                       ? self->d->frame_policy.write_prop(write->key, write->value)
                                       : self->d->view->write_prop(write->component, write->key, write->value));
                    continue;
                }
                auto submission = std::get<Frame_Submission>(input);
                self->d->request_frame(std::move(submission));
            }
        }, [](std::exception_ptr exception) {
            if (exception) std::rethrow_exception(exception);
        });
    });
}
void Plot::attach(const void* owner, Frame_Handler handler) {
    ensure_started();
    {
        std::lock_guard lock(d->handlers_mutex);
        d->handlers.insert_or_assign(owner, std::move(handler));
    }
}
void Plot::detach(const void* owner) {
    std::lock_guard lock(d->handlers_mutex);
    d->handlers.erase(owner);
}
void Plot::submit_frame(const void* owner, Plot_Frame_Request request) {
    ensure_started();
    static_cast<void>(d->inputs.try_send(asio::error_code{}, Plot_Input{Frame_Submission{owner, std::move(request)}}));
}
void Plot::submit_input(Plot_Input_Event event) {
    ensure_started();
    if (auto* scene = std::get_if<std::unique_ptr<Scene_2D>>(&d->scene)) dispatch_plot_input(**scene, event);
    else dispatch_plot_input(*std::get<std::unique_ptr<Scene_3D>>(d->scene), event);
}
void Plot::async_schema(Json_Handler handler) {
    ensure_started();
    if (!d->inputs.try_send(asio::error_code{}, Plot_Input{Schema_Query{std::move(handler)}})) throw std::runtime_error("plot input queue is unavailable");
}
void Plot::async_write_prop(std::string component, std::string key, nlohmann::json value, Json_Handler handler) {
    ensure_started();
    if (!d->inputs.try_send(asio::error_code{}, Plot_Input{
                                Prop_Write{std::move(component), std::move(key), std::move(value), std::move(handler)}
                            }))
        throw std::runtime_error("plot input queue is unavailable");
}
}