#include "Gallery_Plot_Session.h"
#include "Gallery_Protocol.h"
#include "common/Gallery_Scene_Interface.h"
#include "render_2D/Gallery_Scene2D.h"
#include "render_3D/Gallery_Scene3D.h"
#include <renderive/scheduling/Scheduler.hpp>
#include <trantor/net/EventLoopThread.h>
#include <nlohmann/json.hpp>
#include <algorithm>
#include <atomic>
#include <chrono>
#include <cmath>
#include <cstdint>
#include <mutex>
#include <optional>
#include <string>
#include <string_view>
#include <type_traits>
#include <utility>
namespace renderive::web {
namespace {
Gallery_View_Input gallery_input(const Event& event) {
    Gallery_View_Input input;
    switch (event.type) {
    case Event_Type::Show:
        input.type = Gallery_View_Input_Type::Show;
        break;
    case Event_Type::Hide:
        input.type = Gallery_View_Input_Type::Hide;
        break;
    case Event_Type::Leave:
        input.type = Gallery_View_Input_Type::Leave;
        break;
    default:
        input.type = Gallery_View_Input_Type::Leave;
        break;
    }
    return input;
}
Gallery_Mouse_Button gallery_mouse_button(Mouse_Button button) {
    switch (button) {
    case Mouse_Button::None:
        return Gallery_Mouse_Button::None;
    case Mouse_Button::Left:
        return Gallery_Mouse_Button::Left;
    case Mouse_Button::Right:
        return Gallery_Mouse_Button::Right;
    case Mouse_Button::Middle:
        return Gallery_Mouse_Button::Middle;
    }
    return Gallery_Mouse_Button::None;
}
Gallery_Key gallery_key(Key key) {
    switch (key) {
    case Key::Escape:
        return Gallery_Key::Escape;
    case Key::Enter:
        return Gallery_Key::Enter;
    case Key::Space:
        return Gallery_Key::Space;
    case Key::Delete:
        return Gallery_Key::Delete;
    case Key::Backspace:
        return Gallery_Key::Backspace;
    case Key::Left:
        return Gallery_Key::Left;
    case Key::Right:
        return Gallery_Key::Right;
    case Key::Up:
        return Gallery_Key::Up;
    case Key::Down:
        return Gallery_Key::Down;
    case Key::Unknown:
        return Gallery_Key::Unknown;
    }
    return Gallery_Key::Unknown;
}
Gallery_Pointer_Input gallery_input(const Pointer_Event& event) {
    Gallery_Pointer_Input input;
    if (event.type == Event_Type::Pointer_Press)
        input.type = Gallery_Pointer_Input_Type::Press;
    else if (event.type == Event_Type::Pointer_Release)
        input.type = Gallery_Pointer_Input_Type::Release;
    else
        input.type = Gallery_Pointer_Input_Type::Move;
    input.x = event.position.x;
    input.y = event.position.y;
    input.global_x = event.global_position.x;
    input.global_y = event.global_position.y;
    input.button = gallery_mouse_button(event.button);
    input.buttons = event.buttons;
    input.modifiers = static_cast<std::uint8_t>(event.modifiers);
    return input;
}
Gallery_Wheel_Input gallery_input(const Wheel_Event& event) {
    Gallery_Wheel_Input input;
    input.x = event.position.x;
    input.y = event.position.y;
    input.global_x = event.global_position.x;
    input.global_y = event.global_position.y;
    input.button = gallery_mouse_button(event.button);
    input.buttons = event.buttons;
    input.modifiers = static_cast<std::uint8_t>(event.modifiers);
    input.angle_delta_x = event.angle_delta_x;
    input.angle_delta_y = event.angle_delta_y;
    input.pixel_delta_x = event.pixel_delta_x;
    input.pixel_delta_y = event.pixel_delta_y;
    return input;
}
Gallery_Key_Input gallery_input(const Key_Event& event) {
    Gallery_Key_Input input;
    input.type = event.type == Event_Type::Key_Press ? Gallery_Key_Input_Type::Press : Gallery_Key_Input_Type::Release;
    input.key = gallery_key(event.key);
    input.native_key = event.native_key;
    input.modifiers = static_cast<std::uint8_t>(event.modifiers);
    input.auto_repeat = event.auto_repeat;
    return input;
}
std::unique_ptr<Gallery_Scene_Interface> make_gallery_scene(std::uint64_t session_id, std::string case_id, Gallery_Frame_Mode mode, bool automatic_low_latency) {
    if (case_id.starts_with("datoviz_"))
        return make_gallery_scene_3d(session_id, std::move(case_id), mode, automatic_low_latency);
    return make_gallery_scene_2d(session_id, std::move(case_id), mode, automatic_low_latency);
}
trantor::EventLoop* automatic_render_loop() {
    static trantor::EventLoopThread thread("RenderiveAutomaticRender");
    static const bool started = [] {
        thread.run();
        return true;
    }();
    static_cast<void>(started);
    return thread.getLoop();
}
}
struct Gallery_Plot_Session::Impl : std::enable_shared_from_this<Gallery_Plot_Session::Impl> {
    using Clock = std::chrono::steady_clock;
    explicit Impl(bool enable_automatic_low_latency)
        : automatic_low_latency(enable_automatic_low_latency), session_id(next_session_id()) {}
    ~Impl() {
        disarm_automatic_render();
    }
    static std::uint64_t next_session_id() noexcept {
        static std::atomic<std::uint64_t> next{1};
        return next.fetch_add(1, std::memory_order_relaxed);
    }
    bool update_client_metrics(std::string_view message) {
        if (!scene)
            return false;
        const auto root = nlohmann::json::parse(message, nullptr, false);
        if (root.is_discarded() || !root.is_object() || !root.contains("client_metrics") ||
            !root["client_metrics"].is_object())
            return false;
        const auto& metrics = root["client_metrics"];
        const auto finite_metric = [&metrics](std::string_view name) {
            const auto iterator = metrics.find(std::string(name));
            if (iterator == metrics.end() || !iterator->is_number())
                return 0.0;
            const double value = iterator->get<double>();
            return std::isfinite(value) ? value : 0.0;
        };
        std::uint64_t buffered_bytes{};
        if (const auto iterator = metrics.find("websocket_buffered_bytes");
            iterator != metrics.end() && iterator->is_number_unsigned()) {
            buffered_bytes = iterator->get<std::uint64_t>();
        }
        const auto unsigned_metric = [&metrics](std::string_view name) {
            const auto iterator = metrics.find(std::string(name));
            if (iterator == metrics.end() || !iterator->is_number_integer())
                return std::uint64_t{};
            const auto value = iterator->get<std::int64_t>();
            return value > 0 ? static_cast<std::uint64_t>(value) : std::uint64_t{};
        };
        Gallery_Client_Performance performance;
        performance.transport_fps = finite_metric("transport_fps");
        performance.presentation_fps = finite_metric("presentation_fps");
        performance.websocket_buffered_bytes = buffered_bytes;
        performance.changed_pixel_frames = unsigned_metric("changed_pixel_frames");
        performance.duplicate_pixel_frames = unsigned_metric("duplicate_pixel_frames");
        performance.frame_request_timeout_count =
            unsigned_metric("frame_request_timeout_count");
        performance.frame_round_trip_ms = finite_metric("frame_round_trip_ms");
        performance.frame_round_trip_average_ms =
            finite_metric("frame_round_trip_average_ms");
        performance.frame_round_trip_deviation_ms =
            finite_metric("frame_round_trip_deviation_ms");
        performance.frame_round_trip_p95_ms = finite_metric("frame_round_trip_p95_ms");
        performance.frame_round_trip_p99_ms = finite_metric("frame_round_trip_p99_ms");
        performance.display_interval_ms = finite_metric("display_interval_ms");
        performance.display_interval_average_ms =
            finite_metric("display_interval_average_ms");
        performance.display_interval_latest_ms =
            finite_metric("display_interval_latest_ms");
        performance.display_interval_p95_ms = finite_metric("display_interval_p95_ms");
        performance.display_interval_p99_ms = finite_metric("display_interval_p99_ms");
        performance.display_interval_deviation_ms =
            finite_metric("display_interval_deviation_ms");
        performance.overwritten_pixel_frames =
            unsigned_metric("overwritten_pixel_frames");
        performance.last_pixel_receive_age_ms =
            finite_metric("last_pixel_receive_age_ms");
        performance.last_pixel_change_age_ms =
            finite_metric("last_pixel_change_age_ms");
        scene->set_client_metrics(performance);
        return true;
    }
    [[nodiscard]] std::unique_lock<std::mutex> acquire_foreground_lock() {
        return std::unique_lock<std::mutex>(mutex);
    }
    void disarm_automatic_render() noexcept {
        ++automatic_timer_revision;
        if (automatic_timer == trantor::InvalidTimerId)
            return;
        automatic_render_loop()->invalidateTimer(automatic_timer);
        automatic_timer = trantor::InvalidTimerId;
    }
    void arm_automatic_render_locked() noexcept {
        if (!automatic_low_latency)
            return;
        disarm_automatic_render();
        if (!scene || !scene->can_render_automatically() || render_task_pending)
            return;
        try {
            const auto interval = std::chrono::nanoseconds(
                std::max<std::uint64_t>(1, scene->kernel_refresh_interval_ns()));
            const auto deadline = last_render_started ? *last_render_started + interval : Clock::now();
            const auto delay = std::max(Clock::duration::zero(), deadline - Clock::now());
            const std::uint64_t revision = automatic_timer_revision;
            automatic_timer = automatic_render_loop()->runAfter(
                std::chrono::duration<double>(delay).count(),
                [session = weak_from_this(), revision] {
                    if (auto value = session.lock())
                        value->automatic_render_due(revision);
                });
        } catch (...) {
            disarm_automatic_render();
        }
    }
    void automatic_render_due(std::uint64_t revision) {
        std::uint64_t generation{};
        {
            std::lock_guard lock(mutex);
            if (revision != automatic_timer_revision)
                return;
            automatic_timer = trantor::InvalidTimerId;
            ++automatic_timer_revision;
            if (!automatic_low_latency || !scene || !scene->can_render_automatically() || render_task_pending)
                return;
            render_task_pending = true;
            generation = scene_generation;
        }
        auto self = shared_from_this();
        try {
            renderive::scheduling::enqueue_task([self = std::move(self), generation] {
                self->run_automatic_render(generation);
            });
        } catch (...) {
            std::lock_guard lock(mutex);
            render_task_pending = false;
            arm_automatic_render_locked();
        }
    }
    void run_automatic_render(std::uint64_t generation) noexcept {
        const auto started = Clock::now();
        try {
            std::lock_guard lock(mutex);
            if (generation == scene_generation && scene && scene->can_render_automatically()) {
                (void)scene->render_latest_frame();
                last_render_started = started;
            }
            render_task_pending = false;
            arm_automatic_render_locked();
        } catch (...) {
            std::lock_guard lock(mutex);
            render_task_pending = false;
            arm_automatic_render_locked();
        }
    }
    static bool affects_render_schedule(const Web_Event& event) {
        return std::visit(
            [](const auto& value) {
                using T = std::decay_t<decltype(value)>;
                if constexpr (std::is_same_v<T, Frame_Request>) {
                    return false;
                }
                else if constexpr (std::is_same_v<T, Gallery_Request>) {
                    return value.kind != Gallery_Request_Kind::Catalog &&
                    value.kind != Gallery_Request_Kind::Observe &&
                    value.kind != Gallery_Request_Kind::Refresh &&
                    value.kind != Gallery_Request_Kind::Reset_Monitoring;
                }
                else {
                    return true;
                }
            },
            event);
    }
    std::unique_ptr<Gallery_Scene_Interface> scene;
    std::mutex mutex;
    std::optional<Clock::time_point> last_render_started;
    std::uint64_t scene_generation{};
    bool automatic_low_latency{};
    bool render_task_pending{};
    std::uint64_t session_id{};
    trantor::TimerId automatic_timer{trantor::InvalidTimerId};
    std::uint64_t automatic_timer_revision{};
    std::optional<Web_Response> handle_gallery(const Gallery_Request& request) {
        if (request.kind == Gallery_Request_Kind::Catalog)
            return Web_Response{Web_Response_Type::Json, Gallery_Protocol::catalog_json()};
        if (request.kind == Gallery_Request_Kind::Open) {
            const auto open = Gallery_Protocol::open_request(request.message);
            if (!open)
                return Web_Response{
                    Web_Response_Type::Json,
                    Gallery_Protocol::error_json("未知的 gallery case 或 frame_mode", "case")
                };
            scene = make_gallery_scene(session_id, open->case_id, open->frame_mode, automatic_low_latency);
            ++scene_generation;
            last_render_started.reset();
            arm_automatic_render_locked();
            return Web_Response{
                Web_Response_Type::Json,
                Gallery_Protocol::case_json_from_controls(scene->case_id(), scene->controls().dump(),
                                            scene->telemetry_json(),
                                            "Renderive/Kernel 独立画布已创建",
                                            scene->frame_mode(), false)
            };
        }
        if (!scene)
            return Web_Response{
                Web_Response_Type::Json,
                Gallery_Protocol::error_json("请先发送 gallery_open")
            };
        if (request.kind == Gallery_Request_Kind::Observe) {
            if (update_client_metrics(request.message))
                arm_automatic_render_locked();
            return Web_Response{
                Web_Response_Type::Json,
                Gallery_Protocol::observer_json(
                    scene->case_id(), scene->frame_mode(), scene->telemetry_json())
            };
        }
        if (request.kind == Gallery_Request_Kind::Refresh) {
            if (update_client_metrics(request.message))
                arm_automatic_render_locked();
            return Web_Response{
                Web_Response_Type::Json,
                Gallery_Protocol::case_json_from_controls(
                    scene->case_id(), scene->controls().dump(),
                    scene->telemetry_json(), "观察数据已手动刷新",
                    scene->frame_mode(), true)
            };
        }
        if (request.kind == Gallery_Request_Kind::Reset_Monitoring) {
            scene->reset_monitoring();
            return Web_Response{
                Web_Response_Type::Json,
                Gallery_Protocol::case_json_from_controls(
                    scene->case_id(), scene->controls().dump(),
                    scene->telemetry_json(), "监测滑动窗口已重置",
                    scene->frame_mode(), true)
            };
        }
        if (request.kind == Gallery_Request_Kind::Patch) {
            const auto patch = Gallery_Protocol::control_patch_request(request.message);
            if (!patch)
                return Web_Response{Web_Response_Type::Json,
                    Gallery_Protocol::error_json("gallery_patch format is invalid")};
            const auto result = scene->apply_patch(
                patch->target, nlohmann::json::parse(patch->patch_json));
            if (!result.success)
                return Web_Response{Web_Response_Type::Json,
                    Gallery_Protocol::error_json(result.message)};
            return Web_Response{
                Web_Response_Type::Json,
                Gallery_Protocol::case_json_from_controls(scene->case_id(), scene->controls().dump(),
                                            scene->telemetry_json(),
                                            "控件 API 已由后端应用",
                                            scene->frame_mode(), false)
            };
        }
        const auto action = Gallery_Protocol::action_request(request.message);
        if (!action)
            return Web_Response{
                Web_Response_Type::Json,
                Gallery_Protocol::error_json("gallery_action 格式无效")
            };
        if (!Gallery_Protocol::action_available(scene->case_id(), scene->frame_mode(),
                                                action->id))
            return Web_Response{
                Web_Response_Type::Json,
                Gallery_Protocol::error_json(
                    "动作不属于当前画布或帧策略", "action")
            };
        if (action->id == "reset") {
            const std::string id = scene->case_id();
            const auto mode = scene->frame_mode();
            scene = make_gallery_scene(session_id, id, mode, automatic_low_latency);
            ++scene_generation;
            last_render_started.reset();
            arm_automatic_render_locked();
            return Web_Response{
                Web_Response_Type::Json,
                Gallery_Protocol::case_json_from_controls(id, scene->controls().dump(),
                                            scene->telemetry_json(),
                                            "本图已恢复后端默认值", mode, false)
            };
        }
        bool recognized{};
        const std::string notice = scene->action(*action, recognized);
        if (!recognized)
            return Web_Response{
                Web_Response_Type::Json,
                Gallery_Protocol::error_json("动作不属于当前画布或参数无效",
                                             "action")
            };
        scene->record_action_notice_if_empty(notice);
        return Web_Response{
            Web_Response_Type::Json,
            Gallery_Protocol::case_json_from_controls(scene->case_id(), scene->controls().dump(),
                                        scene->telemetry_json(), notice,
                                        scene->frame_mode(), false)
        };
    }
    std::optional<Web_Response> handle_frame_request() {
        const auto request_started = std::chrono::steady_clock::now();
        std::optional<std::string> pixels;
        {
            auto lock = acquire_foreground_lock();
            if (!scene)
                return std::nullopt;
            const auto encode_started = std::chrono::steady_clock::now();
            pixels = scene->encode_latest_pixels();
            const auto encode_finished = std::chrono::steady_clock::now();
            if (pixels)
                scene->record_pixel_response(request_started, encode_started, encode_finished,
                                             pixels->size());
        }
        if (!pixels)
            return std::nullopt;
        return Web_Response{Web_Response_Type::Pixels, std::move(*pixels)};
    }
    std::optional<Web_Response> handle(const Web_Event& event) {
        if (std::holds_alternative<Frame_Request>(event))
            return handle_frame_request();
        const bool reschedule = affects_render_schedule(event);
        std::optional<Web_Response> response;
        {
            auto lock = acquire_foreground_lock();
            response = std::visit(
                [this](const auto& value) -> std::optional<Web_Response> {
                    using T = std::decay_t<decltype(value)>;
                    if constexpr (std::is_same_v<T, Gallery_Request>) {
                        return handle_gallery(value);
                    }
                    else if constexpr (std::is_same_v<T, Frame_Request>) {
                        return std::nullopt;
                    }
                    else if constexpr (std::is_same_v<T, Viewport_Resize>) {
                        if (scene)
                            scene->resize(value.size.width, value.size.height);
                    }
                    else if constexpr (std::is_same_v<T, Event>) {
                        if (scene)
                            scene->dispatch(Gallery_Input_Event{gallery_input(value)});
                    }
                    else if constexpr (Event_Object<T>) {
                        if (scene)
                            scene->dispatch(Gallery_Input_Event{gallery_input(value)});
                    }
                    return std::nullopt;
                },
                event);
            if (reschedule)
                arm_automatic_render_locked();
        }
        return response;
    }
};
Gallery_Plot_Session::Gallery_Plot_Session() : Gallery_Plot_Session(false) {}
Gallery_Plot_Session::Gallery_Plot_Session(bool automatic_low_latency)
    : impl_(std::make_shared<Impl>(automatic_low_latency)) {}
Gallery_Plot_Session::~Gallery_Plot_Session() = default;
std::optional<Web_Response> Gallery_Plot_Session::handle(const Web_Event& event) {
    return impl_->handle(event);
}
} // namespace renderive::web