#include "pch.h"

// Use the C++ standard templated min/max
#define NOMINMAX

#include <algorithm>
#include <cmath>
#include <cstdint>
#include <exception>
#include <future>
#include <iterator>
#include <memory>
#include <stdexcept>

#include "winrt/Windows.ApplicationModel.h"
#include "winrt/Windows.ApplicationModel.Core.h"
#include "winrt/Windows.ApplicationModel.Activation.h"
#include "winrt/Windows.Foundation.h"
#include "winrt/Windows.Graphics.Display.h"
#include "winrt/Windows.System.h"
#include "winrt/Windows.UI.Core.h"
#include "winrt/Windows.UI.Input.h"
#include "winrt/Windows.UI.ViewManagement.h"

using namespace winrt::Windows::ApplicationModel;
using namespace winrt::Windows::ApplicationModel::Core;
using namespace winrt::Windows::ApplicationModel::Activation;
using namespace winrt::Windows::UI::Core;
using namespace winrt::Windows::UI::Input;
using namespace winrt::Windows::UI::ViewManagement;
using namespace winrt::Windows::System;
using namespace winrt::Windows::Foundation;
using namespace winrt::Windows::Graphics::Display;

class ViewProvider : public winrt::implements<ViewProvider, IFrameworkView>
{
public:

    // IFrameworkView methods
    void Initialize(CoreApplicationView const & applicationView)
    {
        applicationView.Activated({ this, &ViewProvider::OnActivated });

        CoreApplication::Suspending({ this, &ViewProvider::OnSuspending });

        CoreApplication::Resuming({ this, &ViewProvider::OnResuming });

		application.infoDisplay.active = true;
		application.infoDisplay.watermark = true;
		application.infoDisplay.resolution = true;
		application.infoDisplay.fpsinfo = true;
	}

    void Uninitialize() noexcept
    {
    }

    void SetWindow(CoreWindow const & window)
    {
        window.SizeChanged({ this, &ViewProvider::OnWindowSizeChanged });

        window.VisibilityChanged({ this, &ViewProvider::OnVisibilityChanged });

        window.Closed([this](auto&&, auto&&) { m_exit = true; });

        auto dispatcher = CoreWindow::GetForCurrentThread().Dispatcher();

        dispatcher.AcceleratorKeyActivated({ this, &ViewProvider::OnAcceleratorKeyActivated });

        auto navigation = SystemNavigationManager::GetForCurrentView();

        // UWP on Xbox One triggers a back request whenever the B button is pressed
        // which can result in the app being suspended if unhandled
        navigation.BackRequested([](const winrt::Windows::Foundation::IInspectable&, const BackRequestedEventArgs& args)
        {
            args.Handled(true);
        });

        auto currentDisplayInformation = DisplayInformation::GetForCurrentView();

        currentDisplayInformation.DpiChanged({ this, &ViewProvider::OnDpiChanged });

        DisplayInformation::DisplayContentsInvalidated({ this, &ViewProvider::OnDisplayContentsInvalidated });

        m_DPI = currentDisplayInformation.LogicalDpi();

        m_logicalWidth = window.Bounds().Width;
        m_logicalHeight = window.Bounds().Height;

		application.SetWindow(&window);
	}

    void Load(winrt::hstring const &) noexcept
    {
    }

    void Run()
    {
        while (!m_exit)
        {
            if (m_visible)
            {
				application.Run();

                CoreWindow::GetForCurrentThread().Dispatcher().ProcessEvents(CoreProcessEventsOption::ProcessAllIfPresent);
            }
            else
            {
                CoreWindow::GetForCurrentThread().Dispatcher().ProcessEvents(CoreProcessEventsOption::ProcessOneAndAllPending);
            }
        }
    }

protected:
    // Event handlers
    void OnActivated(CoreApplicationView const & /*applicationView*/, IActivatedEventArgs const & args)
    {
		CoreWindow::GetForCurrentThread().Activate();
    }

    void OnSuspending(IInspectable const & /*sender*/, SuspendingEventArgs const & args)
    {
        auto deferral = args.SuspendingOperation().GetDeferral();

        auto f = std::async(std::launch::async, [this, deferral]()
        {
            deferral.Complete();
        });
    }

    void OnResuming(IInspectable const & /*sender*/, IInspectable const & /*args*/)
    {
    }

    void OnWindowSizeChanged(CoreWindow const & sender, WindowSizeChangedEventArgs const & /*args*/)
    {
		application.SetWindow(&sender);
    }

    void OnVisibilityChanged(CoreWindow const & /*sender*/, VisibilityChangedEventArgs const & args)
    {
        m_visible = args.Visible();
    }

    void OnAcceleratorKeyActivated(CoreDispatcher const &, AcceleratorKeyEventArgs const & args)
    {
        if (args.EventType() == CoreAcceleratorKeyEventType::SystemKeyDown
            && args.VirtualKey() == VirtualKey::Enter
            && args.KeyStatus().IsMenuKeyDown
            && !args.KeyStatus().WasKeyDown)
        {
            // Implements the classic ALT+ENTER fullscreen toggle
            auto view = ApplicationView::GetForCurrentView();

            if (view.IsFullScreenMode())
                view.ExitFullScreenMode();
            else
                view.TryEnterFullScreenMode();

            args.Handled(true);
        }

		if (args.EventType() == CoreAcceleratorKeyEventType::Character && args.VirtualKey() != VirtualKey::Enter)
		{
			wchar_t c = (wchar_t)args.VirtualKey();

			if (c == '\b')
			{
				wi::gui::TextInputField::DeleteFromInput();
			}
			else
			{
				wi::gui::TextInputField::AddInput(c);
			}

		}
    }

    void OnDpiChanged(DisplayInformation const & sender, IInspectable const & /*args*/)
    {
		application.SetWindow(&CoreWindow::GetForCurrentThread());
    }

    void OnDisplayContentsInvalidated(DisplayInformation const & /*sender*/, IInspectable const & /*args*/)
    {
    }

private:
    bool  m_exit = false;
    bool  m_visible = true;
    float m_DPI = 96;
    float m_logicalWidth = 800;
    float m_logicalHeight = 600;
	wi::Application application;

    inline int ConvertDipsToPixels(float dips) const noexcept
    {
        return int(dips * m_DPI / 96.f + 0.5f);
    }

    inline float ConvertPixelsToDips(int pixels) const noexcept
    {
        return (float(pixels) * 96.f / m_DPI);
    }
};

class ViewProviderFactory : public winrt::implements<ViewProviderFactory, IFrameworkViewSource>
{
public:
    IFrameworkView CreateView()
    {
        return winrt::make<ViewProvider>();
    }
};


// Entry point
int WINAPI wWinMain(
    _In_ HINSTANCE /*hInstance*/,
    _In_ HINSTANCE /*hPrevInstance*/,
    _In_ LPWSTR    /*lpCmdLine*/,
    _In_ int       /*nCmdShow*/
)
{
    auto viewProviderFactory = winrt::make<ViewProviderFactory>();
    CoreApplication::Run(viewProviderFactory);
    return 0;
}