stuff-from-scratch/src/windows/ui_interfaces/wayland/WaylandWindowInterface.h

#pragma once

#include "wayland-client.h"
#include "xdg-shell-client-protocol.h"

#include "Window.h"
#include "SharedMemory.h"

#include <iostream>
#include <cstring>

#include <sys/mman.h>
#include <unistd.h>

#include <memory>

class WaylandWindowInterface
{

public:

	WaylandWindowInterface()
	{
		auto registry_handle_global = [](void *data, struct wl_registry *registry,
				uint32_t name, const char *interface, uint32_t version)
		{
			auto thisClass = static_cast<WaylandWindowInterface*>(data);

			printf("interface: '%s', version: %d, name: %d\n", interface, version, name);

			if (strcmp(interface, wl_compositor_interface.name) == 0)
			{
				thisClass->setCompositor(static_cast<wl_compositor*>(wl_registry_bind(registry, name, &wl_compositor_interface, 4)));
			}
			else if (strcmp(interface, wl_shm_interface.name) == 0)
			{
				thisClass->setSharedMemory(static_cast<wl_shm*>(wl_registry_bind(registry, name, &wl_shm_interface, 1)));
		    }
			else if (strcmp(interface, xdg_wm_base_interface.name) == 0)
			{
				thisClass->setXdgBase(static_cast<xdg_wm_base*>(wl_registry_bind(registry, name, &xdg_wm_base_interface, 1)));
			}
		};

		auto registry_handle_global_remove = [](void *data, struct wl_registry *registry,
				uint32_t name)
		{
			// This space deliberately left blank;
		};

		mRegistryListener.global = registry_handle_global;
		mRegistryListener.global_remove = registry_handle_global_remove;
	}

	void setXdgBase(xdg_wm_base* xdg_base)
	{
		mXdgBase = xdg_base;
		auto xdg_ping_handler = [](void *data, struct xdg_wm_base *xdg_wm_base, uint32_t serial)
		{
			auto thisClass = static_cast<WaylandWindowInterface*>(data);
			thisClass->doXdgPong(serial);
		};
		mXdgBaseListener.ping = xdg_ping_handler;
	    xdg_wm_base_add_listener(mXdgBase, &mXdgBaseListener, this);
	}

	void doXdgPong(uint32_t serial)
	{
		xdg_wm_base_pong(mXdgBase, serial);
	}

	void setCompositor(wl_compositor* compositor)
	{
		mCompositor = compositor;
	}

	void setSharedMemory(wl_shm* shared_memory)
	{
		mWlSharedMemory = shared_memory;
	}

	void connect()
	{
		mDisplay = wl_display_connect(nullptr);

		if (!mDisplay)
		{
			std::cout << "Display connect error" << std::endl;
		}

		auto registry = wl_display_get_registry(mDisplay);
		if (!registry)
		{
			std::cout << "Failed to get registry" << std::endl;
		}

		wl_registry_add_listener(registry, &mRegistryListener, this);
		wl_display_roundtrip(mDisplay);
	}

	void createSurface()
	{
		mSurface = wl_compositor_create_surface(mCompositor);
		mXdgSurface = xdg_wm_base_get_xdg_surface(mXdgBase, mSurface);

		auto xdg_surface_configure = [](void *data, struct xdg_surface *xdg_surface, uint32_t serial)
		{
			auto thisClass = static_cast<WaylandWindowInterface*>(data);
			thisClass->onXdgSurfaceConfigure(data, xdg_surface, serial);
		};
		mXdgSurfaceListener.configure = xdg_surface_configure;

		xdg_surface_add_listener(mXdgSurface, &mXdgSurfaceListener, this);

		mXdgTopLevel = xdg_surface_get_toplevel(mXdgSurface);
	    xdg_toplevel_set_title(mXdgTopLevel, "Example client");

	    wl_surface_commit(mSurface);
	}

	void onXdgSurfaceConfigure(void *data, struct xdg_surface *xdg_surface, uint32_t serial)
	{
	    xdg_surface_ack_configure(xdg_surface, serial);

	    auto buffer = draw_frame();
	    wl_surface_attach(mSurface, buffer, 0, 0);
	    //wl_surface_damage(mSurface, 0, 0, UINT32_MAX, UINT32_MAX);
	    wl_surface_commit(mSurface);
	}

	wl_buffer* draw_frame()
	{
		const auto width = mWindow->GetWidth();
		const auto height = mWindow->GetHeight();

		const int bitDepth = 4;

		const int stride = width * bitDepth;
		//const int numBuffers = 2; // i.e. front/back
		const int numBuffers = 1;
		const int shm_pool_size = height * stride * numBuffers;

		initializeSharedBuffer(shm_pool_size);

		if (!mSharedMemory->isValid())
		{
			std::cout << "Failed to allocate shared memory" << std::endl;
			return nullptr;
		}

		if (!mPoolData)
		{
			std::cout << "Failed to mmap pool" << std::endl;
			return nullptr;
		}

		auto pool = wl_shm_create_pool(mWlSharedMemory, mSharedMemory->getFileDescriptor(), shm_pool_size);

		int index = 0;
		// int offset = height * stride * index; // Two buffers, offset to starting point of second
		int offset = 0;

		mWorkingBuffer = wl_shm_pool_create_buffer(pool, offset, width, height, stride, WL_SHM_FORMAT_XRGB8888);

		wl_shm_pool_destroy(pool);
		close(mSharedMemory->getFileDescriptor());

		drawCheckerboard(width, height, offset);

		munmap(mPoolData, shm_pool_size);

		auto wl_buffer_release = [](void *data, struct wl_buffer *wl_buffer)
		{
			wl_buffer_destroy(wl_buffer);
		};
		mBufferListener.release = wl_buffer_release;

		wl_buffer_add_listener(mWorkingBuffer, &mBufferListener, nullptr);

		return mWorkingBuffer;
	}

	void drawCheckerboard(int width, int height, int offset)
	{
		uint32_t *pixels = (uint32_t *)&mPoolData[offset];
		for (int y = 0; y < height; ++y)
		{
		  for (int x = 0; x < width; ++x)
		  {
		    if ((x + y / 8 * 8) % 16 < 8)
		    {
		      pixels[y * width + x] = 0xFF666666;
		    }
		    else
		    {
		      pixels[y * width + x] = 0xFFEEEEEE;
		    }
		  }
		}
	}

	void disconnect()
	{
		if (mDisplay)
		{
			wl_display_disconnect(mDisplay);
		}
	}

	void run()
	{
		while (wl_display_dispatch(mDisplay) != -1) {
		    /* This space deliberately left blank */
		}
	}

	void initializeSharedBuffer(int size)
	{
		mSharedMemory = std::make_unique<SharedMemory>();
		mSharedMemory->allocate("/wl_shm-XXXXXX", size);

		if (!mSharedMemory->isValid())
		{
			return;
		}
		mPoolData = static_cast<uint8_t*>(mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED, mSharedMemory->getFileDescriptor(), 0));
	    if (mPoolData == MAP_FAILED)
	    {
	        close(mSharedMemory->getFileDescriptor());
	        mPoolData = nullptr;
	    }
	}

	void addWindow(mt::Window* window)
	{
		mWindow = window;
	}

private:

	mt::Window* mWindow{nullptr};

	wl_display* mDisplay{nullptr};
	wl_compositor* mCompositor{nullptr};
	wl_registry_listener mRegistryListener;

	xdg_wm_base* mXdgBase{nullptr};
	xdg_wm_base_listener mXdgBaseListener;

	wl_surface* mSurface{nullptr};
	xdg_surface* mXdgSurface{nullptr};
	xdg_surface_listener mXdgSurfaceListener{nullptr};

	xdg_toplevel* mXdgTopLevel{nullptr};

	wl_shm* mWlSharedMemory{nullptr};
	std::unique_ptr<SharedMemory> mSharedMemory;
	uint8_t* mPoolData{nullptr};
	wl_shm_pool* mPool{nullptr};

	wl_buffer* mWorkingBuffer{nullptr};
	wl_buffer_listener mBufferListener;
};