#include <X11/Xlib-xcb.h>
#include <X11/Xlib.h>
#include <xcb/xcb.h>
#include <forstio/io/io.h>

#include <map>
#include <vector>

#include "device.h"

namespace saw {
class xcb_device final : public device {
public:
	::Display *display;
	int screen;

	xcb_connection_t *xcb_connection;
	xcb_screen_t *xcb_screen;

	own<input_stream> async_notifier;
	conveyor_sink async_conveyor;

	std::map<xcb_window_t, xcb_window *> windows;

	std::vector<xcb_generic_event_t *> pending_events;

public:
	xcb_device(::Display *display, int screen, xcb_connection_t *xcb_connection,
			   xcb_screen_t *xcb_screen, own<input_stream> &&an);
	~xcb_device();

	void window_destroyed(xcb_window_t window_id);
	void handle_events();

	own<xcb_window> create_xcb_window(const video_mode &mode,
									  std::string_view title_view,
									  int visual_id);
	own<window> create_window(const video_mode &video_mode,
							  std::string_view title_view) override;

	void flush() override;
};

own<xcb_device> create_xcb_device(io_provider &provider);

class xcb_window final : public window {
public:
	xcb_device &device_;

	xcb_window_t xcb_window_;
	xcb_colormap_t xcb_colormap_;

	video_mode video_mode_;
	std::string window_title_;

	own<conveyor_feeder<window::variant_event>> event_feeder = nullptr;

public:
	xcb_window(xcb_device &dev, xcb_window_t xcb_win,
			   xcb_colormap_t xcb_colormap_, const video_mode &video_mode_,
			   std::string_view title_view_);
	~xcb_window();

	void show() override;
	void hide() override;

	const video_mode &get_video_mode() const override;
	const std::string_view title() const override;

	void resize(size_t width, size_t height) override;

	conveyor<window::variant_event> on_event() override;

	void resize_event(size_t x, size_t y, size_t width, size_t height);
	void mouse_event(int16_t x, int16_t y, uint16_t state, bool pressed);
	void mouse_move_event(int16_t x, int16_t y);
	void keyboard_event(int16_t x, int16_t y, uint32_t keycode, bool pressed,
					   bool repeat);
};

xcb_device::xcb_device(::Display *display, int screen,
					   xcb_connection_t *xcb_connection,
					   xcb_screen_t *xcb_screen, own<input_stream> &&an)
	: display{display}, screen{screen}, xcb_connection{xcb_connection},
	  xcb_screen{xcb_screen}, async_notifier{std::move(an)},
	  async_conveyor{async_notifier->read_ready()
						 .then([this]() { handle_events(); })
						 .sink()} {}

xcb_device::~xcb_device() {
	if (display) {
		xcb_flush(xcb_connection);
		::XCloseDisplay(display);
	}
}

void xcb_device::window_destroyed(xcb_window_t window_id) {
	windows.erase(window_id);
}

void xcb_device::handle_events() {
	while (xcb_generic_event_t *event = xcb_poll_for_event(xcb_connection)) {
		pending_events.push_back(event);
	}
	for (size_t i = 0; i < pending_events.size(); ++i) {
		xcb_generic_event_t *event = pending_events.at(i);
		switch (event->response_type & ~0x80) {
		case XCB_MOTION_NOTIFY: {
			xcb_motion_notify_event_t *motion =
				reinterpret_cast<xcb_motion_notify_event_t *>(event);
			auto find = windows.find(motion->event);
			if (find != windows.end()) {
				assert(find->second);
				find->second->mouse_move_event(motion->event_x,
											   motion->event_y);
			}
		} break;
		case XCB_EXPOSE: {
			xcb_expose_event_t *expose =
				reinterpret_cast<xcb_expose_event_t *>(event);
			auto find = windows.find(expose->window);
			if (find != windows.end()) {
				assert(find->second);
				find->second->resizeevent(static_cast<size_t>(expose->x),
										  static_cast<size_t>(expose->y),
										  static_cast<size_t>(expose->width),
										  static_cast<size_t>(expose->height));
			}
		} break;
		case XCB_BUTTON_RELEASE: {
			xcb_button_release_event_t *button =
				reinterpret_cast<xcb_button_release_event_t *>(event);
			auto find = windows.find(button->event);
			if (find != windows.end()) {
				assert(find->second);
				find->second->mouseevent(button->event_x, button->event_y,
										 button->detail, false);
			}
		} break;
		case XCB_BUTTON_PRESS: {
			xcb_button_press_event_t *button =
				reinterpret_cast<xcb_button_press_event_t *>(event);
			auto find = windows.find(button->event);
			if (find != windows.end()) {
				assert(find->second);
				find->second->mouseevent(button->event_x, button->event_y,
										 button->detail, true);
			}
		} break;
		case XCB_KEY_RELEASE: {
			xcb_key_release_event_t *key =
				reinterpret_cast<xcb_key_release_event_t *>(event);

			bool repeat = false;
			/*
			 * Peek into future events
			 */
			for (size_t j = i + 1; j < pending_events.size(); ++j) {
				xcb_generic_event_t *f_ev = pending_events.at(j);

				if ((f_ev->response_type & ~0x80) == XCB_KEY_PRESS) {
					xcb_key_press_event_t *f_key =
						reinterpret_cast<xcb_key_press_event_t *>(f_ev);

					if (key->detail == f_key->detail &&
						key->event == f_key->event) {
						auto iterator = pending_events.begin() + j;
						assert(iterator != pending_events.end());
						free(*iterator);
						pending_events.erase(iterator);
						repeat = true;
						break;
					}
				}
			}

			auto find = windows.find(key->event);
			if (find != windows.end()) {
				assert(find->second);
				find->second->keyboardevent(key->event_x, key->event_y,
											key->detail, repeat, repeat);
			}
		} break;
		case XCB_KEY_PRESS: {
			xcb_key_press_event_t *key =
				reinterpret_cast<xcb_key_press_event_t *>(event);
			auto find = windows.find(key->event);
			if (find != windows.end()) {
				assert(find->second);
				find->second->keyboardevent(key->event_x, key->event_y,
											key->detail, true, false);
			}
		} break;
		default:
			break;
		}
	}

	for (xcb_generic_event_t *event : pending_events) {
		free(event);
	}
	pending_events.clear();
}

own<xcb_window> xcb_device::create_xcb_window(const video_mode &video_mode,
											  std::string_view title_view,
											  int visual_id) {
	assert(xcb_screen);
	assert(xcb_connection);

	xcb_colormap_t xcb_colormap = xcb_generate_id(xcb_connection);
	xcb_window_t xcb_window = xcb_generate_id(xcb_connection);

	xcb_create_colormap(xcb_connection, XCB_COLORMAP_ALLOC_NONE, xcb_colormap,
						xcb_screen->root, visual_id);

	uint32_t eventmask =
		XCB_EVENT_MASK_EXPOSURE | XCB_EVENT_MASK_KEY_PRESS |
		XCB_EVENT_MASK_KEY_RELEASE | XCB_EVENT_MASK_BUTTON_PRESS |
		XCB_EVENT_MASK_BUTTON_RELEASE | XCB_EVENT_MASK_POINTER_MOTION |
		XCB_EVENT_MASK_BUTTON_MOTION;
	uint32_t valuelist[] = {eventmask, xcb_colormap, 0};
	uint32_t valuemask = XCB_CW_EVENT_MASK | XCB_CW_COLORMAP;

	xcb_create_window(xcb_connection, XCB_COPY_FROM_PARENT, xcb_window,
					  xcb_screen->root, 0, 0, video_mode.width,
					  video_mode.height, 0, XCB_WINDOW_CLASS_INPUT_OUTPUT,
					  visual_id, valuemask, valuelist);

	xcb_change_property(xcb_connection, XCB_PROP_MODE_REPLACE, xcb_window,
						XCB_ATOM_WM_NAME, XCB_ATOM_STRING, 8, title_view.size(),
						title_view.data());

	xcb_flush(xcb_connection);
	auto window = heap<class xcb_window>(*this, xcb_window, xcb_colormap,
										 video_mode, title_view);
	windows[xcb_window] = window.get();

	return window;
}

own<window> xcb_device::create_window(const video_mode &video_mode,
									  std::string_view title_view) {
	assert(xcb_screen);
	return create_xcb_window(video_mode, title_view, xcb_screen->root_visual);
}

void xcb_device::flush() {
	assert(xcb_connection);
	xcb_flush(xcb_connection);
}

own<xcb_device> create_xcb_device(io_provider &provider) {
	::Display *display = ::XOpenDisplay(nullptr);
	if (!display) {
		/// @todo log errors
		return nullptr;
	}

	int screen = ::XDefaultScreen(display);

	xcb_connection_t *xcb_connection = ::XGetXCBConnection(display);
	if (!xcb_connection) {
		/// @todo log errors
		::XCloseDisplay(display);
		return nullptr;
	}

	int fd = xcb_get_file_descriptor(xcb_connection);

	own<input_stream> fd_wrapped = provider.wrap_input_fd(fd);
	if (!fd_wrapped) {
		::XCloseDisplay(display);
		return nullptr;
	}

	::XSetEventQueueOwner(display, XCBOwnsEventQueue);

	xcb_screen_iterator_t screen_iter =
		xcb_setup_roots_iterator(xcb_get_setup(xcb_connection));
	for (int screen_i = screen; screen_iter.rem && screen_i > 0;
		 --screen_i, xcb_screen_next(&screen_iter))
		;

	xcb_screen_t *xcb_screen = screen_iter.data;

	return heap<xcb_device>(display, screen, xcb_connection, xcb_screen,
							std::move(fd_wrapped));
}

own<device> createdevice(io_provider &provider) {
	return create_xcb_device(provider);
}

xcb_window::xcb_window(xcb_device &dev, xcb_window_t xcb_win,
					   xcb_colormap_t xcb_colmap, const video_mode &vid_mode,
					   std::string_view title_view_)
	: device_{dev}, xcb_window_{xcb_win}, xcb_colormap_{xcb_colmap},
	  video_mode_{vid_mode}, window_title_{title_view_} {}

xcb_window::~xcb_window() {
	device_.window_destroyed(xcb_window_);
	xcb_destroy_window(device_.xcb_connection, xcb_window_);
	device_.flush();
}

void xcb_window::show() {
	assert(device_.xcb_connection);
	xcb_map_window(device_.xcb_connection, xcb_window_);
}

void xcb_window::hide() {
	assert(device_.xcb_connection);
	xcb_unmap_window(device_.xcb_connection, xcb_window_);
}

const video_mode &xcb_window::videoMode() const { return video_mode_; }

const std::string_view xcb_window::title() const { return window_title_; }

void xcb_window::resize(size_t width, size_t height) {
	const uint32_t values[2] = {static_cast<uint32_t>(width),
								static_cast<uint32_t>(height)};

	xcb_configure_window(device_.xcb_connection, xcb_window_,
						 XCB_CONFIG_WINDOW_WIDTH | XCB_CONFIG_WINDOW_HEIGHT,
						 values);
	video_mode_.width = width;
	video_mode_.height = height;
}

conveyor<window::variant_event> xcb_window::onevent() {
	auto caf = new_conveyor_and_feeder<window::variant_event>();
	event_feeder = std::move(caf.feeder);
	return std::move(caf.conveyor);
}

void xcb_window::resizeevent(size_t x, size_t y, size_t width, size_t height) {
	(void)x;
	(void)y;
	/// @todo maybe include x and y?
	video_mode_.width = width;
	video_mode_.height = height;

	if (event_feeder) {
		event_feeder->feed(
			window::variant_event{window::event::resize{width, height}});
	}
}

void xcb_window::mouseevent(int16_t x, int16_t y, uint16_t state,
							bool pressed) {
	if (x < 0 || y < 0) {
		return;
	}
	uint32_t ux = static_cast<uint32_t>(x);
	uint32_t uy = static_cast<uint32_t>(y);
	if (ux >= video_mode_.width || uy >= video_mode_.height) {
		return;
	}
	if (event_feeder) {
		event_feeder->feed(window::variant_event{
			window::event::mouse{state, pressed, ux, uy}});
	}
}

void xcb_window::mouse_move_event(int16_t x, int16_t y) {
	if (x < 0 || y < 0) {
		return;
	}
	uint32_t ux = static_cast<uint32_t>(x);
	uint32_t uy = static_cast<uint32_t>(y);
	if (ux >= video_mode_.width || uy >= video_mode_.height) {
		return;
	}
	if (event_feeder) {
		event_feeder->feed(
			window::variant_event{window::event::mouse_move{ux, uy}});
	}
}

void xcb_window::keyboardevent(int16_t x, int16_t y, uint32_t keycode,
							   bool pressed, bool repeat) {
	if (x < 0 || y < 0) {
		return;
	}
	uint32_t ux = static_cast<uint32_t>(x);
	uint32_t uy = static_cast<uint32_t>(y);
	if (ux >= video_mode_.width || uy >= video_mode_.height) {
		return;
	}
	if (event_feeder) {
		event_feeder->feed(window::variant_event{
			window::event::keyboard{keycode, keycode, pressed, repeat}});
	}
}

} // namespace saw