/*
  Copyright 2012-2019 David Robillard <http://drobilla.net>

  Permission to use, copy, modify, and/or distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

/**
   @file win.c Windows implementation.
*/

#include "pugl/detail/implementation.h"
#include "pugl/detail/win.h"
#include "pugl/pugl.h"
#include "pugl/pugl_stub.h"

#include <windows.h>
#include <windowsx.h>

#include <math.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wctype.h>

#ifndef WM_MOUSEWHEEL
#    define WM_MOUSEWHEEL 0x020A
#endif
#ifndef WM_MOUSEHWHEEL
#    define WM_MOUSEHWHEEL 0x020E
#endif
#ifndef WHEEL_DELTA
#    define WHEEL_DELTA 120
#endif
#ifndef GWLP_USERDATA
#    define GWLP_USERDATA (-21)
#endif

#define PUGL_LOCAL_CLOSE_MSG (WM_USER + 50)
#define PUGL_LOCAL_MARK_MSG  (WM_USER + 51)
#define PUGL_RESIZE_TIMER_ID 9461
#define PUGL_URGENT_TIMER_ID 9462

typedef BOOL (WINAPI *PFN_SetProcessDPIAware)(void);

LRESULT CALLBACK
wndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);

static wchar_t*
puglUtf8ToWideChar(const char* const utf8)
{
	const int len = MultiByteToWideChar(CP_UTF8, 0, utf8, -1, NULL, 0);
	if (len > 0) {
		wchar_t* result = (wchar_t*)calloc((size_t)len, sizeof(wchar_t));
		MultiByteToWideChar(CP_UTF8, 0, utf8, -1, result, len);
		return result;
	}

	return NULL;
}

static char*
puglWideCharToUtf8(const wchar_t* const wstr, size_t* len)
{
	int n = WideCharToMultiByte(CP_UTF8, 0, wstr, -1, NULL, 0, NULL, NULL);
	if (n > 0) {
		char* result = (char*)calloc((size_t)n, sizeof(char));
		WideCharToMultiByte(CP_UTF8, 0, wstr, -1, result, n, NULL, NULL);
		*len = (size_t)n;
		return result;
	}

	return NULL;
}

static bool
puglRegisterWindowClass(const char* name)
{
	WNDCLASSEX wc = { 0 };
	if (GetClassInfoEx(GetModuleHandle(NULL), name, &wc)) {
		return true; // Already registered
	}

	wc.cbSize        = sizeof(wc);
	wc.style         = CS_OWNDC;
	wc.lpfnWndProc   = wndProc;
	wc.hInstance     = GetModuleHandle(NULL);
	wc.hIcon         = LoadIcon(NULL, IDI_APPLICATION);
	wc.hCursor       = LoadCursor(NULL, IDC_ARROW);
	wc.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
	wc.lpszClassName = name;

	return RegisterClassEx(&wc);
}

PuglWorldInternals*
puglInitWorldInternals(void)
{
	PuglWorldInternals* impl = (PuglWorldInternals*)calloc(
		1, sizeof(PuglWorldInternals));
	if (!impl) {
		return NULL;
	}

	HMODULE user32 = LoadLibrary("user32.dll");
	if (user32) {
		PFN_SetProcessDPIAware SetProcessDPIAware =
			(PFN_SetProcessDPIAware)GetProcAddress(
				user32, "SetProcessDPIAware");
		if (SetProcessDPIAware) {
			SetProcessDPIAware();
		}

		FreeLibrary(user32);
	}

	LARGE_INTEGER frequency;
	QueryPerformanceFrequency(&frequency);
	impl->timerFrequency = (double)frequency.QuadPart;

	return impl;
}

void*
puglGetNativeWorld(PuglWorld* PUGL_UNUSED(world))
{
	return GetModuleHandle(NULL);
}

PuglInternals*
puglInitViewInternals(void)
{
	return (PuglInternals*)calloc(1, sizeof(PuglInternals));
}

PuglStatus
puglPollEvents(PuglWorld* world, const double timeout)
{
	(void)world;

	if (timeout < 0) {
		WaitMessage();
	} else {
		MsgWaitForMultipleObjects(
			0, NULL, FALSE, (DWORD)(timeout * 1e3), QS_ALLEVENTS);
	}
	return PUGL_SUCCESS;
}

PuglStatus
puglCreateWindow(PuglView* view, const char* title)
{
	PuglInternals* impl = view->impl;

	title = title ? title : view->world->className;

	// Get refresh rate for resize draw timer
	DEVMODEA devMode = {0};
	EnumDisplaySettingsA(NULL, ENUM_CURRENT_SETTINGS, &devMode);
	view->impl->refreshRate = devMode.dmDisplayFrequency;

	// Register window class if necessary
	if (!puglRegisterWindowClass(view->world->className)) {
		return PUGL_REGISTRATION_FAILED;
	}

	if (!view->backend || !view->backend->configure) {
		return PUGL_BAD_BACKEND;
	}

	PuglStatus st = view->backend->configure(view);
	if (st) {
		return PUGL_SET_FORMAT_FAILED;
	} else if ((st = view->backend->create(view))) {
		return PUGL_CREATE_CONTEXT_FAILED;
	}

	if (title) {
		puglSetWindowTitle(view, title);
	}

	SetWindowLongPtr(impl->hwnd, GWLP_USERDATA, (LONG_PTR)view);

	return PUGL_SUCCESS;
}

PuglStatus
puglShowWindow(PuglView* view)
{
	PuglInternals* impl = view->impl;

	ShowWindow(impl->hwnd, SW_SHOWNORMAL);
	SetFocus(impl->hwnd);
	view->visible = true;
	return PUGL_SUCCESS;
}

PuglStatus
puglHideWindow(PuglView* view)
{
	PuglInternals* impl = view->impl;

	ShowWindow(impl->hwnd, SW_HIDE);
	view->visible = false;
	return PUGL_SUCCESS;
}

void
puglFreeViewInternals(PuglView* view)
{
	if (view) {
		if (view->backend) {
			view->backend->destroy(view);
		}

		ReleaseDC(view->impl->hwnd, view->impl->hdc);
		DestroyWindow(view->impl->hwnd);
		free(view->impl);
	}
}

void
puglFreeWorldInternals(PuglWorld* world)
{
	UnregisterClass(world->className, NULL);
	free(world->impl);
}

static PuglKey
keySymToSpecial(WPARAM sym)
{
	switch (sym) {
	case VK_F1:       return PUGL_KEY_F1;
	case VK_F2:       return PUGL_KEY_F2;
	case VK_F3:       return PUGL_KEY_F3;
	case VK_F4:       return PUGL_KEY_F4;
	case VK_F5:       return PUGL_KEY_F5;
	case VK_F6:       return PUGL_KEY_F6;
	case VK_F7:       return PUGL_KEY_F7;
	case VK_F8:       return PUGL_KEY_F8;
	case VK_F9:       return PUGL_KEY_F9;
	case VK_F10:      return PUGL_KEY_F10;
	case VK_F11:      return PUGL_KEY_F11;
	case VK_F12:      return PUGL_KEY_F12;
	case VK_BACK:     return PUGL_KEY_BACKSPACE;
	case VK_DELETE:   return PUGL_KEY_DELETE;
	case VK_LEFT:     return PUGL_KEY_LEFT;
	case VK_UP:       return PUGL_KEY_UP;
	case VK_RIGHT:    return PUGL_KEY_RIGHT;
	case VK_DOWN:     return PUGL_KEY_DOWN;
	case VK_PRIOR:    return PUGL_KEY_PAGE_UP;
	case VK_NEXT:     return PUGL_KEY_PAGE_DOWN;
	case VK_HOME:     return PUGL_KEY_HOME;
	case VK_END:      return PUGL_KEY_END;
	case VK_INSERT:   return PUGL_KEY_INSERT;
	case VK_SHIFT:
	case VK_LSHIFT:   return PUGL_KEY_SHIFT_L;
	case VK_RSHIFT:   return PUGL_KEY_SHIFT_R;
	case VK_CONTROL:
	case VK_LCONTROL: return PUGL_KEY_CTRL_L;
	case VK_RCONTROL: return PUGL_KEY_CTRL_R;
	case VK_MENU:
	case VK_LMENU:    return PUGL_KEY_ALT_L;
	case VK_RMENU:    return PUGL_KEY_ALT_R;
	case VK_LWIN:     return PUGL_KEY_SUPER_L;
	case VK_RWIN:     return PUGL_KEY_SUPER_R;
	case VK_CAPITAL:  return PUGL_KEY_CAPS_LOCK;
	case VK_SCROLL:   return PUGL_KEY_SCROLL_LOCK;
	case VK_NUMLOCK:  return PUGL_KEY_NUM_LOCK;
	case VK_SNAPSHOT: return PUGL_KEY_PRINT_SCREEN;
	case VK_PAUSE:    return PUGL_KEY_PAUSE;
	}
	return (PuglKey)0;
}

static uint32_t
getModifiers(void)
{
	return (((GetKeyState(VK_SHIFT)   < 0) ? PUGL_MOD_SHIFT  : 0u) |
	        ((GetKeyState(VK_CONTROL) < 0) ? PUGL_MOD_CTRL   : 0u) |
	        ((GetKeyState(VK_MENU)    < 0) ? PUGL_MOD_ALT    : 0u) |
	        ((GetKeyState(VK_LWIN)    < 0) ? PUGL_MOD_SUPER  : 0u) |
	        ((GetKeyState(VK_RWIN)    < 0) ? PUGL_MOD_SUPER  : 0u));
}

static void
initMouseEvent(PuglEvent* event,
               PuglView*  view,
               int        button,
               bool       press,
               LPARAM     lParam)
{
	POINT pt = { GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam) };
	ClientToScreen(view->impl->hwnd, &pt);

	if (press) {
		SetCapture(view->impl->hwnd);
	} else {
		ReleaseCapture();
	}

	event->button.time   = GetMessageTime() / 1e3;
	event->button.type   = press ? PUGL_BUTTON_PRESS : PUGL_BUTTON_RELEASE;
	event->button.x      = GET_X_LPARAM(lParam);
	event->button.y      = GET_Y_LPARAM(lParam);
	event->button.xRoot  = pt.x;
	event->button.yRoot  = pt.y;
	event->button.state  = getModifiers();
	event->button.button = (uint32_t)button;
}

static void
initScrollEvent(PuglEvent* event, PuglView* view, LPARAM lParam)
{
	POINT pt = { GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam) };
	ScreenToClient(view->impl->hwnd, &pt);

	event->scroll.time   = GetMessageTime() / 1e3;
	event->scroll.type   = PUGL_SCROLL;
	event->scroll.x      = pt.x;
	event->scroll.y      = pt.y;
	event->scroll.xRoot  = GET_X_LPARAM(lParam);
	event->scroll.yRoot  = GET_Y_LPARAM(lParam);
	event->scroll.state  = getModifiers();
	event->scroll.dx     = 0;
	event->scroll.dy     = 0;
}

/** Return the code point for buf, or the replacement character on error. */
static uint32_t
puglDecodeUTF16(const wchar_t* buf, const int len)
{
	const uint32_t c0 = buf[0];
	const uint32_t c1 = buf[0];
	if (c0 >= 0xD800 && c0 < 0xDC00) {
		if (len < 2) {
			return 0xFFFD;  // Surrogate, but length is only 1
		} else if (c1 >= 0xDC00 && c1 <= 0xDFFF) {
			return ((c0 & 0x03FF) << 10) + (c1 & 0x03FF) + 0x10000;
		}

		return 0xFFFD;  // Unpaired surrogates
	}

	return c0;
}

static void
initKeyEvent(PuglEventKey* event,
             PuglView*     view,
             bool          press,
             WPARAM        wParam,
             LPARAM        lParam)
{
	POINT rpos = { 0, 0 };
	GetCursorPos(&rpos);

	POINT cpos = { rpos.x, rpos.y };
	ScreenToClient(view->impl->hwnd, &rpos);

	const unsigned scode = (uint32_t)((lParam & 0xFF0000) >> 16);
	const unsigned vkey  = ((wParam == VK_SHIFT)
	                        ? MapVirtualKey(scode, MAPVK_VSC_TO_VK_EX)
	                        : (unsigned)wParam);

	const unsigned vcode = MapVirtualKey(vkey, MAPVK_VK_TO_VSC);
	const unsigned kchar = MapVirtualKey(vkey, MAPVK_VK_TO_CHAR);
	const bool     dead  = kchar >> (sizeof(UINT) * 8 - 1) & 1;
	const bool     ext   = lParam & 0x01000000;

	event->type    = press ? PUGL_KEY_PRESS : PUGL_KEY_RELEASE;
	event->time    = GetMessageTime() / 1e3;
	event->state   = getModifiers();
	event->xRoot   = rpos.x;
	event->yRoot   = rpos.y;
	event->x       = cpos.x;
	event->y       = cpos.y;
	event->keycode = (uint32_t)((lParam & 0xFF0000) >> 16);
	event->key     = 0;

	const PuglKey special = keySymToSpecial(vkey);
	if (special) {
		if (ext && (special == PUGL_KEY_CTRL || special == PUGL_KEY_ALT)) {
			event->key = special + 1u; // Right hand key
		} else {
			event->key = special;
		}
	} else if (!dead) {
		// Translate unshifted key
		BYTE    keyboardState[256] = {0};
		wchar_t buf[5]             = {0};
		const int ulen = ToUnicode(vkey, vcode, keyboardState, buf, 4, 1<<2);
		event->key = puglDecodeUTF16(buf, ulen);
	}
}

static void
initCharEvent(PuglEvent* event, PuglView* view, WPARAM wParam, LPARAM lParam)
{
	const wchar_t utf16[2] = { wParam & 0xFFFF, (wParam >> 16) & 0xFFFF };

	initKeyEvent(&event->key, view, true, wParam, lParam);
	event->type           = PUGL_TEXT;
	event->text.character = puglDecodeUTF16(utf16, 2);

	if (!WideCharToMultiByte(
		    CP_UTF8, 0, utf16, 2, event->text.string, 8, NULL, NULL)) {
		memset(event->text.string, 0, 8);
	}
}

static bool
ignoreKeyEvent(PuglView* view, LPARAM lParam)
{
	return view->hints[PUGL_IGNORE_KEY_REPEAT] && (lParam & (1 << 30));
}

static RECT
handleConfigure(PuglView* view, PuglEvent* event)
{
	RECT rect;
	GetClientRect(view->impl->hwnd, &rect);
	MapWindowPoints(view->impl->hwnd,
	                view->parent ? (HWND)view->parent : HWND_DESKTOP,
	                (LPPOINT)&rect,
	                2);

	const LONG width  = rect.right - rect.left;
	const LONG height = rect.bottom - rect.top;

	view->frame.x = rect.left;
	view->frame.y = rect.top;

	event->configure.type   = PUGL_CONFIGURE;
	event->configure.x      = view->frame.x;
	event->configure.y      = view->frame.y;
	event->configure.width  = width;
	event->configure.height = height;

	if (view->frame.width != width || view->frame.height != height) {
		view->frame.width  = width;
		view->frame.height = height;

		view->backend->resize(view, width, height);
	}

	return rect;
}

static void
handleCrossing(PuglView* view, const PuglEventType type, POINT pos)
{
	POINT root_pos = pos;
	ClientToScreen(view->impl->hwnd, &root_pos);

	const PuglEventCrossing ev = {
		type,
		0,
		GetMessageTime() / 1e3,
		(double)pos.x,
		(double)pos.y,
		(double)root_pos.x,
		(double)root_pos.y,
		getModifiers(),
		PUGL_CROSSING_NORMAL
	};
	puglDispatchEvent(view, (const PuglEvent*)&ev);
}

static void
stopFlashing(PuglView* view)
{
	if (view->impl->flashing) {
		KillTimer(view->impl->hwnd, PUGL_URGENT_TIMER_ID);
		FlashWindow(view->impl->hwnd, FALSE);
	}
}

static void
constrainAspect(const PuglView* const view,
                RECT* const           size,
                const WPARAM          wParam)
{
	const float minA = (float)view->minAspectX / (float)view->minAspectY;
	const float maxA = (float)view->maxAspectX / (float)view->maxAspectY;
	const int   w    = size->right - size->left;
	const int   h    = size->bottom - size->top;
	const float a    = (float)w / (float)h;

	switch (wParam) {
	case WMSZ_TOP:
		size->top = (a < minA ? (LONG)(size->bottom - w * minA) :
		             a > maxA ? (LONG)(size->bottom - w * maxA) :
		             size->top);
		break;
	case WMSZ_TOPRIGHT:
	case WMSZ_RIGHT:
	case WMSZ_BOTTOMRIGHT:
		size->right = (a < minA ? (LONG)(size->left + h * minA) :
		               a > maxA ? (LONG)(size->left + h * maxA) :
		               size->right);
		break;
	case WMSZ_BOTTOM:
		size->bottom = (a < minA ? (LONG)(size->top + w * minA) :
		                a > maxA ? (LONG)(size->top + w * maxA) :
		                size->bottom);
		break;
	case WMSZ_BOTTOMLEFT:
	case WMSZ_LEFT:
	case WMSZ_TOPLEFT:
		size->left = (a < minA ? (LONG)(size->right - h * minA) :
		              a > maxA ? (LONG)(size->right - h * maxA) :
		              size->left);
		break;
	}
}

static LRESULT
handleMessage(PuglView* view, UINT message, WPARAM wParam, LPARAM lParam)
{
	PuglEvent   event;
	void*       dummy_ptr = NULL;
	RECT        rect;
	MINMAXINFO* mmi;
	POINT       pt;

	memset(&event, 0, sizeof(event));

	event.any.type = PUGL_NOTHING;
	if (InSendMessageEx(dummy_ptr)) {
		event.any.flags |= PUGL_IS_SEND_EVENT;
	}

	switch (message) {
	case WM_SHOWWINDOW:
		rect = handleConfigure(view, &event);
		RedrawWindow(view->impl->hwnd, NULL, NULL,
		             RDW_INVALIDATE|RDW_ALLCHILDREN|RDW_INTERNALPAINT);
		break;
	case WM_SIZE:
		rect = handleConfigure(view, &event);
		InvalidateRect(view->impl->hwnd, NULL, false);
		break;
	case WM_SIZING:
		if (view->minAspectX) {
			constrainAspect(view, (RECT*)lParam, wParam);
			return TRUE;
		}
		break;
	case WM_ENTERSIZEMOVE:
	case WM_ENTERMENULOOP:
		view->impl->resizing = true;
		SetTimer(view->impl->hwnd,
		         PUGL_RESIZE_TIMER_ID,
		         1000 / view->impl->refreshRate,
		         NULL);
		break;
	case WM_TIMER:
		if (wParam == PUGL_RESIZE_TIMER_ID) {
			RedrawWindow(view->impl->hwnd, NULL, NULL,
			             RDW_INVALIDATE|RDW_ALLCHILDREN|RDW_INTERNALPAINT);
		} else if (wParam == PUGL_URGENT_TIMER_ID) {
			FlashWindow(view->impl->hwnd, TRUE);
		}
		break;
	case WM_EXITSIZEMOVE:
	case WM_EXITMENULOOP:
		KillTimer(view->impl->hwnd, PUGL_RESIZE_TIMER_ID);
		view->impl->resizing = false;
		puglPostRedisplay(view);
		break;
	case WM_GETMINMAXINFO:
		mmi                   = (MINMAXINFO*)lParam;
		mmi->ptMinTrackSize.x = view->minWidth;
		mmi->ptMinTrackSize.y = view->minHeight;
		break;
	case WM_PAINT:
		GetUpdateRect(view->impl->hwnd, &rect, false);
		event.expose.type   = PUGL_EXPOSE;
		event.expose.x      = rect.left;
		event.expose.y      = rect.top;
		event.expose.width  = rect.right - rect.left;
		event.expose.height = rect.bottom - rect.top;
		event.expose.count  = 0;
		break;
	case WM_ERASEBKGND:
		return true;
	case WM_MOUSEMOVE:
		pt.x = GET_X_LPARAM(lParam);
		pt.y = GET_Y_LPARAM(lParam);

		if (!view->impl->mouseTracked) {
			TRACKMOUSEEVENT tme = {0};
			tme.cbSize    = sizeof(tme);
			tme.dwFlags   = TME_LEAVE;
			tme.hwndTrack = view->impl->hwnd;
			TrackMouseEvent(&tme);

			stopFlashing(view);
			handleCrossing(view, PUGL_ENTER_NOTIFY, pt);
			view->impl->mouseTracked = true;
		}

		ClientToScreen(view->impl->hwnd, &pt);
		event.motion.type    = PUGL_MOTION_NOTIFY;
		event.motion.time    = GetMessageTime() / 1e3;
		event.motion.x       = GET_X_LPARAM(lParam);
		event.motion.y       = GET_Y_LPARAM(lParam);
		event.motion.xRoot   = pt.x;
		event.motion.yRoot   = pt.y;
		event.motion.state   = getModifiers();
		event.motion.isHint  = false;
		break;
	case WM_MOUSELEAVE:
		GetCursorPos(&pt);
		ScreenToClient(view->impl->hwnd, &pt);
		handleCrossing(view, PUGL_LEAVE_NOTIFY, pt);
		view->impl->mouseTracked = false;
		break;
	case WM_LBUTTONDOWN:
		initMouseEvent(&event, view, 1, true, lParam);
		break;
	case WM_MBUTTONDOWN:
		initMouseEvent(&event, view, 2, true, lParam);
		break;
	case WM_RBUTTONDOWN:
		initMouseEvent(&event, view, 3, true, lParam);
		break;
	case WM_LBUTTONUP:
		initMouseEvent(&event, view, 1, false, lParam);
		break;
	case WM_MBUTTONUP:
		initMouseEvent(&event, view, 2, false, lParam);
		break;
	case WM_RBUTTONUP:
		initMouseEvent(&event, view, 3, false, lParam);
		break;
	case WM_MOUSEWHEEL:
		initScrollEvent(&event, view, lParam);
		event.scroll.dy = GET_WHEEL_DELTA_WPARAM(wParam) / (float)WHEEL_DELTA;
		break;
	case WM_MOUSEHWHEEL:
		initScrollEvent(&event, view, lParam);
		event.scroll.dx = GET_WHEEL_DELTA_WPARAM(wParam) / (float)WHEEL_DELTA;
		break;
	case WM_KEYDOWN:
		if (!ignoreKeyEvent(view, lParam)) {
			initKeyEvent(&event.key, view, true, wParam, lParam);
		}
		break;
	case WM_KEYUP:
		initKeyEvent(&event.key, view, false, wParam, lParam);
		break;
	case WM_CHAR:
		initCharEvent(&event, view, wParam, lParam);
		break;
	case WM_SETFOCUS:
		stopFlashing(view);
		event.type = PUGL_FOCUS_IN;
		break;
	case WM_KILLFOCUS:
		event.type = PUGL_FOCUS_OUT;
		break;
	case WM_SYSKEYDOWN:
		initKeyEvent(&event.key, view, true, wParam, lParam);
		break;
	case WM_SYSKEYUP:
		initKeyEvent(&event.key, view, false, wParam, lParam);
		break;
	case WM_SYSCHAR:
		return TRUE;
	case WM_QUIT:
	case PUGL_LOCAL_CLOSE_MSG:
		event.close.type = PUGL_CLOSE;
		break;
	default:
		return DefWindowProc(view->impl->hwnd, message, wParam, lParam);
	}

	puglDispatchEvent(view, &event);

	return 0;
}

PuglStatus
puglGrabFocus(PuglView* view)
{
	SetFocus(view->impl->hwnd);
	return PUGL_SUCCESS;
}

bool
puglHasFocus(const PuglView* view)
{
	return GetFocus() == view->impl->hwnd;
}

PuglStatus
puglRequestAttention(PuglView* view)
{
	if (!view->impl->mouseTracked || !puglHasFocus(view)) {
		FlashWindow(view->impl->hwnd, TRUE);
		SetTimer(view->impl->hwnd, PUGL_URGENT_TIMER_ID, 500, NULL);
		view->impl->flashing = true;
	}

	return PUGL_SUCCESS;
}

PuglStatus
puglWaitForEvent(PuglView* PUGL_UNUSED(view))
{
	WaitMessage();
	return PUGL_SUCCESS;
}

PUGL_API PuglStatus
puglDispatchEvents(PuglWorld* PUGL_UNUSED(world))
{
	/* Windows has no facility to process only currently queued messages, which
	   causes the event loop to run forever in cases like mouse movement where
	   the queue is constantly being filled with new messages.  To work around
	   this, we post a message to ourselves before starting, record its time
	   when it is received, then break the loop on the first message that was
	   created afterwards. */
	PostMessage(NULL, PUGL_LOCAL_MARK_MSG, 0, 0);

	long markTime = 0;
	MSG  msg;
	while (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) {
		if (msg.message == PUGL_LOCAL_MARK_MSG) {
			markTime = GetMessageTime();
		} else {
			TranslateMessage(&msg);
			DispatchMessage(&msg);
			if (markTime != 0 && GetMessageTime() > markTime) {
				break;
			}
		}
	}

	return PUGL_SUCCESS;
}

PuglStatus
puglProcessEvents(PuglView* view)
{
	return puglDispatchEvents(view->world);
}

LRESULT CALLBACK
wndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	PuglView* view = (PuglView*)GetWindowLongPtr(hwnd, GWLP_USERDATA);

	switch (message) {
	case WM_CREATE:
		PostMessage(hwnd, WM_SHOWWINDOW, TRUE, 0);
		return 0;
	case WM_CLOSE:
		PostMessage(hwnd, PUGL_LOCAL_CLOSE_MSG, wParam, lParam);
		return 0;
	case WM_DESTROY:
		return 0;
	default:
		if (view && hwnd == view->impl->hwnd) {
			return handleMessage(view, message, wParam, lParam);
		} else {
			return DefWindowProc(hwnd, message, wParam, lParam);
		}
	}
}

double
puglGetTime(const PuglWorld* world)
{
	LARGE_INTEGER count;
	QueryPerformanceCounter(&count);
	return ((double)count.QuadPart / world->impl->timerFrequency -
	        world->startTime);
}

PuglStatus
puglPostRedisplay(PuglView* view)
{
	InvalidateRect(view->impl->hwnd, NULL, false);
	return PUGL_SUCCESS;
}

PuglStatus
puglPostRedisplayRect(PuglView* view, const PuglRect rect)
{
	const RECT r = {(long)floor(rect.x),
	                (long)floor(rect.y),
	                (long)ceil(rect.x + rect.width),
	                (long)ceil(rect.y + rect.height)};

	InvalidateRect(view->impl->hwnd, &r, false);

	return PUGL_SUCCESS;
}

PuglNativeWindow
puglGetNativeWindow(PuglView* view)
{
	return (PuglNativeWindow)view->impl->hwnd;
}

PuglStatus
puglSetWindowTitle(PuglView* view, const char* title)
{
	puglSetString(&view->title, title);

	wchar_t* wtitle = puglUtf8ToWideChar(title);
	if (wtitle) {
		SetWindowTextW(view->impl->hwnd, wtitle);
		free(wtitle);
	}

	return PUGL_SUCCESS;
}

PuglStatus
puglSetFrame(PuglView* view, const PuglRect frame)
{
	view->frame = frame;

	if (view->impl->hwnd) {
		RECT rect = { (long)frame.x,
		              (long)frame.y,
		              (long)frame.x + (long)frame.width,
		              (long)frame.y + (long)frame.height };

		AdjustWindowRectEx(&rect, puglWinGetWindowFlags(view),
		                   FALSE,
		                   puglWinGetWindowExFlags(view));

		if (!SetWindowPos(view->impl->hwnd, HWND_TOP,
		                  rect.left, rect.top,
		                  rect.right - rect.left, rect.bottom - rect.top,
		                  (SWP_NOACTIVATE|SWP_NOOWNERZORDER|SWP_NOZORDER))) {
			return PUGL_UNKNOWN_ERROR;
		}
	}

	return PUGL_SUCCESS;
}

PuglStatus
puglSetMinSize(PuglView* const view, const int width, const int height)
{
	view->minWidth  = width;
	view->minHeight = height;
	return PUGL_SUCCESS;
}

PuglStatus
puglSetAspectRatio(PuglView* const view,
                   const int       minX,
                   const int       minY,
                   const int       maxX,
                   const int       maxY)
{
	view->minAspectX = minX;
	view->minAspectY = minY;
	view->maxAspectX = maxX;
	view->maxAspectY = maxY;
	return PUGL_SUCCESS;
}

const void*
puglGetClipboard(PuglView* const    view,
                 const char** const type,
                 size_t* const      len)
{
	PuglInternals* const impl = view->impl;

	if (!IsClipboardFormatAvailable(CF_UNICODETEXT) ||
	    !OpenClipboard(impl->hwnd)) {
		return NULL;
	}

	HGLOBAL  mem  = GetClipboardData(CF_UNICODETEXT);
	wchar_t* wstr = mem ? (wchar_t*)GlobalLock(mem) : NULL;
	if (!wstr) {
		CloseClipboard();
		return NULL;
	}

	free(view->clipboard.data);
	view->clipboard.data = puglWideCharToUtf8(wstr, &view->clipboard.len);
	GlobalUnlock(mem);
	CloseClipboard();

	return puglGetInternalClipboard(view, type, len);
}

PuglStatus
puglSetClipboard(PuglView* const   view,
                 const char* const type,
                 const void* const data,
                 const size_t      len)
{
	PuglInternals* const impl = view->impl;

	PuglStatus st = puglSetInternalClipboard(view, type, data, len);
	if (st) {
		return st;
	} else if (!OpenClipboard(impl->hwnd)) {
		return PUGL_UNKNOWN_ERROR;
	}

	// Measure string and allocate global memory for clipboard
	const char* str  = (const char*)data;
	const int   wlen = MultiByteToWideChar(CP_UTF8, 0, str, -1, NULL, 0);
	HGLOBAL     mem  = GlobalAlloc(GMEM_MOVEABLE, (wlen + 1) * sizeof(wchar_t));
	if (!mem) {
		CloseClipboard();
		return PUGL_UNKNOWN_ERROR;
	}

	// Lock global memory
	wchar_t* wstr = (wchar_t*)GlobalLock(mem);
	if (!wstr) {
		GlobalFree(mem);
		CloseClipboard();
		return PUGL_UNKNOWN_ERROR;
	}

	// Convert string into global memory and set it as clipboard data
	MultiByteToWideChar(CP_UTF8, 0, str, (int)len, wstr, wlen);
	wstr[wlen] = 0;
	GlobalUnlock(mem);
	SetClipboardData(CF_UNICODETEXT, mem);
	CloseClipboard();
	return PUGL_SUCCESS;
}

static PuglStatus
puglWinStubEnter(PuglView* view, bool drawing)
{
	if (drawing) {
		PAINTSTRUCT ps;
		BeginPaint(view->impl->hwnd, &ps);
	}

	return PUGL_SUCCESS;
}

static PuglStatus
puglWinStubLeave(PuglView* view, bool drawing)
{
	if (drawing) {
		PAINTSTRUCT ps;
		EndPaint(view->impl->hwnd, &ps);
		SwapBuffers(view->impl->hdc);
	}

	return PUGL_SUCCESS;
}

const PuglBackend*
puglStubBackend(void)
{
	static const PuglBackend backend = {puglWinStubConfigure,
	                                    puglStubCreate,
	                                    puglStubDestroy,
	                                    puglWinStubEnter,
	                                    puglWinStubLeave,
	                                    puglStubResize,
	                                    puglStubGetContext};

	return &backend;
}
