/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 */

// Disable symbol overrides so that we can use system headers.
#define FORBIDDEN_SYMBOL_ALLOW_ALL

#include "backends/platform/ios7/ios7_video.h"

#include "graphics/colormasks.h"
#include "common/system.h"
#include "backends/platform/ios7/ios7_app_delegate.h"

static int g_needsScreenUpdate = 0;

#if 0
static long g_lastTick = 0;
static int g_frames = 0;
#endif

void printError(const char *error_message) {
	NSString *messageString = [NSString stringWithUTF8String:error_message];
	NSLog(@"%@", messageString);
	fprintf(stderr, "%s\n", error_message);
}

#define printOpenGLError() printOglError(__FILE__, __LINE__)

void printOglError(const char *file, int line) {
	GLenum glErr = glGetError();
	while (glErr != GL_NO_ERROR) {
		Common::String error = Common::String::format("glError: %u (%s: %d)", glErr, file, line);
		printError(error.c_str());
		glErr = glGetError();
	}
}

bool iOS7_isBigDevice() {
	return UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad;
}

static inline void execute_on_main_thread(void (^block)(void)) {
	if ([NSThread currentThread] == [NSThread mainThread]) {
		block();
	}
	else {
		dispatch_sync(dispatch_get_main_queue(), block);
	}
}

void iOS7_updateScreen() {
	//printf("Mouse: (%i, %i)\n", mouseX, mouseY);
	if (!g_needsScreenUpdate) {
		g_needsScreenUpdate = 1;
		execute_on_main_thread(^{
			[[iOS7AppDelegate iPhoneView] updateSurface];
		});
	}
}

bool iOS7_fetchEvent(InternalEvent *event) {
	__block bool fetched;
	execute_on_main_thread(^{
		fetched = [[iOS7AppDelegate iPhoneView] fetchEvent:event];
	});
	return fetched;
}

uint getSizeNextPOT(uint size) {
	if ((size & (size - 1)) || !size) {
		int log = 0;

		while (size >>= 1)
			++log;

		size = (2 << log);
	}

	return size;
}

@implementation iPhoneView

+ (Class)layerClass {
	return [CAEAGLLayer class];
}

- (VideoContext *)getVideoContext {
	return &_videoContext;
}

- (void)createContext {
	CAEAGLLayer *eaglLayer = (CAEAGLLayer *)self.layer;

	eaglLayer.opaque = YES;
	eaglLayer.drawableProperties = @{
	                                 kEAGLDrawablePropertyRetainedBacking: @NO,
	                                 kEAGLDrawablePropertyColorFormat: kEAGLColorFormatRGB565
	                                };

	_context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];

	// In case creating the OpenGL ES context failed, we will error out here.
	if (_context == nil) {
		printError("Could not create OpenGL ES context.");
		abort();
	}

	if ([EAGLContext setCurrentContext:_context]) {
		// glEnableClientState(GL_TEXTURE_COORD_ARRAY); printOpenGLError();
		// glEnableClientState(GL_VERTEX_ARRAY); printOpenGLError();
		[self setupOpenGL];
	}
}

- (void)setupOpenGL {
	[self setupFramebuffer];
	[self createOverlaySurface];
	[self compileShaders];
	[self setupVBOs];
	[self setupTextures];

	[self finishGLSetup];
}

- (void)finishGLSetup {
	glViewport(0, 0, _renderBufferWidth, _renderBufferHeight); printOpenGLError();
	glClearColor(0.0f, 0.0f, 0.0f, 1.0f); printOpenGLError();

	glUniform2f(_screenSizeSlot, _renderBufferWidth, _renderBufferHeight);

	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
}

- (void)freeOpenGL {
	[self deleteTextures];
	[self deleteVBOs];
	[self deleteShaders];
	[self deleteFramebuffer];
}

- (void)rebuildFrameBuffer {
	[self deleteFramebuffer];
	[self setupFramebuffer];
	[self finishGLSetup];
}

- (void)setupFramebuffer {
	glGenRenderbuffers(1, &_viewRenderbuffer);
	printOpenGLError();
	glBindRenderbuffer(GL_RENDERBUFFER, _viewRenderbuffer);
	printOpenGLError();
	[_context renderbufferStorage:GL_RENDERBUFFER fromDrawable:(id <EAGLDrawable>) self.layer];

	glGenFramebuffers(1, &_viewFramebuffer);
	printOpenGLError();
	glBindFramebuffer(GL_FRAMEBUFFER, _viewFramebuffer);
	printOpenGLError();
	glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, _viewRenderbuffer);
	printOpenGLError();

	// Retrieve the render buffer size. This *should* match the frame size,
	// i.e. g_fullWidth and g_fullHeight.
	glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH, &_renderBufferWidth);
	printOpenGLError();
	glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &_renderBufferHeight);
	printOpenGLError();

	if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
		NSLog(@"Failed to make complete framebuffer object %x.", glCheckFramebufferStatus(GL_FRAMEBUFFER));
		return;
	}
}

- (void)createOverlaySurface {
	uint overlayWidth = (uint) MAX(_renderBufferWidth, _renderBufferHeight);
	uint overlayHeight = (uint) MIN(_renderBufferWidth, _renderBufferHeight);
	float hdpi_scaler = [UIScreen mainScreen].scale;
	overlayWidth = (uint)(overlayWidth / hdpi_scaler);
	overlayHeight = (uint)(overlayHeight / hdpi_scaler);

	_videoContext.overlayWidth = overlayWidth;
	_videoContext.overlayHeight = overlayHeight;

	uint overlayTextureWidthPOT  = getSizeNextPOT(overlayWidth);
	uint overlayTextureHeightPOT = getSizeNextPOT(overlayHeight);

	// Since the overlay size won't change the whole run, we can
	// precalculate the texture coordinates for the overlay texture here
	// and just use it later on.
	GLfloat u = _videoContext.overlayWidth / (GLfloat) overlayTextureWidthPOT;
	GLfloat v = _videoContext.overlayHeight / (GLfloat) overlayTextureHeightPOT;
	_overlayCoords[0].x = 0; _overlayCoords[0].y = 0; _overlayCoords[0].u = 0; _overlayCoords[0].v = 0;
	_overlayCoords[1].x = 0; _overlayCoords[1].y = 0; _overlayCoords[1].u = u; _overlayCoords[1].v = 0;
	_overlayCoords[2].x = 0; _overlayCoords[2].y = 0; _overlayCoords[2].u = 0; _overlayCoords[2].v = v;
	_overlayCoords[3].x = 0; _overlayCoords[3].y = 0; _overlayCoords[3].u = u; _overlayCoords[3].v = v;

	_videoContext.overlayTexture.create((uint16) overlayTextureWidthPOT, (uint16) overlayTextureHeightPOT, Graphics::createPixelFormat<5551>());
}

- (void)deleteFramebuffer {
	glDeleteRenderbuffers(1, &_viewRenderbuffer);
	glDeleteFramebuffers(1, &_viewFramebuffer);
}

- (void)setupVBOs {
	glGenBuffers(1, &_vertexBuffer);
	glBindBuffer(GL_ARRAY_BUFFER, _vertexBuffer);
}

- (void)deleteVBOs {
	glDeleteBuffers(1, &_vertexBuffer);
}

- (GLuint)compileShader:(const char*)shaderPrg withType:(GLenum)shaderType {
	GLuint shaderHandle = glCreateShader(shaderType);

	int shaderPrgLength = strlen(shaderPrg);
	glShaderSource(shaderHandle, 1, &shaderPrg, &shaderPrgLength);

	glCompileShader(shaderHandle);

	GLint compileSuccess;
	glGetShaderiv(shaderHandle, GL_COMPILE_STATUS, &compileSuccess);
	if (compileSuccess == GL_FALSE) {
		GLchar messages[256];
		glGetShaderInfoLog(shaderHandle, sizeof(messages), 0, &messages[0]);
		printError(messages);
		abort();
	}

	return shaderHandle;
}

- (void)compileShaders {
	const char *vertexPrg =
			"uniform vec2 ScreenSize;"
			"uniform float ShakeX;"
			"uniform float ShakeY;"
			""
			"attribute vec2 Position;"
			"attribute vec2 TexCoord;"
			""
			"varying vec4 DestColor;"
			"varying vec2 o_TexCoord;"
			""
			"void main(void) {"
			"	DestColor = vec4(Position.x, Position.y, 0, 1);"
			"	o_TexCoord = TexCoord;"
			"	gl_Position = vec4(((Position.x + ShakeX) / ScreenSize.x) * 2.0 - 1.0, (1.0 - (Position.y + ShakeY) / ScreenSize.y) * 2.0 - 1.0, 0, 1);"
			"}";

	const char *fragmentPrg =
			"uniform sampler2D Texture;"
			""
			"varying lowp vec4 DestColor;"
			"varying lowp vec2 o_TexCoord;"
			""
			"void main(void) {"
			"	gl_FragColor = texture2D(Texture, o_TexCoord);"
			"}";

	_vertexShader = [self compileShader:vertexPrg withType:GL_VERTEX_SHADER];
	_fragmentShader = [self compileShader:fragmentPrg withType:GL_FRAGMENT_SHADER];

	GLuint programHandle = glCreateProgram();
	glAttachShader(programHandle, _vertexShader);
	glAttachShader(programHandle, _fragmentShader);
	glLinkProgram(programHandle);

	GLint linkSuccess;
	glGetProgramiv(programHandle, GL_LINK_STATUS, &linkSuccess);
	if (linkSuccess == GL_FALSE) {
		printOpenGLError();
		abort();
	}

	glUseProgram(programHandle);

	_screenSizeSlot = (GLuint) glGetUniformLocation(programHandle, "ScreenSize");
	_textureSlot = (GLuint) glGetUniformLocation(programHandle, "Texture");
	_shakeXSlot = (GLuint) glGetUniformLocation(programHandle, "ShakeX");
	_shakeYSlot = (GLuint) glGetUniformLocation(programHandle, "ShakeY");

	_positionSlot = (GLuint) glGetAttribLocation(programHandle, "Position");
	_textureCoordSlot = (GLuint) glGetAttribLocation(programHandle, "TexCoord");

	glEnableVertexAttribArray(_positionSlot);
	glEnableVertexAttribArray(_textureCoordSlot);

	glUniform1i(_textureSlot, 0); printOpenGLError();
}

- (void)deleteShaders {
	glDeleteShader(_vertexShader);
	glDeleteShader(_fragmentShader);
}

- (void)setupTextures {
	glGenTextures(1, &_screenTexture); printOpenGLError();
	glGenTextures(1, &_overlayTexture); printOpenGLError();
	glGenTextures(1, &_mouseCursorTexture); printOpenGLError();

	[self setGraphicsMode];
}

- (void)deleteTextures {
	if (_screenTexture) {
		glDeleteTextures(1, &_screenTexture); printOpenGLError();
		_screenTexture = 0;
	}
	if (_overlayTexture) {
		glDeleteTextures(1, &_overlayTexture); printOpenGLError();
		_overlayTexture = 0;
	}
	if (_mouseCursorTexture) {
		glDeleteTextures(1, &_mouseCursorTexture); printOpenGLError();
		_mouseCursorTexture = 0;
	}
}

- (void)setupGestureRecognizers {
	UIPinchGestureRecognizer *pinchKeyboard = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(keyboardPinch:)];

	UISwipeGestureRecognizer *swipeRight = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingersSwipeRight:)];
	swipeRight.direction = UISwipeGestureRecognizerDirectionRight;
	swipeRight.numberOfTouchesRequired = 2;
	swipeRight.delaysTouchesBegan = NO;
	swipeRight.delaysTouchesEnded = NO;

	UISwipeGestureRecognizer *swipeLeft = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingersSwipeLeft:)];
	swipeLeft.direction = UISwipeGestureRecognizerDirectionLeft;
	swipeLeft.numberOfTouchesRequired = 2;
	swipeLeft.delaysTouchesBegan = NO;
	swipeLeft.delaysTouchesEnded = NO;

	UISwipeGestureRecognizer *swipeUp = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingersSwipeUp:)];
	swipeUp.direction = UISwipeGestureRecognizerDirectionUp;
	swipeUp.numberOfTouchesRequired = 2;
	swipeUp.delaysTouchesBegan = NO;
	swipeUp.delaysTouchesEnded = NO;

	UISwipeGestureRecognizer *swipeDown = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingersSwipeDown:)];
	swipeDown.direction = UISwipeGestureRecognizerDirectionDown;
	swipeDown.numberOfTouchesRequired = 2;
	swipeDown.delaysTouchesBegan = NO;
	swipeDown.delaysTouchesEnded = NO;

	UISwipeGestureRecognizer *swipeRight3 = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(threeFingersSwipeRight:)];
	swipeRight3.direction = UISwipeGestureRecognizerDirectionRight;
	swipeRight3.numberOfTouchesRequired = 3;
	swipeRight3.delaysTouchesBegan = NO;
	swipeRight3.delaysTouchesEnded = NO;

	UISwipeGestureRecognizer *swipeLeft3 = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(threeFingersSwipeLeft:)];
	swipeLeft3.direction = UISwipeGestureRecognizerDirectionLeft;
	swipeLeft3.numberOfTouchesRequired = 3;
	swipeLeft3.delaysTouchesBegan = NO;
	swipeLeft3.delaysTouchesEnded = NO;

	UISwipeGestureRecognizer *swipeUp3 = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(threeFingersSwipeUp:)];
	swipeUp3.direction = UISwipeGestureRecognizerDirectionUp;
	swipeUp3.numberOfTouchesRequired = 3;
	swipeUp3.delaysTouchesBegan = NO;
	swipeUp3.delaysTouchesEnded = NO;

	UISwipeGestureRecognizer *swipeDown3 = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(threeFingersSwipeDown:)];
	swipeDown3.direction = UISwipeGestureRecognizerDirectionDown;
	swipeDown3.numberOfTouchesRequired = 3;
	swipeDown3.delaysTouchesBegan = NO;
	swipeDown3.delaysTouchesEnded = NO;

	UITapGestureRecognizer *doubleTapTwoFingers = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingersDoubleTap:)];
	doubleTapTwoFingers.numberOfTapsRequired = 2;
	doubleTapTwoFingers.numberOfTouchesRequired = 2;
	doubleTapTwoFingers.delaysTouchesBegan = NO;
	doubleTapTwoFingers.delaysTouchesEnded = NO;

	[self addGestureRecognizer:pinchKeyboard];
	[self addGestureRecognizer:swipeRight];
	[self addGestureRecognizer:swipeLeft];
	[self addGestureRecognizer:swipeUp];
	[self addGestureRecognizer:swipeDown];
	[self addGestureRecognizer:swipeRight3];
	[self addGestureRecognizer:swipeLeft3];
	[self addGestureRecognizer:swipeUp3];
	[self addGestureRecognizer:swipeDown3];
	[self addGestureRecognizer:doubleTapTwoFingers];

	[pinchKeyboard release];
	[swipeRight release];
	[swipeLeft release];
	[swipeUp release];
	[swipeDown release];
	[swipeRight3 release];
	[swipeLeft3 release];
	[swipeUp3 release];
	[swipeDown3 release];
	[doubleTapTwoFingers release];
}

- (id)initWithFrame:(struct CGRect)frame {
	self = [super initWithFrame: frame];

	_backgroundSaveStateTask = UIBackgroundTaskInvalid;

#if defined(USE_SCALERS) || defined(USE_HQ_SCALERS)
	InitScalers(565);
#endif

	[self setupGestureRecognizers];

	[self setContentScaleFactor:[[UIScreen mainScreen] scale]];

#ifdef ENABLE_IOS7_SCALERS
	_scalerMemorySrc = NULL;
	_scalerMemoryDst = NULL;
	_scalerMemorySrcSize = 0;
	_scalerMemoryDstSize = 0;
	_scaler = NULL;
	_scalerScale = 1;
#endif

	_keyboardView = nil;
	_keyboardVisible = NO;
	_screenTexture = 0;
	_overlayTexture = 0;
	_mouseCursorTexture = 0;

	_scaledShakeXOffset = 0;
	_scaledShakeYOffset = 0;

	_firstTouch = NULL;
	_secondTouch = NULL;

	_eventLock = [[NSLock alloc] init];

	memset(_gameScreenCoords, 0, sizeof(GLVertex) * 4);
	memset(_overlayCoords, 0, sizeof(GLVertex) * 4);
	memset(_mouseCoords, 0, sizeof(GLVertex) * 4);

	// Initialize the OpenGL ES context
	[self createContext];

	return self;
}

- (void)dealloc {
	[_keyboardView release];

	_videoContext.screenTexture.free();
	_videoContext.overlayTexture.free();
	_videoContext.mouseTexture.free();

#ifdef ENABLE_IOS7_SCALERS
	free(_scalerMemorySrc);
	free(_scalerMemoryDst);
#endif

	[_eventLock release];
	[super dealloc];
}

- (void)setFilterModeForTexture:(GLuint)tex {
	if (!tex)
		return;

	glActiveTexture(GL_TEXTURE0);
	glBindTexture(GL_TEXTURE_2D, tex); printOpenGLError();

	GLint filter = _videoContext.filtering ? GL_LINEAR : GL_NEAREST;

	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, filter); printOpenGLError();
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, filter); printOpenGLError();
	// We use GL_CLAMP_TO_EDGE here to avoid artifacts when linear filtering
	// is used. If we would not use this for example the cursor in Loom would
	// have a line/border artifact on the right side of the covered rect.
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); printOpenGLError();
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); printOpenGLError();
}

#ifdef ENABLE_IOS7_SCALERS
- (void)setScaler {
	ScalerProc *scaler = NULL;
	int scalerScale = 1;

	switch (_videoContext.graphicsMode) {
	case kGraphicsModeNone:
		break;
#ifdef USE_SCALERS
	case kGraphicsMode2xSaI:
		scaler = _2xSaI;
		scalerScale = 2;
		break;

	case kGraphicsModeSuper2xSaI:
		scaler = Super2xSaI;
		scalerScale = 2;
		break;

	case kGraphicsModeSuperEagle:
		scaler = SuperEagle;
		scalerScale = 2;
		break;

	case kGraphicsModeAdvMame2x:
		scaler = AdvMame2x;
		scalerScale = 2;
		break;

	case kGraphicsModeAdvMame3x:
		scaler = AdvMame3x;
		scalerScale = 3;
		break;

#ifdef USE_HQ_SCALERS
	case kGraphicsModeHQ2x:
		scaler = HQ2x;
		scalerScale = 2;
		break;

	case kGraphicsModeHQ3x:
		scaler = HQ3x;
		scalerScale = 3;
		break;
#endif

	case kGraphicsModeTV2x:
		scaler = TV2x;
		scalerScale = 2;
		break;

	case kGraphicsModeDotMatrix:
		scaler = DotMatrix;
		scalerScale = 2;
		break;
#endif

	default:
		break;
	}

	_scaler = scaler;
	_scalerScale = scalerScale;
}
#endif

- (void)setGraphicsMode {
	[self setFilterModeForTexture:_screenTexture];
	[self setFilterModeForTexture:_overlayTexture];
	[self setFilterModeForTexture:_mouseCursorTexture];
#ifdef ENABLE_IOS7_SCALERS
	[self setScaler];
#endif
}

- (void)updateSurface {
	if (!g_needsScreenUpdate) {
		return;
	}
	g_needsScreenUpdate = 0;

	glClear(GL_COLOR_BUFFER_BIT); printOpenGLError();

	[self updateMainSurface];

	if (_videoContext.overlayVisible)
		[self updateOverlaySurface];

	if (_videoContext.mouseIsVisible)
		[self updateMouseSurface];

	[_context presentRenderbuffer:GL_RENDERBUFFER];
	glFinish();
}

- (void)notifyMouseMove {
	const GLint mouseX = (GLint)(_videoContext.mouseX * _mouseScaleX) - _mouseHotspotX;
	const GLint mouseY = (GLint)(_videoContext.mouseY * _mouseScaleY) - _mouseHotspotY;

	_mouseCoords[0].x = _mouseCoords[2].x = mouseX;
	_mouseCoords[0].y = _mouseCoords[1].y = mouseY;
	_mouseCoords[1].x = _mouseCoords[3].x = mouseX + _mouseWidth;
	_mouseCoords[2].y = _mouseCoords[3].y = mouseY + _mouseHeight;
}

- (void)updateMouseCursorScaling {
	CGRect *rect;
	int maxWidth, maxHeight;

	if (!_videoContext.overlayVisible) {
		rect = &_gameScreenRect;
		maxWidth = _videoContext.screenWidth;
		maxHeight = _videoContext.screenHeight;
	} else {
		rect = &_overlayRect;
		maxWidth = _videoContext.overlayWidth;
		maxHeight = _videoContext.overlayHeight;
	}

	if (!maxWidth || !maxHeight) {
		printf("WARNING: updateMouseCursorScaling called when screen was not ready (%d)!\n", _videoContext.overlayVisible);
		return;
	}

	_mouseScaleX = CGRectGetWidth(*rect) / (GLfloat)maxWidth;
	_mouseScaleY = CGRectGetHeight(*rect) / (GLfloat)maxHeight;

	_mouseWidth = (GLint)(_videoContext.mouseWidth * _mouseScaleX);
	_mouseHeight = (GLint)(_videoContext.mouseHeight * _mouseScaleY);

	_mouseHotspotX = (GLint)(_videoContext.mouseHotspotX * _mouseScaleX);
	_mouseHotspotY = (GLint)(_videoContext.mouseHotspotY * _mouseScaleY);

	// We subtract the screen offset to the hotspot here to simplify the
	// screen offset handling in the mouse code. Note the subtraction here
	// makes sure that the offset actually gets added to the mouse position,
	// since the hotspot offset is substracted from the position.
	_mouseHotspotX -= (GLint)CGRectGetMinX(*rect);
	_mouseHotspotY -= (GLint)CGRectGetMinY(*rect);

	// FIXME: For now we also adapt the mouse position here. In reality we
	// would be better off to also adjust the event position when switching
	// from overlay to game screen or vica versa.
	[self notifyMouseMove];
}

- (void)updateMouseCursor {
	[self updateMouseCursorScaling];

	_mouseCoords[1].u = _mouseCoords[3].u = (_videoContext.mouseWidth - 1) / (GLfloat)_videoContext.mouseTexture.w;
	_mouseCoords[2].v = _mouseCoords[3].v = (_videoContext.mouseHeight - 1) / (GLfloat)_videoContext.mouseTexture.h;

	[self setFilterModeForTexture:_mouseCursorTexture];
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, _videoContext.mouseTexture.w, _videoContext.mouseTexture.h, 0, GL_RGBA, GL_UNSIGNED_SHORT_5_5_5_1, _videoContext.mouseTexture.getPixels()); printOpenGLError();
}

- (void)updateMainSurface {
	glBufferData(GL_ARRAY_BUFFER, sizeof(GLVertex) * 4, _gameScreenCoords, GL_STATIC_DRAW);
	glVertexAttribPointer(_positionSlot, 2, GL_FLOAT, GL_FALSE, sizeof(GLVertex), 0);
	glVertexAttribPointer(_textureCoordSlot, 2, GL_FLOAT, GL_FALSE, sizeof(GLVertex), (GLvoid *) (sizeof(GLfloat) * 2));

	[self setFilterModeForTexture:_screenTexture];

	// Unfortunately we have to update the whole texture every frame, since glTexSubImage2D is actually slower in all cases
	// due to the iPhone internals having to convert the whole texture back from its internal format when used.
	// In the future we could use several tiled textures instead.
#ifdef ENABLE_IOS7_SCALERS
	if (_scaler) {
		size_t neededSrcMemorySize = (size_t) (_videoContext.screenTexture.pitch * (_videoContext.screenTexture.h + 4));
		size_t neededDstMemorySize = (size_t) (_videoContext.screenTexture.pitch * (_videoContext.screenTexture.h + 4) * _scalerScale * _scalerScale);
		if (neededSrcMemorySize != _scalerMemorySrcSize) {
			_scalerMemorySrc = (uint8_t *) realloc(_scalerMemorySrc, neededSrcMemorySize);
			_scalerMemorySrcSize = neededSrcMemorySize;
		}
		if (neededDstMemorySize != _scalerMemoryDstSize) {
			_scalerMemoryDst = (uint8_t *) realloc(_scalerMemoryDst, neededDstMemorySize);
			_scalerMemoryDstSize = neededDstMemorySize;
		}

		// Clear two lines before
		memset(_scalerMemorySrc, 0, (size_t) (_videoContext.screenTexture.pitch * 2));
		// Copy original buffer
		memcpy(_scalerMemorySrc + _videoContext.screenTexture.pitch * 2, _videoContext.screenTexture.getPixels(), _videoContext.screenTexture.pitch * _videoContext.screenTexture.h);
		// Clear two lines after
		memset(_scalerMemorySrc + _videoContext.screenTexture.pitch * (2 + _videoContext.screenTexture.h), 0, (size_t) (_videoContext.screenTexture.pitch * 2));
		// Apply scaler
		_scaler(_scalerMemorySrc + _videoContext.screenTexture.pitch * 2,
		        _videoContext.screenTexture.pitch,
		        _scalerMemoryDst,
		        (uint32) (_videoContext.screenTexture.pitch * _scalerScale),
		        _videoContext.screenTexture.w,
		        _videoContext.screenTexture.h);
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, _videoContext.screenTexture.w * _scalerScale, _videoContext.screenTexture.h * _scalerScale, 0, GL_RGB, GL_UNSIGNED_SHORT_5_6_5, _scalerMemoryDst); printOpenGLError();
	}
	else {
#endif
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, _videoContext.screenTexture.w, _videoContext.screenTexture.h, 0, GL_RGB, GL_UNSIGNED_SHORT_5_6_5, _videoContext.screenTexture.getPixels()); printOpenGLError();
#ifdef ENABLE_IOS7_SCALERS
	}
#endif

	glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); printOpenGLError();
}

- (void)updateOverlaySurface {
	glBufferData(GL_ARRAY_BUFFER, sizeof(GLVertex) * 4, _overlayCoords, GL_STATIC_DRAW);
	glVertexAttribPointer(_positionSlot, 2, GL_FLOAT, GL_FALSE, sizeof(GLVertex), 0);
	glVertexAttribPointer(_textureCoordSlot, 2, GL_FLOAT, GL_FALSE, sizeof(GLVertex), (GLvoid *) (sizeof(GLfloat) * 2));

	[self setFilterModeForTexture:_overlayTexture];

	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, _videoContext.overlayTexture.w, _videoContext.overlayTexture.h, 0, GL_RGBA, GL_UNSIGNED_SHORT_5_5_5_1, _videoContext.overlayTexture.getPixels()); printOpenGLError();
	glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); printOpenGLError();
}

- (void)updateMouseSurface {
	glBufferData(GL_ARRAY_BUFFER, sizeof(GLVertex) * 4, _mouseCoords, GL_STATIC_DRAW);
	glVertexAttribPointer(_positionSlot, 2, GL_FLOAT, GL_FALSE, sizeof(GLVertex), 0);
	glVertexAttribPointer(_textureCoordSlot, 2, GL_FLOAT, GL_FALSE, sizeof(GLVertex), (GLvoid *) (sizeof(GLfloat) * 2));

	glBindTexture(GL_TEXTURE_2D, _mouseCursorTexture); printOpenGLError();

	glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); printOpenGLError();
}

- (void)createScreenTexture {
	const uint screenTexWidth = getSizeNextPOT(_videoContext.screenWidth);
	const uint screenTexHeight = getSizeNextPOT(_videoContext.screenHeight);

	_gameScreenCoords[1].u = _gameScreenCoords[3].u = _videoContext.screenWidth / (GLfloat)screenTexWidth;
	_gameScreenCoords[2].v = _gameScreenCoords[3].v = _videoContext.screenHeight / (GLfloat)screenTexHeight;

	_videoContext.screenTexture.create((uint16) screenTexWidth, (uint16) screenTexHeight, Graphics::createPixelFormat<565>());
}

- (void)initSurface {
	if (_context) {
		[self rebuildFrameBuffer];
	}

	BOOL isLandscape = (self.bounds.size.width > self.bounds.size.height); // UIDeviceOrientationIsLandscape([[UIDevice currentDevice] orientation]);

	int screenWidth, screenHeight;
	if (isLandscape) {
		screenWidth = MAX(_renderBufferWidth, _renderBufferHeight);
		screenHeight = MIN(_renderBufferWidth, _renderBufferHeight);
	}
	else {
		screenWidth = MIN(_renderBufferWidth, _renderBufferHeight);
		screenHeight = MAX(_renderBufferWidth, _renderBufferHeight);
	}

	if (_keyboardView == nil) {
		_keyboardView = [[SoftKeyboard alloc] initWithFrame:CGRectZero];
		[_keyboardView setInputDelegate:self];
		[self addSubview:[_keyboardView inputView]];
		[self addSubview: _keyboardView];
		[self showKeyboard];
	}

	glBindRenderbuffer(GL_RENDERBUFFER, _viewRenderbuffer); printOpenGLError();

	[self clearColorBuffer];

	GLfloat adjustedWidth = _videoContext.screenWidth;
	GLfloat adjustedHeight = _videoContext.screenHeight;
	if (_videoContext.asprectRatioCorrection) {
		if (_videoContext.screenWidth == 320 && _videoContext.screenHeight == 200)
			adjustedHeight = 240;
		else if (_videoContext.screenWidth == 640 && _videoContext.screenHeight == 400)
			adjustedHeight = 480;
	}

	float overlayPortraitRatio;

	if (isLandscape) {
		GLfloat gameScreenRatio = adjustedWidth / adjustedHeight;
		GLfloat screenRatio = (GLfloat)screenWidth / (GLfloat)screenHeight;

		// These are the width/height according to the portrait layout!
		int rectWidth, rectHeight;
		int xOffset, yOffset;

		if (gameScreenRatio < screenRatio) {
			// When the game screen ratio is less than the screen ratio
			// we need to scale the width, since the game screen was higher
			// compared to the width than our output screen is.
			rectWidth = (int)(screenHeight * gameScreenRatio);
			rectHeight = screenHeight;
			xOffset = (screenWidth - rectWidth) / 2;
			yOffset = 0;
		} else {
			// When the game screen ratio is bigger than the screen ratio
			// we need to scale the height, since the game screen was wider
			// compared to the height than our output screen is.
			rectWidth = screenWidth;
			rectHeight = (int)(screenWidth / gameScreenRatio);
			xOffset = 0;
			yOffset = (screenHeight - rectHeight) / 2;
		}

		//printf("Rect: %i, %i, %i, %i\n", xOffset, yOffset, rectWidth, rectHeight);
		_gameScreenRect = CGRectMake(xOffset, yOffset, rectWidth, rectHeight);
		overlayPortraitRatio = 1.0f;
	} else {
		GLfloat ratio = adjustedHeight / adjustedWidth;
		int height = (int)(screenWidth * ratio);
		//printf("Making rect (%u, %u)\n", screenWidth, height);
        
		_gameScreenRect = CGRectMake(0, 0, screenWidth, height);

		overlayPortraitRatio = (_videoContext.overlayHeight * ratio) / _videoContext.overlayWidth;
	}
	_overlayRect = CGRectMake(0, 0, screenWidth, screenHeight * overlayPortraitRatio);

	_gameScreenCoords[0].x = _gameScreenCoords[2].x = CGRectGetMinX(_gameScreenRect);
	_gameScreenCoords[0].y = _gameScreenCoords[1].y = CGRectGetMinY(_gameScreenRect);
	_gameScreenCoords[1].x = _gameScreenCoords[3].x = CGRectGetMaxX(_gameScreenRect);
	_gameScreenCoords[2].y = _gameScreenCoords[3].y = CGRectGetMaxY(_gameScreenRect);

	_overlayCoords[1].x = _overlayCoords[3].x = CGRectGetMaxX(_overlayRect);
	_overlayCoords[2].y = _overlayCoords[3].y = CGRectGetMaxY(_overlayRect);

	[self setViewTransformation];
	[self updateMouseCursorScaling];
    [self adjustViewFrameForSafeArea];
}

#ifndef __has_builtin
#define __has_builtin(x) 0
#endif

-(void)adjustViewFrameForSafeArea {
	// The code below does not quite compile with SDKs older than 11.0.
	// warning: instance method '-safeAreaInsets' not found (return type defaults to 'id')
	// error: no viable conversion from 'id' to 'UIEdgeInsets'
	// So for now disable this code when compiled with an older SDK, which means it is only
	// available when running on iOS 11+ if it has been compiled on iOS 11+
#ifdef __IPHONE_11_0
#if __has_builtin(__builtin_available)
    if ( @available(iOS 11,*) ) {
#else
    if ( [[[UIApplication sharedApplication] keyWindow] respondsToSelector:@selector(safeAreaInsets)] ) {
#endif
        CGRect screenSize = [[UIScreen mainScreen] bounds];
        UIEdgeInsets inset = [[[UIApplication sharedApplication] keyWindow] safeAreaInsets];
        UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation];
        CGRect newFrame = screenSize;
        if ( orientation == UIInterfaceOrientationPortrait ) {
            newFrame = CGRectMake(screenSize.origin.x, screenSize.origin.y + inset.top, screenSize.size.width, screenSize.size.height - inset.top);
        } else if ( orientation == UIInterfaceOrientationLandscapeLeft ) {
            newFrame = CGRectMake(screenSize.origin.x, screenSize.origin.y, screenSize.size.width - inset.right, screenSize.size.height);
        } else if ( orientation == UIInterfaceOrientationLandscapeRight ) {
            newFrame = CGRectMake(screenSize.origin.x + inset.left, screenSize.origin.y, screenSize.size.width - inset.left, screenSize.size.height);
        }
        self.frame = newFrame;
    }
#endif
}

- (void)setViewTransformation {
	// Scale the shake offset according to the overlay size. We need this to
	// adjust the overlay mouse click coordinates when an offset is set.
	_scaledShakeXOffset = (int)(_videoContext.shakeXOffset / (GLfloat)_videoContext.screenWidth * CGRectGetWidth(_overlayRect));
	_scaledShakeYOffset = (int)(_videoContext.shakeYOffset / (GLfloat)_videoContext.screenHeight * CGRectGetHeight(_overlayRect));

	glUniform1f(_shakeXSlot, _scaledShakeXOffset);
	glUniform1f(_shakeYSlot, _scaledShakeYOffset);
}

- (void)clearColorBuffer {
	// The color buffer is triple-buffered, so we clear it multiple times right away to avid doing any glClears later.
	int clearCount = 5;
	while (clearCount-- > 0) {
		glClear(GL_COLOR_BUFFER_BIT); printOpenGLError();
		[_context presentRenderbuffer:GL_RENDERBUFFER];
		glFinish();
	}
}

- (void)addEvent:(InternalEvent)event {
	[_eventLock lock];
	_events.push_back(event);
	[_eventLock unlock];
}

- (bool)fetchEvent:(InternalEvent *)event {
	[_eventLock lock];
	if (_events.empty()) {
		[_eventLock unlock];
		return false;
	}

	*event = *_events.begin();
	_events.pop_front();
	[_eventLock unlock];
	return true;
}

- (bool)getMouseCoords:(CGPoint)point eventX:(int *)x eventY:(int *)y {
	// We scale the input according to our scale factor to get actual screen
	// coordinates.
	point.x *= self.contentScaleFactor;
	point.y *= self.contentScaleFactor;

	CGRect *area;
	int width, height, offsetX, offsetY;
	if (_videoContext.overlayVisible) {
		area = &_overlayRect;
		width = _videoContext.overlayWidth;
		height = _videoContext.overlayHeight;
		offsetX = _scaledShakeXOffset;
		offsetY = _scaledShakeYOffset;
	} else {
		area = &_gameScreenRect;
		width = _videoContext.screenWidth;
		height = _videoContext.screenHeight;
		offsetX = _videoContext.shakeXOffset;
		offsetY = _videoContext.shakeYOffset;
	}

	point.x = (point.x - CGRectGetMinX(*area)) / CGRectGetWidth(*area);
	point.y = (point.y - CGRectGetMinY(*area)) / CGRectGetHeight(*area);

	*x = (int)(point.x * width + offsetX);
	// offsetY describes the translation of the screen in the upward direction,
	// thus we need to add it here.
	*y = (int)(point.y * height + offsetY);

	if (!iOS7_touchpadModeEnabled()) {
		// Clip coordinates
		if (*x < 0 || *x > width || *y < 0 || *y > height)
			return false;
	}

	return true;
}

- (void)deviceOrientationChanged:(UIDeviceOrientation)orientation {
	[self addEvent:InternalEvent(kInputOrientationChanged, orientation, 0)];

  BOOL isLandscape = (self.bounds.size.width > self.bounds.size.height);
  if (isLandscape) {
    [self hideKeyboard];
  } else {
    [self showKeyboard];
  }
}

- (void)showKeyboard {
	[_keyboardView showKeyboard];
	_keyboardVisible = YES;
}

- (void)hideKeyboard {
	[_keyboardView hideKeyboard];
	_keyboardVisible = NO;
}

- (BOOL)isKeyboardShown {
	return _keyboardVisible;
}

- (UITouch *)secondTouchOtherTouchThan:(UITouch *)touch in:(NSSet *)set {
	NSArray *all = [set allObjects];
	for (UITouch *t in all) {
		if (t != touch) {
			return t;
		}
	}
	return nil;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
	int x, y;

	NSSet *allTouches = [event allTouches];
	if (allTouches.count == 1) {
		_firstTouch = [allTouches anyObject];
		CGPoint point = [_firstTouch locationInView:self];
		if (![self getMouseCoords:point eventX:&x eventY:&y])
			return;

		[self addEvent:InternalEvent(kInputMouseDown, x, y)];
	}
	else if (allTouches.count == 2) {
		_secondTouch = [self secondTouchOtherTouchThan:_firstTouch in:allTouches];
		if (_secondTouch) {
			CGPoint point = [_secondTouch locationInView:self];
			if (![self getMouseCoords:point eventX:&x eventY:&y])
				return;

			[self addEvent:InternalEvent(kInputMouseSecondDown, x, y)];
		}
	}
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
	int x, y;

	NSSet *allTouches = [event allTouches];
	for (UITouch *touch in allTouches) {
		if (touch == _firstTouch) {
			CGPoint point = [touch locationInView:self];
			if (![self getMouseCoords:point eventX:&x eventY:&y])
				return;

			[self addEvent:InternalEvent(kInputMouseDragged, x, y)];
		} else if (touch == _secondTouch) {
			CGPoint point = [touch locationInView:self];
			if (![self getMouseCoords:point eventX:&x eventY:&y])
				return;

			[self addEvent:InternalEvent(kInputMouseSecondDragged, x, y)];
		}
	}
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
	int x, y;

	NSSet *allTouches = [event allTouches];
	if (allTouches.count == 1) {
		UITouch *touch = [allTouches anyObject];
		CGPoint point = [touch locationInView:self];
		if (![self getMouseCoords:point eventX:&x eventY:&y]) {
			return;
		}

		[self addEvent:InternalEvent(kInputMouseUp, x, y)];
	}
	else if (allTouches.count == 2) {
		UITouch *touch = [[allTouches allObjects] objectAtIndex:1];
		CGPoint point = [touch locationInView:self];
		if (![self getMouseCoords:point eventX:&x eventY:&y])
			return;

		[self addEvent:InternalEvent(kInputMouseSecondUp, x, y)];
	}
	_firstTouch = nil;
	_secondTouch = nil;
}

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
	_firstTouch = nil;
	_secondTouch = nil;
}

- (void)keyboardPinch:(UIPinchGestureRecognizer *)recognizer {
	if ([recognizer scale] < 0.8)
		[self showKeyboard];
	else if ([recognizer scale] > 1.25)
		[self hideKeyboard];
}

- (void)twoFingersSwipeRight:(UISwipeGestureRecognizer *)recognizer {
	[self addEvent:InternalEvent(kInputSwipe, kUIViewSwipeRight, 2)];
}

- (void)twoFingersSwipeLeft:(UISwipeGestureRecognizer *)recognizer {
	[self addEvent:InternalEvent(kInputSwipe, kUIViewSwipeLeft, 2)];
}

- (void)twoFingersSwipeUp:(UISwipeGestureRecognizer *)recognizer {
	[self addEvent:InternalEvent(kInputSwipe, kUIViewSwipeUp, 2)];
}

- (void)twoFingersSwipeDown:(UISwipeGestureRecognizer *)recognizer {
	[self addEvent:InternalEvent(kInputSwipe, kUIViewSwipeDown, 2)];
}

- (void)threeFingersSwipeRight:(UISwipeGestureRecognizer *)recognizer {
	[self addEvent:InternalEvent(kInputSwipe, kUIViewSwipeRight, 3)];
}

- (void)threeFingersSwipeLeft:(UISwipeGestureRecognizer *)recognizer {
	[self addEvent:InternalEvent(kInputSwipe, kUIViewSwipeLeft, 3)];
}

- (void)threeFingersSwipeUp:(UISwipeGestureRecognizer *)recognizer {
	[self addEvent:InternalEvent(kInputSwipe, kUIViewSwipeUp, 3)];
}

- (void)threeFingersSwipeDown:(UISwipeGestureRecognizer *)recognizer {
	[self addEvent:InternalEvent(kInputSwipe, kUIViewSwipeDown, 3)];
}

- (void)twoFingersDoubleTap:(UITapGestureRecognizer *)recognizer {
	[self addEvent:InternalEvent(kInputTap, kUIViewTapDouble, 2)];
}

- (void)handleKeyPress:(unichar)c {
	if (c == '`') {
		[self addEvent:InternalEvent(kInputKeyPressed, '\E', 0)];
	} else {
		[self addEvent:InternalEvent(kInputKeyPressed, c, 0)];
	}
}

- (void)handleMainMenuKey {
	[self addEvent:InternalEvent(kInputMainMenu, 0, 0)];
}

- (void)applicationSuspend {
	[self addEvent:InternalEvent(kInputApplicationSuspended, 0, 0)];
}

- (void)applicationResume {
	[self addEvent:InternalEvent(kInputApplicationResumed, 0, 0)];
}

- (void)saveApplicationState {
	[self addEvent:InternalEvent(kInputApplicationSaveState, 0, 0)];
}

- (void)clearApplicationState {
	[self addEvent:InternalEvent(kInputApplicationClearState, 0, 0)];
}

- (void)restoreApplicationState {
	[self addEvent:InternalEvent(kInputApplicationRestoreState, 0, 0)];
}

- (void) beginBackgroundSaveStateTask {
	if (_backgroundSaveStateTask == UIBackgroundTaskInvalid) {
		_backgroundSaveStateTask = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{
			[self endBackgroundSaveStateTask];
		}];
	}
}

- (void) endBackgroundSaveStateTask {
	if (_backgroundSaveStateTask != UIBackgroundTaskInvalid) {
		[[UIApplication sharedApplication] endBackgroundTask: _backgroundSaveStateTask];
		_backgroundSaveStateTask = UIBackgroundTaskInvalid;
	}
}

@end