text: // Copyright 2015 The Go Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style
  // license that can be found in the LICENSE file.
  
  // +build darwin
  // +build arm arm64
  
  #include "_cgo_export.h"
  #include <pthread.h>
  #include <stdio.h>
  #include <sys/utsname.h>
  
  #import <UIKit/UIKit.h>
  #import <GLKit/GLKit.h>
  
  struct utsname sysInfo;
  
  @interface GoAppAppController : GLKViewController<UIContentContainer>
  @end
  
  @interface GoAppAppDelegate : UIResponder<UIApplicationDelegate>
  @property (strong, nonatomic) UIWindow *window;
  @property (strong, nonatomic) GoAppAppController *controller;
  @end
  
  @implementation GoAppAppDelegate
  - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
  	self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
  	self.controller = [[GoAppAppController alloc] initWithNibName:nil bundle:nil];
  	self.window.rootViewController = self.controller;
  	[self.window makeKeyAndVisible];
  	return YES;
  }
  @end
  
  @interface GoAppAppController ()
  @property (strong, nonatomic) EAGLContext *context;
  @end
  
  @implementation GoAppAppController
  - (void)viewDidLoad {
  	[super viewDidLoad];
  	self.preferredFramesPerSecond = 60;
  	self.context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
  	GLKView *view = (GLKView *)self.view;
  	view.context = self.context;
  	view.drawableDepthFormat = GLKViewDrawableDepthFormat24;
  	view.multipleTouchEnabled = true; // TODO expose setting to user.
  
  	int scale = 1;
  	if ([[UIScreen mainScreen] respondsToSelector:@selector(displayLinkWithTarget:selector:)]) {
  		scale = (int)[UIScreen mainScreen].scale; // either 1.0, 2.0, or 3.0.
  	}
  	setScreen(scale);
  
  	CGSize size = [UIScreen mainScreen].bounds.size;
  	UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation];
  	updateConfig((int)size.width, (int)size.height, orientation);
  }
  
  - (void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator {
  	[coordinator animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> context) {
  		// TODO(crawshaw): come up with a plan to handle animations.
  	} completion:^(id<UIViewControllerTransitionCoordinatorContext> context) {
  		UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation];
  		updateConfig((int)size.width, (int)size.height, orientation);
  	}];
  }
  
  - (void)update {
  	drawgl((GoUintptr)self.context);
  }
  
  #define TOUCH_TYPE_BEGIN 0 // touch.TypeBegin
  #define TOUCH_TYPE_MOVE  1 // touch.TypeMove
  #define TOUCH_TYPE_END   2 // touch.TypeEnd
  
  static void sendTouches(int change, NSSet* touches) {
  	CGFloat scale = [UIScreen mainScreen].scale;
  	for (UITouch* touch in touches) {
  		CGPoint p = [touch locationInView:touch.view];
  		sendTouch((GoUintptr)touch, (GoUintptr)change, p.x*scale, p.y*scale);
  	}
  }
  
  - (void)touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event {
  	sendTouches(TOUCH_TYPE_BEGIN, touches);
  }
  
  - (void)touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event {
  	sendTouches(TOUCH_TYPE_MOVE, touches);
  }
  
  - (void)touchesEnded:(NSSet*)touches withEvent:(UIEvent*)event {
  	sendTouches(TOUCH_TYPE_END, touches);
  }
  @end
  
  void runApp(void) {
  	@autoreleasepool {
  		UIApplicationMain(0, nil, nil, NSStringFromClass([GoAppAppDelegate class]));
  	}
  }
  
  void setContext(void* context) {
  	EAGLContext* ctx = (EAGLContext*)context;
  	if (![EAGLContext setCurrentContext:ctx]) {
  		// TODO(crawshaw): determine how terrible this is. Exit?
  		NSLog(@"failed to set current context");
  	}
  }
  
  uint64_t threadID() {
  	uint64_t id;
  	if (pthread_threadid_np(pthread_self(), &id)) {
  		abort();
  	}
  	return id;
  }
  