ImagesScrollViewController.m

    //
//  ImagesScrollViewController.m
//  SimpleGallery
//
//  Created by anonymous on 11/28/11.
//  Copyright 2011 comanyName. All rights reserved.
//

#import "ImagesScrollViewController.h"
#import "MyViewController.h"
#import "BookShelfManager.h"
#import "SHK.h"
#import "AppDelegate_iPad.h"

@implementation ImagesScrollViewController

@synthesize scrollView, viewControllers;

// The designated initializer.  Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization.
		
		// view controllers are created lazily
		// in the meantime, load the array with placeholders which will be replaced on demand
		NSMutableArray *controllers = [[NSMutableArray alloc] init];
		for (unsigned i = 0; i < 20; i++)
		{
			[controllers addObject:[NSNull null]];
		}
		self.viewControllers = controllers;
		//self.delegate = self;
		[controllers release];
		
		imageSwipeControlledByHuman = YES;
    }
    return self;
}


-(BOOL) canBecomeFirstResponder {
	return YES;
}

/*
// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView {
}
*/


// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
-(void)viewDidLoad {
    [super viewDidLoad];
	
	imageSwipeControlledByHuman = YES;
	scrollView.pagingEnabled = YES;
	scrollView.contentSize = CGSizeMake(scrollView.frame.size.width * 20, scrollView.frame.size.height);
	scrollView.showsHorizontalScrollIndicator = NO;
	scrollView.showsVerticalScrollIndicator = NO;
	scrollView.scrollsToTop = NO;
	scrollView.delegate = self;

	// pages are created on demand
	// load the visible page and load the page on either side to avoid flashes when the user starts scrolling
	// TODO: code smells bad.
	[BookShelfManager sharedInstance].currentProcessingImageID =  [BookShelfManager sharedInstance].targetImageID - 1;
	NSLog(@"[BookShelfManager sharedInstance].currentProcessingImageID  is  [ %d ]", [BookShelfManager sharedInstance].currentProcessingImageID);
	[self loadScrollViewWithPage:[BookShelfManager sharedInstance].currentProcessingImageID ];
	
	[BookShelfManager sharedInstance].currentProcessingImageID =  [BookShelfManager sharedInstance].targetImageID ;
	[self loadScrollViewWithPage:[BookShelfManager sharedInstance].currentProcessingImageID ];
	
	// test if last image is selected or not.
	if ( [BookShelfManager sharedInstance].targetImageID == [[[BookShelfManager sharedInstance]allMaterials]count] - 1 ) {
		[BookShelfManager sharedInstance].currentProcessingImageID =  0;
		[self loadScrollViewWithPage:[BookShelfManager sharedInstance].currentProcessingImageID ];
	}else {
		[BookShelfManager sharedInstance].currentProcessingImageID =  [BookShelfManager sharedInstance].targetImageID + 1;
		[self loadScrollViewWithPage:[BookShelfManager sharedInstance].currentProcessingImageID ];
	}


	
	
	float xOffset = (([BookShelfManager sharedInstance].targetImageID ) * self.view.bounds.size.width);
	NSLog(@"xOffset when loading page [ %d ] is calculated for [ %f ]", [BookShelfManager sharedInstance].currentProcessingImageID,xOffset);
	CGPoint offset = CGPointMake(xOffset , 0) ;
	[scrollView setContentOffset:offset  animated:YES];
	
	// imageSwipeControlledByHuman = YES;	  // TODO: still need tuning?
	
	//[self loadScrollViewWithPage:0];
	//[self loadScrollViewWithPage:1];
	
	
	// set timer to hide the control buttons.
	autoHideControlButtonsTimer = [NSTimer scheduledTimerWithTimeInterval:5.0
																   target:self
																 selector:@selector(hideControlResetTimer)
																 userInfo:nil
																  repeats:NO];
	
	
	UITapGestureRecognizer *oneFingerOneTap = 
	[[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(oneFingerOneTap)] autorelease];
	
	// Set required taps and number of touches
	[oneFingerOneTap setNumberOfTapsRequired:1];
	[oneFingerOneTap setNumberOfTouchesRequired:1];
	oneFingerOneTap.cancelsTouchesInView = NO;
	// Add the gesture to the view
	[[self view] addGestureRecognizer:oneFingerOneTap];
	
	
}




/*
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    // Return YES for supported orientations.
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
*/

- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];    
    // Release any cached data, images, etc. that aren't in use.
}

- (void)viewDidUnload {
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}


- (void)dealloc {
	[scrollView release];
	[viewControllers release];
    [super dealloc];
}


#pragma mark -
#pragma mark Utilities
- (void)loadScrollViewWithPage:(int)page
{
    if (page < 0)
        return;
    if (page >= 20)
        return;
	
	NSLog(@"loading .... %d", page);
    
    // replace the placeholder if necessary
    MyViewController *controller = [viewControllers objectAtIndex:page];
    if ((NSNull *)controller == [NSNull null])
    {
        controller = [[MyViewController alloc] initWithPageNumber:page];
        [viewControllers replaceObjectAtIndex:page withObject:controller];
        [controller release];
    }
    
    // add the controller's view to the scroll view
    if (controller.view.superview == nil)
    {
        CGRect frame = scrollView.frame;
        frame.origin.x = frame.size.width * page;
        frame.origin.y = 0;
        controller.view.frame = frame;
				
		NSLog(@"the new view controller will be added to the scrollview, \n origin is at ( %f, %f )", frame.origin.x, frame.origin.y);
        [scrollView addSubview:controller.view];
        
        //NSDictionary *numberItem = [self.contentList objectAtIndex:page];
        //controller.numberImage.image = [UIImage imageNamed:[numberItem valueForKey:ImageKey]];
		//controller.numberImage.image = [UIImage imageNamed:@"thumbPG1.jpg"];
        //controller.numberTitle.text = @"thumb";
    }
}


- (void)unloadScrollViewWithPage:(int)page
{
	
    if (page < 0)
        return;
    if (page >= 20)
        return;
	
	NSLog(@"un ... loading .... %d", page);
	
	if (page >= [viewControllers count]) {
		return ;
	}
    
    // replace the placeholder if necessary
    MyViewController *controller = [viewControllers objectAtIndex:page];
    if ((NSNull *)controller == [NSNull null]){
		// do nothing as it's empty
	}else {
		//[viewControllers removeObjectAtIndex:page] ;
		[controller.view removeFromSuperview];
        [viewControllers replaceObjectAtIndex:page withObject:[NSNull null]];
		// TODO: anything else? 
	}
}

#pragma mark -
#pragma mark UIScrollViewDelegate methods
- (void)scrollViewDidScroll:(UIScrollView *)sender
{
    // We don't want a "feedback loop" between the UIPageControl and the scroll delegate in
    // which a scroll event generated from the user hitting the page control triggers updates from
    // the delegate method. We use a boolean to disable the delegate logic when the page control is used.
//    if ( imageSwipeControlledByHuman)
//    {
//        // do nothing - the scroll was initiated from the page control, not the user dragging
//		
//		// first time load from gridview, scrolling should not be called because it must be issued by user and the autosliding is off.
//		imageSwipeControlledByHuman = !imageSwipeControlledByHuman;
//		// Q: what about the scenario when scrolling to the first one? A:
//		
//        return;
//    }
	
    // Switch the indicator when more than 50% of the previous/next page is visible
    CGFloat pageWidth = scrollView.frame.size.width;
    int page = floor((scrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
    // pageControl.currentPage = page;
    
	// [BookShelfManager sharedInstance].currentProcessingImageID = page;
	
	NSLog(@"scroll did scrolling,  page for indexing is %d", page);
	
	
	// NOTE: first we handle first detail view loading
	if (page == [BookShelfManager sharedInstance].targetImageID ) {  
		// actually there is no need to load side page as they are already loaded in viewDidLoad.
		// NOTE: this condition happens to be at work during several calls to didScroll  
	} else if (  abs( page - [BookShelfManager sharedInstance].targetImageID) == 1 ) { // one scrolling, no matter if auto or human
		// load the visible page and the page on either side of it (to avoid flashes when the user starts scrolling)
		[self loadScrollViewWithPage:page - 1];
		[self loadScrollViewWithPage:page];
		if ( page == [[[BookShelfManager sharedInstance]allMaterials] count] -1 ) {  // avoid empty of first page 
			//[self loadScrollViewWithPage:-1];
			[self loadScrollViewWithPage:0];
		}else {
			[self loadScrollViewWithPage:page + 1];
		}
		
        
		// A possible optimization would be to unload the views+controllers which are no longer visible
		// ESP.
		if ( page == 0) {
			// handling clean of tails when restarting from the left most image
			[self unloadScrollViewWithPage: [[[BookShelfManager sharedInstance]allMaterials]count]-1  ];	
			[self unloadScrollViewWithPage: [[[BookShelfManager sharedInstance]allMaterials]count]-2  ];
		}else if ( page == 1) {
			// cleaned when page == 0	 
		}else {
			[self unloadScrollViewWithPage:page - 2];
		}
		// NOTE: because the scrolling is one way towards right, there is much to do with following clause, it's a place holder.
		[self unloadScrollViewWithPage:page + 2];	
		// TODO: anything else? Try to get some info from some profiling tool!
		
		// REMEMBER: to update the targetImageID to allow next around loading process. Q: or shall we add this to other delegate method?
		[BookShelfManager sharedInstance].targetImageID = page; 		
	}else {
		
	}    
}

- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView {
	NSLog(@"scrollViewDidEndScrollingAnimation   is called.");
}


#pragma mark -
#pragma mark IBAction

// NOTE: for more issues, remember to check 

// TODO:  twitter auth problem, http://jayrparro.posterous.com/incorrect-signature-sharekittwitter-error
// DONE: quick fix of acitivity indicator orientation, see: https://github.com/simonmaddox/ShareKit/commit/e2587fc6d5ab2ff234584dfe10f258aea213783e#diff-0
-(IBAction) shareSocially:(id)sender{	
	//code example http://getsharekit.com/docs/#image
	NSMutableArray *shelf = [[BookShelfManager sharedInstance] allMaterials];
	NSString *name = ((Material *)[shelf objectAtIndex: [BookShelfManager sharedInstance].currentProcessingImageID]).name;
	UIImage *image = [UIImage imageNamed:name];
	SHKItem *item = [SHKItem image:image title:@"Look at this picture!"];
	
	// Get the ShareKit action sheet
	SHKActionSheet *actionSheet = [SHKActionSheet actionSheetForItem:item];
	
	//AppDelegate_iPad *delegate = (AppDelegate_iPad *)[[UIApplication sharedApplication] delegate];
	//[delegate.navController popViewControllerAnimated:YES];
	//[actionSheet showFromToolbar:delegate.navController.toolbar];
	[actionSheet showInView:self.view]; 
}

-(IBAction) saveToCameraRoll:(id)sender{
	NSMutableArray *shelf = [[BookShelfManager sharedInstance] allMaterials];
	NSString *filepath = ((Material *)[shelf objectAtIndex: [BookShelfManager sharedInstance].currentProcessingImageID]).coverFullPathAtDevice;
	NSString *name = ((Material *)[shelf objectAtIndex: [BookShelfManager sharedInstance].currentProcessingImageID]).name;
	
	NSLog(@"saveToCameraRoll  .....%@, %@", filepath, name);
	UIImage *img = [UIImage imageNamed:name ];  
	
	// Request to save the image to camera roll
	UIImageWriteToSavedPhotosAlbum(img, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
	
}

// TODO: more attractive animation detail.
-(IBAction) returnToGridView:(id)sender{
	AppDelegate_iPad *delegate = (AppDelegate_iPad *)[[UIApplication sharedApplication] delegate];
	[delegate.navController popViewControllerAnimated:YES];
}


-(IBAction) setAutoSlideshow:(id)sender{
	if (autoSlideShowTimer) {  
		[autoSlideShowTimer invalidate];  // kill the timer
		autoSlideShowTimer = nil;
	}else {
		autoSlideShowTimer = [NSTimer scheduledTimerWithTimeInterval:3.0
															  target:self
															selector:@selector(showNextArt)
															userInfo:nil
															 repeats:YES];
		
	}
	isAutoSlideShow = !isAutoSlideShow;
	NSLog(@"isAutoSlideShow    is   %@", isAutoSlideShow? @"ON": @"OFF");
	
}


// TODO: refactor, duplicated code from IBAction code.
-(void) showNextArt {
	[BookShelfManager sharedInstance].targetImageID +=1;
	int theArtId = [BookShelfManager sharedInstance].targetImageID ;
	
	NSLog(@"In showNextArt, theArtId  is  [ %d ]",theArtId);
	if (theArtId == [[[BookShelfManager sharedInstance]allMaterials]count] ) {  // end of scrolling
		[BookShelfManager sharedInstance].targetImageID = theArtId = 0;
		//CGPoint offset = CGPointMake( - 480 * ( [[[BookShelfManager sharedInstance]allMaterials]count] - 2 )  , 0) ;
		CGPoint offset = CGPointMake(0,0); //NOTE: haha! This bug causes my one day! offset shouldn't be negative! CGPointMake( - self.scrollView.bounds.size.width * ( [[[BookShelfManager sharedInstance]allMaterials]count] - 1 )  , 0) ;
		
		NSLog(@"before moving to the first, the content offset is [ %f ], \n to move to the first, offset  is [ %f ] ",scrollView.contentOffset.x ,offset.x );
		
		 // exp: it looks like sth. goes wrong during scrolling to the first.
		//imageSwipeControlledByHuman = NO;
		
		[self loadScrollViewWithPage:0];
		
		[scrollView setContentOffset:offset animated:YES];
		
	}else {
		// shift one view.
		NSLog(@"self.view.bounds.size.width   (%f, %f)", self.view.bounds.size.width, self.view.bounds.size.height);
		CGPoint offset = CGPointMake( self.view.bounds.size.width * [BookShelfManager sharedInstance].targetImageID  , 0) ;
		[scrollView setContentOffset:offset animated:YES];
	}

	

}


-(void) showPrevArt {
	[BookShelfManager sharedInstance].targetImageID -=1;
	int theArtId = [BookShelfManager sharedInstance].targetImageID ;
	
	if (theArtId == -1 ) { 
		
	}else {
		CGPoint offset = CGPointMake( - self.view.bounds.size.width , 0) ;
		[scrollView setContentOffset:offset animated:YES];
	}
	//[BookShelfManager sharedInstance].currentProcessingImageID = theArtId = [[[BookShelfManager sharedInstance]allMaterials]count] -1;
	//[self setImageTo:theArtId];
	
}



#pragma mark -
#pragma mark callback 
- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo
{
    // Was there an error?
    if (error != NULL)
    {
		UIAlertView *alert =
        [[UIAlertView alloc] initWithTitle: @"Error"
								   message: [NSString stringWithFormat:@"Can't save the image, sorry!  Description: %@", [error localizedDescription]]
								  delegate: self
						 cancelButtonTitle: @"OK"
						 otherButtonTitles: nil];
		[alert show];
		[alert release];		
    }
    else  // No errors
    {
		// Show message image successfully saved
		UIAlertView *alert =
        [[UIAlertView alloc] initWithTitle: @"Information"
								   message: [NSString stringWithFormat:@"Art work saved to camera roll."]
								  delegate: self
						 cancelButtonTitle: @"OK"
						 otherButtonTitles: nil];
		[alert show];
		[alert release];
    }
}


-(void) oneFingerOneTap {
	[self displayControls];
}

-(void)hideControlResetTimer {
	shareSocially.hidden = YES;
	returnToGridView.hidden = YES;
	saveToCameraRoll.hidden = YES;
	//sliderToolbar.hidden = YES;
	setAutoSliding.hidden = YES;
	
	[autoHideControlButtonsTimer invalidate];
	autoHideControlButtonsTimer = nil;
}




#pragma mark -

- (void) displayControls  {
	// no matter if timer existes or not, always should controls, TODO: duplicated code,

	shareSocially.hidden = NO;
	returnToGridView.hidden = NO;
	saveToCameraRoll.hidden = NO;
	//sliderToolbar.hidden = NO;
	setAutoSliding.hidden = NO;
	
	// recreate the auto hider timer if not presented	
	if (autoHideControlButtonsTimer == nil) {
		autoHideControlButtonsTimer = [NSTimer scheduledTimerWithTimeInterval:5.0
																	   target:self
																	 selector:@selector(hideControlResetTimer)
																	 userInfo:nil
																	  repeats:NO];
	}else {
		// if timer exisis, buttons should set
	}

}

#pragma mark -
#pragma mark TouchEvent handling
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
	NSLog(@"touchesBegan  detected.  making controls re-appear");
	[self displayControls];
	
}


#pragma mark -
#pragma mark UIGestureRecognizerDelegate

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch {
    // test if our control subview is on-screen
	
	
//    if (self.controlSubview.superview != nil) {
//        if ([touch.view isDescendantOfView:self.controlSubview]) {
//            // we touched our control surface
//            return NO; // ignore the touch
//        }
//    }
//    return YES; // handle the touch
}


@end