EventDisplayViewController.m

//
//  EventDisplayViewController.m
//  CernVM Co-Pilot
//
//  Created by Eamon Ford on 7/15/12.
//  Copyright (c) 2012 The Byte Factory. All rights reserved.
//

#import "EventDisplayViewController.h"

#define SOURCE_DESCRIPTION @"Description"
#define SOURCE_URL @"URL"
#define SOURCE_BOUNDARY_RECTS @"Boundaries"
#define RESULT_IMAGE @"Image"
#define RESULT_LAST_UPDATED @"Last Updated"

@interface EventDisplayViewController ()

@end

@implementation EventDisplayViewController
@synthesize segmentedControl, sources, downloadedResults, scrollView, refreshButton, pageControl, titleLabel, dateLabel;

- (id)initWithCoder:(NSCoder *)aDecoder
{
    if (self = [super initWithCoder:aDecoder]) {
        self.sources = [NSMutableArray array];
        numPages = 0;
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.navigationController.navigationBar.tintColor = [UIColor blackColor];
    
    CGRect titleViewFrame = CGRectMake(0.0, 0.0, 200.0, 44.0);
    UIView *titleView = [[UIView alloc] initWithFrame:titleViewFrame];
    titleView.backgroundColor = [UIColor clearColor];
    
    titleLabel = [[UILabel alloc] initWithFrame:CGRectMake(0.0, 0.0, titleView.frame.size.width, 24.0)];
    titleLabel.backgroundColor = [UIColor clearColor];
    titleLabel.textColor = [UIColor whiteColor];
    titleLabel.font = [UIFont boldSystemFontOfSize:20.0];
    titleLabel.textAlignment = UITextAlignmentCenter;
    titleLabel.text = self.title;
    [titleView addSubview:titleLabel];
    
    dateLabel = [[UILabel alloc] initWithFrame:CGRectMake(0.0, titleLabel.frame.size.height, titleView.frame.size.width, titleView.frame.size.height-titleLabel.frame.size.height)];
    dateLabel.backgroundColor = [UIColor clearColor];
    dateLabel.textColor = [UIColor whiteColor];
    dateLabel.font = [UIFont boldSystemFontOfSize:13.0];
    dateLabel.textAlignment = UITextAlignmentCenter;
    [titleView addSubview:dateLabel];
    
    self.navigationItem.titleView = titleView;
    
    self.pageControl.numberOfPages = numPages;
    self.scrollView.backgroundColor = [UIColor blackColor];
}

- (void)viewDidAppear:(BOOL)animated
{
    self.scrollView.contentSize = CGSizeMake(self.scrollView.frame.size.width*numPages, 1.0);
    for (int i=0; i<numPages; i++) {
        [self addSpinnerToPage:i];
    }
    
    [self refresh:self];
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    for (UIView *subview in self.scrollView.subviews) {
        if ([subview class] == [UIImageView class]) {
            ((UIImageView *)subview).image = nil;
        }
        [subview removeFromSuperview];
    }
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
        return YES;
    else
        return (interfaceOrientation == UIInterfaceOrientationPortrait);
}


- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
    currentPage = self.pageControl.currentPage;
}

- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
    CGFloat oldScreenWidth = UIInterfaceOrientationIsPortrait([UIApplication sharedApplication].statusBarOrientation)?[UIScreen mainScreen].bounds.size.height:[UIScreen mainScreen].bounds.size.width;
    
    float scrollViewWidth = self.scrollView.frame.size.width;
    float scrollViewHeight = self.scrollView.frame.size.height;
    self.scrollView.contentSize = CGSizeMake(scrollViewWidth*numPages, 1.0);
    [self.scrollView setContentOffset:CGPointMake(self.scrollView.frame.size.width*currentPage, 0.0)];
    
    [UIView animateWithDuration:duration animations:^{
        for (UIView *subview in self.scrollView.subviews) {
            int page = floor((subview.frame.origin.x - oldScreenWidth / 2) / oldScreenWidth) + 1;
            subview.frame = CGRectMake(scrollViewWidth*page, 0.0, scrollViewWidth, scrollViewHeight);
        }
    }];
}

- (void)addSourceWithDescription:(NSString *)description URL:(NSURL *)url boundaryRects:(NSArray *)boundaryRects
{
    NSMutableDictionary *source = [NSMutableDictionary dictionary];
    [source setValue:description forKey:SOURCE_DESCRIPTION];
    [source setValue:url forKey:SOURCE_URL];
    if (boundaryRects) {
        [source setValue:boundaryRects forKey:SOURCE_BOUNDARY_RECTS];
        // If the image downloaded from this source is going to be divided into multiple images, we will want a separate page for each of these.
        numPages += boundaryRects.count;
    } else {
        numPages += 1;
    }
    [self.sources addObject:source];
}

#pragma mark - Loading event display images

- (IBAction)refresh:(id)sender
{
    self.refreshButton.enabled = NO;
    self.downloadedResults = [NSMutableArray array];
    
    // If the event display images from a previous load are already in the scrollview, remove all of them before refreshing.
    for (UIView *subview in self.scrollView.subviews) {
        if ([subview class] == [UIImageView class]) {
            [subview removeFromSuperview];
        }
    }
    
    for (NSDictionary *source in self.sources) {
        // ASYNCHRONOUSLY download the image for each source of the event display.
        [self performSelectorInBackground:@selector(synchronouslyDownloadImageForSource:) withObject:source];
    }
}

- (void)synchronouslyDownloadImageForSource:(NSDictionary *)source
{
    // Download the image from the specified source
    NSURL *url = [source objectForKey:SOURCE_URL];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    NSHTTPURLResponse *response = [[NSHTTPURLResponse alloc] init];
    NSData *imageData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];
    UIImage *image = [UIImage imageWithData:imageData];
    
    NSDate *lastUpdated = [self lastModifiedDateFromHTTPResponse:response];

    // Just set the date in the nav bar to the date of the first image, because they should all be pretty much the same anyway
    if (self.downloadedResults.count == 0) {
        self.dateLabel.text = [self timeAgoStringFromDate:lastUpdated];
    }
    
    // If the downloaded image needs to be divided into several smaller images, do that now and add each
    // smaller image to the results array.
    NSArray *boundaryRects = [source objectForKey:SOURCE_BOUNDARY_RECTS];
    if (boundaryRects) {
        for (NSDictionary *boundaryInfo in boundaryRects) {
            NSValue *rectValue = [boundaryInfo objectForKey:@"Rect"];
            CGRect boundaryRect = [rectValue CGRectValue];
            CGImageRef imageRef = CGImageCreateWithImageInRect(image.CGImage, boundaryRect);
            UIImage *partialImage = [UIImage imageWithCGImage:imageRef];

            NSDictionary *imageInfo = [NSMutableDictionary dictionary];
            [imageInfo setValue:partialImage forKey:RESULT_IMAGE];
            [imageInfo setValue:[boundaryInfo objectForKey:SOURCE_DESCRIPTION] forKey:SOURCE_DESCRIPTION];
            [imageInfo setValue:lastUpdated forKey:RESULT_LAST_UPDATED];
            [self.downloadedResults addObject:imageInfo];
            [self addDisplay:imageInfo toPage:self.downloadedResults.count-1];
        }
    } else {    // Otherwise if the image does not need to be divided, just add the image to the results array.
        NSDictionary *imageInfo = [NSMutableDictionary dictionary];
        [imageInfo setValue:image forKey:RESULT_IMAGE];
        [imageInfo setValue:[source objectForKey:SOURCE_DESCRIPTION] forKey:SOURCE_DESCRIPTION];
        [imageInfo setValue:lastUpdated forKey:RESULT_LAST_UPDATED];
        [self.downloadedResults addObject:imageInfo];
        [self addDisplay:imageInfo toPage:self.downloadedResults.count-1];
    }
    
    if (self.downloadedResults.count == numPages) {
        self.refreshButton.enabled = YES;
    }
}

- (NSDate *)lastModifiedDateFromHTTPResponse:(NSHTTPURLResponse *)response
{
    NSDictionary *allHeaderFields = response.allHeaderFields;
    NSString *lastModifiedString = [allHeaderFields objectForKey:@"Last-Modified"];
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"EEE',' dd' 'MMM' 'yyyy HH':'mm':'ss zzz"];
    
    return [dateFormatter dateFromString:lastModifiedString];
}

- (NSString *)timeAgoStringFromDate:(NSDate *)date
{
    int secondsAgo = abs([date timeIntervalSinceNow]);
    NSString *dateString;
    if (secondsAgo<60*60) {
        dateString = [NSString stringWithFormat:@"%d minutes ago", secondsAgo/60];
    } else if (secondsAgo<60*60*24) {
        dateString = [NSString stringWithFormat:@"%0.1f hours ago", (float)secondsAgo/(60*60)];
    } else {
        dateString = [NSString stringWithFormat:@"%0.1f days ago", (float)secondsAgo/(60*60*24)];
    }
    return dateString;
}
        
#pragma mark - UI methods

- (void)addDisplay:(NSDictionary *)eventDisplayInfo toPage:(int)page
{
    UIImage *image = [eventDisplayInfo objectForKey:RESULT_IMAGE];
    CGRect imageViewFrame = CGRectMake(self.scrollView.frame.size.width*page, 0.0, self.scrollView.frame.size.width, self.scrollView.frame.size.height);
    UIImageView *imageView = [[UIImageView alloc] initWithFrame:imageViewFrame];
    imageView.contentMode = UIViewContentModeScaleAspectFit;
    imageView.image = image;
    [self.scrollView addSubview:imageView];
}

- (void)addSpinnerToPage:(int)page
{
    UIActivityIndicatorView *spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
    spinner.frame = CGRectMake(self.scrollView.frame.size.width*page, 0.0, self.scrollView.frame.size.width, self.scrollView.frame.size.height);
    [spinner startAnimating];
    [self.scrollView addSubview:spinner];
}

- (void)scrollViewDidScroll:(UIScrollView *)sender {
    CGFloat pageWidth = self.scrollView.frame.size.width;
    int page = floor((self.scrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
    self.pageControl.currentPage = page;
}

@end