/*

     File: AssetViewController.m 

 Abstract: n/a 

  Version: 1.1 

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*/

#import "ApplicationConstants.h"

#import "AssetViewController.h"

#import "FavoriteAssets.h"

#import <ImageIO/ImageIO.h>

#define ZOOM_VIEW_TAG 100

#define ZOOM_STEP 1.5

@interface AssetViewController()

- (void)updateFavoriteButtonState;

- (CGRect)zoomRectForScale:(float)scale withCenter:(CGPoint)center;

- (UIImage *)fullSizeImageForAssetRepresentation:(ALAssetRepresentation *)assetRepresentation;

@end

@implementation AssetViewController

@synthesize metadataViewController;

@synthesize asset;

@synthesize favoriteAssets;

- (void)viewDidLoad {

    [imageScrollView setBackgroundColor:[UIColor blackColor]];

    [imageScrollView setDelegate:self];

    [imageScrollView setBouncesZoom:YES];

    imageScrollView.showsVerticalScrollIndicator = NO;

    imageScrollView.showsHorizontalScrollIndicator = NO;

    ALAssetRepresentation *assetRepresentation = [asset defaultRepresentation];

    UIImage *fullSizeImage = [self fullSizeImageForAssetRepresentation:assetRepresentation];

    // add touch-sensitive image view to the scroll view

    TapDetectingImageView *imageView = [[TapDetectingImageView alloc] initWithImage:fullSizeImage];

    [imageView setDelegate:self];

    [imageView setTag:ZOOM_VIEW_TAG];

    [imageScrollView setContentSize:[imageView frame].size];

    [imageScrollView addSubview:imageView];

    [imageView release];

    // calculate minimum scale to perfectly fit image width, and begin at that scale

    float minimumScale = [imageScrollView frame].size.width  / [imageView frame].size.width;

    [imageScrollView setMinimumZoomScale:minimumScale];

    [self updateFavoriteButtonState];

    self.title = @"Full Resolution Image";

}

#pragma mark -

#pragma mark UIScrollViewDelegate methods

- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {

    return [(UIScrollView *)self.view viewWithTag:ZOOM_VIEW_TAG];

}

#pragma mark -

#pragma mark TapDetectingImageViewDelegate methods

- (void)tapDetectingImageView:(TapDetectingImageView *)view gotSingleTapAtPoint:(CGPoint)tapPoint {

    // single tap does nothing for now

}

- (void)tapDetectingImageView:(TapDetectingImageView *)view gotDoubleTapAtPoint:(CGPoint)tapPoint {

    // double tap zooms in

    float newScale = [imageScrollView zoomScale] * ZOOM_STEP;

    CGRect zoomRect = [self zoomRectForScale:newScale withCenter:tapPoint];

    [imageScrollView zoomToRect:zoomRect animated:YES];

}

- (void)tapDetectingImageView:(TapDetectingImageView *)view gotTwoFingerTapAtPoint:(CGPoint)tapPoint {

    // two-finger tap zooms out

    float newScale = [imageScrollView zoomScale] / ZOOM_STEP;

    CGRect zoomRect = [self zoomRectForScale:newScale withCenter:tapPoint];

    [imageScrollView zoomToRect:zoomRect animated:YES];

}

#pragma mark -

#pragma mark Utility methods

- (CGRect)zoomRectForScale:(float)scale withCenter:(CGPoint)center {

    CGRect zoomRect;

    // the zoom rect is in the content view's coordinates. 

    //    At a zoom scale of 1.0, it would be the size of the imageScrollView's bounds.

    //    As the zoom scale decreases, so more content is visible, the size of the rect grows.

    zoomRect.size.height = [imageScrollView frame].size.height / scale;

    zoomRect.size.width  = [imageScrollView frame].size.width  / scale;

    // choose an origin so as to get the right center.

    zoomRect.origin.x    = center.x - (zoomRect.size.width  / 2.0);

    zoomRect.origin.y    = center.y - (zoomRect.size.height / 2.0);

    return zoomRect;

}

- (UIImage *)fullSizeImageForAssetRepresentation:(ALAssetRepresentation *)assetRepresentation {

    UIImage *result = nil;

    NSData *data = nil;

    uint8_t *buffer = (uint8_t *)malloc(sizeof(uint8_t)*[assetRepresentation size]);

    if (buffer != NULL) {

        NSError *error = nil;

        NSUInteger bytesRead = [assetRepresentation getBytes:buffer fromOffset:0 length:[assetRepresentation size] error:&error];        

        data = [NSData dataWithBytes:buffer length:bytesRead];

        free(buffer);

    }

    if ([data length]) {

        CGImageSourceRef sourceRef = CGImageSourceCreateWithData((CFDataRef)data, nil);

        NSMutableDictionary *options = [NSMutableDictionary dictionary];

        [options setObject:(id)kCFBooleanTrue forKey:(id)kCGImageSourceCreateThumbnailFromImageIfAbsent];

        CGImageRef imageRef = CGImageSourceCreateThumbnailAtIndex(sourceRef, 0, (CFDictionaryRef)options);

        if (imageRef) {

            result = [UIImage imageWithCGImage:imageRef scale:[assetRepresentation scale] orientation:[assetRepresentation orientation]];

            CGImageRelease(imageRef);

        }

        if (sourceRef) CFRelease(sourceRef);

    }

    return result;

}

#pragma mark -

#pragma mark Favorite Status

- (void)toggleFavoriteStatus:(id)sender {

    NSURL *assetURL = [[self.asset defaultRepresentation] url];

    [[NSNotificationCenter defaultCenter] postNotificationName:kToggleFavoriteStatusNotification object:nil userInfo:[NSDictionary dictionaryWithObject:assetURL forKey:kToggleFavoriteStatusNotificationAssetURLKey]];

    [self updateFavoriteButtonState];

}

- (void)updateFavoriteButtonState {

    static UIImage *notFavorite = nil;

    static UIImage *favorite    = nil;

    if (!notFavorite) {

        notFavorite  = [UIImage imageNamed:@"grey-star.png"];

    }

    if (!favorite) {

        favorite = [UIImage imageNamed:@"gold-star.png"];

    }

    if ([self.favoriteAssets isFavorite:asset]) {

        [setAsFavoriteButton setImage:favorite forState:UIControlStateNormal];

    } else {

        [setAsFavoriteButton setImage:notFavorite forState:UIControlStateNormal];

    }

    [setAsFavoriteButton setNeedsDisplay];

}

#pragma mark -

#pragma mark Metadata View Controller

- (void)displayAssetMetadata:(id)sender {

    metadataViewController = [[MetadataViewController alloc] initWithNibName:@"MetadataViewController" bundle:nil];

    metadataViewController.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;

    metadataViewController.delegate = self;

    metadataViewController.asset = asset;

    [self presentViewController:metadataViewController animated:YES completion:nil];

}

- (void)dismissMetadataViewController {

    metadataViewController.delegate = nil;

    [[self navigationController] dismissViewControllerAnimated:YES completion:nil];

    [metadataViewController release];

}

#pragma mark -

#pragma mark Memory management

- (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)dealloc {

    self.asset = nil;

    self.favoriteAssets = nil;

    [super dealloc];

}

@end