/*

    File:       PhotoDetailViewController.h

    Contains:   Shows a photo in a scroll view.

    Written by: DTS

    Copyright:  Copyright (c) 2010 Apple Inc. All Rights Reserved.

    Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple Inc.

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                this notice, no other rights or licenses, express or implied,

                are granted by Apple herein, including but not limited to any

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                The Apple Software is provided by Apple on an "AS IS" basis. 

                APPLE MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING

                WITHOUT LIMITATION THE IMPLIED WARRANTIES OF NON-INFRINGEMENT,

                MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, REGARDING

                THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN

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*/

#import "PhotoDetailViewController.h"

#import "QImageScrollView.h"

#import "PhotoGallery.h"

#import "Photo.h"

#import "Logging.h"

@implementation PhotoDetailViewController

- (id)initWithPhoto:(Photo *)photo photoGallery:(PhotoGallery *)photoGallery

{

    assert(photo != nil);

    assert(photoGallery != nil);

    self = [super initWithNibName:@"PhotoDetailViewController" bundle:nil];

    if (self != nil) {

        self->_photo        = [photo retain];

        self->_photoGallery = [photoGallery retain];

        [self.photo addObserver:self forKeyPath:@"displayName"  options:NSKeyValueObservingOptionInitial context:&self->_photo];

    }

    return self;

}

- (void)dealloc

{

    [self.photo removeObserver:self forKeyPath:@"displayName"];

    [self->_scrollView release];

    [self->_loadingLabel release];

    [self->_photo release];

    [self->_photoGallery release];

    [super dealloc];

}

#pragma mark * Keeping everything up-to-date

@synthesize photo        = _photo;

@synthesize photoGallery = _photoGallery;

- (void)photoWasDeleted

    // If the underlying photos was deleted while we're displaying it (typically 

    // because a sync ran), we just pop ourselves off the view controller stack.

{

    if ([self.navigationController.viewControllers containsObject:self]) {

        [self.navigationController popToViewController:self animated:NO];

        [self.navigationController popViewControllerAnimated:YES];

    }

}

- (void)contextChanged:(NSNotification *)note

    // This notification is issued by the NSManagedObjectContext that controls the photo 

    // object we're displaying.  If that phono object is deleted (as can happen if a sync 

    // occurs while we're on screen), we call -photoWasDeleted (which pops us off the 

    // navigation controller stack).

{

    NSSet * deletedObjects;

    deletedObjects = [[note userInfo] objectForKey:NSDeletedObjectsKey];

    if (deletedObjects != nil) {

        assert([deletedObjects isKindOfClass:[NSSet class]]);

        if ([deletedObjects containsObject:self.photo]) {

            [self photoWasDeleted];

        }

    }

}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context

{

    if (context == &self->_photo) {

        // Called when various properties of our photo change.  We update our UI 

        // accordingly.

        assert(object == self.photo);

        if ([keyPath isEqual:@"displayName"]) {

            // Sync the photo name into the navigation item title.

            self.title = self.photo.displayName;

        } else if (self.isViewLoaded) {

            if ([keyPath isEqual:@"photoImage"]) {

                UIImage *   image;

                // If the photo changed, update our UI.  All of the hard work is done 

                // by the QImageScrollView class.

                image = self.photo.photoImage;

                self.scrollView.image = image;

                self.scrollView.hidden = (image == nil);

                self.loadingLabel.hidden = (image != nil);

            } else if ([keyPath isEqual:@"photoGetting"]) {

                // Update our loading label as the photo hits the network.

                if (self.photo.photoGetting) {

                    self.loadingLabel.text = @"Loading…";

                } else {

                    // This assert isn't valid because if we get bad photo data we don't 

                    // detect that at the time of the get, we detect that when we try to 

                    // create a UIImage from the file on disk.  In that case photoImage 

                    // will be nil but photoGetError will also be nil.  This doesn't materially 

                    // affect our code; we still want to display "Load failed".

                    //

                    // assert( (self.photo.photoImage != nil) || (self.photo.photoGetError != nil) );

                    self.loadingLabel.text = @"Load failed";

                }

            } else {

                assert(NO);

            }

        }

    } else if (NO) {   // Disabled because the super class does nothing useful with it.

        [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];

    }

}

#pragma mark * View controller stuff

@synthesize scrollView   = _scrollView;

@synthesize loadingLabel = _loadingLabel;

- (void)viewDidLoad

{

    [super viewDidLoad];

    assert([self.scrollView isKindOfClass:[QImageScrollView class]]);

    assert(self.loadingLabel != nil);

    self.view.backgroundColor = [UIColor groupTableViewBackgroundColor];

}

- (void)viewDidUnload

{

    [super viewDidUnload];

    self.scrollView = nil;

    self.loadingLabel = nil;

}

- (void)viewWillAppear:(BOOL)animated

{

    [super viewWillAppear:animated];

    // Tell the model object that we want it to keep the photo image up-to-date.

    [self.photo assertPhotoNeeded];

    // Configure our view.  We hide the scroll view, which leaves the loading label 

    // visible.

    self.scrollView.hidden   = YES;

    [self.navigationController setToolbarHidden:YES animated:animated];

}

- (void)viewDidAppear:(BOOL)animated

{

    [super viewDidAppear:animated];

    // Add the observers here so that the initial call sees the correct size 

    // of the scroll view (that is, after the toolbar has hidden).

    [self.photo addObserver:self forKeyPath:@"photoImage"   options:NSKeyValueObservingOptionInitial context:&self->_photo];

    [self.photo addObserver:self forKeyPath:@"photoGetting" options:NSKeyValueObservingOptionInitial context:&self->_photo];

    // Unfortunately -[NSManagedObject isDeleted] doesn't really do what I want 

    // here, so I just watch the context directly.

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(contextChanged:) name:NSManagedObjectContextObjectsDidChangeNotification object:self.photo.managedObjectContext];

}

- (void)viewWillDisappear:(BOOL)animated

{

    [super viewWillDisappear:animated];

    // Undo the stuff we did in -viewDidAppear.

    [[NSNotificationCenter defaultCenter] removeObserver:self name:NSManagedObjectContextObjectsDidChangeNotification object:self.photo.managedObjectContext];

    [self.photo removeObserver:self forKeyPath:@"photoImage"];

    [self.photo removeObserver:self forKeyPath:@"photoGetting"];

    // We show the navigation controller's toolbar here, so that you 

    // can see the animation.

    [self.navigationController setToolbarHidden:NO animated:animated];

}

- (void)viewDidDisappear:(BOOL)animated

{

    [super viewDidDisappear:animated];

    // Tell the model object is no longer needs to keep the photo image up-to-date.

    [self.photo deassertPhotoNeeded];

}

@end