/*

     File: RootViewController.m

 Abstract: Main View Controller.

  Version: 1.1

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 MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION

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 */

#import "RootViewController.h"

#import "AlbumContentsViewController.h"

#import "AssetsDataIsInaccessibleViewController.h"

@interface RootViewController ()

@property (nonatomic, strong) ALAssetsLibrary *assetsLibrary;

@property (nonatomic, strong) NSMutableArray *groups;

@end

#pragma mark -

@implementation RootViewController

#pragma mark - View lifecycle

- (void)viewDidLoad {

    [super viewDidLoad];

    if (self.assetsLibrary == nil) {

        _assetsLibrary = [[ALAssetsLibrary alloc] init];

    }

    if (self.groups == nil) {

        _groups = [[NSMutableArray alloc] init];

    } else {

        [self.groups removeAllObjects];

    }

    // setup our failure view controller in case enumerateGroupsWithTypes fails

    ALAssetsLibraryAccessFailureBlock failureBlock = ^(NSError *error) {

        AssetsDataIsInaccessibleViewController *assetsDataInaccessibleViewController =

            [self.storyboard instantiateViewControllerWithIdentifier:@"inaccessibleViewController"];

        NSString *errorMessage = nil;

        switch ([error code]) {

            case ALAssetsLibraryAccessUserDeniedError:

            case ALAssetsLibraryAccessGloballyDeniedError:

                errorMessage = @"The user has declined access to it.";

                break;

            default:

                errorMessage = @"Reason unknown.";

                break;

        }

        assetsDataInaccessibleViewController.explanation = errorMessage;

        [self presentViewController:assetsDataInaccessibleViewController animated:NO completion:nil];

    };

    // emumerate through our groups and only add groups that contain photos

    ALAssetsLibraryGroupsEnumerationResultsBlock listGroupBlock = ^(ALAssetsGroup *group, BOOL *stop) {

        ALAssetsFilter *onlyPhotosFilter = [ALAssetsFilter allPhotos];

        [group setAssetsFilter:onlyPhotosFilter];

        if ([group numberOfAssets] > 0)

        {

            [self.groups addObject:group];

        }

        else

        {

            [self.tableView performSelectorOnMainThread:@selector(reloadData) withObject:nil waitUntilDone:NO];

        }

    };

    // enumerate only photos

    NSUInteger groupTypes = ALAssetsGroupAlbum | ALAssetsGroupEvent | ALAssetsGroupFaces | ALAssetsGroupSavedPhotos;

    [self.assetsLibrary enumerateGroupsWithTypes:groupTypes usingBlock:listGroupBlock failureBlock:failureBlock];

}

#pragma mark - UITableViewDataSource

// determine the number of rows in the table view

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {

    return self.groups.count;

}

// determine the appearance of table view cells

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];

    ALAssetsGroup *groupForCell = self.groups[indexPath.row];

    CGImageRef posterImageRef = [groupForCell posterImage];

    UIImage *posterImage = [UIImage imageWithCGImage:posterImageRef];

    cell.imageView.image = posterImage;

    cell.textLabel.text = [groupForCell valueForProperty:ALAssetsGroupPropertyName];

    cell.detailTextLabel.text = [@(groupForCell.numberOfAssets) stringValue];

    return cell;

}

#pragma mark - Segue support

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {

    if ([[segue identifier] isEqualToString:@"showDetail"]) {

        NSIndexPath *selectedIndexPath = [self.tableView indexPathForSelectedRow];

        if (self.groups.count > (NSUInteger)selectedIndexPath.row) {

            // hand off the asset group (i.e. album) to the next view controller

            AlbumContentsViewController *albumContentsViewController = [segue destinationViewController];

            albumContentsViewController.assetsGroup = self.groups[selectedIndexPath.row];

        }

    }

}

@end