custom layout collection view

//
//  FFMarketSelector.m
//  FMF Football
//
//  Created by Samuel Sutch on 9/24/13.
//  Copyright (c) 2013 FairMarketFantasy. All rights reserved.
//

#import "FFMarketSelector.h"

@interface FFMarketSelector () <UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout>

@property(nonatomic) UICollectionView* collectionView;
@property(nonatomic) UICollectionViewFlowLayout* flowLayout;

@end

@implementation FFMarketSelector

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        _flowLayout = [[UICollectionViewFlowLayout alloc] init];
        _flowLayout.scrollDirection = UICollectionViewScrollDirectionHorizontal;
        _flowLayout.sectionInset = UIEdgeInsetsZero;
        _flowLayout.minimumInteritemSpacing = 0;
        _flowLayout.minimumLineSpacing = 0;

        _collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(45, 0, frame.size.width - 90, frame.size.height)
                                             collectionViewLayout:_flowLayout];
        _collectionView.delegate = self;
        _collectionView.dataSource = self;
        _collectionView.pagingEnabled = YES;
        _collectionView.backgroundColor = [FFStyle white];
        _collectionView.autoresizingMask = UIViewAutoresizingFlexibleWidth;
        _collectionView.alwaysBounceHorizontal = YES;
        _collectionView.showsHorizontalScrollIndicator = NO;
        [_collectionView registerClass:[UICollectionViewCell class]
            forCellWithReuseIdentifier:@"MarketCell"];
        [self addSubview:_collectionView];

        UIButton* left = [UIButton buttonWithType:UIButtonTypeCustom];
        [left setImage:[UIImage imageNamed:@"leftshuttle.png"]
              forState:UIControlStateNormal];
        left.frame = CGRectMake(10, 0, 35, frame.size.height);
        left.autoresizingMask = UIViewAutoresizingNone;
        [left addTarget:self
                      action:@selector(left:)
            forControlEvents:UIControlEventTouchUpInside];
        [self addSubview:left];

        UIButton* right = [UIButton buttonWithType:UIButtonTypeCustom];
        [right setImage:[UIImage imageNamed:@"rightshuttle.png"]
               forState:UIControlStateNormal];
        right.frame = CGRectMake(frame.size.width - 35 - 10, 0, 35, frame.size.height);
        right.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin;
        [right addTarget:self
                      action:@selector(right:)
            forControlEvents:UIControlEventTouchUpInside];
        [self addSubview:right];
    }
    return self;
}

- (void)left:(UIButton*)sender
{
    NSArray* selected = [self.collectionView indexPathsForVisibleItems];
    if (selected && selected.count) {
        NSIndexPath* path = [selected objectAtIndex:0];
        if (path.item == 0)
            return; // already at the first item
        [self.collectionView scrollToItemAtIndexPath:[NSIndexPath indexPathForItem:path.item - 1
                                                                         inSection:0]
                                    atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally
                                            animated:YES];
        _selectedMarket = self.markets[path.item - 1];
        if (self.delegate && [self.delegate respondsToSelector:@selector(didUpdateToNewMarket:)]) {
            [self.delegate didUpdateToNewMarket:_selectedMarket];
        }
    }
}

- (void)right:(UIButton*)sender
{
    NSArray* selected = [self.collectionView indexPathsForVisibleItems];
    if (selected && selected.count) {
        NSIndexPath* path = [selected lastObject];
        if (path.item == (self.markets.count - 1))
            return; // already at last item
        [self.collectionView scrollToItemAtIndexPath:[NSIndexPath indexPathForItem:path.item + 1
                                                                         inSection:0]
                                    atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally
                                            animated:YES];
        _selectedMarket = self.markets[path.item + 1];
        if (self.delegate && [self.delegate respondsToSelector:@selector(didUpdateToNewMarket:)]) {
            [self.delegate didUpdateToNewMarket:_selectedMarket];
        }
    }
}

- (void)setMarkets:(NSArray*)markets
{
    if (self.markets == markets) {
        return;
    }
    _markets = [markets copy];
    [self.collectionView reloadData];
    if (self.markets.count > 0) {
        self.selectedMarket = self.markets.firstObject;
     }
    self.selectedMarket = nil;
}

- (void)setSelectedMarket:(NSUInteger)selectedMarket
{
    if (self.selectedMarket == selectedMarket) {
        return;
    }
    if (self.delegate &&
        self.delegate.markets.count <= selectedMarket
        ) {
        return;
    }
    _selectedMarket = selectedMarket;
    [self.collectionView scrollToItemAtIndexPath:[NSIndexPath indexPathForItem:self.selectedMarket
                                                                     inSection:0]
                                atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally
                                        animated:YES];
}

- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView*)collectionView
{
    return 1;
}

- (NSInteger)collectionView:(UICollectionView*)collectionView numberOfItemsInSection:(NSInteger)section
{
    return [self.markets count];
}

- (CGSize)collectionView:(UICollectionView*)collectionView
                    layout:(UICollectionViewLayout*)collectionViewLayout
    sizeForItemAtIndexPath:(NSIndexPath*)indexPath
{
    return CGSizeMake(self.collectionView.frame.size.width, self.collectionView.frame.size.height);
}

- (UICollectionViewCell*)collectionView:(UICollectionView*)collectionView cellForItemAtIndexPath:(NSIndexPath*)indexPath
{
    UICollectionViewCell* cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"MarketCell"
                                                                           forIndexPath:indexPath];
    [cell.contentView.subviews makeObjectsPerformSelector:@selector(removeFromSuperview)];

    FFMarket* market = self.markets[indexPath.item];

    UILabel* marketLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, cell.contentView.frame.size.width, 30)];
    marketLabel.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
    marketLabel.font = [FFStyle boldFont:17];
    marketLabel.textColor = [FFStyle darkGreyTextColor];
    marketLabel.backgroundColor = [UIColor clearColor];
    marketLabel.textAlignment = NSTextAlignmentCenter;

    if (market.name && market.name.length) {
        marketLabel.text = market.name;
    } else {
        marketLabel.text = NSLocalizedString(@"Market", nil);
    }

    NSDateFormatter* dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"E d @ h:mm a"];

    UILabel* timeLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 30, cell.contentView.frame.size.width, 25)];
    timeLabel.autoresizingMask = UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleHeight;
    timeLabel.font = [FFStyle regularFont:17.f];
    timeLabel.textColor = [FFStyle black];
    timeLabel.textAlignment = NSTextAlignmentCenter;
    timeLabel.backgroundColor = [UIColor clearColor];
    timeLabel.text = [dateFormatter stringFromDate:market.startedAt];

    [cell.contentView addSubview:timeLabel];
    [cell.contentView addSubview:marketLabel];

    return cell;
}

- (void)scrollViewDidEndDecelerating:(UIScrollView*)scrollView
{
    NSArray* visible = [self.collectionView indexPathsForVisibleItems];
    if (visible && visible.count) {
        NSIndexPath* path = visible[0];
        if (self.delegate && [self.delegate respondsToSelector:@selector(didUpdateToNewMarket:)]) {
            [self.delegate didUpdateToNewMarket:self.markets[path.item]];
        }
    }
}

@end