/*

 Copyright (C) 2014 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

  The matches view controller in the application.  Allows users to view matches suggested by the app.

 */

#import "AAPLMatchesViewController.h"

#import "AAPLPerson.h"

#import "AAPLStyleUtilities.h"

#import "AAPLCardView.h"

static const CGFloat AAPLHelloGoodbyeVerticalMargin = 5.0;

static const NSTimeInterval AAPLSwipeAnimationDuration = 0.5;

static const NSTimeInterval AAPLZoomAnimationDuration = 0.3;

static const NSTimeInterval AAPLFadeAnimationDuration = 0.3;

@interface AAPLMatchesViewController ()

@property (nonatomic) AAPLCardView *cardView;

@property (nonatomic) UIView *swipeInstructionsView;

@property (nonatomic) UIView *allMatchesViewedExplanatoryView;

@property (nonatomic) NSArray *cardViewVerticalConstraints;

// Array of AAPLPersons

@property (nonatomic) NSArray *matches;

@property (nonatomic) NSUInteger currentMatchIndex;

@end

@implementation AAPLMatchesViewController

- (instancetype)init {

    self = [super init];

    if (self) {

        NSArray *serializedMatches = [NSArray arrayWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"matches" ofType:@"plist"]];

        NSMutableArray *matches = [NSMutableArray arrayWithCapacity:[serializedMatches count]];

        for (NSDictionary *serializedMatch in serializedMatches) {

            AAPLPerson *match = [AAPLPerson personWithDictionary:serializedMatch];

            [matches addObject:match];

        }

        self.title = NSLocalizedString(@"Matches", @"Title of the matches page");

        self.matches = matches;

        self.backgroundImage = [UIImage imageNamed:@"dessert"];

    }

    return self;

}

- (void)viewDidLoad {

    [super viewDidLoad];

    UIView *containerView = self.view;

    NSMutableArray *constraints = [NSMutableArray array];

    // Show instructions for how to say hello and goodbye

    self.swipeInstructionsView = [self addSwipeInstructionsToContainerView:containerView constraints:constraints];

    // Add a dummy view to center the card between the explanatory view and the bottom layout guide

    UIView *dummyView = [self addDummyViewToContainerView:containerView topItem:self.swipeInstructionsView bottomItem:[self bottomLayoutGuide] constraints:constraints];

    // Create and add the card

    AAPLCardView *cardView = [self addCardViewToView:containerView];

    // Define the vertical positioning of the card

    // These constraints will be removed when the card animates off screen

    self.cardViewVerticalConstraints =

    @[

      [NSLayoutConstraint constraintWithItem:cardView attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:dummyView attribute:NSLayoutAttributeCenterY multiplier:1.0 constant:0.0],

      [NSLayoutConstraint constraintWithItem:cardView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationGreaterThanOrEqual toItem:self.swipeInstructionsView attribute:NSLayoutAttributeBottom multiplier:1.0 constant:AAPLHelloGoodbyeVerticalMargin]

      ];

    [constraints addObjectsFromArray:self.cardViewVerticalConstraints];

    // Ensure that the card is centered horizontally within the container view, and doesn't exceed its width

    [constraints addObjectsFromArray:

     @[

       [NSLayoutConstraint constraintWithItem:cardView attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:containerView attribute:NSLayoutAttributeCenterX multiplier:1.0 constant:0.0],

       [NSLayoutConstraint constraintWithItem:cardView attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationGreaterThanOrEqual toItem:containerView attribute:NSLayoutAttributeLeft multiplier:1.0 constant:0.0],

       [NSLayoutConstraint constraintWithItem:cardView attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationLessThanOrEqual toItem:containerView attribute:NSLayoutAttributeRight multiplier:1.0 constant:0.0],

       ]];

    // When the matches run out, we'll show this message

    self.allMatchesViewedExplanatoryView = [self addAllMatchesViewExplanatoryViewToContainerView:containerView constraints:constraints];

    [containerView addConstraints:constraints];

}

- (UIView *)addDummyViewToContainerView:(UIView *)containerView topItem:(id)topItem bottomItem:(id)bottomItem constraints:(NSMutableArray *)constraints {

    UIView *dummyView = [[UIView alloc] init];

    dummyView.translatesAutoresizingMaskIntoConstraints = NO;

    [containerView addSubview:dummyView];

    // The horizontal layout of the dummy view does not matter, but for completeness, we give it a width of 0 and center it horizontally.

    [constraints addObjectsFromArray:

     @[

       [NSLayoutConstraint constraintWithItem:dummyView attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:0.0 constant:0.0],

       [NSLayoutConstraint constraintWithItem:dummyView attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:containerView attribute:NSLayoutAttributeCenterX multiplier:1.0 constant:0.0],

       [NSLayoutConstraint constraintWithItem:dummyView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:topItem attribute:NSLayoutAttributeBottom multiplier:1.0 constant:0.0],

       [NSLayoutConstraint constraintWithItem:dummyView attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:bottomItem attribute:NSLayoutAttributeTop multiplier:1.0 constant:0.0]

       ]];

    return dummyView;

}

- (AAPLCardView *)addCardViewToView:(UIView *)containerView {

    AAPLCardView *cardView = [[AAPLCardView alloc] init];

    [cardView updateWithPerson:[self currentMatch]];

    cardView.translatesAutoresizingMaskIntoConstraints = NO;

    self.cardView = cardView;

    [containerView addSubview:cardView];

    UISwipeGestureRecognizer *swipeUpRecognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeUp:)];

    swipeUpRecognizer.direction = UISwipeGestureRecognizerDirectionUp;

    [cardView addGestureRecognizer:swipeUpRecognizer];

    UISwipeGestureRecognizer *swipeDownRecognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeDown:)];

    swipeDownRecognizer.direction = UISwipeGestureRecognizerDirectionDown;

    [cardView addGestureRecognizer:swipeDownRecognizer];

    UIAccessibilityCustomAction *helloAction = [[UIAccessibilityCustomAction alloc] initWithName:NSLocalizedString(@"Say hello", @"Accessibility action to say hello") target:self selector:@selector(sayHello)];

    UIAccessibilityCustomAction *goodbyeAction = [[UIAccessibilityCustomAction alloc] initWithName:NSLocalizedString(@"Say goodbye", @"Accessibility action to say goodbye") target:self selector:@selector(sayGoodbye)];

    for (UIView *element in cardView.accessibilityElements) {

        element.accessibilityCustomActions = @[helloAction, goodbyeAction];

    }

    return cardView;

}

- (UIView *)addOverlayViewToContainerView:(UIView *)containerView {

    UIView *overlayView = [[UIView alloc] init];

    overlayView.backgroundColor = [AAPLStyleUtilities overlayColor];

    overlayView.layer.cornerRadius = [AAPLStyleUtilities overlayCornerRadius];

    overlayView.translatesAutoresizingMaskIntoConstraints = NO;

    [containerView addSubview:overlayView];

    return overlayView;

}

- (UIView *)addSwipeInstructionsToContainerView:(UIView *)containerView constraints:(NSMutableArray *)constraints {

    UIView *overlayView = [self addOverlayViewToContainerView:containerView];

    UILabel *swipeInstructionsLabel = [AAPLStyleUtilities standardLabel];

    swipeInstructionsLabel.font = [AAPLStyleUtilities largeFont];

    [overlayView addSubview:swipeInstructionsLabel];

    swipeInstructionsLabel.text = NSLocalizedString(@"Swipe ↑ to say \"Hello!\"\nSwipe ↓ to say \"Goodbye...\"", @"Instructions for the Matches page");

    swipeInstructionsLabel.accessibilityLabel = NSLocalizedString(@"Swipe up to say \"Hello!\"\nSwipe down to say \"Goodbye\"", @"Accessibility instructions for the Matches page");

    CGFloat overlayMargin = [AAPLStyleUtilities overlayMargin];

    NSLayoutConstraint *topMarginConstraint = [NSLayoutConstraint constraintWithItem:overlayView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:[self topLayoutGuide] attribute:NSLayoutAttributeBottom multiplier:1.0 constant:overlayMargin];

    topMarginConstraint.priority = UILayoutPriorityRequired - 1;

    [constraints addObject:topMarginConstraint];

    // Position the label inside the overlay view

    [constraints addObject:[NSLayoutConstraint constraintWithItem:swipeInstructionsLabel attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:overlayView attribute:NSLayoutAttributeTop multiplier:1.0 constant:AAPLHelloGoodbyeVerticalMargin]];

    [constraints addObject:[NSLayoutConstraint constraintWithItem:swipeInstructionsLabel attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:overlayView attribute:NSLayoutAttributeCenterX multiplier:1.0 constant:0.0]];

    [constraints addObject:[NSLayoutConstraint constraintWithItem:overlayView attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:swipeInstructionsLabel attribute:NSLayoutAttributeBottom multiplier:1.0 constant:AAPLHelloGoodbyeVerticalMargin]];

    // Center the overlay view horizontally

    [constraints addObject:[NSLayoutConstraint constraintWithItem:overlayView attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:containerView attribute:NSLayoutAttributeLeft multiplier:1.0 constant:overlayMargin]];

    [constraints addObject:[NSLayoutConstraint constraintWithItem:overlayView attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:containerView attribute:NSLayoutAttributeRight multiplier:1.0 constant:-overlayMargin]];

    return overlayView;

}

- (UIView *)addAllMatchesViewExplanatoryViewToContainerView:(UIView *)containerView constraints:(NSMutableArray *)constraints {

    UIView *overlayView = [self addOverlayViewToContainerView:containerView];

    // Start out hidden

    // This view will become visible once all matches have been viewed

    overlayView.alpha = 0.0;

    UILabel *label = [AAPLStyleUtilities standardLabel];

    label.font = [AAPLStyleUtilities largeFont];

    label.text = NSLocalizedString(@"Stay tuned for more matches!", @"Shown when all matches have been viewed");

    [overlayView addSubview:label];

    // Center the overlay view

    [constraints addObject:[NSLayoutConstraint constraintWithItem:overlayView attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:containerView attribute:NSLayoutAttributeCenterX multiplier:1.0 constant:0.0]];

    [constraints addObject:[NSLayoutConstraint constraintWithItem:overlayView attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:containerView attribute:NSLayoutAttributeCenterY multiplier:1.0 constant:0.0]];

    // Position the label in the overlay view

    [constraints addObject:[NSLayoutConstraint constraintWithItem:label attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:overlayView attribute:NSLayoutAttributeTop multiplier:1.0 constant:[AAPLStyleUtilities contentVerticalMargin]]];

    [constraints addObject:[NSLayoutConstraint constraintWithItem:label attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:overlayView attribute:NSLayoutAttributeBottom multiplier:1.0 constant:-1 * [AAPLStyleUtilities contentVerticalMargin]]];

    [constraints addObject:[NSLayoutConstraint constraintWithItem:label attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:overlayView attribute:NSLayoutAttributeLeading multiplier:1.0 constant:[AAPLStyleUtilities contentHorizontalMargin]]];

    [constraints addObject:[NSLayoutConstraint constraintWithItem:label attribute:NSLayoutAttributeTrailing relatedBy:NSLayoutRelationEqual toItem:overlayView attribute:NSLayoutAttributeTrailing multiplier:1.0 constant:-1 * [AAPLStyleUtilities contentHorizontalMargin]]];

    return overlayView;

}

- (AAPLPerson *)currentMatch {

    AAPLPerson *currentMatch = nil;

    if (self.currentMatchIndex < [self.matches count]) {

        currentMatch = self.matches[self.currentMatchIndex];

    }

    return currentMatch;

}

- (void)zoomCardIntoView {

    self.cardView.transform = CGAffineTransformMakeScale(0.0, 0.0);

    [UIView animateWithDuration:AAPLZoomAnimationDuration animations:^{

        self.cardView.transform = CGAffineTransformIdentity;

    }];

}

- (void)animateCardOffScreenToTop:(BOOL)toTop completion:(void (^)())completion {

    NSLayoutConstraint *offScreenConstraint = nil;

    if (toTop) {

        offScreenConstraint = [NSLayoutConstraint constraintWithItem:self.cardView attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTop multiplier:1.0 constant:0.0];

    } else {

        offScreenConstraint = [NSLayoutConstraint constraintWithItem:self.cardView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeBottom multiplier:1.0 constant:0.0];

    }

    [self.view layoutIfNeeded];

    [UIView animateWithDuration:AAPLSwipeAnimationDuration animations:^{

        // Slide the card off screen

        [self.view removeConstraints:self.cardViewVerticalConstraints];

        [self.view addConstraint:offScreenConstraint];

        [self.view layoutIfNeeded];

    } completion:^(BOOL finished) {

        // Bring the card back into view

        [self.view removeConstraint:offScreenConstraint];

        [self.view addConstraints:self.cardViewVerticalConstraints];

        if (completion) {

            completion();

        }

    }];

}

- (void)fadeCardIntoView {

    self.cardView.alpha = 0.0;

    [UIView animateWithDuration:AAPLFadeAnimationDuration animations:^{

        self.cardView.alpha = 1.0;

    }];

}

- (void)animateCardsForHello:(BOOL)forHello {

    [self animateCardOffScreenToTop:forHello completion:^{

        self.currentMatchIndex++;

        AAPLPerson *nextMatch = [self currentMatch];

        if (nextMatch) {

            // Show the next match's profile in the card

            [self.cardView updateWithPerson:nextMatch];

            // Ensure that the view's layout is up to date before we animate it

            [self.view layoutIfNeeded];

            if (UIAccessibilityIsReduceMotionEnabled()) {

                // Fade the card into view

                [self fadeCardIntoView];

            } else {

                // Zoom the new card from a tiny point into full view

                [self zoomCardIntoView];

            }

        } else {

            // Hide the card

            self.cardView.hidden = YES;

            // Fade in the "Stay tuned for more matches" blurb

            [UIView animateWithDuration:AAPLFadeAnimationDuration animations:^{

                self.swipeInstructionsView.alpha = 0.0;

                self.allMatchesViewedExplanatoryView.alpha = 1.0;

            }];

        }

        UIAccessibilityPostNotification(UIAccessibilityLayoutChangedNotification, nil);

    }];

}

- (BOOL)sayHello {

    [self animateCardsForHello:YES];

    return YES;

}

- (BOOL)sayGoodbye {

    [self animateCardsForHello:NO];

    return YES;

}

- (void)handleSwipeUp:(UISwipeGestureRecognizer *)gestureRecognizer {

    if (gestureRecognizer.state == UIGestureRecognizerStateRecognized) {

        [self sayHello];

    }

}

- (void)handleSwipeDown:(UISwipeGestureRecognizer *)gestureRecognizer {

    if (gestureRecognizer.state == UIGestureRecognizerStateRecognized) {

        [self sayGoodbye];

    }

}

@end