MapLibreParticleLab/platform/ios/src/MLNCompassButton.mm

#import "MLNCompassButton_Private.h"
#import "MLNCompassDirectionFormatter.h"

#import "MLNGeometry.h"

#import "MLNMapView_Private.h"
#import "NSBundle+MLNAdditions.h"
#import "UIImage+MLNAdditions.h"

#include <mln/math/wrap.hpp>

@interface MLNCompassButton ()

@property (nonatomic, weak) MLNMapView *mapView;
@property (nonatomic) MLNCompassDirectionFormatter *accessibilityCompassFormatter;

@end

@implementation MLNCompassButton

+ (instancetype)compassButtonWithMapView:(MLNMapView *)mapView {
  return [[MLNCompassButton alloc] initWithMapView:mapView];
}

- (instancetype)initWithMapView:(MLNMapView *)mapView {
  if (self = [super init]) {
    self.mapView = mapView;
    [self commonInit];
  }
  return self;
}

- (void)commonInit {
  self.image = self.compassImage;

  self.compassVisibility = MLNOrnamentVisibilityAdaptive;

  self.alpha = 0;
  self.userInteractionEnabled = YES;
  self.translatesAutoresizingMaskIntoConstraints = NO;

  UITapGestureRecognizer *tapGesture =
      [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTapGesture:)];
  [self addGestureRecognizer:tapGesture];

  self.accessibilityTraits = UIAccessibilityTraitButton;
  self.accessibilityLabel = NSLocalizedStringWithDefaultValue(@"COMPASS_A11Y_LABEL", nil, nil,
                                                              @"Compass", @"Accessibility label");
  self.accessibilityHint = NSLocalizedStringWithDefaultValue(
      @"COMPASS_A11Y_HINT", nil, nil, @"Rotates the map to face due north", @"Accessibility hint");

  self.accessibilityCompassFormatter = [[MLNCompassDirectionFormatter alloc] init];
  self.accessibilityCompassFormatter.unitStyle = NSFormattingUnitStyleLong;

  [self sizeToFit];
}

- (void)setCompassVisibility:(MLNOrnamentVisibility)compassVisibility {
  if (_compassVisibility == compassVisibility) {
    return;
  }
  _compassVisibility = compassVisibility;

  [self updateCompassAnimated:NO];
}

- (UIImage *)compassImage {
  UIImage *scaleImage = [UIImage mgl_resourceImageNamed:@"Compass"];
  UIGraphicsBeginImageContextWithOptions(scaleImage.size, NO, UIScreen.mainScreen.scale);
  [scaleImage drawInRect:{CGPointZero, scaleImage.size}];

  UIFont *northFont;
  if (@available(iOS 13.0, *)) {
    northFont = [UIFont systemFontOfSize:11 weight:UIFontWeightLight];
  } else {
    northFont = [UIFont systemFontOfSize:11 weight:UIFontWeightUltraLight];
  }

  NSAttributedString *north = [[NSAttributedString alloc]
      initWithString:NSLocalizedStringWithDefaultValue(@"COMPASS_NORTH", nil, nil, @"N",
                                                       @"Compass abbreviation for north")
          attributes:@{
            NSFontAttributeName : northFont,
            NSForegroundColorAttributeName : [UIColor whiteColor],
          }];
  CGRect stringRect =
      CGRectMake((scaleImage.size.width - north.size.width) / 2, scaleImage.size.height * 0.435,
                 north.size.width, north.size.height);
  [north drawInRect:stringRect];

  UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();
  return image;
}

- (void)handleTapGesture:(__unused UITapGestureRecognizer *)sender {
  [self.mapView resetNorth];
}

- (void)updateCompass {
  [self updateCompassAnimated:YES];
}

- (void)updateCompassAnimated:(BOOL)animated {
  CLLocationDirection direction = self.mapView.direction;
  CLLocationDirection plateDirection = mln::util::wrap(-direction, 0., 360.);
  self.transform = CGAffineTransformMakeRotation(MLNRadiansFromDegrees(plateDirection));

  self.isAccessibilityElement = direction > 0;
  self.accessibilityValue = [self.accessibilityCompassFormatter stringFromDirection:direction];

  switch (self.compassVisibility) {
    case MLNOrnamentVisibilityAdaptive:
      if (direction > 0 && self.alpha < 1) {
        [self showCompass:animated];
      } else if (direction == 0 && self.alpha > 0) {
        [self hideCompass:animated];
      }
      break;
    case MLNOrnamentVisibilityVisible:
      [self showCompass:animated];
      break;
    case MLNOrnamentVisibilityHidden:
      [self hideCompass:animated];
      break;
  }
}

- (void)showCompass:(BOOL)animated {
  animated ? [self animateToAlpha:1] : [self setAlpha:1];
}

- (void)hideCompass:(BOOL)animated {
  animated ? [self animateToAlpha:0] : [self setAlpha:0];
  self.isAccessibilityElement = NO;
  self.accessibilityElementsHidden = YES;
}

- (void)animateToAlpha:(CGFloat)alpha {
  [UIView animateWithDuration:MLNAnimationDuration
                        delay:0
                      options:UIViewAnimationOptionBeginFromCurrentState
                   animations:^{
                     self.alpha = alpha;
                   }
                   completion:nil];
}

@end