#import "MBXSnapshotTestViewController.h"
#import "MLNMapView+Impl.h"
#import "MLNMapView_Private.h"
#import "Mapbox.h"

@interface MBXSnapshotTestViewController () <MLNMapViewDelegate>
@property (nonatomic) UIImageView *snapshotImageView;
@property (nonatomic, weak) id<MLNMapViewDelegate> originalDelegate;
@property (nonatomic, weak) UIView *originalSuperview;
@property (nonatomic) NSArray<NSLayoutConstraint *> *mapConstraints;
@end

@implementation MBXSnapshotTestViewController

- (void)viewDidLoad {
  [super viewDidLoad];
  self.title = @"Live Snapshot";
  self.view.backgroundColor = [UIColor blackColor];

  _snapshotImageView = [[UIImageView alloc] init];
  _snapshotImageView.contentMode = UIViewContentModeScaleAspectFit;
  _snapshotImageView.backgroundColor = [UIColor darkGrayColor];
  _snapshotImageView.translatesAutoresizingMaskIntoConstraints = NO;
  [self.view addSubview:_snapshotImageView];

  UILayoutGuide *safe = self.view.safeAreaLayoutGuide;

  if (_sourceMapView) {
    _originalDelegate = _sourceMapView.delegate;
    _originalSuperview = _sourceMapView.superview;

    _sourceMapView.delegate = self;
    _sourceMapView.translatesAutoresizingMaskIntoConstraints = NO;
    [self.view addSubview:_sourceMapView];

    _mapConstraints = @[
      [_snapshotImageView.topAnchor constraintEqualToAnchor:safe.topAnchor],
      [_snapshotImageView.leadingAnchor constraintEqualToAnchor:safe.leadingAnchor],
      [_snapshotImageView.trailingAnchor constraintEqualToAnchor:safe.trailingAnchor],
      [_snapshotImageView.heightAnchor constraintEqualToAnchor:safe.heightAnchor multiplier:0.5],

      [_sourceMapView.topAnchor constraintEqualToAnchor:_snapshotImageView.bottomAnchor],
      [_sourceMapView.leadingAnchor constraintEqualToAnchor:safe.leadingAnchor],
      [_sourceMapView.trailingAnchor constraintEqualToAnchor:safe.trailingAnchor],
      [_sourceMapView.bottomAnchor constraintEqualToAnchor:safe.bottomAnchor],
    ];
    [NSLayoutConstraint activateConstraints:_mapConstraints];
  } else {
    [NSLayoutConstraint activateConstraints:@[
      [_snapshotImageView.topAnchor constraintEqualToAnchor:safe.topAnchor],
      [_snapshotImageView.leadingAnchor constraintEqualToAnchor:safe.leadingAnchor],
      [_snapshotImageView.trailingAnchor constraintEqualToAnchor:safe.trailingAnchor],
      [_snapshotImageView.bottomAnchor constraintEqualToAnchor:safe.bottomAnchor],
    ]];
  }
}

- (void)viewWillDisappear:(BOOL)animated {
  [super viewWillDisappear:animated];

  if (self.isMovingFromParentViewController && _sourceMapView && _originalSuperview) {
    _sourceMapView.delegate = _originalDelegate;

    if (_mapConstraints) {
      [NSLayoutConstraint deactivateConstraints:_mapConstraints];
      _mapConstraints = nil;
    }

    // Re-pin to all edges; original storyboard constraints were
    // removed when the map view was reparented into this VC.
    [_originalSuperview addSubview:_sourceMapView];
    _sourceMapView.translatesAutoresizingMaskIntoConstraints = NO;
    [NSLayoutConstraint activateConstraints:@[
      [_sourceMapView.topAnchor constraintEqualToAnchor:_originalSuperview.topAnchor],
      [_sourceMapView.leadingAnchor constraintEqualToAnchor:_originalSuperview.leadingAnchor],
      [_sourceMapView.trailingAnchor constraintEqualToAnchor:_originalSuperview.trailingAnchor],
      [_sourceMapView.bottomAnchor constraintEqualToAnchor:_originalSuperview.bottomAnchor],
    ]];
  }
}

- (void)takeSnapshot {
  if (!_sourceMapView) return;
  UIImage *image = [_sourceMapView viewImpl]->snapshot();
  if (image) {
    self.snapshotImageView.image = image;
  }
}

#pragma mark - MLNMapViewDelegate

- (void)mapViewDidFinishRenderingFrame:(MLNMapView *)mapView fullyRendered:(BOOL)fullyRendered {
  [self takeSnapshot];
}

@end