/**
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

#import "AIRMap.h"

#import "RCTEventDispatcher.h"
#import "AIRMapMarker.h"
#import "UIView+React.h"
#import "AIRMapPolyline.h"
#import "AIRMapPolygon.h"
#import "AIRMapCircle.h"

const CLLocationDegrees AIRMapDefaultSpan = 0.005;
const NSTimeInterval AIRMapRegionChangeObserveInterval = 0.1;
const CGFloat AIRMapZoomBoundBuffer = 0.01;


@interface MKMapView (UIGestureRecognizer)

// this tells the compiler that MKMapView actually implements this method
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch;

@end


@implementation AIRMap
{
    UIView *_legalLabel;
    CLLocationManager *_locationManager;
    BOOL _initialRegionSet;

    // Array to manually track RN subviews
    //
    // AIRMap implicitly creates subviews that aren't regular RN children
    // (SMCalloutView injects an overlay subview), which otherwise confuses RN
    // during component re-renders:
    // https://github.com/facebook/react-native/blob/v0.16.0/React/Modules/RCTUIManager.m#L657
    //
    // Implementation based on RCTTextField, another component with indirect children
    // https://github.com/facebook/react-native/blob/v0.16.0/Libraries/Text/RCTTextField.m#L20
    NSMutableArray<UIView *> *_reactSubviews;
}

- (instancetype)init
{
    if ((self = [super init])) {
        _hasStartedRendering = NO;
        _reactSubviews = [NSMutableArray new];

        // Find Apple link label
        for (UIView *subview in self.subviews) {
            if ([NSStringFromClass(subview.class) isEqualToString:@"MKAttributionLabel"]) {
                // This check is super hacky, but the whole premise of moving around
                // Apple's internal subviews is super hacky
                _legalLabel = subview;
                break;
            }
        }

        // 3rd-party callout view for MapKit that has more options than the built-in. It's painstakingly built to
        // be identical to the built-in callout view (which has a private API)
        self.calloutView = [SMCalloutView platformCalloutView];
        self.calloutView.delegate = self;
    }
    return self;
}

- (void)dealloc
{
    [_regionChangeObserveTimer invalidate];
}

- (void)insertReactSubview:(id<RCTComponent>)subview atIndex:(NSInteger)atIndex {
    // Our desired API is to pass up markers/overlays as children to the mapview component.
    // This is where we intercept them and do the appropriate underlying mapview action.
    if ([subview isKindOfClass:[AIRMapMarker class]]) {
        [self addAnnotation:(id <MKAnnotation>) subview];
    } else if ([subview isKindOfClass:[AIRMapPolyline class]]) {
        [self addOverlay:(id<MKOverlay>)subview];
    } else if ([subview isKindOfClass:[AIRMapPolygon class]]) {
        ((AIRMapPolygon *)subview).map = self;
        [self addOverlay:(id<MKOverlay>)subview];
    } else if ([subview isKindOfClass:[AIRMapCircle class]]) {
        [self addOverlay:(id<MKOverlay>)subview];
    }
    [_reactSubviews insertObject:subview atIndex:atIndex];
}

- (void)removeReactSubview:(id<RCTComponent>)subview {
    // similarly, when the children are being removed we have to do the appropriate
    // underlying mapview action here.
    if ([subview isKindOfClass:[AIRMapMarker class]]) {
        [self removeAnnotation:(id<MKAnnotation>)subview];
    } else if ([subview isKindOfClass:[AIRMapPolyline class]]) {
        [self removeOverlay:(id <MKOverlay>) subview];
    } else if ([subview isKindOfClass:[AIRMapPolygon class]]) {
        [self removeOverlay:(id <MKOverlay>) subview];
    } else if ([subview isKindOfClass:[AIRMapCircle class]]) {
        [self removeOverlay:(id <MKOverlay>) subview];
    }
    [_reactSubviews removeObject:subview];
}

- (NSArray<id<RCTComponent>> *)reactSubviews {
    return _reactSubviews;
}

#pragma mark Overrides for Callout behavior

// override UIGestureRecognizer's delegate method so we can prevent MKMapView's recognizer from firing
// when we interact with UIControl subclasses inside our callout view.
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch {
    if ([touch.view isDescendantOfView:self.calloutView])
        return NO;
    else
        return [super gestureRecognizer:gestureRecognizer shouldReceiveTouch:touch];
}

// Allow touches to be sent to our calloutview.
// See this for some discussion of why we need to override this: https://github.com/nfarina/calloutview/pull/9
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {

    UIView *calloutMaybe = [self.calloutView hitTest:[self.calloutView convertPoint:point fromView:self] withEvent:event];
    if (calloutMaybe) return calloutMaybe;

    return [super hitTest:point withEvent:event];
}

#pragma mark SMCalloutViewDelegate

- (NSTimeInterval)calloutView:(SMCalloutView *)calloutView delayForRepositionWithSize:(CGSize)offset {

    // When the callout is being asked to present in a way where it or its target will be partially offscreen, it asks us
    // if we'd like to reposition our surface first so the callout is completely visible. Here we scroll the map into view,
    // but it takes some math because we have to deal in lon/lat instead of the given offset in pixels.

    CLLocationCoordinate2D coordinate = self.region.center;

    // where's the center coordinate in terms of our view?
    CGPoint center = [self convertCoordinate:coordinate toPointToView:self];

    // move it by the requested offset
    center.x -= offset.width;
    center.y -= offset.height;

    // and translate it back into map coordinates
    coordinate = [self convertPoint:center toCoordinateFromView:self];

    // move the map!
    [self setCenterCoordinate:coordinate animated:YES];

    // tell the callout to wait for a while while we scroll (we assume the scroll delay for MKMapView matches UIScrollView)
    return kSMCalloutViewRepositionDelayForUIScrollView;
}

#pragma mark Accessors

- (void)setShowsUserLocation:(BOOL)showsUserLocation
{
    if (self.showsUserLocation != showsUserLocation) {
        if (showsUserLocation && !_locationManager) {
            _locationManager = [CLLocationManager new];
            if ([_locationManager respondsToSelector:@selector(requestWhenInUseAuthorization)]) {
                [_locationManager requestWhenInUseAuthorization];
            }
        }
        super.showsUserLocation = showsUserLocation;

        // If it needs to show user location, force map view centered
        // on user's current location on user location updates
        _followUserLocation = showsUserLocation;
    }
}

- (void)setRegion:(MKCoordinateRegion)region animated:(BOOL)animated
{
    // If location is invalid, abort
    if (!CLLocationCoordinate2DIsValid(region.center)) {
        return;
    }

    // If new span values are nil, use old values instead
    if (!region.span.latitudeDelta) {
        region.span.latitudeDelta = self.region.span.latitudeDelta;
    }
    if (!region.span.longitudeDelta) {
        region.span.longitudeDelta = self.region.span.longitudeDelta;
    }

    // Animate/move to new position
    [super setRegion:region animated:animated];
}

- (void)setInitialRegion:(MKCoordinateRegion)initialRegion {
    if (!_initialRegionSet) {
        _initialRegionSet = YES;
        [self setRegion:initialRegion animated:NO];
    }
}

@end