MapLibreParticleLab/platform/darwin/src/MGLFeature.mm

#import "MGLFeature_Private.h"

#import "MGLPointAnnotation.h"
#import "MGLPolyline.h"
#import "MGLPolygon.h"

#import "MGLMultiPoint_Private.h"

#import <mbgl/util/geometry.hpp>

@protocol MGLFeaturePrivate <MGLFeature>

@property (nonatomic, copy, nullable, readwrite) id identifier;
@property (nonatomic, copy, readwrite) NS_DICTIONARY_OF(NSString *, id) *attributes;

@end

@interface MGLPointFeature () <MGLFeaturePrivate>
@end

@implementation MGLPointFeature

@synthesize identifier;
@synthesize attributes;

- (id)attributeForKey:(NSString *)key {
    return self.attributes[key];
}

@end

@interface MGLPolylineFeature () <MGLFeaturePrivate>
@end

@implementation MGLPolylineFeature

@synthesize identifier;
@synthesize attributes;

- (id)attributeForKey:(NSString *)key {
    return self.attributes[key];
}

@end

@interface MGLPolygonFeature () <MGLFeaturePrivate>
@end

@implementation MGLPolygonFeature

@synthesize identifier;
@synthesize attributes;

- (id)attributeForKey:(NSString *)key {
    return self.attributes[key];
}

@end

@interface MGLMultiPointFeature () <MGLFeaturePrivate>
@end

@implementation MGLMultiPointFeature

@synthesize identifier;
@synthesize attributes;

- (id)attributeForKey:(NSString *)key {
    return self.attributes[key];
}

@end

@interface MGLMultiPolylineFeature () <MGLFeaturePrivate>
@end

@implementation MGLMultiPolylineFeature

@synthesize identifier;
@synthesize attributes;

- (id)attributeForKey:(NSString *)key {
    return self.attributes[key];
}

@end

@interface MGLMultiPolygonFeature () <MGLFeaturePrivate>
@end

@implementation MGLMultiPolygonFeature

@synthesize identifier;
@synthesize attributes;

- (id)attributeForKey:(NSString *)key {
    return self.attributes[key];
}

@end

@interface MGLShapeCollectionFeature () <MGLFeaturePrivate>
@end

@implementation MGLShapeCollectionFeature

@synthesize identifier;
@synthesize attributes;

- (id)attributeForKey:(NSString *)key {
    return self.attributes[key];
}

@end

/**
 Recursively transforms a C++ type into the corresponding Foundation type.
 */
class PropertyValueEvaluator {
public:
    id operator()(const mbgl::NullValue &) const {
        return [NSNull null];
    }
    
    id operator()(const bool &value) const {
        return value ? @YES : @NO;
    }
    
    id operator()(const uint64_t &value) const {
        return @(value);
    }
    
    id operator()(const int64_t &value) const {
        return @(value);
    }
    
    id operator()(const double &value) const {
        return @(value);
    }
    
    id operator()(const std::string &value) const {
        return @(value.c_str());
    }
    
    id operator()(const std::vector<mbgl::Value> &values) const {
        NSMutableArray *objects = [NSMutableArray arrayWithCapacity:values.size()];
        for (const auto &v : values) {
            [objects addObject:mbgl::Value::visit(v, *this)];
        }
        return objects;
    }
    
    id operator()(const std::unordered_map<std::string, mbgl::Value> &items) const {
        NSMutableDictionary *attributes = [NSMutableDictionary dictionaryWithCapacity:items.size()];
        for (auto &item : items) {
            attributes[@(item.first.c_str())] = mbgl::Value::visit(item.second, *this);
        }
        return attributes;
    }
};

/**
 Transforms an `mbgl::geometry::geometry` type into an instance of the
 corresponding Objective-C geometry class.
 */
template <typename T>
class GeometryEvaluator {
public:
    MGLShape <MGLFeaturePrivate> * operator()(const mbgl::Point<T> &geometry) const {
        MGLPointFeature *feature = [[MGLPointFeature alloc] init];
        feature.coordinate = toLocationCoordinate2D(geometry);
        return feature;
    }
    
    MGLShape <MGLFeaturePrivate> * operator()(const mbgl::LineString<T> &geometry) const {
        std::vector<CLLocationCoordinate2D> coordinates = toLocationCoordinates2D(geometry);
        return [MGLPolylineFeature polylineWithCoordinates:&coordinates[0] count:coordinates.size()];
    }
    
    MGLShape <MGLFeaturePrivate> * operator()(const mbgl::Polygon<T> &geometry) const {
        return toShape<MGLPolygonFeature>(geometry);
    }
    
    MGLShape <MGLFeaturePrivate> * operator()(const mbgl::MultiPoint<T> &geometry) const {
        std::vector<CLLocationCoordinate2D> coordinates = toLocationCoordinates2D(geometry);
        return [[MGLMultiPointFeature alloc] initWithCoordinates:&coordinates[0] count:coordinates.size()];
    }
    
    MGLShape <MGLFeaturePrivate> * operator()(const mbgl::MultiLineString<T> &geometry) const {
        NSMutableArray *polylines = [NSMutableArray arrayWithCapacity:geometry.size()];
        for (auto &lineString : geometry) {
            std::vector<CLLocationCoordinate2D> coordinates = toLocationCoordinates2D(lineString);
            MGLPolyline *polyline = [MGLPolyline polylineWithCoordinates:&coordinates[0] count:coordinates.size()];
            [polylines addObject:polyline];
        }
        
        return [MGLMultiPolylineFeature multiPolylineWithPolylines:polylines];
    }
    
    MGLShape <MGLFeaturePrivate> * operator()(const mbgl::MultiPolygon<T> &geometry) const {
        NSMutableArray *polygons = [NSMutableArray arrayWithCapacity:geometry.size()];
        for (auto &polygon : geometry) {
            [polygons addObject:toShape(polygon)];
        }
        
        return [MGLMultiPolygonFeature multiPolygonWithPolygons:polygons];
    }
    
    MGLShape <MGLFeaturePrivate> * operator()(const mapbox::geometry::geometry_collection<T> &collection) const {
        NSMutableArray *shapes = [NSMutableArray arrayWithCapacity:collection.size()];
        for (auto &geometry : collection) {
            // This is very much like the transformation that happens in MGLFeaturesFromMBGLFeatures(), but these are raw geometries with no associated feature IDs or attributes.
            MGLShape <MGLFeaturePrivate> *shape = mapbox::geometry::geometry<T>::visit(geometry, *this);
            [shapes addObject:shape];
        }
        return [MGLShapeCollectionFeature shapeCollectionWithShapes:shapes];
    }
    
private:
    static CLLocationCoordinate2D toLocationCoordinate2D(const mbgl::Point<T> &point) {
        return CLLocationCoordinate2DMake(point.y, point.x);
    }
    
    static std::vector<CLLocationCoordinate2D> toLocationCoordinates2D(const std::vector<mbgl::Point<T>> &points) {
        std::vector<CLLocationCoordinate2D> coordinates;
        coordinates.reserve(points.size());
        std::transform(points.begin(), points.end(), std::back_inserter(coordinates), toLocationCoordinate2D);
        return coordinates;
    }
    
    template<typename U = MGLPolygon>
    static U *toShape(const mbgl::Polygon<T> &geometry) {
        auto &linearRing = geometry.front();
        std::vector<CLLocationCoordinate2D> coordinates = toLocationCoordinates2D(linearRing);
        NSMutableArray *innerPolygons;
        if (geometry.size() > 1) {
            innerPolygons = [NSMutableArray arrayWithCapacity:geometry.size() - 1];
            for (auto iter = geometry.begin() + 1; iter != geometry.end(); iter++) {
                auto &innerRing = *iter;
                std::vector<CLLocationCoordinate2D> coordinates = toLocationCoordinates2D(innerRing);
                MGLPolygon *innerPolygon = [MGLPolygon polygonWithCoordinates:&coordinates[0] count:coordinates.size()];
                [innerPolygons addObject:innerPolygon];
            }
        }
        
        return [U polygonWithCoordinates:&coordinates[0] count:coordinates.size() interiorPolygons:innerPolygons];
    }
};

NS_ARRAY_OF(MGLShape <MGLFeature> *) *MGLFeaturesFromMBGLFeatures(const std::vector<mbgl::Feature> &features) {
    NSMutableArray *shapes = [NSMutableArray arrayWithCapacity:features.size()];
    for (const auto &feature : features) {
        NSMutableDictionary *attributes = [NSMutableDictionary dictionaryWithCapacity:feature.properties.size()];
        for (auto &pair : feature.properties) {
            auto &value = pair.second;
            PropertyValueEvaluator evaluator;
            attributes[@(pair.first.c_str())] = mbgl::Value::visit(value, evaluator);
        }
        
        GeometryEvaluator<double> evaluator;
        MGLShape <MGLFeaturePrivate> *shape = mapbox::geometry::geometry<double>::visit(feature.geometry, evaluator);
        if (feature.id) {
            shape.identifier = mbgl::FeatureIdentifier::visit(*feature.id, PropertyValueEvaluator());
        }
        shape.attributes = attributes;
        [shapes addObject:shape];
    }
    return shapes;
}