Repo created

iphone/Maps/Core/Location/MWMLocationPredictor.mm

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+#import "MWMLocationPredictor.h"
+
+#include <CoreApi/Framework.h>
+
+namespace
+{
+NSTimeInterval constexpr kPredictionIntervalInSeconds = 0.5;
+NSUInteger constexpr kMaxPredictionCount = 20;
+}  // namespace
+
+@interface MWMLocationPredictor ()
+
+@property(copy, nonatomic) CLLocation * lastLocation;
+@property(nonatomic) BOOL isLastLocationValid;
+@property (nonatomic) BOOL isLastPositionModeValid;
+@property (nonatomic) NSUInteger predictionsCount;
+@property (copy, nonatomic) TPredictionBlock onPredictionBlock;
+
+@end
+
+@implementation MWMLocationPredictor
+
+- (instancetype)initWithOnPredictionBlock:(TPredictionBlock)onPredictionBlock
+{
+  self = [super init];
+  if (self)
+    _onPredictionBlock = [onPredictionBlock copy];
+  return self;
+}
+
+- (void)setMyPositionMode:(MWMMyPositionMode)mode
+{
+  self.isLastPositionModeValid = (mode == MWMMyPositionModeFollowAndRotate);
+  [self restart];
+}
+
+- (void)reset:(CLLocation *)location
+{
+  self.isLastLocationValid = (location.speed >= 0.0 && location.course >= 0.0);
+  if (self.isLastLocationValid)
+    self.lastLocation = location;
+
+  [self restart];
+}
+
+- (BOOL)isActive
+{
+  return self.isLastLocationValid && self.isLastPositionModeValid &&
+         self.predictionsCount < kMaxPredictionCount;
+}
+
+- (void)restart
+{
+  self.predictionsCount = 0;
+  [self schedule];
+}
+
+- (void)schedule
+{
+  SEL const predict = @selector(predict);
+  [NSObject cancelPreviousPerformRequestsWithTarget:self selector:predict object:nil];
+  [self performSelector:predict withObject:nil afterDelay:kPredictionIntervalInSeconds];
+}
+
+- (void)predict
+{
+  if (!self.isActive)
+    return;
+
+  self.predictionsCount++;
+
+  CLLocation * l = self.lastLocation;
+  CLLocationCoordinate2D coordinate = l.coordinate;
+  CLLocationDistance altitude = l.altitude;
+  CLLocationAccuracy hAccuracy = l.horizontalAccuracy;
+  CLLocationAccuracy vAccuracy = l.verticalAccuracy;
+  CLLocationDirection course = l.course;
+  CLLocationSpeed speed = l.speed;
+  NSDate * timestamp = [NSDate date];
+  Framework::PredictLocation(coordinate.latitude, coordinate.longitude, hAccuracy, course, speed,
+                             timestamp.timeIntervalSince1970 - l.timestamp.timeIntervalSince1970);
+  CLLocation * location = [[CLLocation alloc] initWithCoordinate:coordinate
+                                                        altitude:altitude
+                                              horizontalAccuracy:hAccuracy
+                                                verticalAccuracy:vAccuracy
+                                                          course:course
+                                                           speed:speed
+                                                       timestamp:timestamp];
+  self.onPredictionBlock(location);
+  [self schedule];
+}
+
+@end