[ios] adapt Mapbox Streets–sourced layers for user preferred language (#9582)

* [ios] Update label localization

* [ios, macos] Move MGLVectorSource+MBXAdditions.h to darwin.

* [ios, macos] Adapt Mapbox Streets to the user preferred language.

* [ios, macos] Clarify style localization documentation.

* [ios, macos] Update localization examples

* [ios, macos] Add style language reset to original.

* [ios, macos] Update changelogs.

* [ios, macos] Rename Vector Source Additions to MGL standard.

* [ios, macos] Add suport for stop localization.

1 files changed, 53 insertions, 0 deletions

diff --git a/platform/darwin/src/MGLVectorSource+MGLAdditions.m b/platform/darwin/src/MGLVectorSource+MGLAdditions.m
new file mode 100644
index 0000000000..a305388117
--- /dev/null
+++ b/platform/darwin/src/MGLVectorSource+MGLAdditions.m
@@ -0,0 +1,53 @@
+#import "MGLVectorSource+MGLAdditions.h"
+
+@implementation MGLVectorSource (MGLAdditions)
+
++ (NS_SET_OF(NSString *) *)mapboxStreetsLanguages {
+    // https://www.mapbox.com/vector-tiles/mapbox-streets-v7/#overview
+    static dispatch_once_t onceToken;
+    static NS_SET_OF(NSString *) *mapboxStreetsLanguages;
+    dispatch_once(&onceToken, ^{
+        // https://www.mapbox.com/vector-tiles/mapbox-streets-v7/#overview
+        mapboxStreetsLanguages = [NSSet setWithObjects:@"ar", @"de", @"en", @"es", @"fr", @"pt", @"ru", @"zh", @"zh-Hans", nil];
+    });
+    return mapboxStreetsLanguages;
+}
+
++ (NSString *)preferredMapboxStreetsLanguage {
+    NSArray<NSString *> *supportedLanguages = [MGLVectorSource mapboxStreetsLanguages].allObjects;
+    NSArray<NSString *> *preferredLanguages = [NSBundle preferredLocalizationsFromArray:supportedLanguages
+                                                                         forPreferences:[NSLocale preferredLanguages]];
+    NSString *mostSpecificLanguage;
+    for (NSString *language in preferredLanguages) {
+        if (language.length > mostSpecificLanguage.length) {
+            mostSpecificLanguage = language;
+        }
+    }
+    return mostSpecificLanguage ?: @"en";
+}
+
+- (BOOL)isMapboxStreets {
+    NSURL *url = self.configurationURL;
+    if (![url.scheme isEqualToString:@"mapbox"]) {
+        return NO;
+    }
+    NSArray *identifiers = [url.host componentsSeparatedByString:@","];
+    return [identifiers containsObject:@"mapbox.mapbox-streets-v7"] || [identifiers containsObject:@"mapbox.mapbox-streets-v6"];
+}
+
+- (NS_DICTIONARY_OF(NSString *, NSString *) *)localizedKeysByKeyForPreferredLanguage:(nullable NSString *)preferredLanguage {
+    if (!self.mapboxStreets) {
+        return @{};
+    }
+
+    // Replace {name} and {name_*} with the matching localized name tag.
+    NSString *localizedKey = preferredLanguage ? [NSString stringWithFormat:@"name_%@", preferredLanguage] : @"name";
+    NSMutableDictionary *localizedKeysByKey = [NSMutableDictionary dictionaryWithObject:localizedKey forKey:@"name"];
+    for (NSString *languageCode in [MGLVectorSource mapboxStreetsLanguages]) {
+        NSString *key = [NSString stringWithFormat:@"name_%@", languageCode];
+        localizedKeysByKey[key] = localizedKey;
+    }
+    return localizedKeysByKey;
+}
+
+@end