[ios, macos] More robust Streets localization

Added Arabic, Portuguese, and Simplified Chinese to the list of languages with specialized fields in the Mapbox Streets source.

Rely on NSBundle to select the most appropriate locale based on the user’s preferred languages.

Author: 1ec5

platform/ios/app/MBXViewController.m

@@ -1397,19 +1397,20 @@ - (void)styleLabelLanguageForLayersNamed:(NSArray<NSString *> *)layers
 
 - (NSString *)bestLanguageForUser
 {
-    NSArray *supportedLanguages = @[ @"en", @"es", @"fr", @"de", @"ru", @"zh" ];
-    NSArray<NSString *> *preferredLanguages = [NSLocale preferredLanguages];
-    NSString *bestLanguage;
-
-    for (NSString *language in preferredLanguages) {
-        NSString *thisLanguage = [[NSLocale localeWithLocaleIdentifier:language] objectForKey:NSLocaleLanguageCode];
-        if ([supportedLanguages containsObject:thisLanguage]) {
-            bestLanguage = thisLanguage;
-            break;
+    // https://www.mapbox.com/vector-tiles/mapbox-streets-v7/#overview
+    NSArray *supportedLanguages = @[ @"ar", @"en", @"es", @"fr", @"de", @"pt", @"ru", @"zh", @"zh-Hans" ];
+    NSArray<NSString *> *preferredLanguages = [NSBundle preferredLocalizationsFromArray:supportedLanguages forPreferences:[NSLocale preferredLanguages]];
+    NSString *mostSpecificLanguage;
+
+    for (NSString *language in preferredLanguages)
+    {
+        if (language.length > mostSpecificLanguage.length)
+        {
+            mostSpecificLanguage = language;
         }
     }
 
-    return bestLanguage ?: @"en";
+    return mostSpecificLanguage ?: @"en";
 }
 
 - (IBAction)startWorldTour

platform/macos/app/MGLVectorSource+MBXAdditions.h

@@ -4,7 +4,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 @interface MGLVectorSource (MBXAdditions)
 
-+ (nullable NSString *)preferredMapboxStreetsLanguage;
++ (NSString *)preferredMapboxStreetsLanguage;
 
 - (NS_DICTIONARY_OF(NSString *, NSString *) *)localizedKeysByKeyForPreferredLanguage:(nullable NSString *)preferredLanguage;
 

platform/macos/app/MGLVectorSource+MBXAdditions.m

@@ -7,19 +7,23 @@ @implementation MGLVectorSource (MBXAdditions)
     static dispatch_once_t onceToken;
     static NS_SET_OF(NSString *) *mapboxStreetsLanguages;
     dispatch_once(&onceToken, ^{
-        mapboxStreetsLanguages = [NSSet setWithObjects:@"en", @"es", @"fr", @"de", @"ru", @"zh", nil];
+        // 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;
 }
 
-+ (nullable NSString *)preferredMapboxStreetsLanguage {
-    for (NSString *language in [NSLocale preferredLanguages]) {
-        NSString *languageCode = [[NSLocale localeWithLocaleIdentifier:language] objectForKey:NSLocaleLanguageCode];
-        if ([[MGLVectorSource mapboxStreetsLanguages] containsObject:languageCode]) {
-            return languageCode;
++ (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 nil;
+    return mostSpecificLanguage ?: @"en";
 }
 
 - (BOOL)isMapboxStreets {

platform/macos/app/MapDocument.m

@@ -345,7 +345,7 @@ - (IBAction)setLabelLanguage:(NSMenuItem *)sender {
 
 - (void)updateLabels {
     MGLStyle *style = self.mapView.style;
-    NSString *preferredLanguage = _isLocalizingLabels ? ([MGLVectorSource preferredMapboxStreetsLanguage] ?: @"en") : nil;
+    NSString *preferredLanguage = _isLocalizingLabels ? [MGLVectorSource preferredMapboxStreetsLanguage] : nil;
     NSMutableDictionary *localizedKeysByKeyBySourceIdentifier = [NSMutableDictionary dictionary];
     for (MGLSymbolStyleLayer *layer in style.layers) {
         if (![layer isKindOfClass:[MGLSymbolStyleLayer class]]) {
@@ -855,8 +855,7 @@ - (BOOL)validateMenuItem:(NSMenuItem *)menuItem {
         if (menuItem.tag) {
             NSLocale *locale = [NSLocale localeWithLocaleIdentifier:[NSBundle mainBundle].developmentLocalization];
             NSString *preferredLanguage = [MGLVectorSource preferredMapboxStreetsLanguage];
-            menuItem.enabled = !!preferredLanguage;
-            menuItem.title = [locale displayNameForKey:NSLocaleIdentifier value:preferredLanguage ?: @"Preferred Language"];
+            menuItem.title = [locale displayNameForKey:NSLocaleIdentifier value:preferredLanguage];
         }
         return YES;
     }