From 89bc8efc1564f61a7741e2c55383c1ca4d5ac1c9 Mon Sep 17 00:00:00 2001
From: Jason Wray <jason@mapbox.com>
Date: Tue, 25 Oct 2016 18:20:19 -0700
Subject: [PATCH] Select best language based on locale setting and our support

---
 platform/ios/app/MBXViewController.m | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/platform/ios/app/MBXViewController.m b/platform/ios/app/MBXViewController.m
index 5b4385479c8..40be7dc8fec 100644
--- a/platform/ios/app/MBXViewController.m
+++ b/platform/ios/app/MBXViewController.m
@@ -914,12 +914,31 @@ - (void)styleDynamicPointCollection
 
 - (void)styleCountryLabelLanguage
 {
+    NSString *bestLanguageForUser = [NSString stringWithFormat:@"{name_%@}", [self bestLanguageForUser]];
     MGLSymbolStyleLayer *countryLayer = (MGLSymbolStyleLayer *)[self.mapView.style layerWithIdentifier:@"country-label-lg"];
     MGLStyleConstantValue<NSString *> *countryLabel = (MGLStyleConstantValue<NSString *> *)countryLayer.textField;
-    NSString *language = [countryLabel.rawValue isEqual:@"{name_zh}"] ? @"{name_en}" : @"{name_zh}";
+    NSString *language = [countryLabel.rawValue isEqual:bestLanguageForUser] ? @"{name}" : bestLanguageForUser;
     countryLayer.textField = [MGLStyleValue<NSString *> valueWithRawValue:language];
 }
 
+- (NSString *)bestLanguageForUser
+{
+    NSArray *supportedLanguages = @[ @"en", @"es", @"fr", @"de", @"ru", @"zh" ];
+    NSArray<NSString *> *preferredLanguages = [NSLocale preferredLanguages];
+    NSString *bestLanguage;
+
+    for (NSString *language in preferredLanguages) {
+        NSString *thisLanguage = [language substringToIndex:2];
+        if ([supportedLanguages containsObject:thisLanguage])
+        {
+            bestLanguage = thisLanguage;
+            break;
+        }
+    }
+
+    return bestLanguage ?: @"en";
+}
+
 - (IBAction)startWorldTour
 {
     _isTouringWorld = YES;