Backport pull request #18150 from jellyfin/release-12.z

Read the image region when determining TMDb image language in `TmdbUtils`

Original-merge: 1d3ee4dd5118daeb83f84b155315f5bf957fb5cd

Merged-by: crobibero <cody@robibe.ro>

Backported-by: Cody Robibero <cody@robibe.ro>

3 files changed, 43 insertions, 21 deletions

diff --git a/MediaBrowser.Providers/Plugins/Tmdb/TmdbClientManager.cs b/MediaBrowser.Providers/Plugins/Tmdb/TmdbClientManager.cs
index d75ebae988..8dd1a546fa 100644
--- a/MediaBrowser.Providers/Plugins/Tmdb/TmdbClientManager.cs
+++ b/MediaBrowser.Providers/Plugins/Tmdb/TmdbClientManager.cs
@@ -675,7 +675,7 @@ namespace MediaBrowser.Providers.Plugins.Tmdb
                 var image = images[i];
 
                 var imageType = type;
-                var language = TmdbUtils.AdjustImageLanguage(image.Iso_639_1, requestLanguage);
+                var language = TmdbUtils.GetImageLanguage(image.Iso_639_1, image.Iso_3166_1, requestLanguage);
 
                 // Return Backdrops with a language specified (it has text) as Thumb.
                 if (imageType == ImageType.Backdrop && !string.IsNullOrEmpty(language))
diff --git a/MediaBrowser.Providers/Plugins/Tmdb/TmdbUtils.cs b/MediaBrowser.Providers/Plugins/Tmdb/TmdbUtils.cs
index f004251594..c8db90799d 100644
--- a/MediaBrowser.Providers/Plugins/Tmdb/TmdbUtils.cs
+++ b/MediaBrowser.Providers/Plugins/Tmdb/TmdbUtils.cs
@@ -464,30 +464,41 @@ namespace MediaBrowser.Providers.Plugins.Tmdb
         }
 
         /// <summary>
-        /// Adjusts the image's language code preferring the 5 letter language code eg. en-US.
+        /// Determines the language code to report for an image.
         /// </summary>
-        /// <param name="imageLanguage">The image's actual language code.</param>
+        /// <remarks>
+        /// TMDb keeps an image's region in iso_3166_1, which is what separates a pt-PT poster from a pt-BR
+        /// one. The region is added to the returned code only when it differs from the requested one, as in
+        /// a pt-PT image for a pt-BR request. TMDb files nearly every image under a region, so adding it
+        /// unconditionally would return en-US for an image that has to keep matching a plain "en" request.
+        /// </remarks>
+        /// <param name="imageLanguage">The image's ISO 639-1 language code.</param>
+        /// <param name="imageRegion">The image's ISO 3166-1 country code.</param>
         /// <param name="requestLanguage">The requested language code.</param>
         /// <returns>The language code.</returns>
-        public static string AdjustImageLanguage(string? imageLanguage, string requestLanguage)
+        public static string GetImageLanguage(string? imageLanguage, string? imageRegion, string? requestLanguage)
         {
-            if (string.IsNullOrEmpty(imageLanguage))
+            // TMDb now returns xx for no language instead of an empty string.
+            if (string.IsNullOrEmpty(imageLanguage) || string.Equals(imageLanguage, "xx", StringComparison.OrdinalIgnoreCase))
             {
                 return string.Empty;
             }
 
-            if (!string.IsNullOrEmpty(requestLanguage)
-                && requestLanguage.Length > 2
-                && imageLanguage.Length == 2
-                && requestLanguage.StartsWith(imageLanguage, StringComparison.OrdinalIgnoreCase))
+            if (string.IsNullOrEmpty(requestLanguage))
             {
-                return requestLanguage;
+                return imageLanguage;
             }
 
-            // TMDb now returns xx for no language instead of an empty string.
-            return string.Equals(imageLanguage, "xx", StringComparison.OrdinalIgnoreCase)
-                ? string.Empty
-                : imageLanguage;
+            var requestParts = requestLanguage.Split('-');
+
+            if (requestParts.Length != 2 || !string.Equals(requestParts[0], imageLanguage, StringComparison.OrdinalIgnoreCase))
+            {
+                return imageLanguage;
+            }
+
+            return string.IsNullOrEmpty(imageRegion) || string.Equals(imageRegion, requestParts[1], StringComparison.OrdinalIgnoreCase)
+                ? requestLanguage
+                : imageLanguage + "-" + imageRegion.ToUpperInvariant();
         }
 
         /// <summary>
diff --git a/tests/Jellyfin.Providers.Tests/Tmdb/TmdbUtilsTests.cs b/tests/Jellyfin.Providers.Tests/Tmdb/TmdbUtilsTests.cs
index 03bad3555e..8342621d97 100644
--- a/tests/Jellyfin.Providers.Tests/Tmdb/TmdbUtilsTests.cs
+++ b/tests/Jellyfin.Providers.Tests/Tmdb/TmdbUtilsTests.cs
@@ -30,14 +30,25 @@ namespace Jellyfin.Providers.Tests.Tmdb
         }
 
         [Theory]
-        [InlineData("en", "en-US", "en-US")]
-        [InlineData("fr-CA", "fr-BE", "fr-CA")]
-        [InlineData("fr-CA", "fr", "fr-CA")]
-        [InlineData("de", "en-US", "de")]
-        [InlineData("", "en-US", "")]
-        public static void AdjustImageLanguage_Valid_Success(string imageLanguage, string requestLanguage, string? expected)
+        // A regional request is only answered with a region when the image contradicts it.
+        [InlineData("pt", "BR", "pt-BR", "pt-BR")]
+        [InlineData("pt", "PT", "pt-BR", "pt-PT")]
+        [InlineData("en", "GB", "en-US", "en-GB")]
+        [InlineData("en", "US", "en-US", "en-US")]
+        [InlineData("en", null, "en-US", "en-US")]
+        // TMDb files nearly every image under a region, which must not stop a plain request matching.
+        [InlineData("en", "US", "en", "en")]
+        [InlineData("pt", "PT", "pt", "pt")]
+        // An image in another language keeps its bare code, so the English fallback still resolves.
+        [InlineData("en", "US", "pt-BR", "en")]
+        [InlineData("de", "DE", "en-US", "de")]
+        // TMDb returns xx rather than an empty string for an image with no text.
+        [InlineData("xx", "US", "en-US", "")]
+        [InlineData("", "US", "en-US", "")]
+        [InlineData(null, null, "en-US", "")]
+        public static void GetImageLanguage_Valid_Success(string? imageLanguage, string? imageRegion, string? requestLanguage, string expected)
         {
-            Assert.Equal(expected, TmdbUtils.AdjustImageLanguage(imageLanguage, requestLanguage));
+            Assert.Equal(expected, TmdbUtils.GetImageLanguage(imageLanguage, imageRegion, requestLanguage));
         }
 
         [Theory]