Initial support to use named tokens for backend translations

Towards #3003

(cherry picked from commit 11f96c31048c2d1aafca0c91736d439f7f9a95a8)

src/NzbDrone.Core.Test/Localization/LocalizationServiceFixture.cs

@@ -0,0 +1,81 @@
+using System;
+using FluentAssertions;
+using NUnit.Framework;
+using NzbDrone.Common.EnvironmentInfo;
+using NzbDrone.Core.Configuration;
+using NzbDrone.Core.Languages;
+using NzbDrone.Core.Localization;
+using NzbDrone.Core.Test.Framework;
+using NzbDrone.Test.Common;
+
+namespace NzbDrone.Core.Test.Localization
+{
+    [TestFixture]
+    public class LocalizationServiceFixture : CoreTest<LocalizationService>
+    {
+        [SetUp]
+        public void Setup()
+        {
+            Mocker.GetMock<IConfigService>().Setup(m => m.UILanguage).Returns((int)Language.English);
+
+            Mocker.GetMock<IAppFolderInfo>().Setup(m => m.StartUpFolder).Returns(TestContext.CurrentContext.TestDirectory);
+        }
+
+        [Test]
+        public void should_get_string_in_dictionary_if_lang_exists_and_string_exists()
+        {
+            var localizedString = Subject.GetLocalizedString("UiLanguage");
+
+            localizedString.Should().Be("UI Language");
+        }
+
+        [Test]
+        public void should_get_string_in_french()
+        {
+            Mocker.GetMock<IConfigService>().Setup(m => m.UILanguage).Returns((int)Language.French);
+
+            var localizedString = Subject.GetLocalizedString("UiLanguage");
+
+            localizedString.Should().Be("Langue de l'IU");
+
+            ExceptionVerification.ExpectedErrors(1);
+        }
+
+        [Test]
+        public void should_get_string_in_default_dictionary_if_unknown_language_and_string_exists()
+        {
+            Mocker.GetMock<IConfigService>().Setup(m => m.UILanguage).Returns(0);
+            var localizedString = Subject.GetLocalizedString("UiLanguage");
+
+            localizedString.Should().Be("UI Language");
+        }
+
+        [Test]
+        public void should_return_argument_if_string_doesnt_exists()
+        {
+            var localizedString = Subject.GetLocalizedString("badString");
+
+            localizedString.Should().Be("badString");
+        }
+
+        [Test]
+        public void should_return_argument_if_string_doesnt_exists_default_lang()
+        {
+            var localizedString = Subject.GetLocalizedString("badString");
+
+            localizedString.Should().Be("badString");
+        }
+
+        [Test]
+        public void should_throw_if_empty_string_passed()
+        {
+            Assert.Throws<ArgumentNullException>(() => Subject.GetLocalizedString(""));
+        }
+
+        [Test]
+        public void should_throw_if_null_string_passed()
+        {
+            Assert.Throws<ArgumentNullException>(() => Subject.GetLocalizedString(null));
+        }
+    }
+}

src/NzbDrone.Core/Localization/LocalizationService.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Text.Json;
+using System.Text.RegularExpressions;
 using System.Threading.Tasks;
 using NLog;
 using NzbDrone.Common.Cache;
@@ -18,13 +19,16 @@ namespace NzbDrone.Core.Localization
     public interface ILocalizationService
     {
         Dictionary<string, string> GetLocalizationDictionary();
+
         string GetLocalizedString(string phrase);
-        string GetLocalizedString(string phrase, string language);
+        string GetLocalizedString(string phrase, Dictionary<string, object> tokens);
     }
 
     public class LocalizationService : ILocalizationService, IHandleAsync<ConfigSavedEvent>
     {
         private const string DefaultCulture = "en";
+        private static readonly Regex TokenRegex = new Regex(@"(?:\{)(?<token>[a-z0-9]+)(?:\})",
+            RegexOptions.Compiled | RegexOptions.IgnoreCase | RegexOptions.CultureInvariant);
 
         private readonly ICached<Dictionary<string, string>> _cache;
 
@@ -52,22 +56,17 @@ namespace NzbDrone.Core.Localization
 
         public string GetLocalizedString(string phrase)
         {
-            var language = GetSetLanguageFileName();
-
-            return GetLocalizedString(phrase, language);
+            return GetLocalizedString(phrase, new Dictionary<string, object>());
         }
 
-        public string GetLocalizedString(string phrase, string language)
+        public string GetLocalizedString(string phrase, Dictionary<string, object> tokens)
         {
             if (string.IsNullOrEmpty(phrase))
             {
                 throw new ArgumentNullException(nameof(phrase));
             }
 
-            if (language.IsNullOrWhiteSpace())
-            {
-                language = GetSetLanguageFileName();
-            }
+            var language = GetSetLanguageFileName();
 
             if (language == null)
             {
@@ -78,12 +77,26 @@ namespace NzbDrone.Core.Localization
 
             if (dictionary.TryGetValue(phrase, out var value))
             {
-                return value;
+                return ReplaceTokens(value, tokens);
             }
 
             return phrase;
         }
 
+        private string ReplaceTokens(string input, Dictionary<string, object> tokens)
+        {
+            tokens.TryAdd("appName", "Readarr");
+
+            return TokenRegex.Replace(input, (match) =>
+            {
+                var tokenName = match.Groups["token"].Value;
+
+                tokens.TryGetValue(tokenName, out var token);
+
+                return token?.ToString() ?? $"{{{tokenName}}}";
+            });
+        }
+
         private string GetSetLanguageFileName()
         {
             var isoLanguage = IsoLanguages.Get((Language)_configService.UILanguage);