Compare language codes in MessageContent::Choose()

If there is no exact match, compare language codes so that a more
generic match is preferred over just returning the English content.

This means that if a locale code is given, Choose() will also look for
the locale's language code (but will not match another locale with the
same language code), and if a language code is given, Choose() will also
look for a locale with that language code.

src/api/metadata/message_content.cpp

@@ -24,6 +24,8 @@
 
 #include "loot/metadata/message_content.h"
 
+#include <optional>
+
 #include <boost/algorithm/string.hpp>
 
 namespace loot {
@@ -33,8 +35,7 @@ MessageContent::MessageContent() : language_(MessageContent::defaultLanguage) {}
 
 MessageContent::MessageContent(const std::string& text,
                                const std::string& language) :
-    text_(text),
-    language_(language) {}
+    text_(text), language_(language) {}
 
 std::string MessageContent::GetText() const { return text_; }
 
@@ -63,13 +64,39 @@ MessageContent MessageContent::Choose(const std::vector<MessageContent> content,
   else if (content.size() == 1)
     return content[0];
   else {
+    auto languageCode = language.substr(0, language.find("_"));
+    auto isCountryCodeGiven = languageCode.length() != language.length();
+
+    std::optional<MessageContent> matchedLanguage;
     MessageContent english;
     for (const auto& mc : content) {
-      if (mc.GetLanguage() == language) {
+      auto contentLanguage = mc.GetLanguage();
+
+      if (contentLanguage == language) {
         return mc;
-      } else if (mc.GetLanguage() == MessageContent::defaultLanguage)
-        english = mc;
+      } else if (!matchedLanguage.has_value()) {
+        if (isCountryCodeGiven && contentLanguage == languageCode) {
+          matchedLanguage = mc;
+        } else if (!isCountryCodeGiven) {
+          auto underscorePos = contentLanguage.find("_");
+          if (underscorePos != std::string::npos) {
+            auto contentLanguageCode = contentLanguage.substr(0, underscorePos);
+            if (contentLanguageCode == language) {
+              matchedLanguage = mc;
+            }
+          }
+        }
+
+        if (contentLanguage == MessageContent::defaultLanguage) {
+          english = mc;
+        }
+      }
     }
+
+    if (matchedLanguage.has_value()) {
+      return matchedLanguage.value();
+    }
+
     return english;
   }
 }

src/tests/api/internals/metadata/message_content_test.h

@@ -25,11 +25,10 @@ along with LOOT.  If not, see
 #ifndef LOOT_TESTS_API_INTERNALS_METADATA_MESSAGE_CONTENT_TEST
 #define LOOT_TESTS_API_INTERNALS_METADATA_MESSAGE_CONTENT_TEST
 
-#include "loot/metadata/message_content.h"
-
 #include <gtest/gtest.h>
 
 #include "api/metadata/yaml/message_content.h"
+#include "loot/metadata/message_content.h"
 
 namespace loot {
 namespace test {
@@ -240,6 +239,98 @@ TEST(
   EXPECT_TRUE(content1 >= content2);
 }
 
+TEST(MessageContent,
+     chooseShouldReturnAnEmptyEnglishMessageIfTheVectorIsEmpty) {
+  auto content = MessageContent::Choose(std::vector<MessageContent>(), "fr");
+
+  EXPECT_EQ("en", content.GetLanguage());
+  EXPECT_EQ("", content.GetText());
+}
+
+TEST(MessageContent, chooseShouldReturnTheOnlyElementOfASingleElementVector) {
+  MessageContent content("test", "de");
+  auto chosen = MessageContent::Choose({MessageContent("test", "de")}, "fr");
+
+  EXPECT_EQ(content, chosen);
+}
+
+TEST(
+    MessageContent,
+    chooseShouldReturnAnEmptyEnglishMessageIfTheVectorHasNoEnglishOrMatchingLanguageContentWithTwoOrMoreElements) {
+  auto contents = {MessageContent("test1", "de"),
+                   MessageContent("test2", "fr")};
+  auto content = MessageContent::Choose(contents, "pt");
+
+  EXPECT_EQ("en", content.GetLanguage());
+  EXPECT_EQ("", content.GetText());
+}
+
+TEST(MessageContent,
+     chooseShouldReturnElementWithExactlyMatchingLocaleCodeIfPresent) {
+  auto contents = {MessageContent("test1", "en"),
+                   MessageContent("test2", "de"),
+                   MessageContent("test3", "pt"),
+                   MessageContent("test4", "pt_PT"),
+                   MessageContent("test5", "pt_BR")};
+  auto content = MessageContent::Choose(contents, "pt_BR");
+
+  EXPECT_EQ("pt_BR", content.GetLanguage());
+  EXPECT_EQ("test5", content.GetText());
+}
+
+TEST(
+    MessageContent,
+    chooseShouldReturnElementWithMatchingLanguageCodeIfExactlyMatchingLocaleCodeIsNotPresent) {
+  auto contents = {MessageContent("test1", "en"),
+                   MessageContent("test2", "de"),
+                   MessageContent("test3", "pt_PT"),
+                   MessageContent("test4", "pt")};
+  auto content = MessageContent::Choose(contents, "pt_BR");
+
+  EXPECT_EQ("pt", content.GetLanguage());
+  EXPECT_EQ("test4", content.GetText());
+}
+
+TEST(
+    MessageContent,
+    chooseShouldReturnElementWithEnLanguageCodeIfNoMatchingLanguageCodeIsPresent) {
+  auto contents = {MessageContent("test1", "en"),
+                   MessageContent("test2", "de"),
+                   MessageContent("test3", "pt_PT")};
+  auto content = MessageContent::Choose(contents, "pt_BR");
+
+  EXPECT_EQ("en", content.GetLanguage());
+  EXPECT_EQ("test1", content.GetText());
+}
+
+TEST(
+    MessageContent,
+    chooseShouldReturnElementWithExactlyMatchingLanguageCodeIfLanguageCodeIsGiven) {
+  auto contents = {
+      MessageContent("test1", "en"),
+      MessageContent("test2", "de"),
+      MessageContent("test3", "pt_BR"),
+      MessageContent("test4", "pt"),
+  };
+  auto content = MessageContent::Choose(contents, "pt");
+
+  EXPECT_EQ("pt", content.GetLanguage());
+  EXPECT_EQ("test4", content.GetText());
+}
+
+TEST(
+    MessageContent,
+    chooseShouldReturnFirstElementWithMatchingLanguageCodeIfLanguageCodeIsGivenAndNoExactMatchIsPresent) {
+  auto contents = {MessageContent("test1", "en"),
+                   MessageContent("test2", "de"),
+                   MessageContent("test3", "pt_PT"),
+                   MessageContent("test4", "pt_BR")};
+  auto content = MessageContent::Choose(contents, "pt");
+
+  EXPECT_EQ("pt_PT", content.GetLanguage());
+  EXPECT_EQ("test3", content.GetText());
+}
+
 TEST(MessageContent, emittingAsYamlShouldOutputDataCorrectly) {
   MessageContent content("content", french);
   YAML::Emitter emitter;