Adds a converter to embed subtitles

src/main/java/net/knarcraft/ffmpegconverter/utility/FFMpegHelper.java

@@ -19,6 +19,7 @@ import java.util.List;
 public final class FFMpegHelper {
 
     private static final String PROBE_SPLIT_CHARACTER = "øæåÆØå";
+    private static String[] subtitleFormats = null;
 
     private FFMpegHelper() {
 
@@ -305,7 +306,9 @@ public final class FFMpegHelper {
             throws IOException {
         List<StreamObject> parsedStreams = new ArrayList<>();
         //Find all files in the same directory with external subtitle formats
-        String[] subtitleFormats = FileUtil.readFileLines("subtitle_formats.txt");
+        if (subtitleFormats == null) {
+            subtitleFormats = FileUtil.readFileLines("subtitle_formats.txt");
+        }
         File[] subtitleFiles = FileUtil.listFilesRecursive(directory, subtitleFormats, 1);
 
         //Return early if no files were found
@@ -315,9 +318,11 @@ public final class FFMpegHelper {
 
         String fileTitle = FileUtil.stripExtension(convertingFile);
         List<File> subtitleFilesList = new ArrayList<>(Arrays.asList(subtitleFiles));
+
         //Finds the files which are subtitles probably belonging to the file
         subtitleFilesList = ListUtil.getMatching(subtitleFilesList,
                 (subtitleFile) -> subtitleFile.getName().contains(fileTitle));
+
         for (File subtitleFile : subtitleFilesList) {
             //Probe the files and add them to the result list
             String[] streams = probeForStreams(ffprobePath, subtitleFile);

src/main/java/net/knarcraft/ffmpegconverter/utility/FileUtil.java

@@ -1,5 +1,8 @@
 package net.knarcraft.ffmpegconverter.utility;
 
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
 import java.io.BufferedReader;
 import java.io.File;
 import java.io.IOException;
@@ -139,4 +142,43 @@ public final class FileUtil {
         return file.substring(0, file.lastIndexOf('.'));
     }
 
+    /**
+     * Gets the locale specifying the language of the given file name
+     *
+     * @param fileName <p>The file name to check</p>
+     * @return <p>The locale, or null if no locale could be parsed</p>
+     */
+    public static @Nullable String getLanguage(@NotNull String fileName) {
+        fileName = stripExtension(fileName);
+
+        String possibleLanguage = getExtension(fileName);
+        // NRK Nett-TV has a tendency to use nb-ttv for Norwegian for some reason 
+        possibleLanguage = possibleLanguage.replace("nb-ttv", "nb-nor");
+
+        // TODO: Some languages are specified by using "-en" or "-English" or ".en" or ".English" at the end of file names
+        if (possibleLanguage.length() <= 1 || (possibleLanguage.length() >= 4 &&
+                (!possibleLanguage.contains("-") || possibleLanguage.length() >= 8))) {
+            return null;
+        }
+
+        // Hope the text is an actual valid language
+        if (!possibleLanguage.contains("-")) {
+            return possibleLanguage;
+        }
+
+        // Make sure the "-" has at least two characters on each side
+        String[] parts = possibleLanguage.split("-");
+        if (parts[0].length() < 2 || parts[1].length() < 2) {
+            return null;
+        }
+
+        if (parts[1].length() == 3) {
+            // Return three-letter country code
+            return parts[1].toLowerCase();
+        } else {
+            // Return en-US country code
+            return parts[0].substring(0, 2).toLowerCase() + "-" + parts[1].substring(0, 2).toUpperCase();
+        }
+    }
+
 }