feat: Enable downloading of song lyrics for offline viewing

app/src/main/java/com/cappielloantonio/tempo/repository/LyricsRepository.java

@@ -0,0 +1,92 @@
+package com.cappielloantonio.tempo.repository;
+
+import androidx.lifecycle.LiveData;
+
+import com.cappielloantonio.tempo.database.AppDatabase;
+import com.cappielloantonio.tempo.database.dao.LyricsDao;
+import com.cappielloantonio.tempo.model.LyricsCache;
+
+public class LyricsRepository {
+    private final LyricsDao lyricsDao = AppDatabase.getInstance().lyricsDao();
+
+    public LyricsCache getLyrics(String songId) {
+        GetLyricsThreadSafe getLyricsThreadSafe = new GetLyricsThreadSafe(lyricsDao, songId);
+        Thread thread = new Thread(getLyricsThreadSafe);
+        thread.start();
+
+        try {
+            thread.join();
+            return getLyricsThreadSafe.getLyrics();
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+
+        return null;
+    }
+
+    public LiveData<LyricsCache> observeLyrics(String songId) {
+        return lyricsDao.observeOne(songId);
+    }
+
+    public void insert(LyricsCache lyricsCache) {
+        InsertThreadSafe insert = new InsertThreadSafe(lyricsDao, lyricsCache);
+        Thread thread = new Thread(insert);
+        thread.start();
+    }
+
+    public void delete(String songId) {
+        DeleteThreadSafe delete = new DeleteThreadSafe(lyricsDao, songId);
+        Thread thread = new Thread(delete);
+        thread.start();
+    }
+
+    private static class GetLyricsThreadSafe implements Runnable {
+        private final LyricsDao lyricsDao;
+        private final String songId;
+        private LyricsCache lyricsCache;
+
+        public GetLyricsThreadSafe(LyricsDao lyricsDao, String songId) {
+            this.lyricsDao = lyricsDao;
+            this.songId = songId;
+        }
+
+        @Override
+        public void run() {
+            lyricsCache = lyricsDao.getOne(songId);
+        }
+
+        public LyricsCache getLyrics() {
+            return lyricsCache;
+        }
+    }
+
+    private static class InsertThreadSafe implements Runnable {
+        private final LyricsDao lyricsDao;
+        private final LyricsCache lyricsCache;
+
+        public InsertThreadSafe(LyricsDao lyricsDao, LyricsCache lyricsCache) {
+            this.lyricsDao = lyricsDao;
+            this.lyricsCache = lyricsCache;
+        }
+
+        @Override
+        public void run() {
+            lyricsDao.insert(lyricsCache);
+        }
+    }
+
+    private static class DeleteThreadSafe implements Runnable {
+        private final LyricsDao lyricsDao;
+        private final String songId;
+
+        public DeleteThreadSafe(LyricsDao lyricsDao, String songId) {
+            this.lyricsDao = lyricsDao;
+            this.songId = songId;
+        }
+
+        @Override
+        public void run() {
+            lyricsDao.delete(songId);
+        }
+    }
+}