content: package com.alium.orin.lastfm.rest;
  
  import android.content.Context;
  import android.support.annotation.NonNull;
  import android.support.annotation.Nullable;
  
  import com.alium.orin.lastfm.rest.service.LastFMService;
  
  import java.io.File;
  import java.io.IOException;
  
  import okhttp3.Cache;
  import okhttp3.Call;
  import okhttp3.Interceptor;
  import okhttp3.OkHttpClient;
  import okhttp3.Request;
  import okhttp3.Response;
  import retrofit2.Retrofit;
  import retrofit2.converter.gson.GsonConverterFactory;
  
  /**
   * @author Karim Abou Zeid (kabouzeid)
   */
  public class LastFMRestClient {
      public static final String BASE_URL = "http://ws.audioscrobbler.com/2.0/";
  
      private LastFMService apiService;
  
      public LastFMRestClient(@NonNull Context context) {
          this(createDefaultOkHttpClientBuilder(context).build());
      }
  
      public LastFMRestClient(@NonNull Call.Factory client) {
          Retrofit restAdapter = new Retrofit.Builder()
                  .baseUrl(BASE_URL)
                  .callFactory(client)
                  .addConverterFactory(GsonConverterFactory.create())
                  .build();
  
          apiService = restAdapter.create(LastFMService.class);
      }
  
      public LastFMService getApiService() {
          return apiService;
      }
  
      @Nullable
      public static Cache createDefaultCache(Context context) {
          File cacheDir = new File(context.getCacheDir().getAbsolutePath(), "/okhttp-lastfm/");
          if (cacheDir.mkdirs() || cacheDir.isDirectory()) {
              return new Cache(cacheDir, 1024 * 1024 * 10);
          }
          return null;
      }
  
      public static Interceptor createCacheControlInterceptor() {
          return new Interceptor() {
              @Override
              public Response intercept(Chain chain) throws IOException {
                  Request modifiedRequest = chain.request().newBuilder()
                          .addHeader("Cache-Control", String.format("max-age=%d, max-stale=%d", 31536000, 31536000))
                          .build();
                  return chain.proceed(modifiedRequest);
              }
          };
      }
  
      public static OkHttpClient.Builder createDefaultOkHttpClientBuilder(Context context) {
          return new OkHttpClient.Builder()
                  .cache(createDefaultCache(context))
                  .addInterceptor(createCacheControlInterceptor());
      }
  }
  