/*
 * Copyright 2019 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.firebase.ml.md.java.productsearch;

import android.content.Context;
import android.util.Log;
import com.android.volley.RequestQueue;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.Volley;
import com.google.android.gms.tasks.Tasks;
import com.google.firebase.ml.md.java.objectdetection.DetectedObject;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/** A fake search engine to help simulate the complete work flow. */
public class SearchEngine {

  private static final String TAG = "SearchEngine";

  public interface SearchResultListener {
    void onSearchCompleted(DetectedObject object, List<Product> productList);
  }

  private final RequestQueue searchRequestQueue;
  private final ExecutorService requestCreationExecutor;

  public SearchEngine(Context context) {
    searchRequestQueue = Volley.newRequestQueue(context);
    requestCreationExecutor = Executors.newSingleThreadExecutor();
  }

  public void search(DetectedObject object, SearchResultListener listener) {
    // Crops the object image out of the full image is expensive, so do it off the UI thread.
    Tasks.call(requestCreationExecutor, () -> createRequest(object))
        .addOnSuccessListener(productRequest -> searchRequestQueue.add(productRequest.setTag(TAG)))
        .addOnFailureListener(
            e -> {
              Log.e(TAG, "Failed to create product search request!", e);
              // Remove the below dummy code after your own product search backed hooked up.
              List<Product> productList = new ArrayList<>();
              for (int i = 0; i < 8; i++) {
                productList.add(
                    new Product(/* imageUrl= */ "", "Product title " + i, "Product subtitle " + i));
              }
              listener.onSearchCompleted(object, productList);
            });
  }

  private static JsonObjectRequest createRequest(DetectedObject searchingObject) throws Exception {
    byte[] objectImageData = searchingObject.getImageData();
    if (objectImageData == null) {
      throw new Exception("Failed to get object image data!");
    }

    // Hooks up with your own product search backend here.
    throw new Exception("Hooks up with your own product search backend.");
  }

  public void shutdown() {
    searchRequestQueue.cancelAll(TAG);
    requestCreationExecutor.shutdown();
  }
}