/*
 * Copyright (C) 2018 The Android Open Source Project
 *
 * 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
 *
 *      http://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.android.textclassifier.testing;

import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.anyInt;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

import android.content.ComponentName;
import android.content.Context;
import android.content.ContextWrapper;
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import androidx.test.core.app.ApplicationProvider;
import com.google.common.base.Preconditions;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;
import javax.annotation.Nullable;
import org.mockito.stubbing.Answer;

/** A builder used to build a fake context for testing. */
public final class FakeContextBuilder {

  /** A component name that can be used for tests. */
  public static final ComponentName DEFAULT_COMPONENT = new ComponentName("pkg", "cls");

  private final PackageManager packageManager;
  private final ContextWrapper context;
  private final Map<String, ComponentName> components = new HashMap<>();
  private final Map<String, CharSequence> appLabels = new HashMap<>();
  @Nullable private ComponentName allIntentComponent;

  public FakeContextBuilder() {
    packageManager = mock(PackageManager.class);
    when(packageManager.resolveActivity(any(Intent.class), anyInt())).thenReturn(null);
    context =
        new ContextWrapper(ApplicationProvider.getApplicationContext()) {
          @Override
          public PackageManager getPackageManager() {
            return packageManager;
          }
        };
  }

  /**
   * Sets the component name of an activity to handle the specified intent action.
   *
   * <p><strong>NOTE: </strong>By default, no component is set to handle any intent.
   */
  @CanIgnoreReturnValue
  public FakeContextBuilder setIntentComponent(
      String intentAction, @Nullable ComponentName component) {
    Preconditions.checkNotNull(intentAction);
    components.put(intentAction, component);
    return this;
  }

  /** Sets the app label res for a specified package. */
  @CanIgnoreReturnValue
  public FakeContextBuilder setAppLabel(String packageName, @Nullable CharSequence appLabel) {
    Preconditions.checkNotNull(packageName);
    appLabels.put(packageName, appLabel);
    return this;
  }

  /**
   * Sets the component name of an activity to handle all intents.
   *
   * <p><strong>NOTE: </strong>By default, no component is set to handle any intent.
   */
  @CanIgnoreReturnValue
  public FakeContextBuilder setAllIntentComponent(@Nullable ComponentName component) {
    allIntentComponent = component;
    return this;
  }

  /** Builds and returns a fake context. */
  public Context build() {
    when(packageManager.resolveActivity(any(Intent.class), anyInt()))
        .thenAnswer(
            (Answer<ResolveInfo>)
                invocation -> {
                  final String action = ((Intent) invocation.getArgument(0)).getAction();
                  final ComponentName component =
                      components.containsKey(action) ? components.get(action) : allIntentComponent;
                  return getResolveInfo(component);
                });
    when(packageManager.getApplicationLabel(any(ApplicationInfo.class)))
        .thenAnswer(
            (Answer<CharSequence>)
                invocation -> {
                  ApplicationInfo applicationInfo = invocation.getArgument(0);
                  return appLabels.get(applicationInfo.packageName);
                });
    return context;
  }

  /** Returns a component name with random package and class names. */
  public static ComponentName newComponent() {
    return new ComponentName(UUID.randomUUID().toString(), UUID.randomUUID().toString());
  }

  private static ResolveInfo getResolveInfo(ComponentName component) {
    final ResolveInfo info;
    if (component == null) {
      info = null;
    } else {
      // NOTE: If something breaks in TextClassifier because we expect more fields to be set
      // in here, just add them.
      info = new ResolveInfo();
      info.activityInfo = new ActivityInfo();
      info.activityInfo.packageName = component.getPackageName();
      info.activityInfo.name = component.getClassName();
      info.activityInfo.exported = true;
      info.activityInfo.applicationInfo = new ApplicationInfo();
      info.activityInfo.applicationInfo.packageName = component.getPackageName();
      info.activityInfo.applicationInfo.icon = 0;
    }
    return info;
  }
}