/*
 * Copyright (C) 2015 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.google.android.setupdesign.util;

import android.content.Context;
import android.content.Intent;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.pm.ResolveInfo;
import android.content.res.Resources;
import android.graphics.drawable.Drawable;
import android.os.Build.VERSION;
import android.os.Build.VERSION_CODES;
import androidx.annotation.AnyRes;
import androidx.annotation.ColorRes;
import androidx.annotation.DrawableRes;
import androidx.annotation.Nullable;
import androidx.annotation.StringRes;
import androidx.annotation.VisibleForTesting;
import android.util.Log;
import java.util.List;

/**
 * Utilities to discover and interact with partner customizations. An overlay package is one that
 * registers the broadcast receiver for {@code com.android.setupwizard.action.PARTNER_CUSTOMIZATION}
 * in its manifest. There can only be one customization APK on a device, and it must be bundled with
 * the system.
 *
 * <p>Derived from {@code com.android.launcher3/Partner.java}
 */
public class Partner {

  private static final String TAG = "(setupdesign) Partner";

  /** Marker action used to discover partner. */
  private static final String ACTION_PARTNER_CUSTOMIZATION =
      "com.android.setupwizard.action.PARTNER_CUSTOMIZATION";

  private static boolean searched = false;
  @Nullable private static Partner partner;

  /**
   * Gets a drawable from partner overlay, or if not available, the drawable from the original
   * context.
   *
   * @see #getResourceEntry(android.content.Context, int)
   */
  public static Drawable getDrawable(Context context, @DrawableRes int id) {
    final ResourceEntry entry = getResourceEntry(context, id);
    return entry.resources.getDrawable(entry.id);
  }

  /**
   * Gets a string from partner overlay, or if not available, the string from the original context.
   *
   * @see #getResourceEntry(android.content.Context, int)
   */
  public static String getString(Context context, @StringRes int id) {
    final ResourceEntry entry = getResourceEntry(context, id);
    return entry.resources.getString(entry.id);
  }

  /**
   * Gets a color from partner overlay, or if not available, the color from the original context.
   */
  public static int getColor(Context context, @ColorRes int id) {
    final ResourceEntry resourceEntry = getResourceEntry(context, id);
    return resourceEntry.resources.getColor(resourceEntry.id);
  }

  /**
   * Gets a CharSequence from partner overlay, or if not available, the text from the original
   * context.
   */
  public static CharSequence getText(Context context, @StringRes int id) {
    final ResourceEntry entry = getResourceEntry(context, id);
    return entry.resources.getText(entry.id);
  }

  /**
   * Finds an entry of resource in the overlay package provided by partners. It will first look for
   * the resource in the overlay package, and if not available, will return the one in the original
   * context.
   *
   * @return a ResourceEntry in the partner overlay's resources, if one is defined. Otherwise the
   *     resources from the original context is returned. Clients can then get the resource by
   *     {@code entry.resources.getString(entry.id)}, or other methods available in {@link
   *     android.content.res.Resources}.
   */
  public static ResourceEntry getResourceEntry(Context context, @AnyRes int id) {
    final Partner partner = Partner.get(context);
    if (partner != null) {
      final Resources ourResources = context.getResources();
      final String name = ourResources.getResourceEntryName(id);
      final String type = ourResources.getResourceTypeName(id);
      final int partnerId = partner.getIdentifier(name, type);
      if (partnerId != 0) {
        return new ResourceEntry(partner.getPackageName(), partner.resources, partnerId, true);
      }
    }
    return new ResourceEntry(context.getPackageName(), context.getResources(), id, false);
  }

  public static class ResourceEntry {
    public String packageName;
    public Resources resources;
    public int id;
    public boolean isOverlay;

    ResourceEntry(String packageName, Resources resources, int id, boolean isOverlay) {
      this.packageName = packageName;
      this.resources = resources;
      this.id = id;
      this.isOverlay = isOverlay;
    }
  }

  /**
   * Finds and returns partner details, or {@code null} if none exists. A partner package is marked
   * by a broadcast receiver declared in the manifest that handles the {@code
   * com.android.setupwizard.action.PARTNER_CUSTOMIZATION} intent action. The overlay package must
   * also be a system package.
   */
  public static synchronized Partner get(Context context) {
    if (!searched) {
      PackageManager pm = context.getPackageManager();
      final Intent intent = new Intent(ACTION_PARTNER_CUSTOMIZATION);
      List<ResolveInfo> receivers;
      if (VERSION.SDK_INT >= VERSION_CODES.N) {
        receivers =
            pm.queryBroadcastReceivers(
                intent,
                PackageManager.MATCH_SYSTEM_ONLY
                    | PackageManager.MATCH_DIRECT_BOOT_AWARE
                    | PackageManager.MATCH_DIRECT_BOOT_UNAWARE
                    | PackageManager.MATCH_DISABLED_COMPONENTS);
      } else {
        // On versions before N, direct boot doesn't exist. And the MATCH_SYSTEM_ONLY flag
        // doesn't exist so we filter for system apps in code below.
        receivers = pm.queryBroadcastReceivers(intent, PackageManager.GET_DISABLED_COMPONENTS);
      }

      for (ResolveInfo info : receivers) {
        if (info.activityInfo == null) {
          continue;
        }
        final ApplicationInfo appInfo = info.activityInfo.applicationInfo;
        if ((appInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0) {
          try {
            final Resources res = pm.getResourcesForApplication(appInfo);
            partner = new Partner(appInfo.packageName, res);
            break;
          } catch (NameNotFoundException e) {
            Log.w(TAG, "Failed to find resources for " + appInfo.packageName);
          }
        }
      }
      searched = true;
    }
    return partner;
  }

  @VisibleForTesting
  public static synchronized void resetForTesting() {
    searched = false;
    partner = null;
  }

  private final String packageName;
  private final Resources resources;

  private Partner(String packageName, Resources res) {
    this.packageName = packageName;
    resources = res;
  }

  public String getPackageName() {
    return packageName;
  }

  public Resources getResources() {
    return resources;
  }

  public int getIdentifier(String name, String defType) {
    return resources.getIdentifier(name, defType, packageName);
  }
}