/*
 * Copyright (C) 2016 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.voicemail.impl.scheduling;

import android.content.Intent;
import android.os.Bundle;
import android.telecom.PhoneAccountHandle;
import com.android.voicemail.impl.VoicemailStatus;
import com.android.voicemail.impl.VvmLog;

/**
 * A task with this policy will automatically re-queue itself if {@link BaseTask#fail()} has been
 * called during {@link BaseTask#onExecuteInBackgroundThread()}. A task will be retried at most
 * <code>retryLimit</code> times and with a <code>retryDelayMillis</code> interval in between.
 */
public class RetryPolicy implements Policy {

  private static final String TAG = "RetryPolicy";
  private static final String EXTRA_RETRY_COUNT = "extra_retry_count";

  private final int retryLimit;
  private final int retryDelayMillis;

  private BaseTask task;

  private int retryCount;
  private boolean failed;

  private VoicemailStatus.DeferredEditor voicemailStatusEditor;

  public RetryPolicy(int retryLimit, int retryDelayMillis) {
    this.retryLimit = retryLimit;
    this.retryDelayMillis = retryDelayMillis;
  }

  private boolean hasMoreRetries() {
    return retryCount < retryLimit;
  }

  /**
   * Error status should only be set if retries has exhausted or the task is successful. Status
   * writes to this editor will be deferred until the task has ended, and will only be committed if
   * the task is successful or there are no retries left.
   */
  public VoicemailStatus.Editor getVoicemailStatusEditor() {
    return voicemailStatusEditor;
  }

  @Override
  public void onCreate(BaseTask task, Bundle extras) {
    this.task = task;
    retryCount = extras.getInt(EXTRA_RETRY_COUNT, 0);
    if (retryCount > 0) {
      VvmLog.i(
          TAG,
          "retry #"
              + retryCount
              + " for "
              + this.task
              + " queued, executing in "
              + retryDelayMillis);
      this.task.setExecutionTime(this.task.getTimeMillis() + retryDelayMillis);
    }
    PhoneAccountHandle phoneAccountHandle = task.getPhoneAccountHandle();
    if (phoneAccountHandle == null) {
      VvmLog.e(TAG, "null phone account for phoneAccountHandle " + task.getPhoneAccountHandle());
      // This should never happen, but continue on if it does. The status write will be
      // discarded.
    }
    voicemailStatusEditor = VoicemailStatus.deferredEdit(task.getContext(), phoneAccountHandle);
  }

  @Override
  public void onBeforeExecute() {}

  @Override
  public void onCompleted() {
    if (!failed || !hasMoreRetries()) {
      if (!failed) {
        VvmLog.i(TAG, task + " completed successfully");
      }
      if (!hasMoreRetries()) {
        VvmLog.i(TAG, "Retry limit for " + task + " reached");
      }
      VvmLog.i(TAG, "committing deferred status: " + voicemailStatusEditor.getValues());
      voicemailStatusEditor.deferredApply();
      return;
    }
    VvmLog.i(TAG, "discarding deferred status: " + voicemailStatusEditor.getValues());
    Intent intent = task.createRestartIntent();
    intent.putExtra(EXTRA_RETRY_COUNT, retryCount + 1);

    task.getContext().sendBroadcast(intent);
  }

  @Override
  public void onFail() {
    failed = true;
  }

  @Override
  public void onDuplicatedTaskAdded() {}
}