package com.linkedin.parseq.retry;

import com.linkedin.parseq.retry.backoff.BackoffPolicy;
import com.linkedin.parseq.retry.termination.TerminationPolicy;

import java.util.function.Function;


/**
 * A policy builder that enables customizable retries for arbitrary parseq tasks.
 *
 * @author Oleg Anashkin (oleg.anashkin@gmail.com)
 */
public final class RetryPolicyBuilder {
  private final RetryPolicyImpl _retryPolicy = new RetryPolicyImpl();

  public RetryPolicy build() {
    if (_retryPolicy.getTerminationPolicy() == null) {
      throw new IllegalArgumentException("Unable to build retry policy because termination policy is not specified");
    }
    if (_retryPolicy.getBackoffPolicy() == null) {
      _retryPolicy.setBackoffPolicy(BackoffPolicy.noBackoff());
    }
    if (_retryPolicy.getErrorClassifier() == null) {
      _retryPolicy.setErrorClassifier(ErrorClassification.DEFAULT);
    }
    if (_retryPolicy.getName() == null) {
      StringBuilder policyName = new StringBuilder("RetryPolicy");
      String terminationPolicyName = _retryPolicy.getTerminationPolicy().getClass().getSimpleName();
      if (!terminationPolicyName.contains("$$")) {
        policyName.append(".");
        policyName.append(terminationPolicyName);
      }
      String backoffPolicyName = _retryPolicy.getBackoffPolicy().getClass().getSimpleName();
      if (!backoffPolicyName.contains("$$")) {
        policyName.append(".");
        policyName.append(backoffPolicyName);
      }
      _retryPolicy.setName(policyName.toString());
    }
    return _retryPolicy;
  }

  /**
   * Set a name of this policy. It is used to configure parseq tasks.
   */
  public RetryPolicyBuilder setName(String name) {
    _retryPolicy.setName(name);
    return this;
  }

  /**
   * Set a strategy for determining when to abort a retry operation.
   */
  public RetryPolicyBuilder setTerminationPolicy(TerminationPolicy terminationPolicy) {
    _retryPolicy.setTerminationPolicy(terminationPolicy);
    return this;
  }

  /**
   * Set a strategy used to calculate delays between retries.
   */
  public RetryPolicyBuilder setBackoffPolicy(BackoffPolicy backoffPolicy) {
    _retryPolicy.setBackoffPolicy(backoffPolicy);
    return this;
  }

  /**
   * Set a classifier for errors raised during retry operations.
   */
  public RetryPolicyBuilder setErrorClassifier(Function<Throwable, ErrorClassification> errorClassifier) {
    _retryPolicy.setErrorClassifier(errorClassifier);
    return this;
  }
}