/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.hadoop.registry.client.types;

import com.google.common.base.Preconditions;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.registry.client.exceptions.InvalidRecordException;
import org.codehaus.jackson.annotate.JsonAnyGetter;
import org.codehaus.jackson.annotate.JsonAnySetter;
import org.codehaus.jackson.map.annotate.JsonSerialize;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * JSON-marshallable description of a single component.
 * It supports the deserialization of unknown attributes, but does
 * not support their creation.
 */
@InterfaceAudience.Public
@InterfaceStability.Evolving
@JsonSerialize(include = JsonSerialize.Inclusion.NON_NULL)
public class ServiceRecord implements Cloneable {

  /**
   * A type string which MUST be in the serialized json. This permits
   * fast discarding of invalid entries
   */
  public static final String RECORD_TYPE = "JSONServiceRecord";

  /**
   * The type field. This must be the string {@link #RECORD_TYPE}
   */
  public String type = RECORD_TYPE;

  /**
   * Description string
   */
  public String description;

  /**
   * map to handle unknown attributes.
   */
  private Map<String, String> attributes = new HashMap<String, String>(4);

  /**
   * List of endpoints intended for use to external callers
   */
  public List<Endpoint> external = new ArrayList<Endpoint>();

  /**
   * List of endpoints for use <i>within</i> an application.
   */
  public List<Endpoint> internal = new ArrayList<Endpoint>();

  /**
   * Create a service record with no ID, description or registration time.
   * Endpoint lists are set to empty lists.
   */
  public ServiceRecord() {
  }

  /**
   * Deep cloning constructor
   * @param that service record source
   */
  public ServiceRecord(ServiceRecord that) {
    this.description = that.description;
    // others
    Map<String, String> thatAttrs = that.attributes;
    for (Map.Entry<String, String> entry : thatAttrs.entrySet()) {
      attributes.put(entry.getKey(), entry.getValue());
    }
    // endpoints
    List<Endpoint> src = that.internal;
    if (src != null) {
      internal = new ArrayList<Endpoint>(src.size());
      for (Endpoint endpoint : src) {
        internal.add(new Endpoint(endpoint));
      }
    }
    src = that.external;
    if (src != null) {
      external = new ArrayList<Endpoint>(src.size());
      for (Endpoint endpoint : src) {
        external.add(new Endpoint(endpoint));
      }
    }
  }

  /**
   * Add an external endpoint
   * @param endpoint endpoint to set
   */
  public void addExternalEndpoint(Endpoint endpoint) {
    Preconditions.checkArgument(endpoint != null);
    endpoint.validate();
    external.add(endpoint);
  }

  /**
   * Add an internal endpoint
   * @param endpoint endpoint to set
   */
  public void addInternalEndpoint(Endpoint endpoint) {
    Preconditions.checkArgument(endpoint != null);
    endpoint.validate();
    internal.add(endpoint);
  }

  /**
   * Look up an internal endpoint
   * @param api API
   * @return the endpoint or null if there was no match
   */
  public Endpoint getInternalEndpoint(String api) {
    return findByAPI(internal, api);
  }

  /**
   * Look up an external endpoint
   * @param api API
   * @return the endpoint or null if there was no match
   */
  public Endpoint getExternalEndpoint(String api) {
    return findByAPI(external, api);
  }

  /**
   * Handle unknown attributes by storing them in the
   * {@link #attributes} map
   * @param key attribute name
   * @param value attribute value.
   */
  @JsonAnySetter
  public void set(String key, Object value) {
    attributes.put(key, value.toString());
  }

  /**
   * The map of "other" attributes set when parsing. These
   * are not included in the JSON value of this record when it
   * is generated.
   * @return a map of any unknown attributes in the deserialized JSON.
   */
  @JsonAnyGetter
  public Map<String, String> attributes() {
    return attributes;
  }

  /**
   * Get the "other" attribute with a specific key
   * @param key key to look up
   * @return the value or null
   */
  public String get(String key) {
    return attributes.get(key);
  }

  /**
   * Get the "other" attribute with a specific key.
   * @param key key to look up
   * @param defVal default value
   * @return the value as a string,
   * or <code>defval</code> if the value was not present
   */
  public String get(String key, String defVal) {
    String val = attributes.get(key);
    return val != null ? val: defVal;
  }

  /**
   * Find an endpoint by its API
   * @param list list
   * @param api api name
   * @return the endpoint or null if there was no match
   */
  private Endpoint findByAPI(List<Endpoint> list,  String api) {
    for (Endpoint endpoint : list) {
      if (endpoint.api.equals(api)) {
        return endpoint;
      }
    }
    return null;
  }

  @Override
  public String toString() {
    final StringBuilder sb =
        new StringBuilder("ServiceRecord{");
    sb.append("description='").append(description).append('\'');
    sb.append("; external endpoints: {");
    for (Endpoint endpoint : external) {
      sb.append(endpoint).append("; ");
    }
    sb.append("}; internal endpoints: {");
    for (Endpoint endpoint : internal) {
      sb.append(endpoint != null ? endpoint.toString() : "NULL ENDPOINT");
      sb.append("; ");
    }
    sb.append('}');

    if (!attributes.isEmpty()) {
      sb.append(", attributes: {");
      for (Map.Entry<String, String> attr : attributes.entrySet()) {
        sb.append("\"").append(attr.getKey()).append("\"=\"")
          .append(attr.getValue()).append("\" ");
      }
    } else {

      sb.append(", attributes: {");
    }
    sb.append('}');

    sb.append('}');
    return sb.toString();
  }

  /**
   * Shallow clone: all endpoints will be shared across instances
   * @return a clone of the instance
   * @throws CloneNotSupportedException
   */
  @Override
  protected Object clone() throws CloneNotSupportedException {
    return super.clone();
  }


}
