/*
    * Licensed to The Apereo Foundation under one or more contributor license
    * agreements. See the NOTICE file distributed with this work for additional
    * information regarding copyright ownership.
    *
    *
    * The Apereo Foundation licenses this file to you under the Educational
    * Community 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://opensource.org/licenses/ecl2.txt
   *
   * 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.opencastproject.capture.admin.impl;
  
  import org.opencastproject.capture.CaptureParameters;
  import org.opencastproject.capture.admin.api.Agent;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.IOException;
  import java.io.StringReader;
  import java.io.StringWriter;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Properties;
  import java.util.Set;
  
  import javax.persistence.CollectionTable;
  import javax.persistence.Column;
  import javax.persistence.ElementCollection;
  import javax.persistence.Entity;
  import javax.persistence.Id;
  import javax.persistence.IdClass;
  import javax.persistence.Index;
  import javax.persistence.JoinColumn;
  import javax.persistence.Lob;
  import javax.persistence.NamedQueries;
  import javax.persistence.NamedQuery;
  import javax.persistence.PostLoad;
  import javax.persistence.Table;
  import javax.persistence.Transient;
  import javax.persistence.UniqueConstraint;
  
  /**
   * An in-memory construct to represent the state of a capture agent, and when it was last heard from.
   */
  @Entity @IdClass(AgentImplId.class)
  @Table(name = "oc_capture_agent_state")
  @NamedQueries({
    @NamedQuery(name = "Agent.get", query = "select a from AgentImpl a where a.name = :id and a.organization = :org"),
    @NamedQuery(name = "Agent.byOrganization", query = "SELECT a FROM AgentImpl a where a.organization = :org")
  })
  public class AgentImpl implements Agent {
  
    private static final Logger log = LoggerFactory.getLogger(AgentImpl.class);
  
    /**
     * The name of the agent.
     */
    @Id
    @Column(name = "id", length = 128)
    protected String name;
  
    /**
     * The state of the agent. This should be defined from the constants in AgentState.
     */
    @Lob
    @Column(name = "state", nullable = false, length = 65535)
    protected String state;
  
    /**
     * The URL of the agent. This is determined from the referer header parameter when the agent is registered.
     */
    @Lob
    @Column(name = "url", length = 65535)
    protected String url;
  
    @Id
    @Column(name = "organization", length = 128)
    protected String organization;
  
    /**
     * The time at which the agent last checked in with this service. Note that this is an absolute timestamp (ie,
     * milliseconds since 1970) rather than a relative timestamp (ie, it's been 3000 ms since it last checked in).
     */
    @Column(name = "last_heard_from", nullable = false)
    protected Long lastHeardFrom;
  
    /** The roles allowed to schedule this agent */
   @ElementCollection
   @Column(name = "role", nullable = false)
   @CollectionTable(name = "oc_capture_agent_role", indexes = {
       @Index(name = "IX_oc_capture_agent_role_pk", columnList = "id, organization")
     }, uniqueConstraints = {
       @UniqueConstraint(name = "UNQ_capture_agent_role_id_org_role", columnNames = {"id", "organization", "role"})
     }, joinColumns = {
       @JoinColumn(name = "id", referencedColumnName = "id", nullable = false),
       @JoinColumn(name = "organization", referencedColumnName = "organization", nullable = false) })
   protected Set<String> schedulerRoles = new HashSet<>();
 
   /**
    * The capabilities the agent has Capabilities are the devices this agent can record from, with a friendly name
    * associated to determine their nature (e.g. PRESENTER --&gt; dev/video0)
    */
   @Lob
   @Column(name = "configuration", nullable = true, length = 65535)
   protected String configurationString;
 
   // Private var to store the caps as a properties object.
   @Transient
   private Properties capabilitiesProperties;
 
   // Private var to store the configuration as a properties object.
   @Transient
   private Properties configurationProperties;
 
   /**
    * Required 0-arg constructor for JAXB, creates a blank agent.
    */
   public AgentImpl() {
   };
 
   /**
    * Builds a representation of the agent.
    *
    * @param agentName
    *          The name of the agent.
    * @param organization
    *          The organization identifier to which this agent belongs
    * @param agentState
    *          The state of the agent. This should be defined from the constants in AgentState
    * @param configuration
    *          The configuration of the agent.
    */
   public AgentImpl(String agentName, String organization, String agentState, String agentUrl, Properties configuration) {
     name = agentName;
     this.setState(agentState);
     this.setUrl(agentUrl);
     this.setOrganization(organization);
     // Agents with no capabilities are allowed. These can/will be updated after the agent is built if necessary.
     setConfiguration(configuration);
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.opencastproject.capture.admin.api.Agent#getName()
    */
   public String getName() {
     return name;
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.opencastproject.capture.admin.api.Agent#setState(java.lang.String)
    */
   public void setState(String newState) {
     state = newState;
     setLastHeardFrom(System.currentTimeMillis());
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.opencastproject.capture.admin.api.Agent#getState()
    */
   public String getState() {
     return state;
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.opencastproject.capture.admin.api.Agent#setUrl(java.lang.String)
    */
   public void setUrl(String agentUrl) {
     url = agentUrl;
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.opencastproject.capture.admin.api.Agent#getUrl()
    */
   public String getUrl() {
     return url;
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.opencastproject.capture.admin.api.Agent#setLastHeardFrom(java.lang.Long)
    */
   public void setLastHeardFrom(Long time) {
     lastHeardFrom = time;
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.opencastproject.capture.admin.api.Agent#getLastHeardFrom()
    */
   public Long getLastHeardFrom() {
     return lastHeardFrom;
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.opencastproject.capture.admin.api.Agent#getCapabilities()
    */
   public Properties getCapabilities() {
     return capabilitiesProperties;
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.opencastproject.capture.admin.api.Agent#getConfiguration()
    */
   public Properties getConfiguration() {
     return configurationProperties;
   }
 
   /**
    * @return the schedulerRoles
    */
   public Set<String> getSchedulerRoles() {
     return schedulerRoles;
   }
 
   /**
    * @param schedulerRoles
    *          the schedulerRoles to set
    */
   public void setSchedulerRoles(Set<String> schedulerRoles) {
     this.schedulerRoles = schedulerRoles;
   }
 
   /**
    * @return the organization
    */
   public String getOrganization() {
     return organization;
   }
 
   /**
    * @param organization
    *          the organization to set
    */
   public void setOrganization(String organization) {
     this.organization = organization;
   }
 
   /**
    * {@inheritDoc}
    *
    * @see org.opencastproject.capture.admin.api.Agent#setConfiguration(java.util.Properties)
    */
   public void setConfiguration(Properties configuration) {
     if (configuration == null) {
       return;
     }
 
     // Set the configuration variables
     configurationProperties = configuration;
     try {
       StringWriter sw = new StringWriter();
       configuration.store(sw, "");
       this.configurationString = sw.toString();
     } catch (IOException e) {
       log.warn("Unable to store agent " + "'s capabilities to the database, IO exception occurred.", e);
     }
 
     // Figure out the capabilities variables
 
     capabilitiesProperties = new Properties();
 
     String names = configuration.getProperty(CaptureParameters.CAPTURE_DEVICE_NAMES);
     if (names == null) {
       log.debug("Capture agent '{}' failed to provide device names ({})", name, CaptureParameters.CAPTURE_DEVICE_NAMES);
       return;
     }
 
     capabilitiesProperties.put(CaptureParameters.CAPTURE_DEVICE_NAMES, names);
     // Get the names and setup a hash map of them
     String[] friendlyNames = names.split(",");
     HashMap<String, Integer> propertyCounts = new HashMap<String, Integer>();
     for (String name : friendlyNames) {
       propertyCounts.put(name, 0);
     }
 
     // For each key
     for (String key : configuration.stringPropertyNames()) {
       // For each device
       for (String name : friendlyNames) {
         String check = CaptureParameters.CAPTURE_DEVICE_PREFIX + name;
         // If the key looks like a device prefix + the name, copy it
         if (key.contains(check)) {
           String property = configuration.getProperty(key);
           if (property == null) {
             log.error("Unable to expand variable in value for key {}, returning null!", key);
             capabilitiesProperties = null;
             return;
           }
           capabilitiesProperties.setProperty(key, property);
           propertyCounts.put(name, propertyCounts.get(name) + 1);
         }
       }
     }
   }
 
   /**
    * Post load method to load the capabilities from a string to the properties object
    */
   @SuppressWarnings("unused")
   @PostLoad
   private void loadCaps() {
     configurationProperties = new Properties();
     if (configurationString == null) {
       log.info("No configuration properties set yet for '{}'", name);
     } else {
       try {
         configurationProperties.load(new StringReader(this.configurationString));
         this.setConfiguration(configurationProperties);
       } catch (IOException e) {
         log.warn("Unable to load agent " + name + "'s capabilities, IO exception occurred.", e);
       }
     }
   }
 
   /**
    * {@inheritDoc}
    *
    * @see java.lang.Object#equals(java.lang.Object)
    */
   @Override
   public boolean equals(Object o) {
     if (this == o) {
       return true;
     }
     if (o instanceof AgentImpl) {
       return name.equals(((AgentImpl) o).name);
     } else {
       return false;
     }
   }
 
   /**
    * {@inheritDoc}
    *
    * @see java.lang.Object#hashCode()
    */
   @Override
   public int hashCode() {
     return name.hashCode();
   }
 }