package org.kuali.maven.ec2;
   
   import java.util.ArrayList;
   import java.util.Collections;
   import java.util.List;
   
   import org.apache.commons.lang.StringUtils;
   import org.apache.maven.plugin.MojoExecutionException;
   import org.kuali.maven.ec2.pojo.Column;
  import org.kuali.maven.ec2.pojo.Row;
  import org.kuali.maven.ec2.pojo.RowComparator;
  import org.kuali.maven.ec2.pojo.Table;
  
  import com.amazonaws.services.ec2.AmazonEC2;
  import com.amazonaws.services.ec2.model.DescribeInstancesRequest;
  import com.amazonaws.services.ec2.model.DescribeInstancesResult;
  import com.amazonaws.services.ec2.model.GroupIdentifier;
  import com.amazonaws.services.ec2.model.Instance;
  import com.amazonaws.services.ec2.model.Reservation;
  
  /**
   * Connect to EC2 and list instances associated with this account
   *
   * @goal describeinstances
   */
  public class DescribeInstancesMojo extends AbstractEC2Mojo {
  
      /**
       * The tag to display for each instance.
       *
       * @parameter expression="${ec2.tag}" default-value="Name"
       */
      private String tag;
  
      /**
       * A list of instance id's to display information about
       *
       * @parameter
       */
      private List<String> instanceIds;
  
      @Override
      public void execute() throws MojoExecutionException {
          AmazonEC2 client = getEC2Client();
          DescribeInstancesRequest request = new DescribeInstancesRequest();
          request.setInstanceIds(instanceIds);
          DescribeInstancesResult result = client.describeInstances(request);
          List<Instance> instances = getInstances(result.getReservations());
          Table table = getTable(instances);
          getLog().info(getDisplay(table.getColumns()));
          for (Row row : table.getRows()) {
              getLog().info(getDisplay(table, row));
          }
      }
  
      protected String getDisplay(List<Column> columns) {
          StringBuilder sb = new StringBuilder();
          for (Column c : columns) {
              sb.append(StringUtils.rightPad(c.getTitle(), c.getWidth(), " ") + "  ");
          }
          return sb.toString();
      }
  
      protected String getDisplay(Table table, Row row) {
          StringBuilder sb = new StringBuilder();
          List<String> elements = row.getElements();
          for (int i = 0; i < elements.size(); i++) {
              int width = table.getColumns().get(i).getWidth();
              sb.append(StringUtils.rightPad(elements.get(i), width, " ") + "  ");
          }
          return sb.toString();
      }
  
      protected String getSecurityGroupsDisplay(Instance i) {
          List<GroupIdentifier> groups = i.getSecurityGroups();
          StringBuilder sb = new StringBuilder();
          for (int j = 0; j < groups.size(); j++) {
              if (j != 0) {
                  sb.append(",");
              }
              GroupIdentifier group = groups.get(j);
              sb.append(group.getGroupName());
          }
          return sb.toString();
      }
  
      protected List<Row> getRows(List<Instance> instances) {
          List<Row> rows = new ArrayList<Row>();
          for (Instance i : instances) {
              Row row = new Row();
              List<String> elements = new ArrayList<String>();
              elements.add(getTagValue(i, tag));
              elements.add(i.getInstanceId());
              elements.add(i.getImageId());
              elements.add(i.getPlacement().getAvailabilityZone());
              elements.add(i.getInstanceType());
              elements.add(i.getState().getName());
              elements.add(getSecurityGroupsDisplay(i));
              elements.add(i.getKeyName());
             row.setElements(elements);
             rows.add(row);
         }
         Collections.sort(rows, new RowComparator());
         Collections.reverse(rows);
         return rows;
     }
 
     protected List<Column> getColumns(List<Row> rows) {
         List<Column> columns = new ArrayList<Column>();
         columns.add(new Column(tag));
         columns.add(new Column("Instance"));
         columns.add(new Column("AMI"));
         columns.add(new Column("Availability Zone"));
         columns.add(new Column("Type"));
         columns.add(new Column("State"));
         columns.add(new Column("Security Groups"));
         columns.add(new Column("Key Pair"));
         setWidths(columns, rows);
         return columns;
     }
 
     protected void setWidths(List<Column> columns, List<Row> rows) {
         for (int i = 0; i < rows.size(); i++) {
             List<String> elements = rows.get(i).getElements();
             for (int j = 0; j < elements.size(); j++) {
                 Column c = columns.get(j);
                 c.setWidth(Math.max(c.getWidth(), elements.get(j).length()));
             }
         }
     }
 
     protected Table getTable(List<Instance> instances) {
         Table table = new Table();
         table.setRows(getRows(instances));
         table.setColumns(getColumns(table.getRows()));
         return table;
     }
 
     protected List<Instance> getInstances(List<Reservation> reservations) {
         List<Instance> instances = new ArrayList<Instance>();
         for (Reservation r : reservations) {
             instances.addAll(r.getInstances());
         }
         return instances;
     }
 
     public String getTag() {
         return tag;
     }
 
     public void setTag(String displayTag) {
         this.tag = displayTag;
     }
 
 }