package org.cyclopsgroup.jmxterm.cc;
   
   import java.util.ArrayList;
   import java.util.Collections;
   import java.util.List;
   
   import org.apache.commons.lang3.StringUtils;
   import org.apache.commons.lang3.Validate;
   import org.cyclopsgroup.jcli.jline.CliCompletor;
  import org.cyclopsgroup.jmxterm.Command;
  import org.jline.reader.Candidate;
  import org.jline.reader.Completer;
  import org.jline.reader.LineReader;
  import org.jline.reader.ParsedLine;
  import org.jline.reader.impl.completer.ArgumentCompleter;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * JLine completor that handles tab key
   *
   * @author <a href="mailto:jiaqi.guo@gmail.com">Jiaqi Guo</a>
   */
  public class ConsoleCompletor implements Completer {
    private static final Logger LOG = LoggerFactory.getLogger(ConsoleCompletor.class);
  
    private final CommandCenter commandCenter;
  
    private final List<Candidate> commandNames;
  
    public ConsoleCompletor(CommandCenter commandCenter) {
      Validate.notNull(commandCenter, "Command center can't be NULL");
      this.commandCenter = commandCenter;
      List<String> commandNames = new ArrayList<String>(commandCenter.getCommandNames());
      Collections.sort(commandNames);
      this.commandNames = new ArrayList<Candidate>(commandNames.size());
      for (String commandName : commandNames) {
        this.commandNames.add(new Candidate(commandName));
      }
    }
  
    @Override
    public void complete(LineReader reader, ParsedLine line, List<Candidate> candidates) {
      try {
        String buffer = line.line();
        if (StringUtils.isEmpty(buffer) || buffer.indexOf(' ') == -1) {
          completeCommandName(buffer, candidates);
        }
        int separatorPos = buffer.indexOf(' ');
        String commandName = buffer.substring(0, separatorPos);
        if (LOG.isDebugEnabled()) {
          LOG.debug("Command name is [" + commandName + "]");
        }
        String commandArguments = buffer.substring(separatorPos + 1);
        commandArguments.replaceFirst("^\\s*", "");
        if (LOG.isDebugEnabled()) {
          LOG.debug("Analyzing commmand arguments [" + commandArguments + "]");
        }
        Command cmd = commandCenter.commandFactory.createCommand(commandName);
        cmd.setSession(commandCenter.session);
        CliCompletor commandCompletor = new CliCompletor(cmd, commandCenter.argTokenizer);
        int position = line.cursor();
        commandCompletor.complete(reader,
            new ArgumentCompleter.ArgumentLine(commandArguments, position - separatorPos),
            candidates);
      } catch (RuntimeException e) {
        if (LOG.isDebugEnabled()) {
          LOG.debug("Couldn't complete input", e);
        }
      }
    }
  
    private void completeCommandName(String buf, List<Candidate> candidates) {
      if (buf == null) {
        // Nothing is there
        candidates.addAll(commandNames);
      } else if (buf.indexOf(' ') == -1) {
        // Partial one word
        List<Candidate> matchedNames = new ArrayList<Candidate>();
        for (Candidate commandName : commandNames) {
          if (commandName.value().startsWith(buf)) {
            matchedNames.add(commandName);
          }
        }
        candidates.addAll(matchedNames);
      } else {
        throw new IllegalStateException("Invalid state");
      }
    }
  }