/*
    * 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.maven.scm.provider.hg.command;
  
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.maven.scm.ScmFileStatus;
  import org.apache.maven.scm.util.AbstractConsumer;
  
  /**
   * Base consumer to do common parsing for all hg commands.
   * <p>
   * More specific: log line each line if debug is enabled, get file status
   * and detect warnings from hg.
   *
   * @author <a href="mailto:thurner.rupert@ymono.net">thurner rupert</a>
   */
  public class HgConsumer extends AbstractConsumer {
  
      /**
       * A list of known keywords from hg.
       */
      private static final Map<String, ScmFileStatus> IDENTIFIERS = new HashMap<>();
  
      /**
       * A list of known message prefixes from hg.
       */
      private static final Map<String, String> MESSAGES = new HashMap<>();
  
      /**
       * Number of lines to keep from Std.Err
       * This size is set to ensure that we capture enough info
       * but still keeps a low memory footprint.
       */
      private static final int MAX_STDERR_SIZE = 10;
  
      /**
       * A list of the MAX_STDERR_SIZE last errors or warnings.
       */
      private final List<String> stderr = new ArrayList<>();
  
      static {
          /* Statuses from hg add
           */
          IDENTIFIERS.put("adding", ScmFileStatus.ADDED);
          IDENTIFIERS.put("unknown", ScmFileStatus.UNKNOWN);
          IDENTIFIERS.put("modified", ScmFileStatus.MODIFIED);
          IDENTIFIERS.put("removed", ScmFileStatus.DELETED);
          IDENTIFIERS.put("renamed", ScmFileStatus.MODIFIED);
  
          /* Statuses from hg status;
           */
          IDENTIFIERS.put("A", ScmFileStatus.ADDED);
          IDENTIFIERS.put("?", ScmFileStatus.UNKNOWN);
          IDENTIFIERS.put("M", ScmFileStatus.MODIFIED);
          IDENTIFIERS.put("R", ScmFileStatus.DELETED);
          IDENTIFIERS.put("C", ScmFileStatus.CHECKED_IN);
          IDENTIFIERS.put("!", ScmFileStatus.MISSING);
          IDENTIFIERS.put("I", ScmFileStatus.UNKNOWN); // not precisely the same, but i think semantics work? - rwd
  
          MESSAGES.put("hg: WARNING:", "WARNING");
          MESSAGES.put("hg: ERROR:", "ERROR");
          MESSAGES.put("'hg' ", "ERROR"); // hg isn't found in windows path
      }
  
      public void doConsume(ScmFileStatus status, String trimmedLine) {
          // override this
      }
  
      /**
       * {@inheritDoc}
       */
      public void consumeLine(String line) {
          if (logger.isDebugEnabled()) {
              logger.debug(line);
          }
          String trimmedLine = line.trim();
  
          String statusStr = processInputForKnownIdentifiers(trimmedLine);
 
         // If its not a status report - then maybe its a message?
         if (statusStr == null) {
             boolean isMessage = processInputForKnownMessages(trimmedLine);
             // If it is then its already processed and we can ignore futher processing
             if (isMessage) {
                 return;
             }
         } else {
             // Strip away identifier
             trimmedLine = trimmedLine.substring(statusStr.length());
             trimmedLine = trimmedLine.trim(); // one or more spaces
         }
 
         ScmFileStatus status = statusStr != null ? (IDENTIFIERS.get(statusStr.intern())) : null;
         doConsume(status, trimmedLine);
     }
 
     /**
      * Warnings and errors is usually printed out in Std.Err, thus for derived consumers
      * operating on Std.Out this would typically return an empty string.
      *
      * @return return the last lines interpreted as an warning or an error
      */
     public String getStdErr() {
         StringBuilder str = new StringBuilder();
         for (Iterator<String> it = stderr.iterator(); it.hasNext(); ) {
             str.append(it.next());
         }
         return str.toString();
     }
 
     private static String processInputForKnownIdentifiers(String line) {
         for (Iterator<String> it = IDENTIFIERS.keySet().iterator(); it.hasNext(); ) {
             String id = it.next();
             if (line.startsWith(id)) {
                 return id;
             }
         }
         return null;
     }
 
     private boolean processInputForKnownMessages(String line) {
         for (Iterator<String> it = MESSAGES.keySet().iterator(); it.hasNext(); ) {
             String prefix = it.next();
             if (line.startsWith(prefix)) {
                 stderr.add(line); // Add line
                 if (stderr.size() > MAX_STDERR_SIZE) {
                     stderr.remove(0); // Rotate list
                 }
                 String message = line.substring(prefix.length());
                 if (MESSAGES.get(prefix).equals("WARNING")) {
                     if (logger.isWarnEnabled()) {
                         logger.warn(message);
                     }
                 } else {
                     if (logger.isErrorEnabled()) {
                         logger.error(message);
                     }
                 }
                 return true;
             }
         }
         return false;
     }
 }