/**
 * 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.hbase.util;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
import org.apache.yetus.audience.InterfaceAudience;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.hbase.thirdparty.org.apache.commons.cli.BasicParser;
import org.apache.hbase.thirdparty.org.apache.commons.cli.CommandLine;
import org.apache.hbase.thirdparty.org.apache.commons.cli.CommandLineParser;
import org.apache.hbase.thirdparty.org.apache.commons.cli.DefaultParser;
import org.apache.hbase.thirdparty.org.apache.commons.cli.HelpFormatter;
import org.apache.hbase.thirdparty.org.apache.commons.cli.MissingOptionException;
import org.apache.hbase.thirdparty.org.apache.commons.cli.Option;
import org.apache.hbase.thirdparty.org.apache.commons.cli.Options;
import org.apache.hbase.thirdparty.org.apache.commons.cli.ParseException;

/**
 * Common base class used for HBase command-line tools. Simplifies workflow and
 * command-line argument parsing.
 */
@InterfaceAudience.Private
public abstract class AbstractHBaseTool implements Tool {
  public static final int EXIT_SUCCESS = 0;
  public static final int EXIT_FAILURE = 1;

  public static final String SHORT_HELP_OPTION = "h";
  public static final String LONG_HELP_OPTION = "help";

  private static final Option HELP_OPTION = new Option("h", "help", false,
      "Prints help for this tool.");

  private static final Logger LOG = LoggerFactory.getLogger(AbstractHBaseTool.class);

  protected final Options options = new Options();

  protected Configuration conf = null;

  protected String[] cmdLineArgs = null;

  // To print options in order they were added in help text.
  private HashMap<Option, Integer> optionsOrder = new HashMap<>();
  private int optionsCount = 0;

  private class OptionsOrderComparator implements Comparator<Option> {
    @Override
    public int compare(Option o1, Option o2) {
      return optionsOrder.get(o1) - optionsOrder.get(o2);
    }
  }

  /**
   * Override this to add command-line options using {@link #addOptWithArg}
   * and similar methods.
   */
  protected abstract void addOptions();

  /**
   * This method is called to process the options after they have been parsed.
   */
  protected abstract void processOptions(CommandLine cmd);

  /** The "main function" of the tool */
  protected abstract int doWork() throws Exception;

  /**
   * For backward compatibility. DO NOT use it for new tools.
   * We have options in existing tools which can't be ported to Apache CLI's {@link Option}.
   * (because they don't pass validation, for e.g. "-copy-to". "-" means short name
   * which doesn't allow '-' in name). This function is to allow tools to have, for time being,
   * parameters which can't be parsed using {@link Option}.
   * Overrides should consume all valid legacy arguments. If the param 'args' is not empty on
   * return, it means there were invalid options, in which case we'll exit from the tool.
   * Note that it's called before {@link #processOptions(CommandLine)}, which means new options'
   * values will override old ones'.
   */
  protected void processOldArgs(List<String> args) {
  }

  @Override
  public Configuration getConf() {
    return conf;
  }

  @Override
  public void setConf(Configuration conf) {
    this.conf = conf;
  }

  @Override
  public int run(String[] args) throws IOException {
    cmdLineArgs = args;
    if (conf == null) {
      LOG.error("Tool configuration is not initialized");
      throw new NullPointerException("conf");
    }

    CommandLine cmd;
    List<String> argsList = new ArrayList<>(args.length);
    for (String arg : args) {
      argsList.add(arg);
    }
    // For backward compatibility of args which can't be parsed as Option. See javadoc for
    // processOldArgs(..)
    processOldArgs(argsList);
    try {
      addOptions();
      if (isHelpCommand(args)) {
        printUsage();
        return EXIT_SUCCESS;
      }
      String[] remainingArgs = new String[argsList.size()];
      argsList.toArray(remainingArgs);
      cmd = newParser().parse(options, remainingArgs);
    } catch (MissingOptionException e) {
      LOG.error(e.getMessage());
      LOG.error("Use -h or --help for usage instructions.");
      return EXIT_FAILURE;
    } catch (ParseException e) {
      LOG.error("Error when parsing command-line arguments", e);
      LOG.error("Use -h or --help for usage instructions.");
      return EXIT_FAILURE;
    }

    processOptions(cmd);

    int ret;
    try {
      ret = doWork();
    } catch (Exception e) {
      LOG.error("Error running command-line tool", e);
      return EXIT_FAILURE;
    }
    return ret;
  }

  /**
   * Create the parser to use for parsing and validating the command line. Since commons-cli lacks
   * the capability to validate arbitrary combination of options, it may be helpful to bake custom
   * logic into a specialized parser implementation. See LoadTestTool for examples.
   * @return a new parser specific to the current tool
   */
  protected CommandLineParser newParser() {
    return new DefaultParser();
  }

  private boolean isHelpCommand(String[] args) throws ParseException {
    Options helpOption = new Options().addOption(HELP_OPTION);
    // this parses the command line but doesn't throw an exception on unknown options
    CommandLine cl = new DefaultParser().parse(helpOption, args, true);
    return cl.getOptions().length != 0;
  }

  protected CommandLine parseArgs(String[] args) throws ParseException {
    options.addOption(SHORT_HELP_OPTION, LONG_HELP_OPTION, false, "Show usage");
    addOptions();
    CommandLineParser parser = new BasicParser();
    return parser.parse(options, args);
  }

  protected void printUsage() {
    printUsage("hbase " + getClass().getName() + " <options>", "Options:", "");
  }

  protected void printUsage(final String usageStr, final String usageHeader,
      final String usageFooter) {
    HelpFormatter helpFormatter = new HelpFormatter();
    helpFormatter.setWidth(120);
    helpFormatter.setOptionComparator(new OptionsOrderComparator());
    helpFormatter.printHelp(usageStr, usageHeader, options, usageFooter);
  }

  protected void addOption(Option option) {
    options.addOption(option);
    optionsOrder.put(option, optionsCount++);
  }

  protected void addRequiredOption(Option option) {
    option.setRequired(true);
    addOption(option);
  }

  protected void addRequiredOptWithArg(String opt, String description) {
    Option option = new Option(opt, true, description);
    option.setRequired(true);
    addOption(option);
  }

  protected void addRequiredOptWithArg(String shortOpt, String longOpt, String description) {
    Option option = new Option(shortOpt, longOpt, true, description);
    option.setRequired(true);
    addOption(option);
  }

  protected void addOptNoArg(String opt, String description) {
    addOption(new Option(opt, false, description));
  }

  protected void addOptNoArg(String shortOpt, String longOpt, String description) {
    addOption(new Option(shortOpt, longOpt, false, description));
  }

  protected void addOptWithArg(String opt, String description) {
    addOption(new Option(opt, true, description));
  }

  protected void addOptWithArg(String shortOpt, String longOpt, String description) {
    addOption(new Option(shortOpt, longOpt, true, description));
  }

  public int getOptionAsInt(CommandLine cmd, String opt, int defaultValue) {
    if (cmd.hasOption(opt)) {
      return Integer.parseInt(cmd.getOptionValue(opt));
    } else {
      return defaultValue;
    }
  }

  public long getOptionAsLong(CommandLine cmd, String opt, int defaultValue) {
    if (cmd.hasOption(opt)) {
      return Long.parseLong(cmd.getOptionValue(opt));
    } else {
      return defaultValue;
    }
  }

  public double getOptionAsDouble(CommandLine cmd, String opt, double defaultValue) {
    if (cmd.hasOption(opt)) {
      return Double.parseDouble(cmd.getOptionValue(opt));
    } else {
      return defaultValue;
    }
  }

  /**
   * Parse a number and enforce a range.
   */
  public static long parseLong(String s, long minValue, long maxValue) {
    long l = Long.parseLong(s);
    if (l < minValue || l > maxValue) {
      throw new IllegalArgumentException("The value " + l
          + " is out of range [" + minValue + ", " + maxValue + "]");
    }
    return l;
  }

  public static int parseInt(String s, int minValue, int maxValue) {
    return (int) parseLong(s, minValue, maxValue);
  }

  /** Call this from the concrete tool class's main function. */
  protected void doStaticMain(String args[]) {
    int ret;
    try {
      ret = ToolRunner.run(HBaseConfiguration.create(), this, args);
    } catch (Exception ex) {
      LOG.error("Error running command-line tool", ex);
      ret = EXIT_FAILURE;
    }
    System.exit(ret);
  }

}
