/**
    * 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.hbtop.screen.help;
  
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.hbtop.screen.AbstractScreenView;
  import org.apache.hadoop.hbase.hbtop.screen.Screen;
  import org.apache.hadoop.hbase.hbtop.screen.ScreenView;
  import org.apache.hadoop.hbase.hbtop.terminal.KeyPress;
  import org.apache.hadoop.hbase.hbtop.terminal.Terminal;
  import org.apache.hadoop.hbase.hbtop.terminal.TerminalPrinter;
  
  /**
   * The help screen.
   */
  @InterfaceAudience.Private
  public class HelpScreenView extends AbstractScreenView {
  
    private static final int SCREEN_DESCRIPTION_START_ROW = 0;
    private static final int COMMAND_DESCRIPTION_START_ROW = 3;
  
    private final HelpScreenPresenter helpScreenPresenter;
  
    public HelpScreenView(Screen screen, Terminal terminal, long refreshDelay,
      ScreenView nextScreenView) {
      super(screen, terminal);
      this.helpScreenPresenter = new HelpScreenPresenter(this, refreshDelay, nextScreenView);
    }
  
    @Override
    public void init() {
      helpScreenPresenter.init();
    }
  
    @Override
    public ScreenView handleKeyPress(KeyPress keyPress) {
      return helpScreenPresenter.transitionToNextScreen();
    }
  
    public void showHelpScreen(long refreshDelay, CommandDescription[] commandDescriptions) {
      showScreenDescription(refreshDelay);
  
      TerminalPrinter printer = getTerminalPrinter(COMMAND_DESCRIPTION_START_ROW);
      for (CommandDescription commandDescription : commandDescriptions) {
        showCommandDescription(printer, commandDescription);
      }
  
      printer.endOfLine();
      printer.print("Press any key to continue").endOfLine();
    }
  
    private void showScreenDescription(long refreshDelay) {
      TerminalPrinter printer = getTerminalPrinter(SCREEN_DESCRIPTION_START_ROW);
      printer.startBold().print("Help for Interactive Commands").stopBold().endOfLine();
      printer.print("Refresh delay: ").startBold()
        .print((double) refreshDelay / 1000).stopBold().endOfLine();
    }
  
    private void showCommandDescription(TerminalPrinter terminalPrinter,
      CommandDescription commandDescription) {
      terminalPrinter.print("  ");
      boolean first = true;
      for (String key : commandDescription.getKeys()) {
        if (first) {
          first = false;
        } else {
          terminalPrinter.print(",");
        }
        terminalPrinter.startBold().print(key).stopBold();
      }
  
      terminalPrinter.printFormat(": %s", commandDescription.getDescription()).endOfLine();
    }
  }