/**
    * 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.top;
  
  import edu.umd.cs.findbugs.annotations.Nullable;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  import java.util.Objects;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.hbtop.screen.ScreenView;
  
  /**
   * The presentation logic for the input mode.
   */
  @InterfaceAudience.Private
  public class InputModeScreenPresenter {
  
    public interface ResultListener {
      public ScreenView apply(String inputString);
    }
  
    private final InputModeScreenView inputModeScreenView;
    private final String message;
    private final List<String> histories;
    private final ResultListener resultListener;
  
    private StringBuilder inputString = new StringBuilder();
    private int cursorPosition;
    private int historyPosition = -1;
  
    public InputModeScreenPresenter(InputModeScreenView inputModeScreenView, String message,
      @Nullable List<String> histories, ResultListener resultListener) {
      this.inputModeScreenView = Objects.requireNonNull(inputModeScreenView);
      this.message = Objects.requireNonNull(message);
  
      if (histories != null) {
        this.histories = Collections.unmodifiableList(new ArrayList<>(histories));
      } else {
        this.histories = Collections.emptyList();
      }
  
      this.resultListener = Objects.requireNonNull(resultListener);
    }
  
    public void init() {
      inputModeScreenView.showInput(message, inputString.toString(), cursorPosition);
      inputModeScreenView.refreshTerminal();
    }
  
    public ScreenView returnToNextScreen() {
      inputModeScreenView.hideCursor();
      String result = inputString.toString();
  
      return resultListener.apply(result);
    }
  
    public void character(Character character) {
      inputString.insert(cursorPosition, character);
      cursorPosition += 1;
      inputModeScreenView.showInput(message, inputString.toString(), cursorPosition);
      inputModeScreenView.refreshTerminal();
    }
  
    public void backspace() {
      if (cursorPosition == 0) {
        return;
      }
  
      inputString.deleteCharAt(cursorPosition - 1);
      cursorPosition -= 1;
      inputModeScreenView.showInput(message, inputString.toString(), cursorPosition);
      inputModeScreenView.refreshTerminal();
    }
  
    public void delete() {
      if (inputString.length() == 0 || cursorPosition > inputString.length() - 1) {
        return;
      }
  
      inputString.deleteCharAt(cursorPosition);
      inputModeScreenView.showInput(message, inputString.toString(), cursorPosition);
      inputModeScreenView.refreshTerminal();
    }
 
   public void arrowLeft() {
     if (cursorPosition == 0) {
       return;
     }
 
     cursorPosition -= 1;
     inputModeScreenView.showInput(message, inputString.toString(), cursorPosition);
     inputModeScreenView.refreshTerminal();
   }
 
   public void arrowRight() {
     if (cursorPosition > inputString.length() - 1) {
       return;
     }
 
     cursorPosition += 1;
     inputModeScreenView.showInput(message, inputString.toString(), cursorPosition);
     inputModeScreenView.refreshTerminal();
   }
 
   public void home() {
     cursorPosition = 0;
     inputModeScreenView.showInput(message, inputString.toString(), cursorPosition);
     inputModeScreenView.refreshTerminal();
   }
 
   public void end() {
     cursorPosition = inputString.length();
     inputModeScreenView.showInput(message, inputString.toString(), cursorPosition);
     inputModeScreenView.refreshTerminal();
   }
 
   public void arrowUp() {
     if (historyPosition == 0 || histories.isEmpty()) {
       return;
     }
 
     if (historyPosition == -1) {
       historyPosition = histories.size() - 1;
     } else {
       historyPosition -= 1;
     }
 
     inputString = new StringBuilder(histories.get(historyPosition));
 
     cursorPosition = inputString.length();
     inputModeScreenView.showInput(message, inputString.toString(), cursorPosition);
     inputModeScreenView.refreshTerminal();
   }
 
   public void arrowDown() {
     if (historyPosition == -1 || histories.isEmpty()) {
       return;
     }
 
     if (historyPosition == histories.size() - 1) {
       historyPosition = -1;
       inputString = new StringBuilder();
     } else {
       historyPosition += 1;
       inputString = new StringBuilder(histories.get(historyPosition));
     }
 
     cursorPosition = inputString.length();
     inputModeScreenView.showInput(message, inputString.toString(), cursorPosition);
     inputModeScreenView.refreshTerminal();
   }
 }