/**
    * Copyright 2017 Internet2
    *
    * Licensed 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 edu.internet2.middleware.grouper.app.gsh.jline;
  
  import java.io.ByteArrayInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  
  import org.fusesource.jansi.internal.WindowsSupport;
  import org.fusesource.jansi.internal.Kernel32.INPUT_RECORD;
  import org.fusesource.jansi.internal.Kernel32.KEY_EVENT_RECORD;
  
  import edu.internet2.middleware.grouper.app.gsh.GrouperShell;
  
  import jline.AnsiWindowsTerminal;
  
  public class WindowsTerminal extends AnsiWindowsTerminal {
    
    /**
     * @throws Exception
     */
    public WindowsTerminal() throws Exception {
      super();
    }
    
    @Override
    public InputStream wrapInIfNeeded(InputStream in) throws IOException {
  
      String groovyPreloadString = GrouperShell.getGroovyPreloadString() + "\n";
      final ByteArrayInputStream groovyPreload = new ByteArrayInputStream(groovyPreloadString.getBytes("UTF-8"));
      
      return new InputStream() {
        private byte[] buf = null;
        int bufIdx = 0;
  
        @Override
        public int read() throws IOException {
          if (groovyPreload.available() > 0) {
            return groovyPreload.read();
          }
          
          while (buf == null || bufIdx == buf.length) {
            buf = readConsoleInput();
            bufIdx = 0;
          }
          int c = buf[bufIdx] & 0xFF;
          bufIdx++;
          return c;
        }
      };
    }
  
    // completely copied from jline
    private byte[] readConsoleInput() {
      // XXX does how many events to read in one call matter?
      INPUT_RECORD[] events = null;
      try {
        events = WindowsSupport.readConsoleInput(1);
      } catch (IOException e) {
  
      }
      if (events == null) {
        return new byte[0];
      }
      StringBuilder sb = new StringBuilder();
      for (int i = 0; i < events.length; i++ ) {
        KEY_EVENT_RECORD keyEvent = events[i].keyEvent;
        //Log.trace(keyEvent.keyDown? "KEY_DOWN" : "KEY_UP", "key code:", keyEvent.keyCode, "char:", (long)keyEvent.uchar); 
        if (keyEvent.keyDown) {
          if (keyEvent.uchar > 0) {
            // support some C1 control sequences: ALT + [@-_] (and [a-z]?) => ESC <ascii>
            // http://en.wikipedia.org/wiki/C0_and_C1_control_codes#C1_set
            final int altState = KEY_EVENT_RECORD.LEFT_ALT_PRESSED | KEY_EVENT_RECORD.RIGHT_ALT_PRESSED;
            // Pressing "Alt Gr" is translated to Alt-Ctrl, hence it has to be checked that Ctrl is _not_ pressed,
            // otherwise inserting of "Alt Gr" codes on non-US keyboards would yield errors
            final int ctrlState = KEY_EVENT_RECORD.LEFT_CTRL_PRESSED | KEY_EVENT_RECORD.RIGHT_CTRL_PRESSED;
            if (((keyEvent.uchar >= '@' && keyEvent.uchar <= '_') || (keyEvent.uchar >= 'a' && keyEvent.uchar <= 'z'))
                && ((keyEvent.controlKeyState & altState) != 0) && ((keyEvent.controlKeyState & ctrlState) == 0)) {
              sb.append('\u001B'); // ESC
            }
  
            sb.append(keyEvent.uchar);
            continue;
          }
          // virtual keycodes: http://msdn.microsoft.com/en-us/library/windows/desktop/dd375731(v=vs.85).aspx
         // just add support for basic editing keys (no control state, no numpad keys)
         String escapeSequence = null;
         switch (keyEvent.keyCode) {
           case 0x21: // VK_PRIOR PageUp
             escapeSequence = "\u001B[5~";
             break;
           case 0x22: // VK_NEXT PageDown
             escapeSequence = "\u001B[6~";
             break;
           case 0x23: // VK_END
             escapeSequence = "\u001B[4~";
             break;
           case 0x24: // VK_HOME
             escapeSequence = "\u001B[1~";
             break;
           case 0x25: // VK_LEFT
             escapeSequence = "\u001B[D";
             break;
           case 0x26: // VK_UP
             escapeSequence = "\u001B[A";
             break;
           case 0x27: // VK_RIGHT
             escapeSequence = "\u001B[C";
             break;
           case 0x28: // VK_DOWN
             escapeSequence = "\u001B[B";
             break;
           case 0x2D: // VK_INSERT
             escapeSequence = "\u001B[2~";
             break;
           case 0x2E: // VK_DELETE
             escapeSequence = "\u001B[3~";
             break;
           default:
             break;
         }
         if (escapeSequence != null) {
           for (int k = 0; k < keyEvent.repeatCount; k++) {
             sb.append(escapeSequence);
           }
         }
       } else {
         // key up event
         // support ALT+NumPad input method
         if (keyEvent.keyCode == 0x12/*VK_MENU ALT key*/ && keyEvent.uchar > 0) {
           sb.append(keyEvent.uchar);
         }
       }
     }
     return sb.toString().getBytes();
   }
 }