var _blue     = mywindow.findChild("_blue");     // QSlider
var _close    = mywindow.findChild("_close");    // QPushButton
var _color    = mywindow.findChild("_color");    // QLabel
var _green    = mywindow.findChild("_green");    // QSlider
var _input    = mywindow.findChild("_input");    // XLineEdit
var _output   = mywindow.findChild("_output");   // XTextEdit
var _red      = mywindow.findChild("_red");      // QSlider
var _send     = mywindow.findChild("_send");     // QPushButton

// set our command constants
var ON                     = 0x42;
var OFF                    = 0x46;
var SETCURSOR              = 0x47;
var HOME                   = 0x48;
var CURSOR_ON              = 0x53;
var CURSOR_OFF             = 0x54;
var LEFT                   = 0x4C;
var RIGHT                  = 0x4D;
var BACKSPACE              = 0x08;
var NEWLINE                = 0x0A;
var CLEAR                  = 0x58;
var SETCONTRAST            = 0x50;
var SETBACKLIGHTBRIGHTNESS = 0x99;
var SETRGBCOLOR            = 0xD0;
var LOADCUSTOMCHARACTER    = 0xC0;
var COMMAND                = 0xFE;

var seriallcd = {};
var sp;

//define the initialization function
seriallcd.init = function(parent, serialport, baudrate) {
  sp = new QSerialPort(parent);
  sp.setPortName(serialport);
  sp.setBaudRate(baudrate);
  
  if (!sp.open(QIODevice.ReadWrite)) {
    QMessageBox.critical(mywindow, "Error", "Could not open serial port, error code returned: "+ sp.error);
    return;
  }
  seriallcd.port = sp;
  seriallcd.clear();
}

// our two command functions
seriallcd.sendCommand = function(input) {
  var t = QByteArray();
  t.append(COMMAND);
  sp.write(t);
  t.clear();
  t.append(input);
  sp.write(t);
  sp.flush();
}

seriallcd.sendCommandWithParam = function(input, param) {
  var t = QByteArray();
  t.append(COMMAND);
  sp.write(t);
  t.clear();
  t.append(input);
  sp.write(t);
  t.clear();
  t.append(param);
  sp.write(t);
  t.clear();
  sp.flush();
}

seriallcd.print = function(text) {
  sp.write(QByteArray(text));
}

seriallcd.write = function(bytes) {
  sp.write(bytes);
}

// the group of helper functions
seriallcd.setLCDContrast = function(contrast) {
  contrast = parseInt(contrast);
  if (contrast == "" || contrast < 1 || contrast > 50) {
    QMessageBox.critical(mywindow, "Invalid Data", "Contrast level can only be between 1 and 50");
  }

  seriallcd.sendCommandWithParam(SETCONTRAST, contrast);
}

seriallcd.setLCDBrightness = function(brightness) {
  brightness = parseInt(brightness);
  if (brightness == "" || brightness < 1 || brightness > 8) {
    QMessageBox.critical(mywindow, "Invalid Data", "Brightness level can only be between 1 and 8");
  }

  seriallcd.sendCommandWithParam(SETBACKLIGHTBRIGHTNESS, brightness);
}

seriallcd.clear = function(){
  seriallcd.sendCommand(CLEAR);
}

//send the Home Cursor command to the LCD
seriallcd.home = function() {
    seriallcd.sendCommand(HOME);	
}

//Turn the LCD ON
seriallcd.on = function() {
    seriallcd.sendCommand(ON);	
}

// Turn the LCD OFF
seriallcd.off = function() {
    seriallcd.sendCommand(OFF);	
}

//Turn the Underline Cursor ON
seriallcd.cursorOn = function() {
    seriallcd.sendCommand(CURSOR_ON);	
}

//Turn the Underline  Cursor OFF
seriallcd.cursorOff = function() {
    seriallcd.sendCommand(CURSOR_OFF);	
}


//Move the cursor left 1 space
seriallcd.left = function() {
    seriallcd.sendCommand(LEFT);	
}

//Move the cursor right 1 space
seriallcd.right = function() {
    seriallcd.sendCommand(RIGHT);
}

//Backspace
seriallcd.backspace = function() {
    seriallcd.sendCommand(BACKSPACE);
}

//Backspace
seriallcd.setRGBColor = function(threebytes) {
    seriallcd.sendCommandWithParam(SETRGBCOLOR, threebytes);
}

// bytes representing the boundaries of our screen
var g_index = [0x00, 0x40, 0x14, 0x54];
// move cursor position
seriallcd.setCursor = function(line, pos){
    seriallcd.sendCommandWithParam(SETCURSOR, g_index[line-1] + pos - 1);
}

function sSend() {
  seriallcd.print(_input.text);
  _output.plainText += _input.text + "\n";
}

function setColor(newcolor) {
  // newcolor ignored
  seriallcd.setRGBColor(QByteArray([_red.value, _green.value, _blue.value]));
  _color.setStyleSheet("background-color: rgb(" + _red.value + ", " + _green.value + ", " + _blue.value + ");");
}
// update for your serial port
seriallcd.init(mywindow, "/dev/ttyACM0", 115200);
_send.clicked.connect(sSend);
_close.clicked.connect(mywindow, "close()");
_red["valueChanged(int)"].connect(setColor);
_green["valueChanged(int)"].connect(setColor);
_blue["valueChanged(int)"].connect(setColor);