/*
  Blink

  Turns an LED on for one second, then off for one second, repeatedly.

  Most Arduinos have an on-board LED you can control. On the UNO, MEGA and ZERO
  it is attached to digital pin 13, on MKR1000 on pin 6. LED_BUILTIN is set to
  the correct LED pin independent of which board is used.
  If you want to know what pin the on-board LED is connected to on your Arduino
  model, check the Technical Specs of your board at:
  https://www.arduino.cc/en/Main/Products

  modified 8 May 2014
  by Scott Fitzgerald
  modified 2 Sep 2016
  by Arturo Guadalupi
  modified 8 Sep 2016
  by Colby Newman

  This example code is in the public domain.

  http://www.arduino.cc/en/Tutorial/Blink
*/

#define RELAY1 2
#define RELAY2 3
#define RELAY3 4
#define RELAY4 5
unsigned int relay[4] = { RELAY1, RELAY2, RELAY3, RELAY4 };

#define BUTTON1 6
#define BUTTON2 7
#define BUTTON3 8
#define BUTTON4 9
unsigned int button[4] = { BUTTON1, BUTTON2, BUTTON3, BUTTON4 };

#define OPTO1 10


boolean relayState[4];
boolean buttonState[4];
boolean buttonLastState[4];
boolean buttonPressed[4];
boolean optoState;


  
String inString;

// the setup function runs once when you press reset or power the board
void setup() {
  // initialize digital pin LED_BUILTIN as an output.
  pinMode(LED_BUILTIN, OUTPUT);
  
  pinMode(RELAY1, OUTPUT);
  pinMode(RELAY2, OUTPUT);
  pinMode(RELAY3, OUTPUT);
  pinMode(RELAY4, OUTPUT);
  
  pinMode(OPTO1, OUTPUT);
  
  pinMode(BUTTON1, INPUT_PULLUP);
  pinMode(BUTTON2, INPUT_PULLUP);
  pinMode(BUTTON3, INPUT_PULLUP);
  pinMode(BUTTON4, INPUT_PULLUP);

  digitalWrite(RELAY1, HIGH);
  digitalWrite(RELAY2, HIGH);
  digitalWrite(RELAY3, HIGH);
  digitalWrite(RELAY4, HIGH);

  digitalWrite(OPTO1, LOW);
  
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }

  
  optoState = false;
  for (int i=0;i<4;i++){
    buttonState[i] = digitalRead(button[i]);
    buttonLastState[i] = buttonState[i];
    
    relayState[i] = false;
  }  
}

// the loop function runs over and over again forever
void loop() {

  
  for (int i=0;i<4;i++){

    //generate the button states...    
    //Button i press
    buttonState[i] = digitalRead(button[i]);   
    if ((buttonState[i] != buttonLastState[i]) && (buttonState[i] == LOW)){
      buttonPressed[i] = true;    
    } else {
      buttonPressed[i] = false;
    }
    buttonLastState[i] = buttonState[i];  

    //invert relay if button i is pressed:
    
    if (buttonPressed[i]){            
      if (relayState[i] == false){
        Serial.print("Command executed: RELAY");Serial.print(i+1);Serial.println("=ON");
        digitalWrite(relay[i], LOW);
        relayState[i] = true;  
      } else {
        Serial.print("Command executed: RELAY");Serial.print(i+1);Serial.println("=OFF");
        digitalWrite(relay[i], HIGH);
        relayState[i] = false;  
      }        
      delay(250);
    }
  }
  

  
  
  //check for new command...
  if (Serial.available() > 0) {
    // get incoming byte:
    inString = Serial.readString();
    Serial.print("Command executed: ");
    Serial.print(inString);

    if (inString.indexOf("LED=ON") >= 0){
      digitalWrite(LED_BUILTIN, HIGH);
    } else
    if (inString.indexOf("LED=OFF") >= 0){
      digitalWrite(LED_BUILTIN, LOW);
    } else
    if (inString.indexOf("RELAY1=ON") >= 0){
      digitalWrite(RELAY1, LOW);
      relayState[0] = true;
    } else
    if (inString.indexOf("RELAY1=OFF") >= 0){
      digitalWrite(RELAY1, HIGH);
      relayState[0] = false;
    } else
    if (inString.indexOf("RELAY2=ON") >= 0){
      digitalWrite(RELAY2, LOW);
      relayState[1] = true;
    } else
    if (inString.indexOf("RELAY2=OFF") >= 0){
      digitalWrite(RELAY2, HIGH);
      relayState[1] = false;
    } else
    if (inString.indexOf("RELAY3=ON") >= 0){
      digitalWrite(RELAY3, LOW);
      relayState[2] = true;
    } else
    if (inString.indexOf("RELAY3=OFF") >= 0){
      digitalWrite(RELAY3, HIGH);
      relayState[2] = false;
    } else
    if (inString.indexOf("RELAY4=ON") >= 0){
      digitalWrite(RELAY4, LOW);
      relayState[3] = true;
    } else
    if (inString.indexOf("RELAY4=OFF") >= 0){
      digitalWrite(RELAY4, HIGH);
      relayState[3] = false;
    } else
    if (inString.indexOf("OPTO1=ON") >= 0){
      digitalWrite(OPTO1, HIGH);
      optoState = true;
    } else
    if (inString.indexOf("OPTO1=OFF") >= 0){
      digitalWrite(OPTO1, LOW);
      optoState = false;
    }
  }  
}