// ***************************************************************
// *        Behringer XR18 Arduino MIDI Remote Control           *
// *                   By Vern Graner                            *
// ***************************************************************
// * This code reads buttons and sends MIDI commands to the      *
// * Behringer XR18. LEDs are used to indicate button status     *
// * (down/up). Each button state can send a MIDI command        *
// ***************************************************************
// * Rev Info: V1.0a (VLG) 01-22-2018 Sysex CC changes
// * Rev Info: V2.0a (VLG) 01-22-2018 Hard coded OSC commands
// * Rev Info: V3.0a (VLG) 01-22-2018 ASCII to HEX OSC commands
// * Rev Info: V4.0a (VLG) 01-22-2018 ported to ESP32
// ***************************************************************

// Include the MIDI stuff
#include <MIDI.h>
#include <midi_Defs.h>
#include <midi_Message.h>
#include <midi_Namespace.h>
#include <midi_Settings.h>


// Assign Arduino pins to tasks
const int  button1 = 26;    // N.O. Pushbutton held HIGH with 100k
const int  button2 = 25;    // 
const int  button3 = 34;    // 
const int  button4 = 39;    // 
const int led1 = 27;       // LED with 330ohm to GND
const int led2 = 33;       // 
const int led3 = 32;       // 
const int led4 = 15;       //

// Define program Variables
int button1State = 0;      // current state of the button
int button2State = 0;      // 
int button3State = 0;      // 
int button4State = 0;      // 
int lastButton1State = 0;  // previous state of the button
int lastButton2State = 0;  // 
int lastButton3State = 0;  // 
int lastButton4State = 0;  // 
int commandLength=0;       //
byte bigMidiCommand[64];   // maximum command length in bytes
byte midiHeader[]= { 0xF0,0x00,0x20,0x32,0x32 }; // XR18 OSC preamble
byte midiFooter[]= { 0xF7 }; // XR18 OSC post-amble


// Blink LED code
// ****************************************************************
const int ledPin =  13;           // the number of the LED pin
int ledState = HIGH;              // ledState used to set the LED
unsigned long previousMillis = 0; // will store last time LED was updated
const long interval = 250;        // interval at which to blink (milliseconds)
// ****************************************************************

HardwareSerial Serial1(2);
MIDI_CREATE_INSTANCE(HardwareSerial,Serial1, midiOut); // create a MIDI object called midiOut

void setup() {
  Serial1.begin(31250); // setup MIDI output
  midiOut.begin();
  pinMode(button1, INPUT); // initialize the button pin as a input
  pinMode(button2, INPUT); // initialize the button pin as a input
  pinMode(button3, INPUT); // initialize the button pin as a input
  pinMode(button4, INPUT); // initialize the button pin as a input
  pinMode(led1, OUTPUT);   // initialize the LED as an output
  pinMode(led2, OUTPUT);   // initialize the LED as an output
  pinMode(led3, OUTPUT);   // initialize the LED as an output
  pinMode(led4, OUTPUT);   // initialize the LED as an output
  pinMode(ledPin, OUTPUT); // Blink LED setup
}

void loop() {
  // ****************************************
  // Button 1 Loop
  // ****************************************
  button1State = digitalRead(button1);          // read the pushbutton input pin
    if (button1State != lastButton1State) {     // compare the buttonState to its previous state (if not equal)
      if (button1State == HIGH) {               // if the current state is HIGH then the button went from OFF to ON
        midiBuildCommand("/ch/16/mix/01/level -127");
        midiOut.sendSysEx(commandLength, bigMidiCommand, true); // send SysEx
        digitalWrite(led1, LOW);                  
      } else {                                  // if the current state is LOW then the button went from ON to OFF
        midiBuildCommand("/ch/16/mix/01/level 0");
        midiOut.sendSysEx(commandLength, bigMidiCommand, true); // send SysEx
        digitalWrite(led1, HIGH);                 
      }                                            
    delay(50);                                  // Delay a little bit to avoid bouncing
  }                                              
  lastButton1State = button1State;              // save the current state as the last state, for next time through the loop
                                                 
                                                
  // ****************************************
  // Button 2 Loop                                
  // ****************************************
  button2State = digitalRead(button2);          // read the pushbutton input pin
    if (button2State != lastButton2State) {     // compare the buttonState to its previous state
      if (button2State == HIGH) {               // if the current state is HIGH then the button went from off to on:
        midiBuildCommand("/ch/16/mix/02/level -127");
        midiOut.sendSysEx(commandLength, bigMidiCommand, true); // send SysEx
        digitalWrite(led2, LOW);                  
      } else {                                  // if the current state is LOW then the button went from on to off:
        midiBuildCommand("/ch/16/mix/02/level 0");
        midiOut.sendSysEx(commandLength, bigMidiCommand, true); // send SysEx
        digitalWrite(led2, HIGH);                
      }                                           
    delay(50);                                  // Delay a little bit to avoid bouncing
  }                                               
  lastButton2State = button2State;              // save the current state as the last state, for next time through the loop

    // ****************************************
    // Button 3 Loop                                
    // ****************************************
  button3State = digitalRead(button3);          // read the pushbutton input pin
    if (button3State != lastButton3State) {     // compare the buttonState to its previous state
      if (button3State == HIGH) {               // if the current state is HIGH then the button went from off to on:
        midiBuildCommand("/ch/16/mix/03/level -127");
        midiOut.sendSysEx(commandLength, bigMidiCommand, true); // send SysEx
        digitalWrite(led3, LOW);                  
      } else {                                  // if the current state is LOW then the button went from on to off:
        midiBuildCommand("/ch/16/mix/03/level 0");
        midiOut.sendSysEx(commandLength, bigMidiCommand, true); // send SysEx
        digitalWrite(led3, HIGH);                
      }                                           
    delay(50);                                  // Delay a little bit to avoid bouncing
  }                                               
  lastButton3State = button3State;              // save the current state as the last state, for next time through the loop

  // ****************************************
  // Button4 Loop
  // ****************************************
  button4State = digitalRead(button4);         // read the pushbutton input pin
    if (button4State != lastButton4State) {    // compare the buttonState to its previous state
      if (button4State == HIGH) {              // if the current state is HIGH then the button went from off to on:
      midiOut.sendControlChange(15,127,2);     // send a MIDI CC -- note,velocity,channel
      digitalWrite(led4, LOW);              
    } else {                                   // if the current state is LOW then the button went from on to off:
      midiOut.sendControlChange(15,0,2);       // send a MIDI CC -- note,velocity,channel
      digitalWrite(led4, HIGH);             
    }                                        
    delay(50);                                 // Delay a little bit to avoid bouncing
  }                                            
  lastButton4State = button4State;             // save the current state as the last state, for next time through the loop

  // ****************************************
  // non-blocking LED Blink routine
  // ****************************************
  if (button1State == LOW || button2State == LOW || button3State == LOW || button4State == LOW) {
    unsigned long currentMillis = millis();
    if (currentMillis - previousMillis >= interval) {
      // save the last time you blinked the LED
      previousMillis = currentMillis;

      // if the LED is off turn it on and vice-versa:
      if (ledState == HIGH) {
        ledState = LOW;
      } else {
        ledState = HIGH;
      }

      // set the LED with the ledState of the variable:
      digitalWrite(ledPin, ledState);
      }
  } else {
      digitalWrite(ledPin, LOW);
      previousMillis = 0;
      ledState = LOW;
  }


// **********************************************************/
} //End of main loop


// Subroutines aka functions
// **********************************************************\

void midiBuildCommand(String body)
{
  commandLength=0;
  for (int i=0 ; i <sizeof(midiHeader); i++)
  {
    bigMidiCommand[commandLength]=midiHeader[i];
    commandLength++;
  }
  Serial.print(body.length(),DEC); Serial.println(" bodylen");
  for (int i=0 ; i <body.length(); i++)
  {
    bigMidiCommand[commandLength]=body[i];
    commandLength++;
  }

  for (int i=0 ; i <sizeof(midiFooter); i++)
  {
    bigMidiCommand[commandLength]=midiFooter[i];
    commandLength++;
  }
 
}