// MARSHALL 8 BUTTON MIDI FOOTSWITCH

#include <MIDI.h>
MIDI_CREATE_DEFAULT_INSTANCE();

const uint8_t ToggleInPins[4] = {A0, A1, A2, A3};
const uint8_t ToggleOutPins[4] = {6, 7, 8, 9};
const uint8_t Togglepatches[4] = {0, 1, 2, 3};
const uint8_t channelInPins[4] = {2, 3, 4, 5};
const uint8_t channelOutPins[4] = {10, 11, 12, 13};
const uint8_t channelpatches[4] = {0, 1, 2, 3};

const size_t numberofChannelsIn = sizeof(channelInPins) / sizeof(channelInPins[0]);
const size_t numberofChannelsOut = sizeof(channelOutPins) / sizeof(channelOutPins[0]);
const size_t numberOfChannelPatches = sizeof(channelpatches) / sizeof(channelpatches[0]);
static_assert(numberofChannelsIn == numberofChannelsOut, "The number of buttons doesn't match the number of LEDs");
static_assert(numberofChannelsIn == numberOfChannelPatches, "The number of buttons doesn't match the number of patches");

const size_t numberofTogglesIn = sizeof(ToggleInPins) / sizeof(ToggleInPins[0]);
const size_t numberofTogglesOut = sizeof(ToggleOutPins) / sizeof(ToggleOutPins[0]);
const size_t numberOfTogglePatches = sizeof(Togglepatches) / sizeof(Togglepatches[0]);
static_assert(numberofTogglesIn == numberofTogglesOut, "The number of buttons doesn't match the number of LEDs");
static_assert(numberofTogglesIn == numberOfTogglePatches, "The number of buttons doesn't match the number of patches");

const uint8_t CCButtonPin = 6;
const uint8_t CCLEDPin = 12;
const uint8_t controller = 14;
const uint8_t ccValueOff = 0;
const uint8_t ccValueOn = 1;
const uint8_t channel = 1;

 
void setup() {
  for (const uint8_t &pin : ToggleInPins)
    pinMode(pin, INPUT_PULLUP);
    pinMode(CCButtonPin, INPUT_PULLUP);
  for (const uint8_t &pin : ToggleOutPins)
    pinMode(pin, OUTPUT);
    pinMode(CCLEDPin, OUTPUT);
  for (const uint8_t &pin : channelInPins)
    pinMode(pin, INPUT_PULLUP);
    pinMode(CCButtonPin, INPUT_PULLUP);
  for (const uint8_t &pin : channelOutPins)
    pinMode(pin, OUTPUT);
    pinMode(CCLEDPin, OUTPUT);

  MIDI.begin(MIDI_CHANNEL_OMNI) ;
}

int8_t getPressedChannelButton() {
  for (int8_t i = 0; i < numberofChannelsIn; i++)
    if (digitalRead(channelInPins[i]) == LOW)
      return i;
      return -1;
}

int8_t getPressedToggleButton() {
  for (int8_t i = 0; i < numberofTogglesIn; i++)
    if (digitalRead(ToggleInPins[i]) == LOW)
      return i;
      return -1;
}

void setToggleOut(int8_t led, bool state) {
  if (led >= 0) 
    digitalWrite(ToggleOutPins[led], state);
}

void setChannelOut(int8_t led, bool state) {
  if (led >= 0) 
    digitalWrite(channelOutPins[led], state);
}

void updateChannelSelect() {
  static int8_t activeSelection = -1;
  int8_t pressedButton = getPressedChannelButton();
  if (pressedButton >= 0 && pressedButton != activeSelection) {
    setChannelOut(activeSelection, LOW);
    activeSelection = pressedButton;
    setChannelOut(activeSelection, HIGH);
    MIDI.sendProgramChange(channelpatches[activeSelection], channel);
  }
}

void updateToggleSelect() {
  static int8_t activeSelection = -1;
  int8_t pressedButton = getPressedToggleButton();
  if (pressedButton >= 0 && pressedButton != activeSelection) {
    setToggleOut(activeSelection, LOW);
    activeSelection = pressedButton;
    setToggleOut(activeSelection, HIGH);
    MIDI.sendProgramChange(Togglepatches[activeSelection], channel);
  }
}

bool controllerButtonIsPressed() {
  const static unsigned long debounceTime = 25;
  const static int8_t rising = LOW - HIGH;
  const static int8_t falling = HIGH - LOW;
  static bool previousState = LOW;
  static unsigned long previousBounceTime = 0;
  bool pressed = false;
  bool state = digitalRead(CCButtonPin);
  int8_t stateChange = state - previousState;
  
  if (stateChange == falling) {
    if (millis() - previousBounceTime > debounceTime) {
      pressed = true;
    }
  } else if (stateChange == rising) {
    previousBounceTime = millis();
  }
  previousState = state;
  return pressed;
}

void updateController() {
  static bool controllerState = false;
    if (controllerButtonIsPressed()) {
      controllerState = !controllerState;
      digitalWrite(CCLEDPin, controllerState);
      MIDI.sendControlChange(controller, controllerState ? ccValueOn : ccValueOff, channel);
    }
}

void loop() {
  updateChannelSelect();
  updateToggleSelect();
  updateController();
}