#include <FastLED.h>
#include <Keypad.h>

//fixed global variables
#define DATA_PIN 7  //Define led data pin in
#define LED_TYPE NEOPIXEL  //define type of led
#define NUM_LEDS 16  //num of leds in strip

CRGBArray<NUM_LEDS> leds;  //Define CRGBSET to be entire string, and call it leds

const byte ROWS = 4; //four rows
const byte COLS = 4; //four columns

// will change the char later
char hexaKeys[ROWS][COLS] = {
  {'A', 'B', 'C', 'D'},
  {'E', 'F', 'G', 'H'},
  {'I', 'J', 'K', 'L'},
  {'M', 'N', 'O', 'P'}
};

byte rowPins[ROWS] = {A0,A1,A2,A3}; //connect to the row pinouts of the keypad
byte colPins[COLS] = {A4,A5,2,3}; //connect to the column pinouts of the keypad
Keypad customKeypad = Keypad(makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLS);

void setup() {
  Serial.begin(9600);
  delay(2000); //for safe startup
  FastLED.addLeds<LED_TYPE, DATA_PIN>(leds, NUM_LEDS);
}

void loop() {
  int key = customKeypad.getKey() - 65;

  leds[key].setRGB(0, 0, 255);
  FastLED.show();
}