#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/gpio.h"
#include "esp_log.h"
//deining the functions the program uses
char readKeyPadSingleScan(char _keys[4][4], int _scanColPins[4], int _rowPins[4]);
void setup_gpio();
char scan_keypad();
//defining the two main variables
#define ROWS 4
#define COLS 4
//defining two arrays, one horizontal and oone vertiacal
int scanRowPins[ROWS] = {10, 9 , 46, 3};
int colPins[COLS] = {8, 18, 17, 16};
//combing rows and colums o make a two dimensional array
char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

void app_main() {
  setup_gpio();
  //main loop

  while (1) {
    //setting key to the scan_keypad function
    // char key = scan_keypad();
    //works unless key doesn't equal the null character
    char k = readKeyPadSingleScan(keys, colPins, scanRowPins);
    if (k != '\0') {
      printf("You pressed: %c\n", k);
    }

    vTaskDelay(pdMS_TO_TICKS(50)); //slight delay
  }
}
/**
  setup_gpio
  sets all the pins to input and makes them use pullup resistor logic
  void
*/
void setup_gpio() {
  for (int i = 0; i < ROWS; i++) {
    gpio_set_direction(scanRowPins[i], GPIO_MODE_OUTPUT);
    gpio_set_level(scanRowPins[i], 1);
  }
  for (int i = 0; i < COLS; i++) {
    gpio_set_direction(colPins[i], GPIO_MODE_INPUT);
    gpio_set_pull_mode(colPins[i], GPIO_PULLUP_ONLY); // all buttons are set as pullup configuration using the internal pullup resistor in the microcontroller
  }
}
/**
  scan_keypad
  scans all of the rows and colums contineously checking for an input
  char
*/
char scan_keypad() {
  uint8_t scanVal;
  for (int i = 0; i < ROWS; i++) {
    scanVal = ~(1 << i);

    for (int j = 0; j < ROWS; j++) {
      gpio_set_level(scanRowPins[j], (scanVal >> j) & 1); // here, 'pins' can be either row pins or column pins. Select the correct one
    }
    vTaskDelay(pdMS_TO_TICKS(5)); //slight delay

    for (int k = 0; k < COLS; k++) {
      if (gpio_get_level(colPins[k]) == 0) { // pullup configuration
        while (gpio_get_level(colPins[k]) == 0) {
          vTaskDelay(pdMS_TO_TICKS(50));
        }
        return keys[k][i];
      }
    }
  }
  return '\0';
}
/**
  readKeyPadSingleScan
  continiously checks the value of the keypad
  char
  char _keys[4][4], int _scanColPins[4], int _rowPins[4]
*/
char readKeyPadSingleScan(char _keys[4][4], int _scanColPins[4], int _rowPins[4]) {
  uint8_t scanVal;
  char retVal = '\0';
  //loops permanently until any is pressed, then it stops and starts anew after
do {
    for (int i = 0; i < ROWS; i++) {
        scanVal = ~(1 << i); 
        printf("scanning in process\n");
        for (int j = 0; j < ROWS; j++) {
            gpio_set_level(scanRowPins[j], (scanVal >> j) & 1); // here, 'pins' can be either row pins or column pins. Select the correct one
        }
        vTaskDelay(pdMS_TO_TICKS(5)); //slight delay

        for (int k = 0; k < COLS; k++) {
            if (gpio_get_level(colPins[k]) == 0) { // pullup configuration
                while (gpio_get_level(colPins[k]) == 0) {
                    vTaskDelay(pdMS_TO_TICKS(50));
                }
                return keys[k][i];
            }
        }
    }
}while(retVal == '/0');
    return '\0';
}