#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/gpio.h"
#include "driver/adc.h"
#include <stdbool.h>
#include <string.h>
#include <math.h>
// setting the password to be four characters long
#define SEQUENCE_LENGTH 4
void setup_gpio();
char scan_keypad();
float readTemperature(adc1_channel_t channel, float nominalRes, float B);
// defining the two main variables
#define ROWS 4
#define COLS 4
// defining two arrays, one horizontal and oone vertiacal
int scanRowPins[ROWS] = {38, 37, 36, 35};
int colPins[COLS] = {0, 45, 48, 47};
// combing rows and colums to make a two dimensional array
char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
// array to define the leds
int leds[3] = {2, 19, 18};

void app_main()
{
  setup_gpio();
  // sets the width of adcto 12 bit
  adc1_config_width(ADC_WIDTH_BIT_12);
  // sets attenuation to GPIO 4
  adc1_config_channel_atten(ADC1_CHANNEL_3, ADC_ATTEN_DB_11);


  printf("Enter your code:\n");
  gpio_set_level(leds[1], 0);
  gpio_set_level(leds[2], 0);
  while (1)
  {
    //creating the hardcoded password
    const char correctCode[] = "1234";
    static char input[5];
    input[0] = '1';
    input[1] = '2';
    input[2] = '3';
    input[3] = '4';
    input[4] = '\0';
    static int index = 0;


    // Blink blue LED
    gpio_set_level(leds[0], 1);
    vTaskDelay(pdMS_TO_TICKS(500));
    gpio_set_level(leds[0], 0);
    vTaskDelay(pdMS_TO_TICKS(500));

    // Check keypad using non-blocking
    char key = scan_keypad();
    if (key != '\0')
    {
      input[index++] = key;

      printf("*");
      fflush(stdout);
      if (index == SEQUENCE_LENGTH)
      {
        input[index] = '\0'; // null-terminate string before comparing
        if (strcmp(input, correctCode) == 0)
        {



          printf("\nAccess granted! Correct sequence entered.\n");
          gpio_set_level(leds[0], 0);
          //calling the function with specific values for it to calculate
          float tempC = readTemperature(ADC1_CHANNEL_3, 10000, 3950); 
          printf("\nCurrent temperature: %.2f°C\n", tempC);
          gpio_set_level(leds[2], 1);
          vTaskDelay(pdMS_TO_TICKS(5000));
          gpio_set_level(leds[2], 0);


        }
        else
        {
          printf("\nAccess denied! Incorrect sequence.\n");
          gpio_set_level(leds[0], 0);
          for (int i = 0; i <= 1; i++)
          {
            gpio_set_level(leds[1], 1);
            vTaskDelay(pdMS_TO_TICKS(1000));
            gpio_set_level(leds[1], 0);
            vTaskDelay(pdMS_TO_TICKS(1000));
            index = 0;
          }
        }
        //set to remove possible overflow
        key = 0;
      }
    }
    vTaskDelay(pdMS_TO_TICKS(10));
  }
}

/**
  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
  }
  gpio_set_direction(leds[0], GPIO_MODE_OUTPUT);
  gpio_set_direction(leds[1], GPIO_MODE_OUTPUT);
  gpio_set_direction(leds[2], GPIO_MODE_OUTPUT);
}

/**
  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
    }

    for (int k = 0; k < COLS; k++)
    {
      if (gpio_get_level(colPins[k]) == 0)
      { // pullup configuration
        if (gpio_get_level(colPins[k]) == 0)
        {
          return keys[i][k]; //
        }
        return keys[i][k];
      }
    }
  }
  return '\0';
}
/*
  readTemperature
  It reads analog value from the thermistor and converts to °C.
  adc1_channel_t channel, float nominalRes,float B
  Returns: float, the temp in Celsius
*/
float readTemperature(adc1_channel_t channel, float nominalRes, float B)
{
  // setting it into celcius format
  float T1 = 25 + 273.15;

  // total resistance
  float RT;
  // Voltage
  float VRT;
  // current temerature
  float T2;
  float R2 = 10000;
  // getting the raw data and setting it to adc_value
  int adc_value = adc1_get_raw(channel);
  int adc_10bit = adc_value >> 2;
  // setting the voltage to be equal to the raw times 3.3 divided by max adc value for 10bit resolution
  VRT = (adc_10bit * 3.3f) / 4095;
  // total resistance
  RT = (R2 * VRT) / (3.3 - VRT);
  // temperature
  T2 = 1 / ((1 / T1) + (logf(RT / nominalRes) / B));
  // setting it to celcius
  float celcius = T2 - 273.15;
  return celcius;
}