#include <stdio.h>
#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/gpio.h"

#define RELAY_PIN 23

// Keypad pins
int rowPins[4] = {19, 18, 5, 17};
int colPins[4] = {16, 4, 2, 15};

char keys[4][4] = {
    {'1','2','3','A'},
    {'4','5','6','B'},
    {'7','8','9','C'},
    {'*','0','#','D'}
};

char password[] = "1234";
char input[5];
int pos = 0;

// Initialize GPIO
void gpio_init_all() {

    // Set rows as OUTPUT
    for(int i = 0; i < 4; i++) {
        gpio_reset_pin(rowPins[i]);
        gpio_set_direction(rowPins[i], GPIO_MODE_OUTPUT);
        gpio_set_level(rowPins[i], 1);
    }

    // Set columns as INPUT with pull-up
    for(int i = 0; i < 4; i++) {
        gpio_reset_pin(colPins[i]);
        gpio_set_direction(colPins[i], GPIO_MODE_INPUT);
        gpio_set_pull_mode(colPins[i], GPIO_PULLUP_ONLY);
    }

    // Relay pin
    gpio_reset_pin(RELAY_PIN);
    gpio_set_direction(RELAY_PIN, GPIO_MODE_OUTPUT);
    gpio_set_level(RELAY_PIN, 0);
}

// Scan keypad
char scan_keypad() {

    for(int row = 0; row < 4; row++) {

        gpio_set_level(rowPins[row], 0);  // activate row

        for(int col = 0; col < 4; col++) {

            if(gpio_get_level(colPins[col]) == 0) {
                vTaskDelay(pdMS_TO_TICKS(200)); // debounce
                gpio_set_level(rowPins[row], 1);
                return keys[row][col];
            }
        }

        gpio_set_level(rowPins[row], 1); // deactivate row
    }

    return '\0';
}

void app_main() {

    gpio_init_all();
    memset(input, 0, sizeof(input));

    while(1) {

        char key = scan_keypad();

        if(key != '\0') {

            printf("Pressed: %c\n", key);

            if(key == '#') {

                input[pos] = '\0';

                if(strcmp(input, password) == 0) {
                    printf("Access Granted\n");
                    gpio_set_level(RELAY_PIN, 1);
                    vTaskDelay(pdMS_TO_TICKS(5000));
                    gpio_set_level(RELAY_PIN, 0);
                } else {
                    printf("Access Denied\n");
                }

                pos = 0;
                memset(input, 0, sizeof(input));
            }

            else if(key == '*') {
                pos = 0;
                memset(input, 0, sizeof(input));
                printf("Cleared\n");
            }

            else {
                if(pos < 4) {
                    input[pos++] = key;
                }
            }
        }

        vTaskDelay(pdMS_TO_TICKS(100));
    }
}