#include <stdio.h>
#include "pico/stdlib.h"
#include "hardware/i2c.h"
#include "hardware/pwm.h"

/* -------------PINS------------ */
#define I2C_PORT i2c0
#define SDA_PIN 4 /*Pins to connect the DS3231 we must make sure that if they are SDA and SCL */
#define SCL_PIN 5
#define DS3231_ADDR 0x68

#define SERVO_PIN 13  /*Pin to connect the servo */
#define BUZZER_PIN 7  /*Pin to connect the buzzer */
#define BOTON_PIN 19 /*Pin to connect the button*/

// With this part of the code we convert from binary to decimal.

/* The watch stores the data in two parts that are a binary number and a binary number. 
For example, 25 looks like this: 0010 (2) 0101 (5) Then it becomes val >> 4: Move everything to the right to keep only the 2.
Then multiply it by 10 (20). 
And val & 0x0F: Delete the left side to keep only the 5. then add it and there are 25. */
uint8_t bcd_to_dec(uint8_t val) {
    return ((val >> 4) * 10) + (val & 0x0F);
}

/* ------------SERVO----------------*/
void setup_servo(uint pin) {
    gpio_set_function(pin, GPIO_FUNC_PWM);   //configure the pin for the servo with PWM
    uint slice = pwm_gpio_to_slice_num(pin);

    pwm_set_clkdiv(slice, 64.0f);
    pwm_set_wrap(slice, 39062);     
    pwm_set_enabled(slice, true);
}

void set_servo_position(uint pin, int degrees) {
    uint32_t duty = (degrees * 2000 / 180) + 1000; // Function that helps us map the servo position from degrees to PWM units
    pwm_set_gpio_level(pin, duty);
}

/* ------------BUZZER------------- */
void setup_buzzer(uint pin) {
    gpio_set_function(pin, GPIO_FUNC_PWM);
    uint slice = pwm_gpio_to_slice_num(pin);

    pwm_set_clkdiv(slice, 4.0f);      // Reduce base frequency
    pwm_set_wrap(slice, 31250);       // Audible base
    pwm_set_enabled(slice, true);
}

void set_buzzer_freq(uint pin, uint freq) {     //give it specific sound commands.
    uint slice = pwm_gpio_to_slice_num(pin);

    if (freq == 0) {
        pwm_set_gpio_level(pin, 0);   //Line to prevent our buzzer from sounding
        return;
    }

    uint32_t wrap = 125000000 / 4 / freq;
    pwm_set_wrap(slice, wrap);
    pwm_set_gpio_level(pin, wrap / 2); // This line calculates how long a clock cycle needs to be to fit exactly the amount of "vibrations" (freq) you want to hear in one second.
}

/* --------------- MAIN ------------------- */
int main() {
    stdio_init_all();

    i2c_init(I2C_PORT, 100000);
    gpio_set_function(SDA_PIN, GPIO_FUNC_I2C);
    gpio_set_function(SCL_PIN, GPIO_FUNC_I2C);
    gpio_pull_up(SDA_PIN);
    gpio_pull_up(SCL_PIN);

    setup_servo(SERVO_PIN);
    setup_buzzer(BUZZER_PIN);

    gpio_init(BOTON_PIN);
    gpio_set_dir(BOTON_PIN, GPIO_IN);
    gpio_pull_up(BOTON_PIN);

    //We initialize our pins as output or input

    int h_alarma, m_alarma;
    bool alarma_disparada = false;

    // For the user to enter the time
    printf("Configuración de Alarma Hamster\n");
    printf("Hora (0-23): ");
    scanf("%d", &h_alarma);
    printf("Minuto (0-59): ");
    scanf("%d", &m_alarma);
    printf("Alarma fijada a las %02d:%02d\n", h_alarma, m_alarma);

    uint8_t reg = 0x00;
    uint8_t data[3];
    //Timer registration

    while (true) {
        // Read the RTC (DS1307)
        i2c_write_blocking(I2C_PORT, DS3231_ADDR, &reg, 1, true);
        i2c_read_blocking(I2C_PORT, DS3231_ADDR, data, 3, false);

        uint8_t minutos = bcd_to_dec(data[1]);
        uint8_t horas = bcd_to_dec(data[2] & 0x3F);

        //activate the alarm at the time the user logged in
        if (horas == h_alarma && minutos == m_alarma && !alarma_disparada) {
            alarma_disparada = true;
            printf("¡Alarma activada!\n");
        }

        if (alarma_disparada) {
            // if the alarm is activate the buzzer and the servo are activated
            set_servo_position(SERVO_PIN, 20);
            set_buzzer_freq(BUZZER_PIN, 1000);
            sleep_ms(200);

            set_servo_position(SERVO_PIN, 270);
            set_buzzer_freq(BUZZER_PIN, 1500);
            sleep_ms(200);

            // if the button is activated the buzzer and the servo are desactivated
            if (gpio_get(BOTON_PIN) == 0) {
                alarma_disparada = false;
                set_buzzer_freq(BUZZER_PIN, 0);
                set_servo_position(SERVO_PIN, 90);
                printf("Alarma apagada.\n");
                sleep_ms(60000);
            }
        } else {
            printf("Hora actual: %02d:%02d\n", horas, minutos);
            sleep_ms(1000);
        }
    }
}