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

#define DS1307_ADDRESS 0x68
#define SDA_PIN 4
#define SCL_PIN 5

void i2c_write(uint8_t address, uint8_t *data, size_t length)
{
    i2c_write_blocking(i2c_default, address, data, length, false);
}

void i2c_read(uint8_t address, uint8_t *data, size_t length)
{
    i2c_read_blocking(i2c_default, address, data, length, false);
}

// Conversão de BCD para Decimal
uint8_t bcd_to_decimal(uint8_t bcd)
{
    return (bcd / 16 * 10) + (bcd % 16);
}

// Conversão de Decimal para BCD
uint8_t decimal_to_bcd(uint8_t decimal)
{
    return (decimal / 10 << 4) | (decimal % 10);
}

void initialize_ds1307()
{
    i2c_init(i2c_default, 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);

    uint8_t data[2] = {0x00, 0x00};
    i2c_write(DS1307_ADDRESS, data, 2);
}

void set_ds1307_time(uint8_t hour, uint8_t minute, uint8_t second, uint8_t date, uint8_t month, uint8_t year)
{
    uint8_t time_data[8];
    time_data[0] = 0x00;                   
    time_data[1] = decimal_to_bcd(second);
    time_data[2] = decimal_to_bcd(minute); 
    time_data[3] = decimal_to_bcd(hour);  
    time_data[5] = decimal_to_bcd(date);  
    time_data[6] = decimal_to_bcd(month);  
    time_data[7] = decimal_to_bcd(year);  

    i2c_write(DS1307_ADDRESS, time_data, 8);
}

void get_ds1307_time(uint8_t *hour, uint8_t *minute, uint8_t *second, uint8_t *date, uint8_t *month, uint8_t *year)
{
    uint8_t time_data[7];
    uint8_t reg = 0x00;

    // Solicita leitura a partir do registrador 0x00
    i2c_write(DS1307_ADDRESS, &reg, 1);
    i2c_read(DS1307_ADDRESS, time_data, 7);

    // Converte BCD para decimal
    *second = bcd_to_decimal(time_data[0]);
    *minute = bcd_to_decimal(time_data[1]);
    *hour = bcd_to_decimal(time_data[2]);
    *date = bcd_to_decimal(time_data[4]);
    *month = bcd_to_decimal(time_data[5]);
    *year = bcd_to_decimal(time_data[6]);
}

int main()
{
    stdio_init_all();

    printf("Iniciando DS1307...\n");
    initialize_ds1307();

    printf("Configurando horário...\n");
    set_ds1307_time(13, 27, 00, 24, 9, 24);

    while (true)
    {
        uint8_t hour, minute, second, date, month, year;

        get_ds1307_time(&hour, &minute, &second, &date, &month, &year);

        printf("Hora: %02d:%02d:%02d, Data: %02d/%02d/20%02d\n",
               hour, minute, second, date, month, year);

        sleep_ms(5000);
    }

    return 0;
}