#ifndef __ds3231_h_
#define __ds3231_h_

//#if ARDUINO >= 100
#include <Arduino.h>
//#else
//#include <WProgram.h>
//#endif

#include "config.h"

#define	DS3231_TRANSACTION_TIMEOUT	100 // Wire NAK/Busy timeout in ms

#define SECONDS_FROM_1970_TO_2000 946684800

// i2c slave address of the DS3231 chip
#define DS3231_I2C_ADDR             0x68

// timekeeping registers
#define DS3231_TIME_CAL_ADDR        0x00
#define DS3231_ALARM1_ADDR          0x07
#define DS3231_ALARM2_ADDR          0x0B
#define DS3231_CONTROL_ADDR         0x0E
#define DS3231_STATUS_ADDR          0x0F
#define DS3231_AGING_OFFSET_ADDR    0x10
#define DS3231_TEMPERATURE_ADDR     0x11

// control register bits
#define DS3231_CONTROL_A1IE     0x1		/* Alarm 2 Interrupt Enable */
#define DS3231_CONTROL_A2IE     0x2		/* Alarm 2 Interrupt Enable */
#define DS3231_CONTROL_INTCN    0x4		/* Interrupt Control */
#define DS3231_CONTROL_RS1	    0x8		/* square-wave rate select 2 */
#define DS3231_CONTROL_RS2    	0x10	/* square-wave rate select 2 */
#define DS3231_CONTROL_CONV    	0x20	/* Convert Temperature */
#define DS3231_CONTROL_BBSQW    0x40	/* Battery-Backed Square-Wave Enable */
#define DS3231_CONTROL_EOSC	    0x80	/* not Enable Oscillator, 0 equal on */


// status register bits
#define DS3231_STATUS_A1F      0x01		/* Alarm 1 Flag */
#define DS3231_STATUS_A2F      0x02		/* Alarm 2 Flag */
#define DS3231_STATUS_BUSY     0x04		/* device is busy executing TCXO */
#define DS3231_STATUS_EN32KHZ  0x08		/* Enable 32KHz Output  */
#define DS3231_STATUS_OSF      0x80		/* Oscillator Stop Flag */


struct ts {
    uint8_t sec;         /* seconds */
    uint8_t min;         /* minutes */
    uint8_t hour;        /* hours */
    uint8_t mday;        /* day of the month */
    uint8_t mon;         /* month */
    int16_t year;        /* year */
    uint8_t wday;        /* day of the week */
    uint8_t yday;        /* day in the year */
    uint8_t isdst;       /* daylight saving time */
    uint8_t year_s;      /* year in short notation*/
#ifdef CONFIG_UNIXTIME
    uint32_t unixtime;   /* seconds since 01.01.1970 00:00:00 UTC*/
#endif
};

void DS3231_init(const uint8_t creg);
void DS3231_set(struct ts t);
void DS3231_get(struct ts *t);

void DS3231_set_addr(const uint8_t addr, const uint8_t val);
uint8_t DS3231_get_addr(const uint8_t addr);

// control/status register
void DS3231_set_creg(const uint8_t val);
uint8_t DS3231_get_creg(void);

void DS3231_set_sreg(const uint8_t val);
uint8_t DS3231_get_sreg(void);

// aging offset register
void DS3231_set_aging(const int8_t val);
int8_t DS3231_get_aging(void);

// temperature register
float DS3231_get_treg(void);

void DS3231_set_32kHz_output(const uint8_t on);

// alarms
void DS3231_set_a1(const uint8_t s, const uint8_t mi, const uint8_t h, const uint8_t d,
                   const uint8_t * flags);
void DS3231_get_a1(char *buf, const uint8_t len);
void DS3231_clear_a1f(void);
uint8_t DS3231_triggered_a1(void);

void DS3231_set_a2(const uint8_t mi, const uint8_t h, const uint8_t d, const uint8_t * flags);
void DS3231_get_a2(char *buf, const uint8_t len);
void DS3231_clear_a2f(void);
uint8_t DS3231_triggered_a2(void);

// helpers
uint32_t get_unixtime(struct ts t);
uint8_t dectobcd(const uint8_t val);
uint8_t bcdtodec(const uint8_t val);
uint8_t inp2toi(char *cmd, const uint16_t seek);

#endif