/*********************************************************************************
 *      Copyright:  (C) 2019 LingYun IoT System Studio
 *                  All rights reserved.
 *
 *       Filename:  tsl2561.c
 *    Description:  This file is the Lux sensor TSL2561 API functions on RaspberryPi,
 *                  which connected to I2C-1
 *
 *        Version:  1.0.0(04/07/19)
 *         Author:  Guo Wenxue <guowenxue@gmail.com>
 *      ChangeLog:  1, Release initial version on "04/07/19 17:39:38"
 *                 
 ********************************************************************************/

#include <wiringPi.h>
#include <wiringPiI2C.h> 
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <math.h>
#include <errno.h>
#include <time.h>

#include "tsl2561.h"


int tsl_fd = -1;

static const int  regs_addr[REG_COUNT]={DATA0LOW, DATA0HIGH, DATA1LOW, DATA1HIGH};

int tsl2561_init(void)
{
    if(tsl_fd > 0)
        return 0;

    tsl_fd = wiringPiI2CSetup(TSL2561_I2C_ADDR);
    if(tsl_fd < 0)
    {
        printf("TSL2561 I2C setup failure: %s\n", strerror(errno));
    }
    else
    {
        printf("TSL2561 initialise ok, tsl_fd=%d\n", tsl_fd);
    }


    return tsl_fd;
}


int tsl2561_get_lux(void)
{
    int                 i;
    int                 reg_data[REG_COUNT];

    int                 chn0_data = 0;
    int                 chn1_data = 0;

    double              div = 0.0;
    double              lux = 0.0;
 
    /* Power up TSL2561 */
    wiringPiI2CWrite(tsl_fd, CONTROL_REG);
    wiringPiI2CWrite(tsl_fd, POWER_UP);

    delay(410);  /* t(CONV) MAX 400ms */

    /* Read register Channel0 and channel1 data from register */
    for(i=0; i<REG_COUNT; i++)
    {
        wiringPiI2CWrite(tsl_fd, regs_addr[i]);
        reg_data[i] = wiringPiI2CRead(tsl_fd);
        //printf("write and read register: 0x%0x->%d\n", regs_addr[i], reg_data[i]);
    }

    chn0_data = reg_data[1]*256 + reg_data[0]; /* Channel0 = DATA0HIGH<<8 + DATA0LOW  */
    chn1_data = reg_data[3]*256 + reg_data[2]; /* channel1 = DATA1HIGH<<8 +  DATA1LOW */

    if( chn0_data<=0 || chn1_data<0 )
    {
        //printf("TSL2561 get date chn0_data[%d] chn1_data[%d]\n", chn0_data, chn1_data);
        lux = 0.0;
        goto OUT;
    }

    div = (double)chn1_data / (double)chn0_data;

    if( div>0 && div<=0.5 )
        lux = 0.304*chn0_data-0.062*chn0_data*pow(div,1.4);

    else if( div>0.5 && div<=0.61 )
        lux = 0.0224*chn0_data-0.031*chn1_data;

    else if( div>0.61 && div<=0.8 )
        lux = 0.0128*chn0_data-0.0153*chn1_data;

    else if( div>0.8 && div<=1.3 )
        lux = 0.00146*chn0_data-0.00112*chn1_data;

    else if( div>1.3 )
        lux = 0.0;

OUT:
    printf("TSLl2561 get lux: %.3f\n", lux);

    wiringPiI2CWrite(tsl_fd, CONTROL_REG);
    wiringPiI2CWrite(tsl_fd, POWER_DOWN);
}

void print_datime(void)
{
    time_t         tmp;
    struct tm     *p;

    time(&tmp);

    p=localtime(&tmp);


    printf("%d-%02d-%02d %02d:%02d:%02d\t", (p->tm_year+1900),(p->tm_mon+1), 
            p->tm_mday, p->tm_hour, p->tm_min, p->tm_sec);

}

int main(int argc, char **argv)
{
    int            interval = 1;

    if( argc >= 2 )
    {
        interval = atoi(argv[1]);
    }

    tsl2561_init();

    while(1)
    {
        print_datime();
        tsl2561_get_lux();
        sleep(interval);
    }

}