/**
 *
 */


#include "bme280/bme280.h"
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <linux/i2c-dev.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <fcntl.h>
#include <time.h>
#include <json-c/json_object.h>
#include <json-c/json_tokener.h>

#define IIC_Dev  "/dev/i2c-1"

int file_descriptor; // maybe file descriptor? example had it as 'fd'

int8_t check_file_exists(const char *filename)
{
    FILE *file;
    file = fopen(filename, "r");
    if (file != NULL)
    {
        fclose(file);
        return 1;
    }

    return 0;
}

void user_delay_ms(uint32_t period)
{
  usleep(period*1000);
}

#ifdef BME280_FLOAT_ENABLE
double celsius_to_fahrenheit(double celsius)
{
    return (celsius * 1.8) + 32;
}

double pascals_to_mbar(double pascals)
{
    return pascals / 100;
}
#else
uint32_t celsius_to_fahrenheit(uint32_t celsius)
{
    return (celsius * 1.8) + 32;
}

uint32_t pascals_to_mbar(uint32_t pascals)
{
    return pascals / 100;
}
#endif

int8_t user_i2c_read(uint8_t id, uint8_t reg_addr, uint8_t *data, uint16_t len)
{
    write(file_descriptor, &reg_addr, 1);
    read(file_descriptor, data, len);
    return 0;
}

int8_t user_i2c_write(uint8_t id, uint8_t reg_addr, uint8_t *data, uint16_t len)
{
    int8_t *buf;
    buf = malloc(len +1);
    buf[0] = reg_addr;
    memcpy(buf +1, data, len);
    write(file_descriptor, buf, len +1);
    free(buf);
    return 0;
}

void print_sensor_data(struct bme280_data *sensor_readings_data)
{
#ifdef BME280_FLOAT_ENABLE
    double fahrenheit = celsius_to_fahrenheit(sensor_readings_data->temperature);
    double celsius = sensor_readings_data->temperature;
    double pascals = sensor_readings_data->pressure;
    double millibars = pascals_to_mbar(sensor_readings_data->pressure);
    double humidity = sensor_readings_data->humidity;
    printf("%0.2f\xc2\xb0\x46 / %0.2f\xc2\xb0\x43, %0.2fPa, %0.2fmbar, %0.2f%% \r\n", fahrenheit, celsius, pascals, millibars, humidity);
#else
    uint32_t fahrenheit = celsius_to_fahrenheit(sensor_readings_data->temperature);
    uint32_t celsius = sensor_readings_data->temperature;
    uint32_t pascals = sensor_readings_data->pressure;
    uint32_t millibars = pascals_to_mbar(sensor_readings_data->pressure);
    uint32_t humidity = sensor_readings_data->humidity;
    printf("%ld\xc2\xb0\x46 / %ld\xc2\xb0\x43, %ldPa, %ldmbar, %ld%% \r\n", fahrenheit, celsius, pascals, millibars, humidity);
#endif
}

int8_t save_data_to_json_file(struct bme280_data *sensor_readings_data)
{
    time_t rawtime = time(NULL);
    struct tm *timeinfo;
    char dateString[32];
    char timeString[32];
    char filename[100];
    char jsonBuffer[1024];
    FILE *jsonFilePtr;

    struct json_object *parsed_json;
    struct json_object *latest_reading_object = json_object_new_object();
    struct json_object *temperature_object = json_object_new_object();
    struct json_object *pressure_object = json_object_new_object();

    timeinfo = localtime(&rawtime);
    strftime(dateString, 32, "%F", timeinfo);
    strftime(timeString, 32, "%H_%M_%S", timeinfo);
    //puts(dateString);
    //time(&rawtime);

    snprintf(filename, sizeof(filename), "readings_%s.json", dateString);

    if (!check_file_exists(filename))
    {
        printf("File for today does not exist! Creating... \n");
        FILE *jsonFile = fopen(filename, "w");
        fputs("{}", jsonFile);
        fclose(jsonFile);
    }

    jsonFilePtr = fopen(filename, "r+");
    if (jsonFilePtr == NULL)
    {
        sprintf("Failed to open %s", filename);
        exit(1);
    }
    fread(jsonBuffer, 1024, 1, jsonFilePtr);
//printf("raw json read in: %s \n", jsonBuffer);
    parsed_json = json_tokener_parse(jsonBuffer);

//printf("json read in: %s \n", json_object_to_json_string(parsed_json));

#ifdef BME280_FLOAT_ENABLE
    double fahrenheit = celsius_to_fahrenheit(sensor_readings_data->temperature);
    double celsius = sensor_readings_data->temperature;
    double pascals = sensor_readings_data->pressure;
    double millibars = pascals_to_mbar(sensor_readings_data->pressure);
    double humidity = sensor_readings_data->humidity;

    json_object_object_add(temperature_object, "celsius", json_object_new_double(celsius));
    json_object_object_add(temperature_object, "fahrenheit", json_object_new_double(fahrenheit));
    json_object_object_add(pressure_object, "pascals", json_object_new_double(pascals));
    json_object_object_add(pressure_object, "millibars", json_object_new_double(millibars));

    json_object_object_add(latest_reading_object, "temperature", temperature_object);
    json_object_object_add(latest_reading_object, "pressure", pressure_object);
    json_object_object_add(latest_reading_object, "humidity_percent", json_object_new_double(humidity));

    //json_object_object_add(parsed_json, "timeString", latest_reading_object);

    //fprintf(jsonFilePtr, "{\"temperature\":{\"celsius\":%0.2f,\"fahrenheit\":%0.2f}}", celsius, fahrenheit);
#else
    uint32_t fahrenheit = celsius_to_fahrenheit(sensor_readings_data->temperature);
    uint32_t celsius = sensor_readings_data->temperature;
    uint32_t pascals = sensor_readings_data->pressure;
    uint32_t millibars = pascals_to_mbar(sensor_readings_data->pressure);
    uint32_t humidity = sensor_readings_data->humidity;

    json_object_object_add(temperature_object, "celsius", json_object_new_int(celsius));
    json_object_object_add(temperature_object, "fahrenheit", json_object_new_int(fahrenheit));

    json_object_object_add(pressure_object, "pascals", json_object_new_int(pascals));
    json_object_object_add(pressure_object, "millibars", json_object_new_int(millibars));

    json_object_object_add(latest_reading_object, "temperature", temperature_object);
    json_object_object_add(latest_reading_object, "pressure", pressure_object);
    json_object_object_add(latest_reading_object, "humidity_percent", json_object_new_int(humidity));

    //json_object_object_add(parsed_json, "timeString", latest_reading_object);

    //fprintf(jsonFilePtr, "{\"temperature\":{\"celsius\":%ld,\"fahrenheit\":%ld}}", celsius, fahrenheit);
#endif

    json_object_object_add(parsed_json, timeString, latest_reading_object);
    //fprintf(jsonFilePtr, json_object_to_json_string(parsed_json));
    fputs(json_object_to_json_string(parsed_json), jsonFilePtr);
printf("json to write out: %s \n", json_object_to_json_string(latest_reading_object));
printf("new json to write out: %s \n", json_object_to_json_string(parsed_json));
    fclose(jsonFilePtr);
    return 0;
}

int8_t read_sensor_data_normal_mode(struct bme280_dev *dev)
{
    int8_t readings_result;
    uint8_t settings_sel;
    struct bme280_data sensor_readings_data;

    /* Recommended mode of operation: Indoor navigation */
    dev->settings.osr_h = BME280_OVERSAMPLING_1X;
    dev->settings.osr_p = BME280_OVERSAMPLING_16X;
    dev->settings.osr_t = BME280_OVERSAMPLING_2X;
    dev->settings.filter = BME280_FILTER_COEFF_16;
    dev->settings.standby_time = BME280_STANDBY_TIME_62_5_MS;

    settings_sel = BME280_OSR_PRESS_SEL;
    settings_sel |= BME280_OSR_TEMP_SEL;
    settings_sel |= BME280_OSR_HUM_SEL;
    settings_sel |= BME280_STANDBY_SEL;
    settings_sel |= BME280_FILTER_SEL;
    readings_result = bme280_set_sensor_settings(settings_sel, dev);
    readings_result = bme280_set_sensor_mode(BME280_NORMAL_MODE, dev);
    readings_result = bme280_get_sensor_data(BME280_ALL, &sensor_readings_data, dev);
    print_sensor_data(&sensor_readings_data);
    //save_data_to_json_file(&sensor_readings_data);

    return readings_result;
}

int main(int argc, char* argv[])
{
    struct bme280_dev dev;
    int8_t init_result = BME280_OK;

    if ((file_descriptor = open(IIC_Dev, O_RDWR)) < 0) {
        printf("Failed to open the i2c bus %s", argv[1]);
        exit(1);
    }
    if (ioctl(file_descriptor, I2C_SLAVE, 0x76) < 0) {
        printf("Failed to acquire bus access and/or talk to slave.\n");
        exit(1);
    }

    dev.dev_id = BME280_I2C_ADDR_PRIM; //0x76
    //dev.dev_id = BME280_I2C_ADDR_SEC; //0x77
    dev.intf = BME280_I2C_INTF;
    dev.read = user_i2c_read;
    dev.write = user_i2c_write;
    dev.delay_ms = user_delay_ms;

    init_result = bme280_init(&dev);
    printf("\r\n BME280 Init Result is:%d \r\n", init_result);

    read_sensor_data_normal_mode(&dev);
    
    return 0;
}