#include "dht22.h"
#include "sdkconfig.h"

#define DATA_GPIO CONFIG_DHT22_DATA_GPIO

#if DATA_GPIO == -1
#error "Please define your DHT22 GPIO Data Pin"
#endif /* CONFIG_DHT22_DATA_GPIO == -1 */

static const char* TAG = "DHT22";
deci_percent   _dht22_relative_humidity = UINT16_MAX;
deci_degrees_c _dht22_temperature = INT16_MIN;


dht22_error dht22_read() {
  uint8_t data[5] = {0};


  // TODO: Actually figure out how to read the data from the chip.
  
  // TODO test that data[x] << 8 will be promoted to 16bits otherwise I'm shifting them to just zeros
  _dht22_relative_humidity = data[0] << 8 | data[1];
  _dht22_temperature = (data[2] & 0x7f) << 8 | data[3];
  if (data[2] & 0x80) {
      _dht22_temperature = -1 * _dht22_temperature;
  }
  uint8_t checksum_val = (data[0] + data[1] + data[2] + data[3]) & 0xff;
  if (checksum_val != data[4]) {
    _dht22_relative_humidity = UINT16_MAX;
    _dht22_temperature = INT16_MIN;
    return DHT22_CHECKSUM_ERROR;
  }
  
  return DHT22_OK;
}

deci_percent dht22_relative_humidity() {
  return _dht22_relative_humidity;
}
deci_degrees_c dht22_temperature() {
  return _dht22_temperature;
}