#include "dht22.h"
#include "esp_log.h"
#include "hal/gpio_types.h"
#include "sdkconfig.h"
#include "driver/gpio.h"
#include <rom/ets_sys.h>
#include "esp_timer.h"
#include "freertos/portmacro.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;

void dht22_handle_error(dht22_error e) {
  if (e == DHT22_OK) {
    ESP_LOGI(TAG, "No errors reading DHT22 value");
  } else if (e == DHT22_CHECKSUM_ERROR) {
    ESP_LOGE(TAG, "Error calculating checksum");
  } else if (e == DHT22_TIMING_ERROR) {
    ESP_LOGE(TAG, "Timing error while obtaining data");
  }
}

dht22_error dht22_read() {
  uint8_t data[5] = {0};
  uint32_t tick_total = 0;

  /*
   * From datasheet:
   *  - Host pulls low "beyond at least 1ms"
   *  - Host pulls up 20us to 40us
   */
  gpio_set_direction(CONFIG_DHT22_DATA_GPIO, GPIO_MODE_OUTPUT);

  gpio_set_level(CONFIG_DHT22_DATA_GPIO, 0);
  ets_delay_us(5000);

  gpio_set_level(CONFIG_DHT22_DATA_GPIO, 1);
  ets_delay_us(25);

  /*
   * From datasheet:
   *  - DHT pulls low 80us
   *  - DHT pulls high 80us
   */
  gpio_set_direction(CONFIG_DHT22_DATA_GPIO, GPIO_MODE_INPUT);

  // Maybe wait here until it goes high?
  while (gpio_get_level(CONFIG_DHT22_DATA_GPIO) == 1) {
    // wait for a while - should only be 20 uS
  }


  uint64_t start_time = esp_timer_get_time();

  while (gpio_get_level(CONFIG_DHT22_DATA_GPIO) == 0) {
    tick_total += 1;
    if (tick_total == UINT32_MAX - 1) {
      return DHT22_TIMING_ERROR;
    }
  }
  uint64_t next_time = esp_timer_get_time();
  uint32_t elapsed_time = next_time - start_time;
  if (elapsed_time < 75 || elapsed_time > 85) {
    return DHT22_TIMING_ERROR;
  }

  tick_total = 0;
  start_time = esp_timer_get_time();
  while (gpio_get_level(CONFIG_DHT22_DATA_GPIO) == 0) {
    tick_total += 1;
    if (tick_total == UINT32_MAX - 1) {
      return DHT22_TIMING_ERROR;
    }
  }
  next_time = esp_timer_get_time();
  elapsed_time = next_time - start_time;

  portENABLE_INTERRUPTS();
  ESP_LOGW(TAG, "etime: %lu", elapsed_time);

  if (elapsed_time < 70 || elapsed_time > 90) {
    return DHT22_TIMING_ERROR;
  }

  // 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; }