#include "esphome.h"


#define DS75_ADDR 0b1001000


class Ds75Sensor : public PollingComponent, public Sensor {
 public:
  Ds75Sensor() : PollingComponent(60000) {}

  float get_setup_priority() const override {
    return esphome::setup_priority::DATA;
  }

  void setup() override {
    uint8_t err = 0;
    // ... and set up 12-bit conversion.
    Wire.beginTransmission(DS75_ADDR);
    Wire.write((uint8_t)0b00000001);  // Configuration pointer byte.
    Wire.write((uint8_t)0b01100000);  // Configuration value.
    err = Wire.endTransmission();
    if (err) {
      ESP_LOGD("error", "Could not configure DS75 resolution!");
    }

    Wire.beginTransmission(DS75_ADDR);
    Wire.write((uint8_t)0b00000000);  // Temperature pointer byte.
    err = Wire.endTransmission();
    if (err) {
      ESP_LOGD("error", "Could not configure DS75 for reads!");
    }
  }

  void update() override {
    Wire.requestFrom(DS75_ADDR, 2);
    uint8_t i = 0;
    while (true) {
      if (Wire.available() >= 2) break;
      if (i++ == 250) {
        return;
      }
      delay(6);
    }

    // Union helps us cast the raw bits read from the Wire into the 16 bit
    // twos-complement value.
    union ds75_reading {
      int16_t val;
      uint8_t buf[2];
    };
    ds75_reading r;
    r.buf[1] = Wire.read(); // MS byte, whole part.
    r.buf[0] = Wire.read(); // LS byte, fractional part.

    // Raw value (after shifting out the four unused LSBs) divided into float:
    // 12 bit reading minus 8 bit whole part leaves 4 bit fractional part.
    float deg_c = (float)(r.val>>4) / (float)(1<<4);

    ESP_LOGD("ds75", "Got temperature=%.1f°C",  deg_c);

    publish_state(deg_c);
  }
};