#include <LiquidCrystal_I2C.h>
#include <DHT.h>
#include <EEPROM.h>

#define EEPROM_MIN_V 0 
#define EEPROM_MAX_V (EEPROM_MIN_V + 2)

#define DHTTYPE DHT22 // Sensor DHT11
#define DHTPIN 7    // Digital pin connected to the DHT sensor

#define BTN_PIN 8 

bool STATE = false;

float MIN_t;
float MAX_t;
float CUR_t;

DHT dht(DHTPIN, DHTTYPE);

int button_state = 1;
int last_button_state = 1;

LiquidCrystal_I2C lcd(0x27,16,2);

byte dcircle[] = {
  B00110,
  B01001,
  B01001,
  B00110,
  B00000,
  B00000,
  B00000,
  B00000
};


void write_temperature(int pos, float t) 
{
  int it = (int)(t*10);
  EEPROM.put(pos, it);
}


float read_temperature(int pos)
{
  int it;
  EEPROM.get(pos, it);
  float t = (float)(it/10);
  return t;
}

float c_to_f(float c)
{
    return (c * 1.8) + 32;
}

void setup()
{
  lcd.init();
  lcd.clear();         
  lcd.backlight();
  lcd.createChar(0, dcircle);
 
  pinMode(BTN_PIN, INPUT_PULLUP);
  dht.begin();
  
  // CUR_t = analogRead(TMP36_PIN) * (5000 / 1024.0);
  CUR_t = dht.readTemperature();
  write_temperature(EEPROM_MIN_V, CUR_t);
  write_temperature(EEPROM_MAX_V, CUR_t);
  
  MIN_t = CUR_t;
  MAX_t = CUR_t;

  Serial.begin(9600);
}

long long last_debounce_time = millis();
long long debounce_delay_expected = 2000;


void loop()
{
  CUR_t = dht.readTemperature();
  
  Serial.println(CUR_t);
  
  if (CUR_t > MAX_t) {
    MAX_t = CUR_t;
    write_temperature(EEPROM_MAX_V, MAX_t);
  } else if (CUR_t < MIN_t) {
    MIN_t = CUR_t;
    write_temperature(EEPROM_MIN_V, MIN_t);
  }  
  
  lcd.setCursor(0, 0);
  lcd.print("CUR: ");
  if (!STATE) lcd.print(CUR_t, 1);
  else lcd.print(c_to_f(CUR_t), 1);
  lcd.setCursor(14, 0);
  
  lcd.write(0);
  if (!STATE) lcd.print("C");
  else lcd.print("F");
  
  lcd.setCursor(0, 1);
  if (!STATE) lcd.print(MIN_t, 1);
  else lcd.print(c_to_f(MIN_t), 1);
  lcd.setCursor(9, 1);
  if (!STATE) lcd.print(MAX_t, 1);
  else lcd.print(c_to_f(MAX_t), 1);
  
  button_state = digitalRead(BTN_PIN);
  if (button_state != last_button_state) {
    last_debounce_time = millis();
    if (button_state == LOW) {
      STATE = !STATE;
    }
    delay(50);
  }
  /* ENTRA SE => o botão ainda estiver pressionado, 
        * & o tempo desde que ele foi inicialmente pressionado > 2000ms */
  if ((button_state == LOW) && (millis() - last_debounce_time > debounce_delay_expected)) {
    write_temperature(EEPROM_MIN_V, CUR_t);
    write_temperature(EEPROM_MAX_V, CUR_t);
    MIN_t = CUR_t;
    MAX_t = CUR_t;
    Serial.println("zerando estatisticas");
  }
  last_button_state = button_state;
  
}