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

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

#define BTN_PIN 8

#define EEPROM_MIN_T 0 
#define EEPROM_MIN_H (EEPROM_MIN_T + 2) 
#define EEPROM_MAX_T (EEPROM_MIN_H + 2) 
#define EEPROM_MAX_H (EEPROM_MAX_T + 2) 

LiquidCrystal_I2C lcd(0x27,16,2);

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

DHT dht(DHTPIN, DHTTYPE);
float h, t;
float max_t, max_h, min_t, min_h;
bool STATE = true;
bool button_state, last_button_state;

void write_eeprom(int pos, float v) 
{
  int iv = (int)(v*10);
  EEPROM.put(pos, iv);
}


float read_eeprom(int pos)
{
  int iv;
  EEPROM.get(pos, iv);
  float v = (float)(iv/10);
  return v;
}


void setup()
{
  lcd.init();
  lcd.clear();
  lcd.backlight();
  lcd.createChar(0, dcircle);

  dht.begin();

  pinMode(BTN_PIN, INPUT_PULLUP);

  Serial.begin(9600);

  h = dht.readHumidity();
  // Read temperature as Celsius (the default)
  t = dht.readTemperature();

  write_eeprom(EEPROM_MAX_H, h);
  write_eeprom(EEPROM_MIN_H, h);
  write_eeprom(EEPROM_MAX_T, t);
  write_eeprom(EEPROM_MIN_T, t);
}


bool first = true; 
void loop() {
  if (first) {
    max_h = read_eeprom(EEPROM_MAX_H);
    max_t = read_eeprom(EEPROM_MAX_T);
    min_h = read_eeprom(EEPROM_MIN_H);
    min_t = read_eeprom(EEPROM_MIN_T);
    first = false;
  }

  h = dht.readHumidity();
  t = dht.readTemperature(); // Celsius (the default)

  if (STATE)
    print_cur_status();
  else 
    print_hist_status();
  
  if (h > max_h) {
    write_eeprom(EEPROM_MAX_H, h);
    max_h = h;
  }
  if (h < min_h) {
    write_eeprom(EEPROM_MIN_H, h);
    min_h = h;
  }
  if (t > max_t) {
    write_eeprom(EEPROM_MAX_T, t);
    max_t = t;
  }
  if (t < min_t) {
    write_eeprom(EEPROM_MIN_T, t);
    min_t = t;
  }

  
  // capture button value (change dino pos)
  button_state = digitalRead(BTN_PIN);
  if (button_state != last_button_state) {
    if (button_state == LOW) {
      STATE = !STATE;
    }
    delay(50);
  }

  last_button_state = button_state;

  delay(500);
} 

void print_cur_status() 
{
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(t, 1);
  lcd.print(" ");
  lcd.write(0);
  lcd.print("C");
  lcd.setCursor(0, 1);
  lcd.print(h, 1);  
  lcd.print(" %");
}

void print_hist_status()
{
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(min_t, 1);
  lcd.setCursor(7, 0);
  lcd.print(max_t, 1);
  lcd.setCursor(13, 0);
  lcd.write(0);
  lcd.print("C");
  lcd.print("");


  lcd.setCursor(0, 1);
  lcd.print(min_h, 1);
  lcd.setCursor(7, 1);
  lcd.print(max_h, 1);
  lcd.setCursor(14, 0);
  lcd.print("%");
}