#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <DHT.h>
#include "HX711.h"

// Pin Definitions
#define DHTPIN 8
#define DHTTYPE DHT11
#define RELAY_HEATER 4
#define RELAY_FAN 5
#define BUTTON_PARAM 9
#define BUTTON_INC 6
#define BUTTON_START 7
#define LOADCELL_DOUT 3
#define LOADCELL_SCK 2

// LCD I2C address 0x27, 16 columns, 2 rows
LiquidCrystal_I2C lcd(0x27, 16, 2);
DHT dht(DHTPIN, DHTTYPE);
HX711 scale;

// User-defined targets
float targetWeight = 500.0;    // grams
int targetHumidity = 60;       // %
int maxTemperature = 40;       // °C

// Modes
int settingParam = 0; // 0=weight, 1=humidity, 2=temp
bool dryingStarted = false;

void setup() {
  lcd.init();
  lcd.backlight();
  dht.begin();
  scale.begin(LOADCELL_DOUT, LOADCELL_SCK);
  scale.set_scale();  // to calibrate later
  scale.tare();

  pinMode(RELAY_HEATER, OUTPUT);
  pinMode(RELAY_FAN, OUTPUT);
  pinMode(BUTTON_PARAM, INPUT_PULLUP);
  pinMode(BUTTON_INC, INPUT_PULLUP);
  pinMode(BUTTON_START, INPUT_PULLUP);

  digitalWrite(RELAY_HEATER, LOW);
  digitalWrite(RELAY_FAN, LOW);

  lcd.print("Set Parameters:");
  delay(1000);
}

void loop() {
  if (!dryingStarted) {
    parameterSettingMode();
  } else {
    dryingOperationMode();
  }
}

void parameterSettingMode() {
  lcd.clear();
  showCurrentSetting();
  delay(500);

  if (!digitalRead(BUTTON_PARAM)) {
    settingParam = (settingParam + 1) % 3;
    delay(500);
  }
  if (!digitalRead(BUTTON_INC)) {
    switch (settingParam) {
      case 0: targetWeight += 10; break;
      case 1: targetHumidity += 5; break;
      case 2: maxTemperature += 1; break;
    }
    delay(500);
  }
  if (!digitalRead(BUTTON_START)) {
    dryingStarted = true;
    lcd.clear();
    lcd.print("Drying Started");
    delay(1000);
  }
}

void showCurrentSetting() {
  lcd.setCursor(0, 0);
  if (settingParam == 0) lcd.print("Target Wt: " + String(targetWeight) + "g");
  else if (settingParam == 1) lcd.print("Target Hum: " + String(targetHumidity) + "%");
  else if (settingParam == 2) lcd.print("Max Temp: " + String(maxTemperature) + "C");

  lcd.setCursor(0, 1);
  lcd.print("Press Start Btn");
}

void dryingOperationMode() {
  float humidity = dht.readHumidity();
  float temperature = dht.readTemperature();
  float weight = scale.get_units();

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("T:" + String((int)temperature) + "C H:" + String((int)humidity) + "%");
  lcd.setCursor(0, 1);
  lcd.print("Wt:" + String((int)weight) + "g");

  if (temperature < maxTemperature && humidity > targetHumidity) {
    digitalWrite(RELAY_HEATER, HIGH);
  } else {
    digitalWrite(RELAY_HEATER, LOW);
  }

  if (humidity > targetHumidity) {
    digitalWrite(RELAY_FAN, HIGH);
  } else {
    digitalWrite(RELAY_FAN, LOW);
  }

  if (weight <= targetWeight && humidity <= targetHumidity) {
    digitalWrite(RELAY_HEATER, LOW);
    digitalWrite(RELAY_FAN, LOW);
    lcd.clear();
    lcd.print("Drying Complete");
    while (1);
  }

  delay(2000);
}