#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <DHT.h>
#include <DHT_U.h>

// Define pins
#define BUTTON_ADD_PIN 15
#define BUTTON_REMOVE_PIN 4
#define DHT_PIN 13
#define SLIDE_SWITCH_PIN 17
#define TRIGGER_PIN 5
#define ECHO_PIN 18
#define BUZZER_PIN 19
#define RED_LED_PIN 23
#define GREEN_LED_PIN 16

// LED Bar Graph Pins
const int ledBarPins[] = {34, 35, 32, 33, 25, 26, 27, 14, 12, 2}; // Example GPIO pins

// Constants
#define DHT_TYPE DHT22
#define ITEM_THRESHOLD 2
#define TEMP_THRESHOLD 27
#define MAX_ITEMS 10

// Global variables
int itemCount = 0;
DHT dht(DHT_PIN, DHT_TYPE);
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  // Initialize serial communication
  Serial.begin(115200);

  // Initialize pins
  pinMode(BUTTON_ADD_PIN, INPUT_PULLUP);
  pinMode(BUTTON_REMOVE_PIN, INPUT_PULLUP);
  pinMode(SLIDE_SWITCH_PIN, INPUT_PULLUP);
  pinMode(TRIGGER_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(RED_LED_PIN, OUTPUT);
  pinMode(GREEN_LED_PIN, OUTPUT);

  // Initialize LED bar graph pins
  for (int i = 0; i < MAX_ITEMS; i++) {
    pinMode(ledBarPins[i], OUTPUT);
    digitalWrite(ledBarPins[i], LOW);
  }

  // Initialize DHT sensor
  dht.begin();

  // Initialize LCD
  lcd.init();
  lcd.backlight();
  
  // Display initial message
  lcd.setCursor(0, 0);
  lcd.print("Item Count:");
  lcd.setCursor(0, 1);
  lcd.print(itemCount);
}

void loop() {
  // Check slide switch
  if (digitalRead(SLIDE_SWITCH_PIN) == LOW) {
    powerOff();
    return;
  }

  // Check buttons
  if (digitalRead(BUTTON_ADD_PIN) == LOW) {
    addItem();
    delay(200);  // Debounce delay
  }
  if (digitalRead(BUTTON_REMOVE_PIN) == LOW) {
    removeItem();
    delay(200);  // Debounce delay
  }

  // Check temperature
  float temperature = dht.readTemperature();
  if (temperature < TEMP_THRESHOLD) {
    digitalWrite(RED_LED_PIN, HIGH);
    digitalWrite(BUZZER_PIN, HIGH);
  } else {
    digitalWrite(RED_LED_PIN, LOW);
    digitalWrite(BUZZER_PIN, LOW);
  }

  // Update item status
  if (itemCount < ITEM_THRESHOLD) {
    digitalWrite(RED_LED_PIN, HIGH);
    digitalWrite(BUZZER_PIN, HIGH);
    digitalWrite(GREEN_LED_PIN, LOW);
  } else {
    digitalWrite(RED_LED_PIN, LOW);
    digitalWrite(BUZZER_PIN, LOW);
    digitalWrite(GREEN_LED_PIN, HIGH);
  }

  // Update LCD and bar graph
  lcd.setCursor(0, 1);
  lcd.print("                ");  // Clear the line
  lcd.setCursor(0, 1);
  lcd.print(itemCount);

  // Display appropriate message on LCD based on item count
  if (itemCount < ITEM_THRESHOLD) {
    lcd.setCursor(0, 0);
    lcd.print("Please topup this");
    lcd.setCursor(0, 1);
    lcd.print("item in rack 1  ");
  } else {
    lcd.setCursor(0, 0);
    lcd.print("Item is not     ");
    lcd.setCursor(0, 1);
    lcd.print("ready to repl.  ");
  }

  // Update LED bar graph
  updateLEDBarGraph(itemCount);

  delay(100);
}

void addItem() {
  itemCount++;
  if (itemCount > MAX_ITEMS) itemCount = MAX_ITEMS; // Assuming 10 is the max item count
}

void removeItem() {
  itemCount--;
  if (itemCount < 0) itemCount = 0;
}

void powerOff() {
  // Turn off all outputs
  digitalWrite(BUZZER_PIN, LOW);
  digitalWrite(RED_LED_PIN, LOW);
  digitalWrite(GREEN_LED_PIN, LOW);

  for (int i = 0; i < MAX_ITEMS; i++) {
    digitalWrite(ledBarPins[i], LOW);
  }

  // Display power off message
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Power Off");

  // Stay here until the switch is turned back on
  while (digitalRead(SLIDE_SWITCH_PIN) == LOW) {
    delay(100);
  }

  // Clear power off message
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Item Count:");
  lcd.setCursor(0, 1);
  lcd.print(itemCount);
}

void updateLEDBarGraph(int itemCount) {
  for (int i = 0; i < MAX_ITEMS; i++) {
    if (i < itemCount) {
      digitalWrite(ledBarPins[i], HIGH);
    } else {
      digitalWrite(ledBarPins[i], LOW);
    }
  }
}