#include <LiquidCrystal.h>



#define TRIGGER_PIN A0
#define ECHO_PIN A1
#define FAN_PIN A2
#define POT_PIN A5       // Potentimetter

#define VIEW_SWITCH_PIN 6
#define DEL_PIN 5
#define SEL_PIN 4
#define DOWN_PIN 3
#define CANCEL_PIN 7
#define UP_PIN 2
#define MOTOR A2

// Enum of UI
enum DisplayMode {
  MENU_VIEW,
  ORDER_VIEW
};

// Initialization LCD
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

int pressed = 0;

String menuItems[] = {"1.Hamburger $5", "2.Sushi $3", "3.Sandwitch $6", "4.Ice cream $2.5", "5.Cake $10"};
int selected[];  //What User Selected
int itemCount = 0;     //Selected items
bool userPresent = false;
unsigned long leaveTime = 0;
DisplayMode currentView = MENU_VIEW; //UI mode
int currentMenuItem = 0;           

// 按钮状态枚举（需外接按键，示例中未实现具体引脚）
enum Button {
  BTN_UP,
  BTN_DOWN,
  BTN_SEL,
  BTN_DEL,
  BTN_CANCEL,
  BTN_SWITCH
};

void setup() {
  lcd.begin(16, 2);
  Serial.begin(115200);
  pinMode(FAN_PIN, OUTPUT);
  pinMode(LED_PIN, OUTPUT);
  analogWrite(FAN_PIN, 0); //The fan is off at first
  for(int i = 0; i < 6; i++){
    pinMode(2 + i, INPUT);
    Serial.print("We have set ");
    Serial.println(2 + i);
  }
    for(int i = 0; i < 3; i++){
    pinMode(8 + i, OUTPUT);
    Serial.print("We have set ");
    Serial.println(8 + i);
  }
    for(int i = 0; i < 1; i++){
    pinMode(13 + i, OUTPUT);
    Serial.print("We have set 13");
  }
}

void loop() {
  handlePresenceDetection();  
  handleFanControl();         
    handleInterfaceSwitch();    
  handleNavigation();        
  updateDisplay();           
  delay(100);                 

}

// Detect whether user exists
void handlePresenceDetection() {
  int distance = distanceOfUltraSonar();
  bool presence = (distance > 0 && distance < 152); // Detect user in 5 feets.
  
  if (presence != userPresent) {
    digitalWrite(FAN_PIN, presence ? LOW : HIGH); // If 
    if (presence) {
      onUserArrive();
    } else {
      onUserLeave();
    }
    userPresent = presence;
  }
}

// Control of fan
void handleFanControl() {
  if (!userPresent) {
    analogWrite(FAN_PIN, 0); // Turn off when user leave
    return;
  }
  
  int potValue = analogRead(POT_PIN); // Read potentemetter
  int fanSpeed = 0;
  
  // tap position
  if (potValue < 341) {        // 0-33% Tiny
    fanSpeed = 330;            
  } else if (potValue < 682) { // 34-66% Medium
    fanSpeed = 681;  
  } else {                    // 67 to 100% Big
    fanSpeed = 1023;           
  }
  analogWrite(FAN_PIN, fanSpeed);
}

//Awitch the UI
void handleInterfaceSwitch() {
  if (digitalRead(VIEW_SWITCH_PIN) == HIGH) { //When the button is pressed
    currentView = (currentView == MENU_VIEW) ? ORDER_VIEW : MENU_VIEW;
    lcd.clear();
    delay(150); 
  }
}



void updateDisplay() {
  lcd.setCursor(0, 0);
  
  if (currentView == MENU_VIEW) {
    // UI of menu
    lcd.print("Menu:");
    lcd.setCursor(0, 1);
    lcd.print(menuItems[currentMenuItem]); // display now item.
    if(pressed == 2 && currentMenuItem > 0 && pressed != lastPressed){
      currentMenuItem = currentMenuItem - 1;

    }else if(pressed == 3 && currentMenuItem > 0 && pressed != lastPressed){

      currentMenuItem = currentMenuItem + 1;

    }else if(pressed == 4 && currentMenuItem > 0 && pressed != lastPressed){
      for(int i = 0; i < 15; i ++){
        if(selected[i] != 0)
        selected[i] = currentMenuItem;
      }
    }
    else{pressed == 5 && currentMenuItem > 0 && pressed != lastPressed}
      for(int i = 0; i < 15; i ++){
        if(selected[i] == currentItem)
        selected[i] = 0;
      }
    }
  } else
   {
    // UI of Order
    lcd.setCursor(0, 0);
    for(int i = 0; i < itemCount; i++){
      lcd.print("Order:");
      lcd.print(selected[i]); //Show the number of items
      lcd.setCursor(0, 1);
      lcd.print(" Total:$");
      lcd.print(calculateTotal()); // Show total price
      delay(1000);
    }

    }
  }
}

// Total price
int calculateTotal() {
  int total = 0;
  for (int i = 0; i < itemCount; i++) {
    int index = getSelectedIndex(i);
    String priceStr = menuItems[index].substring(menuItems[index].indexOf('$') + 1); // 提取价格
    total += priceStr.toInt();
  }
  return total;
}

// 获取第n个选中项的索引（示例中简化处理，实际需维护选中列表）
int getSelectedIndex(int n) {
  // 示例中仅返回第一个选中项的索引（实际需用数组存储选中项）
  // 完整实现需扩展selectedItems为数组并记录选中状态
  return 0; // 简化处理，实际需替换为真实逻辑
}

// When user arrive
void onUserArrive() {
  Serial.println("New User coming");
  currentView = MENU_VIEW; // 默认显示菜单
  lcd.clear();
}

// When user quit
void onUserLeave() {
  //Serial.println("No user now");
}

double distanceOfUltrasonar(){
  analogWrite(TRIGGER_PIN, 0);
  delayMicroseconds(2);
  analogWrite(TRIGGER_PIN, 1023);
  delayMicroseconds(10);
  analogWrite(TRIGGER_PIN, 0);
  duration = pulseIn(ECHO_PIN, 1023);
  distance = (duration * 0.343)/2;
  Serial.print("Distance:");
  Serial.println(distance);
  return distance
}

int scanButton() {
  //Scan all buttons
  delay(150);
  for (int i = 2; i < 9; i++) {
    pressed = i;
    if (digitalRead(i == HIGH) { //When a button is pressed
     break;                           
    }
    if(i > 7)
    pressed = 0;// No pressed
  }
    return pressed
}