/* ----------------------------------------------------
   AI Queue Assistant (Proof of Concept)
   Board: Raspberry Pi Pico / Pico W (Arduino core)
   Components: I2C LCD 16x2, 3 LEDs, Push Button, Buzzer
   ---------------------------------------------------- */

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

// LCD at I2C address 0x27
LiquidCrystal_I2C lcd(0x27, 16, 2);

// ----- Pin Mapping -----
#define BUTTON_PIN 15
#define LED_GREEN 16
#define LED_YELLOW 17
#define LED_RED 18
#define BUZZER 19

// ----- Variables -----
int tokenNumber = 1;
int estimatedWait = 5; // minutes per token
bool lastButtonState = LOW;

// ----- Helper Functions -----
void buzzerBeep(int times = 1) {
  for (int i = 0; i < times; i++) {
    digitalWrite(BUZZER, HIGH);
    delay(200);
    digitalWrite(BUZZER, LOW);
    delay(200);
  }
}

void showMessage(const char *line1, const char *line2 = "") {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(line1);
  lcd.setCursor(0, 1);
  lcd.print(line2);
}

void setLEDs(bool r, bool y, bool g) {
  digitalWrite(LED_RED, r);
  digitalWrite(LED_YELLOW, y);
  digitalWrite(LED_GREEN, g);
}

// ----- Setup -----
void setup() {
  pinMode(BUTTON_PIN, INPUT_PULLDOWN);
  pinMode(LED_GREEN, OUTPUT);
  pinMode(LED_YELLOW, OUTPUT);
  pinMode(LED_RED, OUTPUT);
  pinMode(BUZZER, OUTPUT);

  lcd.init();
  lcd.backlight();

  setLEDs(HIGH, LOW, LOW);
  showMessage("Queue Assistant", "Initializing...");
  delay(2000);
  setLEDs(LOW, HIGH, LOW); // Waiting state
}

// ----- Loop -----
void loop() {
  bool buttonState = digitalRead(BUTTON_PIN);

  // Display current queue state
  showMessage(
    (String("Token: T-") + String(tokenNumber)).c_str(),
    (String("ETA: ") + String(estimatedWait) + " min").c_str()
  );

  if (buttonState == HIGH && lastButtonState == LOW) {
    // Button pressed — move to serving state
    setLEDs(LOW, LOW, HIGH);
    showMessage("Now Serving", (String("T-") + String(tokenNumber)).c_str());
    buzzerBeep(2);
    delay(2000);

    // Move to next token
    tokenNumber++;
    estimatedWait = 5;

    // Simulate processing
    setLEDs(HIGH, LOW, LOW);
    showMessage("Processing...", "");
    delay(1000);

    setLEDs(LOW, HIGH, LOW); // Back to waiting
  }

  lastButtonState = buttonState;
  delay(100); // debounce
}