#include <Wire.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 20, 4); // change address if needed

// ====== Score Variables ======
int i = 0;  // score
int buzzerbutton = 12;
bool playingMelody = false;
unsigned long lastToneTime = 0;
int melodyStep = 0;
float x,y;

struct ToneStep {
  int frequency;
  int duration;
};

ToneStep melody[] = {
  {165, 200},   // E3
  {294, 200},   // D4
  {932, 500}    // A#5
};
const int melodyLength = sizeof(melody) / sizeof(melody[0]);

// ====== Debounce Variables ======
unsigned long lastButtonPress = 0;
const unsigned long debounceDelay = 200; // ms

// ====== Menu Navigation ======
int level = 0;
int arrow = 0;
int currentIndexMainMenu = 0;
const int listSizeMainMenu = 7;
String mainMenuList[listSizeMainMenu] = {
  "Challenge 1", "Challenge 2", "Challenge 3",
  "Challenge 4", "Challenge 5", "", ""
};

// ====== Volt Sensor Setup ======
int voltInput = A3;
float vout = 0.0;
float vin = 0.0;
float R1 = 30000.0;
float R2 = 7500.0;
int voltvalue = 0;

// ====== Mode Switch ======
int modeSwitch = 9;

// ====== Joystick ======
int JoyStick_X = A0;
int JoyStick_Y = A1;

int selectButton = 10;

// ====== Touch Sensor ======
int touchSensor = 11;

// ====== Challenge Steps ======
const int listSizec1 = 3;
String c1[listSizec1] = {"c1 step 1", "c1 step 2", "c1 step 3"};

const int listSizec2 = 3;
String c2[listSizec2] = {"c2 step 1", "c2 step 2", "c2 step 3"};

const int listSizec3 = 3;
String c3[listSizec3] = {"c3 step 1", "c3 step 2", "c3 step 3"};

const int listSizec4 = 3;
String c4[listSizec4] = {"c4 step 1", "c4 step 2", "c4 step 3"};

const int listSizec5 = 3;
String c5[listSizec5] = {"c5 step 1", "c5 step 2", "c5 step 3"};

// ====== Function Prototypes ======
void updateSevenSegment(int num);
void displayItemMainMenu();

// =====================================================
// MODE 1 FUNCTIONS
// =====================================================
void touch() {
  lcd.setCursor(0, 0);
  lcd.print("The object is a ");
  lcd.setCursor(0, 1);
  if (digitalRead(touchSensor) == 1) {
    lcd.print("conductor!    ");
  } else {
    lcd.print("non-conductor!");
  }
}

void volt() {
  voltvalue = analogRead(voltInput);
  vout = (voltvalue * 5.0) / 1024.0;
  vin = vout / (R2 / (R1 + R2));
  lcd.setCursor(0, 2);
  lcd.print("INPUT V= ");
  lcd.setCursor(0, 3);
  lcd.print(vin, 2);
}

// =====================================================
// MODE 2 FUNCTIONS (Challenges)
// =====================================================
void lcd_main_menu() {
  static unsigned long lastNav = 0;
  if (millis() - lastNav > 250) { // joystick debounce
    x = analogRead (JoyStick_X) * (5.0 / 1023.0);
    y = analogRead (JoyStick_Y) * (5.0 / 1023.0);
    if (x > 4 && y > 2) {
      currentIndexMainMenu++;
      if (currentIndexMainMenu + 2 >= listSizeMainMenu) currentIndexMainMenu = 0;
      displayItemMainMenu();
      lastNav = millis();
    }
  }
}

void displayItemMainMenu() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Select:");
  lcd.setCursor(0, 1);
  lcd.print(">");
  arrow = currentIndexMainMenu + 1;
  lcd.print(mainMenuList[currentIndexMainMenu]);
  lcd.setCursor(0, 2);
  lcd.print(mainMenuList[currentIndexMainMenu + 1]);
  lcd.setCursor(0, 3);
  lcd.print(mainMenuList[currentIndexMainMenu + 2]);
}

void showChallengeIntro(String title) {
  lcd.clear();
  lcd.setCursor(0, 0);
  level = 2;
  lcd.print("Welcome to " + title);
  lcd.setCursor(0, 1);
  lcd.print("Move down to see steps");
}

void showChallengeSteps(String steps[], int size) {
  static int idx = 0;
  static unsigned long lastStep = 0;

  if (millis() - lastStep > 250) { // debounce
    x = analogRead (JoyStick_X) * (5.0 / 1023.0);
    y = analogRead (JoyStick_Y) * (5.0 / 1023.0);
    if (x > 4 && y > 2) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("Step ");
      lcd.print(idx + 1);
      lcd.setCursor(0, 1);
      lcd.print(steps[idx]);
      idx++;
      if (idx >= size) idx = 0;
      lastStep = millis();
    }
  }
}

// =====================================================
// SCORE FUNCTIONS (Non-blocking with millis)
// =====================================================
void startScore() {
  if (!playingMelody) {
    i++;
    if (i > 9) i = 0;   // wrap around after 9

    updateSevenSegment(i);  // update 7-segment immediately

    playingMelody = true;
    melodyStep = 0;
    lastToneTime = millis();
    tone(13, melody[melodyStep].frequency, melody[melodyStep].duration);
  }
}

void handleScore() {
  if (playingMelody) {
    if (millis() - lastToneTime >= (unsigned long)melody[melodyStep].duration + 50) {
      melodyStep++;
      if (melodyStep < melodyLength) {
        lastToneTime = millis();
        tone(13, melody[melodyStep].frequency, melody[melodyStep].duration);
      } else {
        noTone(13);
        playingMelody = false;
      }
    }
  }
}

void updateSevenSegment(int num) {
  switch (num) {
    case 0: digitalWrite(2,HIGH); digitalWrite(3,HIGH); digitalWrite(7,HIGH); digitalWrite(4,HIGH); digitalWrite(6,HIGH); digitalWrite(5,HIGH); digitalWrite(8,LOW); break;
    case 1: digitalWrite(2,LOW);  digitalWrite(3,HIGH); digitalWrite(7,LOW);  digitalWrite(4,HIGH); digitalWrite(6,LOW);  digitalWrite(5,LOW);  digitalWrite(8,LOW); break;
    case 2: digitalWrite(2,HIGH); digitalWrite(3,HIGH); digitalWrite(7,LOW);  digitalWrite(4,LOW);  digitalWrite(6,HIGH); digitalWrite(5,HIGH); digitalWrite(8,HIGH); break;
    case 3: digitalWrite(2,HIGH); digitalWrite(3,HIGH); digitalWrite(7,LOW);  digitalWrite(4,HIGH); digitalWrite(6,LOW);  digitalWrite(5,HIGH); digitalWrite(8,HIGH); break;
    case 4: digitalWrite(2,LOW);  digitalWrite(3,HIGH); digitalWrite(7,HIGH); digitalWrite(4,HIGH); digitalWrite(6,LOW);  digitalWrite(5,LOW);  digitalWrite(8,HIGH); break;
    case 5: digitalWrite(2,HIGH); digitalWrite(3,LOW);  digitalWrite(7,HIGH); digitalWrite(4,HIGH); digitalWrite(6,LOW);  digitalWrite(5,HIGH); digitalWrite(8,HIGH); break;
    case 6: digitalWrite(2,HIGH); digitalWrite(3,LOW);  digitalWrite(7,HIGH); digitalWrite(4,HIGH); digitalWrite(6,HIGH); digitalWrite(5,HIGH); digitalWrite(8,HIGH); break;
    case 7: digitalWrite(2,HIGH); digitalWrite(3,HIGH); digitalWrite(7,LOW);  digitalWrite(4,HIGH); digitalWrite(6,LOW);  digitalWrite(5,LOW);  digitalWrite(8,LOW); break;
    case 8: digitalWrite(2,HIGH); digitalWrite(3,HIGH); digitalWrite(7,HIGH); digitalWrite(4,HIGH); digitalWrite(6,HIGH); digitalWrite(5,HIGH); digitalWrite(8,HIGH); break;
    case 9: digitalWrite(2,HIGH); digitalWrite(3,HIGH); digitalWrite(7,HIGH); digitalWrite(4,HIGH); digitalWrite(6,LOW);  digitalWrite(5,HIGH); digitalWrite(8,HIGH); break;
  }
}

// =====================================================
// SETUP
// =====================================================
void setup() {
  // score pins
  pinMode(buzzerbutton, INPUT_PULLUP);
  pinMode(2, OUTPUT); pinMode(3, OUTPUT); pinMode(7, OUTPUT);
  pinMode(4, OUTPUT); pinMode(6, OUTPUT); pinMode(5, OUTPUT); pinMode(8, OUTPUT);
  pinMode(13, OUTPUT);

  // mode 1
  pinMode(touchSensor, INPUT);
  pinMode(voltInput, INPUT);
  lcd.init();
  lcd.backlight();

  // mode 2
  pinMode(selectButton, INPUT_PULLUP);
  pinMode(modeSwitch, INPUT_PULLUP);
  displayItemMainMenu();
}

// =====================================================
// LOOP
// =====================================================
void loop() {
  // ====== Handle Score Button with Debounce ======
  static bool lastBuzzerState = LOW;
  bool buzzerState = digitalRead(buzzerbutton);
  if (buzzerState == LOW && lastBuzzerState == LOW && millis() - lastButtonPress > debounceDelay) {
    startScore();
    lastButtonPress = millis();
  }
  lastBuzzerState = buzzerState;
  handleScore();

  // ====== Mode Handling ======
  if (digitalRead(modeSwitch) == HIGH) {
    // Mode 1: Sensors
    touch();
    volt();
  } else {
    // Mode 2: Challenges
    if (digitalRead(selectButton) == LOW) {
      level = 1;
    }
    if (level == 0) lcd_main_menu();

    if (level == 1 && arrow == 1) showChallengeIntro("Game 1");
    else if (level == 2 && arrow == 1) showChallengeSteps(c1, listSizec1);

    if (level == 1 && arrow == 2) showChallengeIntro("Game 2");
    else if (level == 2 && arrow == 2) showChallengeSteps(c2, listSizec2);

    if (level == 1 && arrow == 3) showChallengeIntro("Game 3");
    else if (level == 2 && arrow == 3) showChallengeSteps(c3, listSizec3);

    if (level == 1 && arrow == 4) showChallengeIntro("Game 4");
    else if (level == 2 && arrow == 4) showChallengeSteps(c4, listSizec4);

    if (level == 1 && arrow == 5) showChallengeIntro("Game 5");
    else if (level == 2 && arrow == 5) showChallengeSteps(c5, listSizec5);
  }
}