// =====================================================
// PENNY PAL
// XIAO ESP32-C6
//
// B1 = D1  = Rs5
// B2 = D2  = Rs1
// B3 = D5  = Rs10
// B4 = D3  = Rs2
// D8  = IR sensor
// D10 = Solenoid
// D7  (GPIO17) = MP3 RX <- JQ6500 TX
// D6  (GPIO16) = MP3 TX -> JQ6500 RX
//
// MP3 track map:
//   Track 1 = coin detected sound  (IR beam break)
//   Track 2 = coin insert sound    (button press)
//   Track 3 = 25% milestone
//   Track 4 = goal achieved
//
// Parent App:
//   writes /piggy/goal
//
// ESP32:
//   reads  /piggy/goal
//   writes /piggy/total
//   writes /piggy/percentage
//   writes /piggy/lastCoin
//
// New Goal:
//   resets savings challenge
//
// Reboot:
//   restores progress from Firebase
// =====================================================


// ---------------- WIFI ----------------

#include <WiFi.h>

// ---------------- FIREBASE ----------------

#include <Firebase_ESP_Client.h>
#include "addons/TokenHelper.h"
#include "addons/RTDBHelper.h"

// ---------------- MP3 ----------------

#include <JQ6500_Serial.h>

// ---------------- WIFI CREDENTIALS ----------------

const char* ssid     = "MiCho";
const char* password = "Hello1234";

// ---------------- FIREBASE CONFIG ----------------

#define API_KEY      "AIzaSyDpefz07KOuYyj0mZ1YtvJkm5g3z5HU0-I"
#define DATABASE_URL "https://smart-piggy-effc6-default-rtdb.asia-southeast1.firebasedatabase.app/"

FirebaseData   fbdo;
FirebaseAuth   auth;
FirebaseConfig config;

// =====================================================
// BUTTON PINS
//
// B1 = D1 = Rs5
// B2 = D2 = Rs1
// B3 = D5 = Rs10
// B4 = D3 = Rs2
// =====================================================

#define BTN_1   D1    // Rs5
#define BTN_2   D2    // Rs1
#define BTN_3   D5    // Rs10
#define BTN_4   D3    // Rs2

// =====================================================
// IR SENSOR PIN
// =====================================================

#define IR_SENSOR     D8
#define COIN_DETECTED HIGH

// =====================================================
// SOLENOID PIN
// =====================================================

#define SOLENOID  D10

// =====================================================
// MP3 PINS  (JQ6500)
// =====================================================

#define MP3_RX_PIN  17    // D7 -> JQ6500 TX
#define MP3_TX_PIN  16    // D6 -> JQ6500 RX

HardwareSerial mp3Serial(1);
JQ6500_Serial  mp3(mp3Serial);

// =====================================================
// SAVINGS DATA
// =====================================================

int totalAmount = 0;
int goal        = 0;
int lastGoal    = -1;

// =====================================================
// MILESTONE FLAGS
// =====================================================

bool quarterPlayed = false;
bool goalPlayed    = false;

// =====================================================
// IR SENSOR STATE
// =====================================================

bool coinPresent              = false;
int  lastIRState              = LOW;
unsigned long lastTriggerTime = 0;
const int IR_LOCKOUT          = 200;

// =====================================================
// FIREBASE POLL TIMER
// =====================================================

unsigned long lastFirebaseRead       = 0;
const unsigned long firebaseInterval = 2000;

// =====================================================
// BUTTON STATE MEMORY
//
// INPUT_PULLUP:
//   HIGH = not pressed
//   LOW  = pressed
// =====================================================

bool lastBtn1 = HIGH;
bool lastBtn2 = HIGH;
bool lastBtn3 = HIGH;
bool lastBtn4 = HIGH;

// =====================================================
// SETUP
// =====================================================

void setup() {

  Serial.begin(115200);

  Serial.println();
  Serial.println("================================");
  Serial.println("PENNY PAL STARTING");
  Serial.println("================================");

  // Button pins

  pinMode(BTN_1, INPUT_PULLUP);
  pinMode(BTN_2, INPUT_PULLUP);
  pinMode(BTN_3, INPUT_PULLUP);
  pinMode(BTN_4, INPUT_PULLUP);

  // IR sensor

  pinMode(IR_SENSOR, INPUT);
  lastIRState = digitalRead(IR_SENSOR);

  // Solenoid

  pinMode(SOLENOID, OUTPUT);
  digitalWrite(SOLENOID, LOW);

  // ---------------- WIFI ----------------

  Serial.print("Connecting WiFi");

  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println();
  Serial.println("WiFi Connected");
  Serial.print("IP: ");
  Serial.println(WiFi.localIP());

  // ---------------- FIREBASE ----------------

  config.api_key               = API_KEY;
  config.database_url          = DATABASE_URL;
  config.token_status_callback = tokenStatusCallback;

  Firebase.signUp(&config, &auth, "", "");
  Firebase.begin(&config, &auth);
  Firebase.reconnectWiFi(true);

  Serial.println("Waiting for Firebase...");

  while (!Firebase.ready()) {
    delay(100);
  }

  Serial.println("Firebase Ready");

  // Restore previous progress

  loadSavedData();

  // ---------------- MP3 ----------------

  mp3Serial.begin(9600, SERIAL_8N1, MP3_RX_PIN, MP3_TX_PIN);
  delay(3000);
  mp3.reset();
  delay(1000);
  mp3.setSource(MP3_SRC_BUILTIN);
  delay(500);
  mp3.setVolume(30);

  Serial.println("MP3 Ready");
  Serial.println("================================");
}

// =====================================================
// LOOP
// =====================================================

void loop() {

  // Check if parent changed goal

  readGoal();

  // ---- IR SENSOR ----

  int currentIR = digitalRead(IR_SENSOR);

  if (lastIRState == LOW && currentIR == COIN_DETECTED) {

    if (millis() - lastTriggerTime > IR_LOCKOUT) {

      coinPresent     = true;
      lastTriggerTime = millis();

      Serial.println("Coin Detected — waiting for denomination button");

      mp3.playFileByIndexNumber(1);
    }
  }

  if (currentIR != COIN_DETECTED) {
    coinPresent = false;
  }

  lastIRState = currentIR;

  // ---- BUTTONS ----
  // Only act if a coin is present in the slot

  bool b1 = digitalRead(BTN_1);
  bool b2 = digitalRead(BTN_2);
  bool b3 = digitalRead(BTN_3);
  bool b4 = digitalRead(BTN_4);

  if (coinPresent) {

    if (lastBtn1 == HIGH && b1 == LOW) {
      addAmount(5);       // B1 = Rs5
      coinPresent = false;
    }

    if (lastBtn2 == HIGH && b2 == LOW) {
      addAmount(1);       // B2 = Rs1
      coinPresent = false;
    }

    if (lastBtn3 == HIGH && b3 == LOW) {
      addAmount(10);      // B3 = Rs10
      coinPresent = false;
    }

    if (lastBtn4 == HIGH && b4 == LOW) {
      addAmount(2);       // B4 = Rs2
      coinPresent = false;
    }

  } else {

    if ((lastBtn1 == HIGH && b1 == LOW) ||
        (lastBtn2 == HIGH && b2 == LOW) ||
        (lastBtn3 == HIGH && b3 == LOW) ||
        (lastBtn4 == HIGH && b4 == LOW)) {

      Serial.println("Button ignored — no coin detected");
    }
  }

  // Store button states

  lastBtn1 = b1;
  lastBtn2 = b2;
  lastBtn3 = b3;
  lastBtn4 = b4;

  delay(50);
}

// =====================================================
// LOAD SAVED DATA
//
// Called once during startup
// =====================================================

void loadSavedData() {

  if (!Firebase.ready()) return;

  if (Firebase.RTDB.getInt(&fbdo, "/piggy/total")) {
    totalAmount = fbdo.intData();
    Serial.print("Loaded Total: ");
    Serial.println(totalAmount);
  }

  if (Firebase.RTDB.get(&fbdo, "/piggy/goal")) {

    if (fbdo.dataType() == "string")
      goal = fbdo.stringData().toInt();
    else if (fbdo.dataType() == "int")
      goal = fbdo.intData();
    else if (fbdo.dataType() == "float")
      goal = (int)fbdo.floatData();
    else if (fbdo.dataType() == "double")
      goal = (int)fbdo.doubleData();

    lastGoal = goal;

    Serial.print("Loaded Goal: ");
    Serial.println(goal);
  }

  if (goal > 0) {
    if (totalAmount >= (goal / 4)) quarterPlayed = true;
    if (totalAmount >= goal)       goalPlayed    = true;
  }
}

// =====================================================
// READ GOAL
//
// Runs every 2 seconds
// Resets challenge if parent changed goal
// =====================================================

void readGoal() {

  if (!Firebase.ready()) return;

  if (millis() - lastFirebaseRead < firebaseInterval)
    return;

  lastFirebaseRead = millis();

  if (Firebase.RTDB.get(&fbdo, "/piggy/goal")) {

    int newGoal = 0;

    if (fbdo.dataType() == "string")
      newGoal = fbdo.stringData().toInt();
    else if (fbdo.dataType() == "int")
      newGoal = fbdo.intData();
    else if (fbdo.dataType() == "float")
      newGoal = (int)fbdo.floatData();
    else if (fbdo.dataType() == "double")
      newGoal = (int)fbdo.doubleData();

    if (newGoal != lastGoal) {

      goal     = newGoal;
      lastGoal = newGoal;

      Serial.println();
      Serial.println("===== NEW GOAL DETECTED =====");
      Serial.print("Goal = ");
      Serial.println(goal);

      totalAmount   = 0;
      quarterPlayed = false;
      goalPlayed    = false;

      Firebase.RTDB.setInt(&fbdo, "/piggy/total",      0);
      Firebase.RTDB.setInt(&fbdo, "/piggy/percentage", 0);
      Firebase.RTDB.setInt(&fbdo, "/piggy/lastCoin",   0);

      Serial.println("Savings Reset");
    }
  }
}

// =====================================================
// ADD MONEY
//
// Only called after IR confirms coin is present
// =====================================================

void addAmount(int value) {

  mp3.playFileByIndexNumber(2);

  delay(500);
  pulseSolenoid();

  totalAmount += value;

  int percentage = 0;
  if (goal > 0) {
    percentage = (totalAmount * 100) / goal;
  }

  Serial.print("Added Rs");
  Serial.print(value);
  Serial.print(" | Total Rs");
  Serial.print(totalAmount);
  Serial.print(" | ");
  Serial.print(percentage);
  Serial.println("%");

  sendToFirebase(totalAmount, percentage, value);

  checkMilestones();
}

// =====================================================
// PULSE SOLENOID
// =====================================================

void pulseSolenoid() {
  digitalWrite(SOLENOID, HIGH);
  delay(100);
  digitalWrite(SOLENOID, LOW);
}

// =====================================================
// CHECK MILESTONES
// =====================================================

void checkMilestones() {

  if (goal <= 0) return;

  if (!quarterPlayed && totalAmount >= (goal / 4)) {
    quarterPlayed = true;
    Serial.println("25% Goal Reached!");
    mp3.playFileByIndexNumber(3);
  }

  if (!goalPlayed && totalAmount >= goal) {
    goalPlayed = true;
    Serial.println("GOAL ACHIEVED!");
    mp3.playFileByIndexNumber(4);
  }
}

// =====================================================
// UPDATE FIREBASE
//
// ESP32 NEVER WRITES GOAL — app owns it
// =====================================================

void sendToFirebase(int total, int percentage, int lastCoin) {

  if (!Firebase.ready()) return;

  Firebase.RTDB.setInt(&fbdo, "/piggy/total",      total);
  Firebase.RTDB.setInt(&fbdo, "/piggy/percentage", percentage);
  Firebase.RTDB.setInt(&fbdo, "/piggy/lastCoin",   lastCoin);
}