// Libraries
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <Servo.h>
#include <EEPROM.h>

// Initialize the LCD
LiquidCrystal_I2C lcd(0x27, 16, 2); // Set the LCD address to 0x32 for a 16 chars and 2 line display

// Define servo pins
#define SERVO_PIN_1 9
#define SERVO_PIN_2 10
#define SERVO_PIN_3 11

// Create an array to hold servo objects
Servo servo[3];

// Define other pins
#define coinSlot 2
#define buzzer 13
#define button1 4
#define button2 7
#define button3 8
#define changePricesButton 12 // New button for transitioning to phase 2

char lcdBuffer[16];
char prefix[] = "Bal: Php";
volatile int pulse = 0; // Make pulse volatile for use in ISR
char ZZ[] = ".00";
int phase = 1;
int previousPulse = 0; // Variable to store previous pulse value

// Define variant prices
int prices[] = {5, 8, 10}; // Changed from const to allow modification
const int buttons[] = {button1, button2, button3};
const int servoPin[] = {SERVO_PIN_1, SERVO_PIN_2, SERVO_PIN_3};

// Function prototypes
void setup();
void loop();
void insertcoinpage(); // prints "insert coin" on Row 1
void startlcd(); // initializes LCD i2c
void printCredits(); //print updated credits
void dispenseVariant(int index); // dispensing function for all products
void transitionToPhase1(); // Go to phase 1
void transitionToPhase2(); // Go to phase 2
void Buzz(); // buzz for "n" milliseconds
void BuzzLow(); // buzz low for "n" milliseconds
void changePrices(); //Directs to change prices Mode or Admin mode
void savePricesToEEPROM(); // save prices to eeprom, this is used inside the change proces function
void loadPricesFromEEPROM(); //Load saved prices from eeprom
void coinISR(); // ISR function (Interrupt Service Routine, this function is executed once interrupt button is pressed)


// Setup, initialize everything here
void setup() 
{
    startlcd();
    pinMode(coinSlot, INPUT);
    pinMode(changePricesButton, INPUT_PULLUP);
    for (int i = 0; i < 3; i++) {
        pinMode(buttons[i], INPUT_PULLUP);
    }

    // Attach and set initial position of servos to 0 degrees using a loop
    for (int i = 0; i < 3; i++) {
        servo[i].attach(servoPin[i]);
        servo[i].write(0); // Set initial position to 0 degrees
    }

    int prices[] = {5, 8, 10}; // REMOVE THIS AFTER FINISHING THE CODE, everytime the arduino starts, this is the defualt price, so the eeprom prices is deleted when restarted
    savePricesToEEPROM(); // REMOVE THIS AFTER FINISHING THE CODE, everytime the arduino starts, this is the defualt price, so the eeprom prices is deleted when restarted
    
    loadPricesFromEEPROM();
    insertcoinpage();

    // Attach interrupt to the coinSlot pin
    attachInterrupt(digitalPinToInterrupt(coinSlot), coinISR, RISING); //always update credits from coin slot

}

// MAIN LOOP
void loop() {
    if (phase == 1) {
        
        printCredits(); // Always print updated credits
        for (int i = 0; i < 3; i++) {
            dispenseVariant(i);
        }
        if (digitalRead(changePricesButton) == LOW) { // Check if the change prices button is pressed
            transitionToPhase2();
        }
    }

    if (phase == 2) {
        changePrices();
        savePricesToEEPROM();
        transitionToPhase1();
    }
}

// Functions

void insertcoinpage()
{
    lcd.setCursor(0, 0);
    lcd.print("              ");
    delay(200);
    lcd.setCursor(0, 0);
    lcd.print("  Insert Coins");
    delay(100);
    printCredits();
}

void startlcd()
{
    lcd.init();
    lcd.backlight();
    lcd.clear();
}

void printCredits()
{
    if (pulse > previousPulse) {
        Buzz();
        previousPulse = pulse;
    }
    
    sprintf(lcdBuffer, "%s %d%s", prefix, pulse, ZZ);
    lcd.setCursor(0, 1);
    lcd.print(lcdBuffer);
}

void dispenseVariant(int index)
{
    if (digitalRead(buttons[index]) == LOW) {
        if (pulse >= prices[index]) {
            Buzz();
            lcd.clear();
            lcd.setCursor(0, 0);
            lcd.print("   Dispensing");
            lcd.setCursor(0, 1);
            lcd.print("   Product ");
            lcd.print(index + 1);
            delay(500);

            for (int i = 0; i < 2; i++) {
              Buzz();
              delay(500);
            }

            pulse -= prices[index];
            previousPulse = pulse;
            activateServo(servo[index]);
            delay(500);
            lcd.clear();
            insertcoinpage();
            printCredits();
            delay(100);

            for (int i = 0; i < 2; i++) {
              Buzz();
              delay(100);
            }

        } else {

            
          
            lcd.clear();
            lcd.setCursor(0, 0);
            lcd.print("  Insufficient");
            lcd.setCursor(0, 1);
            lcd.print("    Balance   ");

            for (int i = 0; i < 2; i++) { // Loop 10 times
            BuzzLow();
            delay(80);
            }

            delay(500);
            lcd.clear();
            insertcoinpage();
            printCredits();
            delay(100);
        }
    }
}

void transitionToPhase1()
{
    lcd.clear();
    phase = 1;
    insertcoinpage();
}

void transitionToPhase2()
{
    phase = 2;
    lcd.clear();
    loadPricesFromEEPROM(); // Load prices from EEPROM
}

void activateServo(Servo& servo)
{
    servo.write(90); // Example position for activation
    delay(500); // Time for the servo to stay in position
    servo.write(0); // Return to initial position 
}

void Buzz()
{
  tone(buzzer, 3000); // Send 3 kHz tone to pin 9
  delay(30);
  noTone(buzzer);     // Stop the tone
}

void BuzzLow()
{
  tone(buzzer, 250); // Send 3 kHz tone to pin 9
  delay(30);
  noTone(buzzer);     // Stop the tone
}

void changePrices()
{
    lcd.clear();
    delay(200);
    lcd.setCursor(0, 0);
    lcd.print("Please wait...");
    for (int i = 0; i < 2; i++) { // Loop 10 times
            Buzz();
            delay(80);
            }
    delay(2000);
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Entering Admin");
    lcd.setCursor(0, 1);
    lcd.print("Mode...");
    for (int i = 0; i < 2; i++) { // Loop 10 times
            Buzz();
            delay(80);
            }
    delay(2000);
    for (int i = 0; i < 3; i++) {
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("P");
        lcd.print(i + 1);
        lcd.print(" Price: ");
        lcd.print(prices[i]);
        Buzz();
        while (true) {
            if (digitalRead(button1) == LOW) {
                Buzz();
                prices[i] -= 1;
                delay(50); // Debounce delay  
                lcd.clear();
                lcd.setCursor(0, 0);
                lcd.print("P");
                lcd.print(i + 1);
                lcd.print(" Price: ");
                lcd.print(prices[i]);
            }
            if (digitalRead(button2) == LOW) {
                Buzz();
                prices[i] += 1;
                delay(50); // Debounce delay
                lcd.clear();
                lcd.setCursor(0, 0);
                lcd.print("P");
                lcd.print(i + 1);
                lcd.print(" Price: ");
                lcd.print(prices[i]);
            }
            if (digitalRead(button3) == LOW) {
                Buzz();
                delay(500);
                lcd.clear();
                lcd.setCursor(0, 0);
                lcd.print("Saving price...");
                delay(1500);
                lcd.clear();
                lcd.setCursor(0, 0);
                lcd.print("Prices saved");
                delay(500);
                lcd.clear();
                    for (int i = 0; i < 2; i++) { // Loop 10 times
                    Buzz();
                    delay(80);
                    }
                break;
            }
        }
    }
}

void savePricesToEEPROM()
{
    for (int i = 0; i < 3; i++) {
        EEPROM.write(i, prices[i]);
    }
}

void loadPricesFromEEPROM()
{
    for (int i = 0; i < 3; i++) {
        prices[i] = EEPROM.read(i);
    }
}

// ISR to increment pulse
void coinISR()
{
    pulse += 1;
    delayMicroseconds(30000);
}