/*
  Prelemenary Part for buttons and LCD  
  2 interrupt pins working
*/



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

// Interrupt Pins and Variables
#define BILL_COIN_PIN 12  // Change to the desired GPIO pin
#define FLOW_METER_SENSOR 13
volatile float inserted_coin_bill = 0;
volatile float flow_sensor_value = 0;
volatile float deduct_per_turn = 0;

//Variable for print if any change made
volatile bool something_changed = true;

// Product Pins
#define Product_1 14
#define Product_2 27
#define Product_3 26
bool product_1_selected, product_2_selected, product_3_selected;

// Initialize the LCD with the I2C address (usually 0x27 for 20x4 LCDs -> SDA Pin 21, SCL Pin 22)
LiquidCrystal_I2C lcd(0x27, 20, 4);

// Debounce variables
unsigned long lastDebounceTime1 = 0;
unsigned long lastDebounceTime2 = 0;
unsigned long lastDebounceTime3 = 0;
const unsigned long debounceDelay = 10; // milliseconds

// Button state variables
int lastButtonState1 = HIGH;
int lastButtonState2 = HIGH;
int lastButtonState3 = HIGH;
int buttonState1;
int buttonState2;
int buttonState3;

//price of each product
float P_1_price = 10;
float P_2_price = 10;
float P_3_price = 10;

void IRAM_ATTR handleCoinInsert() {
  /*Interrupt service routine (ISR)* -> for coin slot*/
  something_changed = true;
}

void IRAM_ATTR handleFlowMeter() {
  /*Interrupt service routine (ISR)* -> for flow sensor*/
  flow_sensor_value += 1;
  something_changed = true;
}

void setup() {
  Serial.begin(115200);

  // Initialize the LCD
  lcd.init();
  lcd.backlight();

  // Display a welcome message on the LCD
  lcd.setCursor(0, 0);
  lcd.print("Welcome!");
  lcd.setCursor(0, 1);
  lcd.print("Inserted Coins:");

  // Configure the button pins as input with pullup resistor
  pinMode(BILL_COIN_PIN, INPUT_PULLUP);
  pinMode(FLOW_METER_SENSOR, INPUT_PULLUP);
  pinMode(Product_1, INPUT_PULLUP);
  pinMode(Product_2, INPUT_PULLUP);
  pinMode(Product_3, INPUT_PULLUP);

  // Attach the interrupt to the button pins, triggered on falling edge
  attachInterrupt(digitalPinToInterrupt(BILL_COIN_PIN), handleCoinInsert, FALLING);
  attachInterrupt(digitalPinToInterrupt(FLOW_METER_SENSOR), handleFlowMeter, FALLING);
}

void loop() {
  // Debounce logic for each product button
  debounceButton(Product_1, lastButtonState1, buttonState1, lastDebounceTime1, "Product 1");
  debounceButton(Product_2, lastButtonState2, buttonState2, lastDebounceTime2, "Product 2");
  debounceButton(Product_3, lastButtonState3, buttonState3, lastDebounceTime3, "Product 3");

  print_if_changed();
  lcd_print();
}

void print_if_changed() {
  /*Just Print if something Change*/
  if (something_changed) {
    // Print the number of inserted coins to the Serial Monitor
    Serial.println(inserted_coin_bill);
    Serial.println(flow_sensor_value);
    something_changed = false;
  }
}

void debounceButton(int buttonPin, int &lastButtonState, int &buttonState,
                    unsigned long &lastDebounceTime, const char* productName) {
  /* Debounce function */
  int reading = digitalRead(buttonPin);
  if (reading != lastButtonState) {
    lastDebounceTime = millis();
  }
  if ((millis() - lastDebounceTime) > debounceDelay) {
    if (reading != buttonState) {
      buttonState = reading;
      if (buttonState == LOW) {
        // Product button pressed
        select_product(productName);
        something_changed = true;
      }
    }
  }
  lastButtonState = reading;
}

void select_product(String select) {
  /*Select Product Sccording to Clicked Button*/
  if (select == "Product 1") {
    Serial.printf("%s selected\n", select.c_str());
    product_1_selected;
  } else if (select == "Product 2") {
    Serial.printf("%s selected\n", select.c_str());
    product_2_selected;
  } else if (select == "Product 3") {
    Serial.printf("%s selected\n", select.c_str());
    product_3_selected;
  } else {
    Serial.println("Unknown product selected");
  }
}

void lcd_print() {
  if (something_changed) {
    lcd.clear();
  }
  // Display a welcome message on the LCD
  lcd.setCursor(0, 0);
  lcd.print("Welcome!");
  lcd.setCursor(0, 1);
  lcd.print("Inserted Coins:");
}