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

LiquidCrystal_I2C lcd(0x27, 20, 4);

volatile int coins = 0;  // Count of coins
const int buttonPin = A0;
const int relayPins[] = {3, 2, 14, 15, 16, 17};
const int ledPins[] = {A1, A2, A3, A4, A5, A6};
const int coinPulsePin = A14;  // Coin pulse input pin
const int additionalLedPin = A13; // Additional LED pin
int selectedButton = 0;
unsigned long startTimes[] = {0, 0, 0, 0, 0, 0}; // Adjusted to 6 buttons
unsigned long activationTimes[] = {0, 0, 0, 0, 0, 0};
unsigned long lastButtonPressTime = 0;
bool buttonDisabled[] = {false, false, false, false, false, false};

// Function to calculate activation time based on coin pulses
unsigned long calculateActivationTime(int pulseCount) {
    if (pulseCount % 10 == 0) {
        return 10800000; // 180 minutes for 10 or more pulses
    } else if (pulseCount % 5 == 0) {
        return 3600000; // 60 minutes for multiples of 5 (except 10)
    } else {
        return pulseCount * 600000; // 10 minutes for each pulse
    }
}

// Interrupt function for coin pulse detection
void coinPulse() {
    coins++;
}

void setup() {
    lcd.backlight();
    lcd.begin(20, 4);
    lcd.print("   CHARGING STATION");
    lcd.setCursor(0, 2);
    lcd.print("  by: Shirhan A. B.");
    delay(2000);
    lcd.clear();
    
    // Initialize pins
    for (int i = 0; i < 6; i++) {
        pinMode(relayPins[i], OUTPUT);
        pinMode(ledPins[i], OUTPUT);
    }
    pinMode(buttonPin, INPUT_PULLUP);
    pinMode(coinPulsePin, INPUT_PULLUP); // Set coin pulse pin as input
    pinMode(additionalLedPin, OUTPUT);
    digitalWrite(additionalLedPin, HIGH);
    
    // Attach interrupt for coin pulse
    attachInterrupt(digitalPinToInterrupt(coinPulsePin), coinPulse, FALLING);
}

void loop() {
    // Check for button press to select port
    if (digitalRead(buttonPin) == LOW) {
        delay(50);  // Debouncing delay
        if (digitalRead(buttonPin) == LOW) {
            // Button pressed
            selectedButton++;
            if (selectedButton > 6) {
                selectedButton = 1;
            }
            lcd.setCursor(0, 0);
            lcd.print("Choose port:" + String(selectedButton));
            lastButtonPressTime = millis(); // Record the time of the button press
            unsigned long displayDuration = 500; // 10 seconds
            unsigned long startDisplayTime = lastButtonPressTime; // Start the timer
            
            // Display the selected button for 10 seconds or until a coin is inserted
            while (millis() - startDisplayTime < displayDuration) {
                if (coins > 0) { // Check if a coin has been inserted
                    break; // Exit the display loop if a coin is inserted
                }
                // Optionally update the LCD here if needed, e.g., to refresh the display
                delay(100); // Small delay to prevent busy-waiting
            }
        }
    }

    if (coins > 0 && selectedButton != 0) {
        lcd.clear();
        // Set the activation time based on the number of coins
        activationTimes[selectedButton - 1] = calculateActivationTime(coins);
        activateRelayAndLed(relayPins[selectedButton - 1], ledPins[selectedButton - 1], startTimes[selectedButton - 1]);
        coins = 0; // Reset coins after using them
        selectedButton = 0;
    }

    if (millis() - lastButtonPressTime >= 10000) {
        digitalWrite(additionalLedPin, LOW);
    } else {
        digitalWrite(additionalLedPin, HIGH);
    }
    
    lcd.setCursor(0, 0);
    lcd.print("Choose port:");
    for (int i = 0; i < 6; i++) {
        if (startTimes[i] > 0) {
            unsigned long remainingTime = activationTimes[i] - (millis() - startTimes[i]);
            unsigned long remainingMinutes = remainingTime / 60000;
            unsigned long remainingSeconds = (remainingTime % 60000) / 1000;
            lcd.setCursor((i < 3) ? 0 : 10, (i % 3) + 1);
            lcd.print(String(1 + i) + ":" + String(remainingMinutes) + "m " + String(remainingSeconds) + "s");
        }

        if (millis() - startTimes[i] >= activationTimes[i] && digitalRead(relayPins[i]) == LOW) {
            digitalWrite(relayPins[i], HIGH);
            digitalWrite(ledPins[i], LOW);
            startTimes[i] = 0;
            activationTimes[i] = 0;
            selectedButton = 0;
            buttonDisabled[i] = false;
        }
    }
}

void activateRelayAndLed(int relay, int led, unsigned long &startTime) {
    if (startTime == 0) {
        digitalWrite(relay, LOW);
        digitalWrite(led, HIGH);
        startTime = millis();
    }
}