print("Project: Goal 9 (Industries, Innovation & Infrastructure)")
print("Program: Railway Crossing Safety System")
print("Created By: Muhammad Iqmal Najmi B. Zaidi")

# ---------------------------------------------------------------------------------------------
# Import Libraries
# ---------------------------------------------------------------------------------------------
from machine import Pin, SoftI2C, PWM, time_pulse_us
from time import sleep
import dht
from i2c_lcd import I2cLcd

# ---------------------------------------------------------------------------------------------
# Define the LCD I2C address and dimensions
# ---------------------------------------------------------------------------------------------
I2C_ADDR = 0x27
I2C_NUM_ROWS = 2
I2C_NUM_COLS = 16

# ---------------------------------------------------------------------------------------------
# Pin Definitions and Setup
# ---------------------------------------------------------------------------------------------
dht_sensor = dht.DHT11(Pin(4))  # Connect DHT11 data pin to GPIO15
i2c = SoftI2C(scl=Pin(22), sda=Pin(21), freq=400000)  # Use GPIO22 (SCL) and GPIO21 (SDA)
lcd = I2cLcd(i2c, I2C_ADDR, I2C_NUM_ROWS, I2C_NUM_COLS)

trig_pin = Pin(13, Pin.OUT)  # Ultrasonic sensor trigger pin
echo_pin = Pin(12, Pin.IN)   # Ultrasonic sensor echo pin

servo_pin = PWM(Pin(14))     # Servo motor pin
servo_pin.freq(50)

red_signal = Pin(25, Pin.OUT)   # Red LED
yellow_signal = Pin(26, Pin.OUT)  # Yellow LED
green_signal = Pin(27, Pin.OUT)  # Green LED

buzzer = PWM(Pin(16))  # Buzzer
buzzer.duty(0)

# ---------------------------------------------------------------------------------------------
# Direct Coding Logic
# ---------------------------------------------------------------------------------------------
try:
    # Open gate initially
    servo_pin.duty(int((0 / 180.0 * 102) + 26))  # Open gate (0 degrees)
    red_signal.off()
    yellow_signal.off()
    green_signal.on()
    print("System ready. Gate is open.")

    while True:
        # Read temperature and humidity from DHT11
        try:
            dht_sensor.measure()
            temperature = dht_sensor.temperature()
            humidity = dht_sensor.humidity()
        except OSError as e:
            print("Failed to read DHT sensor:", e)
            temperature = None
            humidity = None

        # Measure distance using ultrasonic sensor
        trig_pin.on()
        sleep(0.00000001)  # 10µs pulse
        trig_pin.off()
        pulse_time = time_pulse_us(echo_pin, 1)  # Get pulse duration in microseconds
        distance = pulse_time / 58.0  # Convert to distance in cm
        print(f"Temperature: {temperature}, Humidity: {humidity}, Distance: {distance:.2f} cm")

        # Display temperature and humidity/distance alternately
        lcd.clear()
        lcd.move_to(0, 0)
        if temperature is not None:
            lcd.putstr(f"Temp: {temperature:.1f}C")
        else:
            lcd.putstr("Temp: N/A")

        lcd.move_to(0, 1)
        if humidity is not None:
            lcd.putstr(f"Hum: {humidity:.1f}%")
        else:
            lcd.putstr("Hum: N/A")

        sleep(1)  # Show humidity for 2 seconds

        lcd.clear()
        lcd.move_to(0, 0)
        lcd.putstr(f"Dist: {distance:.2f}cm")
        sleep(0.2)  # Show distance for 2 seconds


        # Check if object is detected (distance <= 10 cm)
        if distance <= 10:
            print("Object detected! Activating buzzer.")
            buzzer.freq(1000)
            buzzer.duty(512)
            sleep(0.2)
            buzzer.duty(0)
            sleep(0.2)

            print("Train approaching! Closing gate.")
            lcd.clear()
            lcd.move_to(0, 0)
            lcd.putstr("Train Approaching!")
            lcd.move_to(0, 1)
            lcd.putstr("Gate Closing...")

            red_signal.off()
            yellow_signal.on()
            green_signal.off()

            # Beep with yellow LED
            for Beep in range(5):
                buzzer.freq(1000)
                buzzer.duty(512)
                sleep(0.2)
                buzzer.duty(0)
                sleep(0.2)

            # Close the gate
            servo_pin.duty(int((90 / 180.0 * 102) + 26))  # 90 degrees
            print("Gate closing...")
            sleep(2)
            red_signal.on()
            yellow_signal.off()
            green_signal.off()
            print("Gate is closed.")

            # Beep with red LED after closure
            for red in range(5):
                buzzer.freq(1000)
                buzzer.duty(512)
                sleep(0.2)
                buzzer.duty(0)
                sleep(0.2)

            # Wait until train departs (distance > 10 cm)
            while distance <= 20:
                trig_pin.on()
                sleep(0.00000001)
                trig_pin.off()
                pulse_time = time_pulse_us(echo_pin, 1)
                distance = pulse_time / 58.0
                sleep(0.01)

            print("Train departed. Opening gate.")
            red_signal.off()
            yellow_signal.off()
            green_signal.on()
            servo_pin.duty(int((0 / 180.0 * 102) + 26))  # Open gate (0 degrees)
            lcd.clear()
            lcd.move_to(0, 0)
            lcd.putstr("Train Departed")
            lcd.move_to(0, 1)
            lcd.putstr("Gate Opening...")
            sleep(2)
            print("Gate is open.")

        sleep(1)  # Delay before checking again

except KeyboardInterrupt:
    print("System shutting down.")
    # Ensure system is in safe state
    red_signal.off()
    yellow_signal.off()
    green_signal.on()
    buzzer.duty(0)
    servo_pin.duty(int((0 / 180.0 * 102) + 26))  # Open gate