import time
import sys
from machine import Pin, SoftI2C, PWM
from i2c_lcd import I2cLcd
import network
import urequests

# Define pins for ultrasonic sensor
trig_pin = Pin(16, Pin.OUT)
echo_pin = Pin(17, Pin.IN)

# Define pins for IR sensor
ir_pin = Pin(14, Pin.IN)

# Define I2C LCD parameters
I2C_ADDR = 0x27 
totalRows = 4 
totalColumns = 20

# WiFi credentials
WIFI_SSID = "Wokwi-GUEST"
WIFI_PASSWORD = ""

# Define pin for buzzer
buzzer_pin = Pin(4, Pin.OUT)
buzzer_pwm = PWM(buzzer_pin)
buzzer_pwm.freq(500)  # Set PWM frequency

# Initialize I2C communication for LCD
i2c = SoftI2C(scl=Pin(22), sda=Pin(21), freq=10000)     
lcd = I2cLcd(i2c, I2C_ADDR, totalRows, totalColumns)

# Function to connect to WiFi
def connect_wifi():
    wifi = network.WLAN(network.STA_IF)
    wifi.active(True)
    wifi.disconnect()
    wifi.connect(WIFI_SSID, WIFI_PASSWORD)
    if not wifi.isconnected():
        print('Connecting to WiFi...')
        timeout = 0
        while not wifi.isconnected() and timeout < 10:
            print(10 - timeout)
            timeout += 1
            time.sleep(1) 
    if wifi.isconnected():
        print('Connected to WiFi')
    else:
        print('Failed to connect to WiFi')
        sys.exit()
    print('Network config:', wifi.ifconfig())

# Connecting to WiFi Router 
connect_wifi()

# ThingSpeak parameters
HTTP_HEADERS = {'Content-Type': 'application/json'} 
THINGSPEAK_WRITE_API_KEY = 'JT8RALN0OLL0XBPC' # Write API of the Channel

# Function to measure distance using ultrasonic sensor
def measure_distance():
    trig_pin.value(1)  # Send a 10us pulse to trigger the ultrasonic sensor
    time.sleep_us(10)
    trig_pin.value(0)

    while echo_pin.value() == 0:  # Wait for echo pin to go high and then low
        pulse_start = time.ticks_us()
    while echo_pin.value() == 1:
        pulse_end = time.ticks_us()

    pulse_duration = time.ticks_diff(pulse_end, pulse_start)  # Calculate duration of echo pulse

    # Convert pulse duration to distance in centimeters
    distance = pulse_duration * 0.034 / 2
    return distance

# Function to detect object using IR sensor
def detect_fire():
    return ir_pin.value()

# Function to activate the buzzer
def activate_buzzer():
    buzzer_pwm.duty(512)  # 50% duty cycle

# Function to deactivate the buzzer
def deactivate_buzzer():
    buzzer_pwm.duty(0)  # Turn off the buzzer

# Main loop
while True:
    try:
        distance = measure_distance()
        ir_state = detect_fire()
        
        print("Distance:", distance, "cm")

        lcd.clear()
        lcd.move_to(0,0)
        
        if ir_state:
            lcd.putstr('Fire detected')
            print("Fire detected")
        else:
            lcd.putstr('Distance:'+ str(distance)+"cm")

        dht_readings = {'field1': distance, 'field2': ir_state} 
        request = urequests.post('http://api.thingspeak.com/update?api_key=' + THINGSPEAK_WRITE_API_KEY, json=dht_readings, headers=HTTP_HEADERS)  
        request.close() 
        
        if distance < 100 or ir_state:  # If an object is closer than 100cm or IR sensor detects an object
            activate_buzzer()
        else:
            deactivate_buzzer()
        
        time.sleep(0.1)  # Wait for a short time before next measurement
    except OSError as e:
        print('Failed to read sensor.')