import machine  # Module to access hardware peripherals like ADC, pins, etc.
import network  # Module to handle network connections
import time  # Module for handling delays and time-based functions
import urequests  # MicroPython library for HTTP requests
import ujson  # MicroPython library for working with JSON data
import dht  # Library for handling DHT temperature and humidity sensors (not used in this script)

# WiFi credentials
WIFI_SSID = "Wokwi-GUEST"  # SSID of the Wi-Fi network
WIFI_PASSWORD = ""  # Password for the Wi-Fi network (empty for Wokwi's open network)

# ThingSpeak API settings
THINGSPEAK_API_KEY = "5B7201QQGT4NQCFA"  # Write API Key for ThingSpeak
THINGSPEAK_URL = "http://api.thingspeak.com/update"  # URL for updating ThingSpeak channel

# LDR sensor connected to an analog pin
LDR_SENSOR_PIN = machine.ADC(1)  # Analog pin to which the LDR is connected

# Function to read analog data from the LDR sensor
def read_ldr():
    """
    Reads the raw analog data from the LDR sensor using the ADC.
    Returns:
        int: The raw ADC value (0 to 65535 for a 16-bit ADC).
    """
    ldr_data = LDR_SENSOR_PIN.read_u16()  # Reads the 16-bit ADC value
    return ldr_data

# Function to calculate lux from ADC value
def cal_lux(ADC):
    """
    Converts the ADC value from the LDR sensor to a lux value.
    Args:
        ADC (int): The raw ADC value from the LDR.
    Returns:
        float: The calculated lux value.
    """
    vout = ADC / 65535 * 5  # Convert ADC value to voltage (assumes a 5V system)
    RLDR = 2000 * vout / (1 - vout / 5)  # Calculate LDR resistance using a voltage divider formula
    lux = pow(50 * 1000 * pow(10, 0.7) / RLDR, 1 / 0.7)  # Convert resistance to lux using a specific formula
    return lux

# Function to send data to ThingSpeak
def send_data_to_thingspeak(ADC, LUX):
    """
    Sends the ADC and lux values to ThingSpeak.
    Args:
        ADC (int): The raw ADC value.
        LUX (float): The calculated lux value.
    """
    # Prepare data in JSON format
    data = {
        "api_key": THINGSPEAK_API_KEY,  # API key for authentication
        "field1": ADC,  # ADC value to be sent to field1
        "field2": LUX,  # Lux value to be sent to field2
    }
    # Send HTTP POST request to ThingSpeak
    response = urequests.post(
        THINGSPEAK_URL, 
        data=ujson.dumps(data),  # Convert the data dictionary to a JSON string
        headers={"Content-Type": "application/json"}  # Specify the content type
    )
    response.close()  # Close the response to free up resources

# Initialize the Wi-Fi connection
wifi = network.WLAN(network.STA_IF)  # Set Wi-Fi interface to station mode
wifi.active(True)  # Activate the Wi-Fi interface
wifi.connect(WIFI_SSID, WIFI_PASSWORD)  # Connect to the specified Wi-Fi network

# Wait for the Wi-Fi connection to establish
while not wifi.isconnected():
    time.sleep(1)  # Retry every second until connected

print("Connected to Wi-Fi")  # Notify that Wi-Fi is connected

# Main loop
while True:
    ADC = read_ldr()  # Read the raw ADC value from the LDR
    LUX = cal_lux(ADC)  # Calculate the lux value from the ADC data
    print("ADC: {}".format(ADC))  # Print the ADC value to the console
    print("LUX: {}".format(LUX))  # Print the lux value to the console
    send_data_to_thingspeak(ADC, LUX)  # Send the ADC and lux values to ThingSpeak
    print("Data sent to ThingSpeak")  # Confirm that data was sent
    time.sleep(15)  # Wait for 15 seconds before repeating (adjustable)
    print("")  # Print a blank line for readability in the console