"""
MicroPython IoT Weather Station Example for Wokwi.com

This example sends temperature and humidity data from a DHT22 sensor to an Nginx proxy
using the CoAP protocol.

Ensure that your Nginx proxy is configured to handle CoAP requests.

Copyright (C) 2022, Uri Shaked

https://wokwi.com/arduino/projects/322577683855704658
"""

import network
import time
import socket
import struct
from machine import Pin
import dht

# CoAP Server (Nginx proxy) details
COAP_SERVER = "192.168.1.100"  # Replace with your Nginx proxy IP
COAP_PORT = 5683
COAP_PATH = b"wokwi-weather"

sensor = dht.DHT22(Pin(4))

print("Connecting to WiFi", end="")
sta_if = network.WLAN(network.STA_IF)
sta_if.active(True)
sta_if.connect('Wokwi-GUEST', '')
while not sta_if.isconnected():
    print(".", end="")
    time.sleep(0.1)
print(" Connected!")

# Function to create a basic CoAP POST request
def build_coap_packet(temp, humidity):
    # CoAP header: Version, Type, Token Length, Code, Message ID
    header = b'\x40\x02' + struct.pack('!H', 12345)  # Type: Confirmable, Code: POST, Message ID: 12345
    token = b'\x00'  # No token
    options = b'\xb5' + struct.pack('!B', len(COAP_PATH)) + COAP_PATH  # Uri-Path
    payload_marker = b'\xff'  # Payload marker
    payload = f'temperature={temp}&humidity={humidity}'.encode()

    return header + token + options + payload_marker + payload

# Create a UDP socket
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

prev_weather = ""
while True:
    print("Measuring weather conditions... ", end="")
    sensor.measure()
    temp = sensor.temperature()
    humidity = sensor.humidity()

    # Build CoAP packet
    coap_packet = build_coap_packet(temp, humidity)

    # Send packet to the CoAP server
    sock.sendto(coap_packet, (COAP_SERVER, COAP_PORT))
    
    print(f"Sent data to CoAP server: temperature={temp}, humidity={humidity}")

    time.sleep(10)