import socket
import struct
import time

def send_dmx(universe=0, num_channels=512, fade_time=5):
    UDP_IP = '255.255.255.255'  # Broadcast address
    UDP_PORT = 6454

    # Create UDP socket
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)

    sequence = 0
    physical = 0

    # Fading parameters
    fade_steps = 100
    fade_interval = fade_time / fade_steps

    try:
        while True:
            # Fade up
            for value in range(0, 256):
                dmx_data = [value] * num_channels
                dmx_packet = build_artdmx_packet(sequence, physical, universe, dmx_data)
                sock.sendto(dmx_packet, (UDP_IP, UDP_PORT))
                time.sleep(fade_interval / 256)

            # Fade down
            for value in range(255, -1, -1):
                dmx_data = [value] * num_channels
                dmx_packet = build_artdmx_packet(sequence, physical, universe, dmx_data)
                sock.sendto(dmx_packet, (UDP_IP, UDP_PORT))
                time.sleep(fade_interval / 256)

    except KeyboardInterrupt:
        print("DMX transmission stopped.")
    finally:
        sock.close()

def build_artdmx_packet(sequence, physical, universe, dmx_data):
    header = b'Art-Net\x00'                 # Protocol identifier
    opcode = struct.pack('<H', 0x5000)      # OpCode: ArtDMX (0x5000), little endian
    protocol_version = struct.pack('>H', 14)  # Protocol version (14 for Art-Net)
    sequence = struct.pack('B', sequence)   # Sequence
    physical = struct.pack('B', physical)   # Physical port
    universe = struct.pack('<H', universe)  # Universe, little endian
    length = struct.pack('>H', len(dmx_data))  # Data length, big endian
    data = bytes(dmx_data)                  # DMX data

    packet = header + opcode + protocol_version + sequence + physical + universe + length + data
    return packet

if __name__ == '__main__':
    send_dmx()