fix: Init printer once, pass object, and remove redundant main block

Co-authored-by: aider (gemini/gemini-2.5-pro) <aider@aider.chat>

main.py

@@ -20,10 +20,7 @@ STATIC_URL = "https://static.spaceport.dns.t0.vc/"
 PRINTER_WIDTH = 384  # Set to your printer's pixel width (common: 384 or 576)
 
 
-def print_picture(filename):
-    # Initialize printer
-    p = Usb(VENDOR_ID, PRODUCT_ID, interface=0, in_ep=0x81, out_ep=0x03)
-
+def print_picture(filename, p):
     try:
         response = requests.get(STATIC_URL + filename, timeout=5)
         response.raise_for_status()
@@ -49,18 +46,18 @@ def print_picture(filename):
         print(f"Error downloading image: {e}")
 
 
-async def process_mqtt(message):
+async def process_mqtt(message, p):
     text = message.payload.decode()
     topic = message.topic.value
     logging.debug('MQTT topic: %s, message: %s', topic, text)
 
     if 'spaceport/drawing/new' in topic:
-        print_picture(text)
+        print_picture(text, p)
     else:
         logging.debug('Invalid topic, returning')
         return
 
-async def fetch_mqtt():
+async def fetch_mqtt(p):
     await asyncio.sleep(3)
 
     async with Client(
@@ -70,7 +67,7 @@ async def fetch_mqtt():
         await client.subscribe('#')
         async for message in client.messages:
             loop = asyncio.get_event_loop()
-            loop.create_task(process_mqtt(message))
+            loop.create_task(process_mqtt(message, p))
 
 
 if __name__ == '__main__':
@@ -78,11 +75,8 @@ if __name__ == '__main__':
     logging.info('==========================')
     logging.info('Booting up...')
 
+    p = Usb(VENDOR_ID, PRODUCT_ID, interface=0, in_ep=0x81, out_ep=0x03)
+
     loop = asyncio.get_event_loop()
-    loop.run_until_complete(fetch_mqtt())
-
-
-
-if __name__ == "__main__":
-    main()
+    loop.run_until_complete(fetch_mqtt(p))