#!/usr/bin/env python3
"""
Read TM-T88V memory switch values back from the printer via USB.
GS ( E fn=4 asks the printer to transmit its current memory switch settings.
"""
import sys, time, select

ESC = b'\x1b'
GS  = b'\x1d'
DEV = "/dev/usb/lp0"

INIT = ESC + b'\x40'
CUT  = GS  + b'\x56\x00'

def gs_e(fn: int, data: bytes = b'') -> bytes:
    payload = bytes([fn]) + data
    pL = len(payload) & 0xFF
    pH = (len(payload) >> 8) & 0xFF
    return GS + b'\x28\x45' + bytes([pL, pH]) + payload

# fn=4: Transmit memory switch (all groups)
QUERY_MSW = gs_e(4, b'')
# fn=6: Transmit customized values
QUERY_CUSTOM = gs_e(6, b'')

try:
    f = open(DEV, "r+b", buffering=0)
except PermissionError:
    print(f"Permission denied on {DEV} -- run: sudo chmod a+rw {DEV}")
    sys.exit(1)

print("Querying memory switches (fn=4)...")
f.write(INIT + QUERY_MSW)
f.flush()
time.sleep(0.5)

# Try to read response
response = b''
deadline = time.time() + 2.0
while time.time() < deadline:
    r, _, _ = select.select([f], [], [], 0.2)
    if r:
        chunk = f.read(64)
        if chunk:
            response += chunk
    else:
        if response:
            break

if response:
    print(f"Memory switch response ({len(response)} bytes):")
    print("  hex:", response.hex())
    print("  dec:", list(response))
    print()
    # GS ( E fn=4 response format: header + 8 bytes (one per MSW group)
    # Find the data bytes after any header
    for i, b in enumerate(response):
        print(f"  byte[{i}] = 0x{b:02x} ({b:08b}b)")
else:
    print("No response to fn=4 query.")

print()
print("Querying customized values (fn=6)...")
f.write(QUERY_CUSTOM)
f.flush()
time.sleep(0.5)

response2 = b''
deadline = time.time() + 2.0
while time.time() < deadline:
    r, _, _ = select.select([f], [], [], 0.2)
    if r:
        chunk = f.read(64)
        if chunk:
            response2 += chunk
    else:
        if response2:
            break

if response2:
    print(f"Customized value response ({len(response2)} bytes):")
    print("  hex:", response2.hex())
    for i, b in enumerate(response2):
        print(f"  byte[{i}] = 0x{b:02x} ({b:08b}b)")
else:
    print("No response to fn=6 query.")

f.close()