#!/usr/bin/env python3
"""
TM-T88V paper width fix tool.
Writes directly to /dev/usb/lp0, bypassing CUPS entirely.

Step 1: Direct USB test print (safe, no NV writes)
Step 2: NV paper-width reset to 80mm (writes to printer NV memory)
"""
import sys, time

ESC = b'\x1b'
GS  = b'\x1d'

INIT      = ESC + b'\x40'
FONT_A    = ESC + b'\x4d\x00'
FONT_B    = ESC + b'\x4d\x01'
SIZE_NORM = GS  + b'\x21\x00'
SP_ZERO   = ESC + b'\x20\x00'
# GS W 576 = full 80mm printable area (576 = 0x0240)
WIDTH_576 = GS  + b'\x57\x40\x02'
# GS W 512
WIDTH_512 = GS  + b'\x57\x00\x02'
CUT       = GS  + b'\x56\x00'

DEV = "/dev/usb/lp0"

RULER42 = "123456789|123456789|123456789|123456789|12"
RULER56 = "123456789|123456789|123456789|123456789|123456789|123456"

def write_dev(data: bytes):
    with open(DEV, "wb") as f:
        f.write(data)

def test_print():
    """Step 1 — safe diagnostic, no NV changes."""
    body = (
        "\n[DIRECT USB - Font A + GS W 576]\n"
        f"{RULER42}\n"
        "The quick brown fox jumps over the lazy dog\n"
        "\n"
        "[DIRECT USB - Font B + GS W 576]\n"
        f"{RULER56}\n"
        "The quick brown fox jumps over the lazy dog\n"
        "\n"
    ).encode("ascii")

    data = (INIT + SIZE_NORM + SP_ZERO + WIDTH_576 +
            FONT_A + body +
            b"\n\n" + CUT)
    write_dev(data)
    print("Test print sent directly via USB (no CUPS).")
    print("Count the ruler chars on each line and report back.")

# ── NV paper-width commands ───────────────────────────────────────────────────
# GS ( E — Set customized value (persists in NV across power cycles)
# Format: GS ( E pL pH fn [data...]
#   pL pH = little-endian length of (fn + data)
#
# TM-T88V firmware 30.xx:
#   fn=2 : Set paper type
#   data : 0x00 = 80mm/RP80,  0x01 = 58mm/RP58
#
# This writes to NV — takes effect after power cycle.
def gs_e(fn: int, data: bytes) -> bytes:
    payload = bytes([fn]) + data
    pL = len(payload) & 0xFF
    pH = (len(payload) >> 8) & 0xFF
    return GS + b'\x28\x45' + bytes([pL, pH]) + payload

NV_80MM = gs_e(0x02, b'\x00')   # fn=2, param=0x00 → 80mm paper
NV_58MM = gs_e(0x02, b'\x01')   # fn=2, param=0x01 → 58mm paper (for reference)

def nv_fix():
    """Step 2 — write 80mm paper width to NV memory, then test."""
    print("Sending NV paper-width reset to 80mm...")
    # Send the NV command alone first, then reinit and test
    data = (
        INIT +
        NV_80MM +          # set 80mm in NV
        INIT +             # re-init so new setting takes effect now
        SIZE_NORM + SP_ZERO + WIDTH_576 + FONT_A +
        (
            "\n[NV SET: 80mm - if this is 42 chars wide, it worked]\n"
            f"{RULER42}\n"
            "The quick brown fox jumps over the lazy dog\n"
            "\n"
        ).encode("ascii") +
        b"\n\n" + CUT
    )
    write_dev(data)
    print("NV write + test strip sent.")
    print("If the ruler shows 42 chars: power-cycle the printer to confirm it sticks.")
    print("If still 30 chars: the fn=2/0x00 command didn't apply; tell me and we'll try alternate byte sequences.")

if __name__ == "__main__":
    cmd = sys.argv[1] if len(sys.argv) > 1 else "test"
    try:
        if cmd == "test":
            test_print()
        elif cmd == "fix":
            nv_fix()
        elif cmd == "fix58":
            # Emergency restore to 58mm if needed
            write_dev(INIT + NV_58MM + INIT + b"\n[restored to 58mm]\n\n" + CUT)
            print("Restored to 58mm NV setting.")
        else:
            print("Usage: fixwidth.py [test|fix|fix58]")
    except PermissionError:
        print(f"Permission denied on {DEV}")
        print(f"Run: sudo chmod a+rw {DEV}  then retry")
    except FileNotFoundError:
        print(f"{DEV} not found — run: sudo modprobe usblp")