#!/usr/bin/env python3
"""
Printer diagnostic v2 — tests print area width, character spacing,
and direct USB device access on Epson TM-T88V.
"""
import subprocess, sys, time, glob

PRINTER = "receipt"

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'    # GS ! 0 — 1x1 character size
SP_ZERO   = ESC + b'\x20\x00'    # ESC SP 0 — zero right-side char spacing
# GS L nL nH — set left margin to 0
MARGIN_L  = GS  + b'\x4c\x00\x00'
# GS W nL nH — set print area width
# 576 dots = full 80mm printable width (203dpi): 576 = 0x0240 -> nL=0x40 nH=0x02
WIDTH_576 = GS  + b'\x57\x40\x02'
# 512 dots — conservative full width
WIDTH_512 = GS  + b'\x57\x00\x02'
# 480 dots (what 42 chars x ~11.4 dots rounds to)
WIDTH_480 = GS  + b'\x57\xe0\x01'

CUT       = GS  + b'\x56\x00'

RULER_42  = "123456789|123456789|123456789|123456789|12"
RULER_56  = "123456789|123456789|123456789|123456789|123456789|123456"

def send_lpr(data: bytes):
    r = subprocess.run(["lpr", "-P", PRINTER, "-o", "raw"],
                       input=data, capture_output=True)
    if r.returncode != 0:
        print("  lpr error:", r.stderr.decode().strip(), file=sys.stderr)
        return False
    return True

def send_usb(data: bytes):
    """Try writing directly to the USB device, bypassing CUPS entirely."""
    devices = sorted(glob.glob("/dev/usb/lp*"))
    if not devices:
        print("  No /dev/usb/lp* devices found", file=sys.stderr)
        return False
    dev = devices[0]
    print(f"  Writing directly to {dev}")
    try:
        with open(dev, "wb") as f:
            f.write(data)
        return True
    except PermissionError:
        print(f"  Permission denied on {dev} -- try: sudo chmod a+rw {dev}", file=sys.stderr)
        return False
    except Exception as e:
        print(f"  USB write error: {e}", file=sys.stderr)
        return False

def strip(label, init_seq, font=FONT_A, ruler=RULER_42, via_usb=False):
    body = (
        f"\n[{label}]\n"
        f"{ruler}\n"
        f"The quick brown fox jumps over...\n"
        f"\n"
    ).encode("ascii")
    data = init_seq + font + body + b"\n\n" + CUT
    ok = send_usb(data) if via_usb else send_lpr(data)
    status = "OK" if ok else "FAILED"
    print(f"  {status}: {label}")
    time.sleep(3)

print("=== Diagnostic v2: print area & spacing tests ===\n")

print("Test 1: Baseline (same as v1 test 1) via lpr")
strip("T1 Font-A baseline lpr",
      INIT + SIZE_NORM)

print("Test 2: ESC SP 0 (zero right-side character spacing)")
strip("T2 Font-A + SP=0",
      INIT + SIZE_NORM + SP_ZERO)

print("Test 3: GS L 0 + GS W 576 (full printable area)")
strip("T3 Font-A + margin=0 width=576",
      INIT + SIZE_NORM + SP_ZERO + MARGIN_L + WIDTH_576)

print("Test 4: GS W 512")
strip("T4 Font-A + width=512",
      INIT + SIZE_NORM + SP_ZERO + MARGIN_L + WIDTH_512)

print("Test 5: Font B + full area reset")
strip("T5 Font-B + SP=0 + width=576",
      INIT + SIZE_NORM + SP_ZERO + MARGIN_L + WIDTH_576,
      font=FONT_B, ruler=RULER_56)

print("\nTest 6: Direct USB write (bypasses CUPS entirely) -- Font A")
strip("T6 Font-A direct USB",
      INIT + SIZE_NORM + SP_ZERO,
      via_usb=True)

print("\nDone.")
print("Key question: does Test 6 (direct USB) give more chars than Test 1?")
print("If yes -> CUPS is modifying the raw data even with -o raw.")
print("If all same -> printer NV memory has a constrained print area.")
print("Report what you see on each strip.")