"""Patch hardcoded C:\ path prefixes out of HAVOC_NOCD.EXE so it loads files
from the current directory instead of C:\ root."""

exe = bytearray(open("HAVOC_NOCD.EXE", "rb").read())

# Each tuple: (bytes_to_find, bytes_to_replace, description)
# Lengths must match -- we strip "C:\" (3 bytes) and pad with nulls at the end.
patches = [
    # C:\MUSIC.FF\0  (12 bytes) -> MUSIC.FF\0 + 3 nulls
    (
        bytes([0x43,0x3a,0x5c,0x4d,0x55,0x53,0x49,0x43,0x2e,0x46,0x46,0x00]),
        bytes([        0x4d,0x55,0x53,0x49,0x43,0x2e,0x46,0x46,0x00,0x00,0x00,0x00]),
        "C:\\MUSIC.FF -> MUSIC.FF",
    ),
    # C:\INTRFACE.FF\0\0  (16 bytes) -> INTRFACE.FF\0 + 4 nulls
    (
        bytes([0x43,0x3a,0x5c,0x49,0x4e,0x54,0x52,0x46,0x41,0x43,0x45,0x2e,0x46,0x46,0x00,0x00]),
        bytes([        0x49,0x4e,0x54,0x52,0x46,0x41,0x43,0x45,0x2e,0x46,0x46,0x00,0x00,0x00,0x00,0x00]),
        "C:\\INTRFACE.FF -> INTRFACE.FF",
    ),
    # C:\WORLDS\  \0\0  (12 bytes) -> WORLDS\ \0 + 4 nulls
    (
        bytes([0x43,0x3a,0x5c,0x57,0x4f,0x52,0x4c,0x44,0x53,0x5c,0x00,0x00]),
        bytes([        0x57,0x4f,0x52,0x4c,0x44,0x53,0x5c,0x00,0x00,0x00,0x00,0x00]),
        "C:\\WORLDS\\ -> WORLDS\\",
    ),
    # C:\BIGFILE.DAT\0\0  (16 bytes) -> BIGFILE.DAT\0 + 4 nulls
    (
        bytes([0x43,0x3a,0x5c,0x42,0x49,0x47,0x46,0x49,0x4c,0x45,0x2e,0x44,0x41,0x54,0x00,0x00]),
        bytes([        0x42,0x49,0x47,0x46,0x49,0x4c,0x45,0x2e,0x44,0x41,0x54,0x00,0x00,0x00,0x00,0x00]),
        "C:\\BIGFILE.DAT -> BIGFILE.DAT",
    ),
]

for search, replace, desc in patches:
    assert len(search) == len(replace), f"Length mismatch for {desc}: {len(search)} vs {len(replace)}"
    idx = bytes(exe).find(search)
    if idx == -1:
        print(f"  NOT FOUND (check bytes): {desc}")
        # print surrounding bytes for debugging
        # try to find just the ascii part
        ascii_part = bytes(b for b in search if 0x20 <= b < 0x7f)
        idx2 = bytes(exe).find(ascii_part)
        if idx2 != -1:
            print(f"    ASCII match at 0x{idx2:06x}: {bytes(exe[idx2-4:idx2+len(ascii_part)+4]).hex(' ')}")
        continue
    exe[idx:idx+len(replace)] = replace
    print(f"  OK  0x{idx:06x}: {desc}")

open("HAVOC_NOCD.EXE", "wb").write(exe)
print("\nDone. HAVOC_NOCD.EXE no longer needs C:\\ symlinks for file loading.")