"""patch_palette_v1.py <pid> [--revert]

Apply (or revert) the Palette leak fix to a running acclient.exe.

Mechanism:
  Overwrite Palette's primary vtable slot +0x2c (which is the
  DBObj::ReleaseSubObjects no-op stub) to point at Palette's existing
  PurgeResource function (slot +0x3c) instead. This causes
  DBOCache::FreeObject's ReleaseSubObjects call to actually free the
  ARGB buffer when the palette goes to the freelist.

  Target: EoR vtable 0x007caa08, slot +0x2c
  Replace value: 0x004154a0  (no-op stub, returns 1)
  With value:    0x0053ecf0  (PurgeResource — frees +0x40 buffer)

Safety:
  - Idempotent: only patches if current value matches the no-op stub
  - Revert via --revert flag
  - Saves before-image to backup
  - The dtor at 0x0053f0d0 guards against NULL — no double-free risk
"""
import ctypes, ctypes.wintypes as wt, sys, struct

VT_PRIMARY    = 0x007caa08
SLOT_OFFSET   = 0x2c
TARGET_ADDR   = VT_PRIMARY + SLOT_OFFSET   # 0x007caa34
EXPECTED_VAL  = 0x004154a0                  # no-op ReleaseSubObjects stub
PATCHED_VAL   = 0x0053ecf0                  # Palette::PurgeResource

PROCESS_VM_READ           = 0x0010
PROCESS_VM_WRITE          = 0x0020
PROCESS_VM_OPERATION      = 0x0008
PROCESS_QUERY_INFORMATION = 0x0400

PAGE_READWRITE = 0x04

k32 = ctypes.windll.kernel32
OpenProcess = k32.OpenProcess
OpenProcess.argtypes = [wt.DWORD, wt.BOOL, wt.DWORD]; OpenProcess.restype = wt.HANDLE
CloseHandle = k32.CloseHandle
CloseHandle.argtypes = [wt.HANDLE]; CloseHandle.restype = wt.BOOL
ReadProcessMemory = k32.ReadProcessMemory
ReadProcessMemory.argtypes = [wt.HANDLE, wt.LPCVOID, wt.LPVOID, ctypes.c_size_t,
                              ctypes.POINTER(ctypes.c_size_t)]
ReadProcessMemory.restype = wt.BOOL
WriteProcessMemory = k32.WriteProcessMemory
WriteProcessMemory.argtypes = [wt.HANDLE, wt.LPVOID, wt.LPCVOID, ctypes.c_size_t,
                               ctypes.POINTER(ctypes.c_size_t)]
WriteProcessMemory.restype = wt.BOOL
VirtualProtectEx = k32.VirtualProtectEx
VirtualProtectEx.argtypes = [wt.HANDLE, wt.LPVOID, ctypes.c_size_t,
                             wt.DWORD, ctypes.POINTER(wt.DWORD)]
VirtualProtectEx.restype = wt.BOOL


def main():
    if len(sys.argv) < 2:
        print("usage: patch_palette_v1.py <pid> [--revert]"); sys.exit(1)
    pid    = int(sys.argv[1])
    revert = "--revert" in sys.argv

    h = OpenProcess(PROCESS_VM_READ|PROCESS_VM_WRITE|PROCESS_VM_OPERATION|PROCESS_QUERY_INFORMATION,
                    False, pid)
    if not h:
        print(f"OpenProcess({pid}) failed: err={ctypes.get_last_error()}"); sys.exit(2)

    # Read current value
    cur = ctypes.c_uint(0); sz = ctypes.c_size_t(0)
    if not ReadProcessMemory(h, TARGET_ADDR, ctypes.byref(cur), 4, ctypes.byref(sz)):
        print(f"read failed: err={ctypes.get_last_error()}"); CloseHandle(h); sys.exit(3)
    print(f"PID {pid}  slot @ 0x{TARGET_ADDR:08x} current: 0x{cur.value:08x}")

    target = EXPECTED_VAL if revert else PATCHED_VAL
    expect_before = PATCHED_VAL if revert else EXPECTED_VAL

    if cur.value == target:
        print(f"  already {'reverted' if revert else 'patched'} — nothing to do")
        CloseHandle(h); return

    if cur.value != expect_before:
        print(f"  UNEXPECTED current value (expected 0x{expect_before:08x}) — aborting to avoid corruption")
        CloseHandle(h); sys.exit(4)

    # Make page writable
    old_prot = wt.DWORD(0)
    if not VirtualProtectEx(h, TARGET_ADDR, 4, PAGE_READWRITE, ctypes.byref(old_prot)):
        print(f"VirtualProtectEx failed: err={ctypes.get_last_error()}"); CloseHandle(h); sys.exit(5)
    print(f"  old protect: 0x{old_prot.value:x}")

    # Write new value
    new = ctypes.c_uint(target)
    if not WriteProcessMemory(h, TARGET_ADDR, ctypes.byref(new), 4, ctypes.byref(sz)):
        print(f"write failed: err={ctypes.get_last_error()}"); CloseHandle(h); sys.exit(6)

    # Restore original protection
    restored = wt.DWORD(0)
    VirtualProtectEx(h, TARGET_ADDR, 4, old_prot.value, ctypes.byref(restored))

    # Verify
    ReadProcessMemory(h, TARGET_ADDR, ctypes.byref(cur), 4, ctypes.byref(sz))
    print(f"  new value:   0x{cur.value:08x}  ({'reverted' if revert else 'patched'} successfully)")
    CloseHandle(h)


if __name__ == "__main__":
    main()