#!/usr/bin/env python3
"""Guard C89 declarations and ownership/order invariants in interpreteridobject.c."""
import sys
from pathlib import Path
from typing import NoReturn


def fail(message: str) -> NoReturn:
    print(message, file=sys.stderr)
    raise SystemExit(1)


def extract_function(source: str, signature: str) -> str:
    start = source.find(signature)
    if start < 0:
        fail(f"missing function signature: {signature}")
    brace = source.find("{", start + len(signature))
    if brace < 0:
        fail("missing function body")
    depth = 0
    for end in range(brace, len(source)):
        if source[end] == "{":
            depth += 1
        elif source[end] == "}":
            depth -= 1
            if depth == 0:
                return source[brace + 1:end]
    fail("unterminated function body")


def ordered(body: str, tokens: tuple[str, ...], message: str) -> None:
    positions = [body.find(token) for token in tokens]
    if any(position < 0 for position in positions) or positions != sorted(positions):
        fail(message)


source = Path(sys.argv[1]).read_text(encoding="utf-8")

newinterpid = extract_function(source, "newinterpid(PyTypeObject *cls, int64_t id, int force)")
for declaration in ("PyInterpreterState *interp;", "interpid *self;"):
    if declaration not in newinterpid:
        fail("newinterpid local must be declared at function entry: " + declaration)
if "PyInterpreterState *interp =" in newinterpid or "interpid *self =" in newinterpid:
    fail("newinterpid must not initialize locals in late declarations")
ordered(newinterpid, (
    "interp = _PyInterpreterState_LookUpID(id);",
    "if (interp == NULL)",
    "if (interp != NULL)",
    "_PyInterpreterState_IDIncref(interp)",
    "self = PyObject_New(interpid, cls);",
    "if (self == NULL)",
    "_PyInterpreterState_IDDecref(interp);",
    "self->id = id;",
    "return self;",
), "newinterpid must preserve lookup, incref, allocation, rollback, and assignment order")

dealloc = extract_function(source, "interpid_dealloc(PyObject *v)")
for declaration in ("int64_t id;", "PyInterpreterState *interp;"):
    if declaration not in dealloc:
        fail("interpid_dealloc local must be declared at function entry: " + declaration)
ordered(dealloc, (
    "id = ((interpid *)v)->id;",
    "interp = _PyInterpreterState_LookUpID(id);",
    "_PyInterpreterState_IDDecref(interp);",
    "PyErr_Clear();",
    "Py_TYPE(v)->tp_free(v);",
), "interpid_dealloc must preserve ID lookup, reference release, and free order")

hash_body = extract_function(source, "interpid_hash(PyObject *self)")
if "Py_hash_t hash;" not in hash_body or "Py_hash_t hash =" in hash_body:
    fail("interpid_hash hash result must be declared before object hashing")
ordered(hash_body, (
    "PyObject *obj = PyLong_FromLongLong(id->id);",
    "if (obj == NULL)",
    "hash = PyObject_Hash(obj);",
    "Py_DECREF(obj);",
    "return hash;",
), "interpid_hash must preserve allocation, hashing, decref, and return order")

richcompare = extract_function(source, "interpid_richcompare(PyObject *self, PyObject *other, int op)")
for declaration in ("interpid *id;", "int equal;"):
    if declaration not in richcompare:
        fail("interpid_richcompare local must be declared at function entry: " + declaration)
ordered(richcompare, (
    "if (op != Py_EQ && op != Py_NE)",
    "if (!PyObject_TypeCheck(self, &_PyInterpreterID_Type))",
    "id = (interpid *)self;",
    "if (PyObject_TypeCheck(other, &_PyInterpreterID_Type))",
    "interpid *otherid = (interpid *)other;",
    "equal = (id->id == otherid->id);",
    "else if (PyLong_CheckExact(other))",
    "int overflow;",
    "PY_LONG_LONG otherid;",
    "otherid = PyLong_AsLongLongAndOverflow(other, &overflow);",
    "equal = !overflow && (otherid >= 0) && (id->id == otherid);",
    "else if (PyNumber_Check(other))",
    "pyid = PyLong_FromLongLong(id->id);",
    "res = PyObject_RichCompare(pyid, other, op);",
    "Py_DECREF(pyid);",
    "return res;",
    "if ((op == Py_EQ && equal) || (op == Py_NE && !equal))",
    "Py_RETURN_TRUE;",
    "Py_RETURN_FALSE;",
), "interpid_richcompare must preserve dispatch, overflow, and reference ordering")

get_id = extract_function(source, "_PyInterpreterState_GetIDObject(PyInterpreterState *interp)")
if "int64_t id;" not in get_id or "int64_t id =" in get_id:
    fail("_PyInterpreterState_GetIDObject ID local must be declared at function entry")
ordered(get_id, (
    "if (_PyInterpreterState_IDInitref(interp) != 0)",
    "id = PyInterpreterState_GetID(interp);",
    "if (id < 0)",
    "return (PyObject *)newinterpid(&_PyInterpreterID_Type, id, 0);",
), "_PyInterpreterState_GetIDObject must preserve initref and ID validation order")

print("interpreteridobject C89 declarations and ownership order: PASS")