#!/usr/bin/env python3
"""Check best_base's base_i declaration and post-validation cast timing."""
import re
from pathlib import Path

source = Path("cpython/Objects/typeobject.c").read_text()
match = re.search(
    r"\nstatic PyTypeObject \*\nbest_base\(PyObject \*bases\)\n\{(.*?)\n\}",
    source,
    re.S,
)
assert match, "best_base definition missing"
body = re.sub(r"/\*.*?\*/|//[^\n]*", "", match.group(1), flags=re.S)
loop = body.split("for (i = 0; i < n; i++) {", 1)[1]
assert re.match(
    r"\s*PyObject \*base_proto = PyTuple_GET_ITEM\(bases, i\);"
    r"\s*PyTypeObject \*base_i;\s*if\b",
    loop,
), "best_base: base_i must be in the loop's opening declaration block (C89)"
assert len(re.findall(r"\bPyTypeObject\s*\*\s*base_i\b", body)) == 1, (
    "declare base_i exactly once"
)
assert len(re.findall(r"\bbase_i\s*=(?!=)", body)) == 1, (
    "assign base_i exactly once"
)
expected = """
        PyObject *base_proto = PyTuple_GET_ITEM(bases, i);
        PyTypeObject *base_i;
        if (!PyType_Check(base_proto)) {
            PyErr_SetString(
                PyExc_TypeError,
                "bases must be types");
            return NULL;
        }
        base_i = (PyTypeObject *)base_proto;

        if (!_PyType_IsReady(base_i)) {
            if (PyType_Ready(base_i) < 0)
                return NULL;
        }
"""
prefix = loop.split("if (!_PyType_HasFeature(base_i, Py_TPFLAGS_BASETYPE))", 1)[0]
assert prefix.split() == expected.split(), (
    "best_base: preserve item retrieval, successful type validation, cast "
    "assignment, and first base_i use in their original order"
)
print("best_base base_i C89 declaration and post-validation cast timing: PASS")