"""GSM8K answer extraction and matching, shared by the eval harness (RS-fast/RS-full) and the T1.4 FP8 check."""
from __future__ import annotations

import math
import re

MATH_SUFFIX = "\nPlease reason step by step, and put your final answer within \\boxed{}."


def extract_answer(text: str) -> str | None:
    """The last \\boxed{...} answer, else the last number in the text, normalised for comparison."""
    boxed = re.findall(r"\\boxed\{((?:[^{}]|\{[^{}]*\})*)\}", text)
    cand = boxed[-1] if boxed else None
    if cand is None:
        nums = re.findall(r"-?\d[\d,]*(?:\.\d+)?", text)
        cand = nums[-1] if nums else None
    if cand is None:
        return None
    cand = cand.replace("\\$", "").replace("\\!", "").replace(",", "").replace("$", "").replace("\\%", "").replace("%", "")
    cand = cand.strip().rstrip(".")
    cand = re.sub(r"\\text\{[^}]*\}", "", cand).strip()
    m = re.fullmatch(r"\\[dt]?frac\{(-?\d+)\}\{(\d+)\}", cand)
    if m:
        return str(int(m.group(1)) / int(m.group(2)))
    return cand


def same_number(pred: str | None, gold: str) -> bool:
    if pred is None:
        return False
    try:
        return math.isclose(float(pred), float(gold), rel_tol=0, abs_tol=1e-6)
    except ValueError:
        return pred.strip() == gold.strip()