"""
grader.py  (Task 2 – Property Discovery)
-----------------------------------------
Deterministic scorer for natural-language property submissions.
One submission attempt per episode.
Grade range: 0.0 – 1.0  (matchscore output, already normalised).
"""

from typing import Tuple
from utils import SemanticMatcher

_SCORE_MIN = 0.001   # grades are strictly (0, 1)
_SCORE_MAX = 0.999

def _clamp(v: float) -> float:
    return max(_SCORE_MIN, min(_SCORE_MAX, v))

class Task2Grader:
    """
    Grades a Task 2 property submission.

    Parameters
    ----------
    function_name : name of the target function
    property      : the 'property' field from the target function's data
    """

    def __init__(self, function_name: str, property: str) -> None:
        self.function_name = function_name
        self.property      = property

    def grade(self, submitted: str) -> Tuple[float, str]:
        """Deterministic grade strictly in (0, 1)."""
        if not submitted or not submitted.strip():
            return _clamp(0.0), "no_match"   # → 0.001

        matcher = SemanticMatcher()
        score   = matcher.matchscore(self.property, submitted)  # already clamped by SemanticMatcher
        return _clamp(score), matcher.confidence()