"""Keyword scorer — checks for presence/absence of required keywords in output.

Configurable with required_present and required_absent keyword lists.
Score is computed as (matches / total_requirements) ratio.
"""

from typing import Any

from engine.scorers.base import BaseScorer


class KeywordScorer(BaseScorer):
    """Score outputs based on keyword presence and absence.

    Args:
        required_present: Keywords that must appear in the output.
        required_absent: Keywords that must not appear in the output.
        case_sensitive: Whether keyword matching is case-sensitive (default False).
    """

    def __init__(
        self,
        required_present: list[str] | None = None,
        required_absent: list[str] | None = None,
        case_sensitive: bool = False,
    ) -> None:
        self.required_present = required_present or []
        self.required_absent = required_absent or []
        self.case_sensitive = case_sensitive

        if not self.required_present and not self.required_absent:
            raise ValueError(
                "At least one of required_present or required_absent must be provided."
            )

    @property
    def name(self) -> str:
        return "keyword"

    def score(self, input_data: Any, output: str, context: dict) -> float:
        """Score output based on keyword presence/absence.

        Returns the ratio of satisfied keyword requirements to total requirements.
        Each keyword in required_present scores a point if found.
        Each keyword in required_absent scores a point if NOT found.
        """
        total = len(self.required_present) + len(self.required_absent)
        if total == 0:
            return 1.0

        check_output = output if self.case_sensitive else output.lower()
        satisfied = 0

        for keyword in self.required_present:
            check_keyword = keyword if self.case_sensitive else keyword.lower()
            if check_keyword in check_output:
                satisfied += 1

        for keyword in self.required_absent:
            check_keyword = keyword if self.case_sensitive else keyword.lower()
            if check_keyword not in check_output:
                satisfied += 1

        return satisfied / total