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from __future__ import annotations

from enum import IntEnum, auto


class SpeculativeAlgorithm(IntEnum):
    NONE = auto()
    EAGLE3 = auto()
    MTP = auto()
    DFLASH = auto()

    def is_none(self) -> bool:
        return self == SpeculativeAlgorithm.NONE

    def needs_draft_decode_prealloc(self) -> bool:
        return self in (SpeculativeAlgorithm.EAGLE3, SpeculativeAlgorithm.MTP)

    @staticmethod
    def from_string(name: str | None) -> SpeculativeAlgorithm:
        if name is None:
            return SpeculativeAlgorithm.NONE
        name_map = {
            "EAGLE3": SpeculativeAlgorithm.EAGLE3,
            "MTP": SpeculativeAlgorithm.MTP,
            "DFLASH": SpeculativeAlgorithm.DFLASH,
        }
        try:
            return name_map[name.upper()]
        except KeyError as exc:
            raise ValueError(f"Unknown speculative algorithm: {name}") from exc