# Copyright (c) 2021 The Regents of the University of California
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from enum import Enum
from typing import Set
import os

class CPUTypes(Enum):
    ATOMIC = "atomic"
    KVM = "kvm"
    O3 = "o3"
    TIMING = "timing"
    MINOR = "minor"

def get_cpu_types_str_set() -> Set[CPUTypes]:
    """
    Returns a set of all the CPU types as strings.
    """
    return {cpu_type.value for cpu_type in CPUTypes}

def get_cpu_type_from_str(input: str) -> CPUTypes:
    """
    Will return the correct enum given the input string. This is matched on
    the enum's value. E.g., "kvm" will return ISA.KVM. Throws an exception if
    the input string is invalid.

    `get_cpu_types_str_set()` can be used to determine the valid strings.

    This is for parsing text inputs that specify CPU Type targets.

    :param input: The CPU Type to return, as a string. Case-insensitive.
    """
    for cpu_type in CPUTypes:
        if input.lower() == cpu_type.value:
            return cpu_type

    valid_cpu_types_list_str =str()
    for cpu_type_str in get_cpu_types_str_set():
        valid_cpu_types_list_str += f"{os.linesep}{cpu_type_str}"

    raise Exception(
        f"CPU type '{input}' does not correspond to a known CPU type. "
        f"Known CPU Types:{valid_cpu_types_list_str}"
    )