from dataclasses import dataclass

from pip._vendor.packaging.version import Version
from pip._vendor.packaging.version import parse as parse_version

from pip._internal.models.link import Link


@dataclass(frozen=True, slots=True)
class InstallationCandidate:
    """Represents a potential "candidate" for installation."""

    name: str
    version: Version
    link: Link
    locked: bool

    def __init__(
        self, name: str, version: str, link: Link, locked: bool = False
    ) -> None:
        object.__setattr__(self, "name", name)
        object.__setattr__(self, "version", parse_version(version))
        object.__setattr__(self, "link", link)
        object.__setattr__(self, "locked", locked)

    def __str__(self) -> str:
        return f"{self.name!r} candidate (version {self.version} at {self.link})"