from dataclasses import dataclass


@dataclass(frozen=True)
class Tarball:
    url: str
    sha256: str
    strip_components: int = 1
    patches: tuple[str, ...] = ()

    @property
    def cache_key(self) -> str:
        return self.sha256


@dataclass(frozen=True)
class Git:
    url: str
    commit: str
    patches: tuple[str, ...] = ()

    @property
    def cache_key(self) -> str:
        return self.commit


def tarball(
    *,
    url: str,
    sha256: str,
    strip_components: int = 1,
    patches: list[str] | tuple[str, ...] = (),
) -> Tarball:
    return Tarball(
        url=url,
        sha256=sha256,
        strip_components=strip_components,
        patches=tuple(patches),
    )


def git(*, url: str, commit: str, patches: list[str] | tuple[str, ...] = ()) -> Git:
    if not commit or commit == "?":
        raise ValueError("git source requires an explicit commit SHA")
    return Git(url=url, commit=commit, patches=tuple(patches))


@dataclass(frozen=True)
class Subpackage:
    name: str
    files: tuple[str, ...]
    description: str = ""
    license: str = ""
    url: str = ""
    maintainer: str = ""


def subpackage(
    name: str,
    *,
    description: str = "",
    license: str = "",
    url: str = "",
    maintainer: str = "",
    files: list[str] | tuple[str, ...] = (),
) -> Subpackage:
    for field_name, value in (
        ("description", description),
        ("license", license),
        ("url", url),
        ("maintainer", maintainer),
    ):
        if not isinstance(value, str):
            raise TypeError(f"subpackage {name}: '{field_name}' must be a string")
    for pat in files:
        if pat.startswith("/") or ".." in pat.split("/"):
            raise ValueError(
                f"subpackage {name}: file pattern {pat!r} must be relative and free of '..'"
            )
    return Subpackage(
        name=name,
        description=description,
        license=license,
        url=url,
        maintainer=maintainer,
        files=tuple(files),
    )


def patches_of(src) -> tuple[str, ...]:
    return src.patches