from dataclasses import dataclass


@dataclass
class BuildSpec:

    project: str
    arch: str
    distro_target: str
    toolchain: str

    # -----------------------------
    # EXECUTION SELECTION
    # -----------------------------
    execution: str          # distcc | lxc | libvirt | tmux
    container_backend: str  # optional fallback layer

    # -----------------------------
    # POLICY PROFILE
    # -----------------------------
    profile: str = "balanced"


def from_request(req):

    return BuildSpec(
        project=req["project"],
        arch=req["arch"],
        distro_target=req["distro_target"],
        toolchain=req["toolchain"],
        execution=req.get("execution", "distcc"),
        container_backend=req.get("container_backend", "lxc"),
        profile=req.get("profile", "balanced")
    )