class Rule:

    def apply(self, action, target, node):
        return 0


# -----------------------------
# EXAMPLES
# -----------------------------

class AvoidHotNodes(Rule):

    def apply(self, action, target, node):

        if node.get("temp", 0) > 80:
            return -100

        return 0


class PreferLXCForARM(Rule):

    def apply(self, action, target, node):

        if target.arch == "arm64" and target.runtime == "lxc":
            return 20

        return 0


class AvoidVMForSmallBuilds(Rule):

    def apply(self, action, target, node):

        if target.runtime == "libvirt" and action.get("size") == "small":
            return -50

        return 0


class SpreadLoad(Rule):

    def apply(self, action, target, node):

        load = node.get("cpu_load", 50)

        return -(load // 2)