package host

import (
	"context"
	"github.com/carlosframework/platform/internal/hostguard"
	"github.com/carlosframework/platform/internal/instancectl"
	"github.com/carlosframework/platform/internal/release"
	"os"
)

func claimLaunchPlacement(units ClaimLaunchUnits, host string) (string, string, error) {
	if bound, ok := units.(interface {
		Placement(string) (string, string, error)
	}); ok {
		return bound.Placement(host)
	}
	return instancectl.UnitName(instancectl.RoleRun, host), instancectl.ClaimUnitControlGroup(host), nil
}

func claimStopInvocation(ctx context.Context, units ClaimLaunchUnits, host, invocation string) error {
	if exact, ok := units.(interface {
		StopInvocation(context.Context, string, string) error
	}); ok {
		return exact.StopInvocation(ctx, host, invocation)
	}
	return units.Stop(ctx, host)
}

func generationBindingGroup(b release.GenerationBinding) string {
	if b.Unit == "" {
		return instancectl.ClaimUnitControlGroup(b.Binding.Host)
	}
	if !instancectl.ValidBoundClaimUnit(b.Unit) {
		return ""
	}
	return instancectl.BoundClaimUnitControlGroup(b.Binding.Host, b.Unit)
}

func (h *ClaimLaunchRoot) checkUnitBinding(ctx context.Context, t hostguard.FenceTarget, cleanup bool) error {
	unit, _, err := claimLaunchPlacement(h.Units, t.Host)
	if err != nil {
		return err
	}
	if unit == instancectl.UnitName(instancectl.RoleRun, t.Host) {
		return nil
	}
	if h.unitBindings == nil {
		return os.ErrPermission
	}
	var b claimUnitBinding
	if cleanup {
		b, err = h.unitBindings.read(t.Host)
	} else {
		b, err = h.unitBindings.check(ctx, t.Host, nil)
	}
	if err != nil {
		return err
	}
	if b.Owner.Host != t.Host || b.Owner.Incarnation != t.Incarnation || b.Owner.Stamp != t.Stamp || b.Owner.Box != t.Box || b.Owner.Enrollment != t.Enrollment || b.Shape.Unit != unit {
		return os.ErrPermission
	}
	return nil
}