package spreadconstraint

import (
	"context"

	clusterv1alpha1 "github.com/karmada-io/karmada/pkg/apis/cluster/v1alpha1"
	policyv1alpha1 "github.com/karmada-io/karmada/pkg/apis/policy/v1alpha1"
	workv1alpha2 "github.com/karmada-io/karmada/pkg/apis/work/v1alpha2"
	"github.com/karmada-io/karmada/pkg/scheduler/framework"
)

const (
	// Name is the name of the plugin used in the plugin registry and configurations.
	Name = "SpreadConstraint"
)

// SpreadConstraint is a plugin that checks if spread property in the Cluster.Spec.
type SpreadConstraint struct{}

var _ framework.FilterPlugin = &SpreadConstraint{}

// New instantiates the spreadconstraint plugin.
func New() (framework.Plugin, error) {
	return &SpreadConstraint{}, nil
}

// Name returns the plugin name.
func (p *SpreadConstraint) Name() string {
	return Name
}

// Filter checks if the cluster Provider/Zone/Region spread is null.
func (p *SpreadConstraint) Filter(
	_ context.Context,
	bindingSpec *workv1alpha2.ResourceBindingSpec,
	_ *workv1alpha2.ResourceBindingStatus,
	cluster *clusterv1alpha1.Cluster,
) *framework.Result {
	for _, spreadConstraint := range bindingSpec.Placement.SpreadConstraints {
		if spreadConstraint.SpreadByField == policyv1alpha1.SpreadByFieldProvider && cluster.Spec.Provider == "" {
			return framework.NewResult(framework.Unschedulable, "cluster(s) did not have provider property")
		} else if spreadConstraint.SpreadByField == policyv1alpha1.SpreadByFieldRegion && cluster.Spec.Region == "" {
			return framework.NewResult(framework.Unschedulable, "cluster(s) did not have region property")
		} else if spreadConstraint.SpreadByField == policyv1alpha1.SpreadByFieldZone && len(cluster.Spec.Zones) == 0 {
			return framework.NewResult(framework.Unschedulable, "cluster(s) did not have zones property")
		}
	}

	return framework.NewResult(framework.Success)
}