package clusteraffinity

import (
	"context"

	clusterv1alpha1 "github.com/karmada-io/karmada/pkg/apis/cluster/v1alpha1"
	policyv1alpha1 "github.com/karmada-io/karmada/pkg/apis/policy/v1alpha1"
	workv1alpha1 "github.com/karmada-io/karmada/pkg/apis/work/v1alpha1"
	"github.com/karmada-io/karmada/pkg/scheduler/framework"
	"github.com/karmada-io/karmada/pkg/util"
)

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

// ClusterAffinity is a plugin that checks if a resource selector matches the cluster label.
type ClusterAffinity struct{}

var _ framework.FilterPlugin = &ClusterAffinity{}
var _ framework.ScorePlugin = &ClusterAffinity{}

// New instantiates the clusteraffinity plugin.
func New() framework.Plugin {
	return &ClusterAffinity{}
}

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

// Filter checks if the cluster matched the placement cluster affinity constraint.
func (p *ClusterAffinity) Filter(ctx context.Context, placement *policyv1alpha1.Placement, resource *workv1alpha1.ObjectReference, cluster *clusterv1alpha1.Cluster) *framework.Result {
	affinity := placement.ClusterAffinity
	if affinity != nil {
		if util.ClusterMatches(cluster, *affinity) {
			return framework.NewResult(framework.Success)
		}
		return framework.NewResult(framework.Unschedulable, "cluster is not matched the placement cluster affinity constraint")
	}

	// If no clusters specified and it is not excluded, mark it matched
	return framework.NewResult(framework.Success)
}

// Score calculates the score on the candidate cluster.
func (p *ClusterAffinity) Score(ctx context.Context, placement *policyv1alpha1.Placement, cluster *clusterv1alpha1.Cluster) (float64, *framework.Result) {
	return 0, framework.NewResult(framework.Success)
}