package addon

import (
	"context"
	"fmt"

	"k8s.io/klog/v2"
	"k8s.io/utils/clock"

	clusterapiv1 "open-cluster-management.io/api/cluster/v1"
	clusterapiv1beta1 "open-cluster-management.io/api/cluster/v1beta1"

	"open-cluster-management.io/ocm/pkg/placement/controllers/framework"
	"open-cluster-management.io/ocm/pkg/placement/plugins"
)

const (
	placementLabel = clusterapiv1beta1.PlacementLabel
	description    = `
	Customize prioritizer get cluster scores from AddOnPlacementScores with sepcific
	resource name and score name. The clusters which doesn't have corresponding
	AddOnPlacementScores resource or has expired score is given score 0.
	`
)

var _ plugins.Prioritizer = &AddOn{}
var AddOnClock = clock.Clock(clock.RealClock{})

type AddOn struct {
	handle          plugins.Handle
	prioritizerName string
	resourceName    string
	scoreName       string
}

type AddOnBuilder struct {
	addOn *AddOn
}

func NewAddOnPrioritizerBuilder(handle plugins.Handle) *AddOnBuilder {
	return &AddOnBuilder{
		addOn: &AddOn{
			handle: handle,
		},
	}
}

func (c *AddOnBuilder) WithResourceName(name string) *AddOnBuilder {
	c.addOn.resourceName = name
	return c
}

func (c *AddOnBuilder) WithScoreName(name string) *AddOnBuilder {
	c.addOn.scoreName = name
	return c
}

func (c *AddOnBuilder) Build() *AddOn {
	c.addOn.prioritizerName = "AddOn" + "/" + c.addOn.resourceName + "/" + c.addOn.scoreName
	return c.addOn
}

func (c *AddOn) Name() string {
	return c.prioritizerName
}

func (c *AddOn) Description() string {
	return description
}

func (c *AddOn) Score(ctx context.Context, placement *clusterapiv1beta1.Placement,
	clusters []*clusterapiv1.ManagedCluster) (plugins.PluginScoreResult, *framework.Status) {
	scores := map[string]int64{}
	expiredScores := ""
	status := framework.NewStatus(c.Name(), framework.Success, "")

	for _, cluster := range clusters {
		namespace := cluster.Name
		// default score is 0
		scores[cluster.Name] = 0

		// get AddOnPlacementScores CR with resourceName
		addOnScores, err := c.handle.ScoreLister().AddOnPlacementScores(namespace).Get(c.resourceName)
		if err != nil {
			klog.FromContext(ctx).Info("Failed to get AddOnPlacementScores", "error", err)
			continue
		}

		// check score valid time
		if (addOnScores.Status.ValidUntil != nil) && AddOnClock.Now().After(addOnScores.Status.ValidUntil.Time) {
			expiredScores = fmt.Sprintf("%s %s/%s", expiredScores, namespace, c.resourceName)
			continue
		}

		// get AddOnPlacementScores score with scoreName
		for _, v := range addOnScores.Status.Scores {
			if v.Name == c.scoreName {
				scores[cluster.Name] = int64(v.Value)
			}
		}
	}

	if len(expiredScores) > 0 {
		status = framework.NewStatus(
			c.Name(),
			framework.Warning,
			fmt.Sprintf("AddOnPlacementScores%s expired", expiredScores),
		)
	}

	return plugins.PluginScoreResult{
		Scores: scores,
	}, status
}

func (c *AddOn) RequeueAfter(ctx context.Context, placement *clusterapiv1beta1.Placement) (plugins.PluginRequeueResult, *framework.Status) {
	return plugins.PluginRequeueResult{}, framework.NewStatus(c.Name(), framework.Success, "")
}