/*
 * Copyright 2024 the KubeSphere Authors.
 * Please refer to the LICENSE file in the root directory of the project.
 * https://github.com/kubesphere/kubesphere/blob/master/LICENSE
 */

package storage

import (
	"strconv"

	"k8s.io/client-go/informers"

	v1 "k8s.io/api/core/v1"
	storageV1 "k8s.io/api/storage/v1"
	"k8s.io/apimachinery/pkg/api/resource"
	"k8s.io/apimachinery/pkg/labels"
)

type ScMetrics struct {
	Capacity  string `json:"capacity,omitempty"`
	Usage     string `json:"usage,omitempty"`
	PvcNumber string `json:"pvcNumber"`
}

type PersistentVolumeClaimGetter interface {
	GetPersistentVolumeClaimByStorageClass(storageClassName string) ([]*v1.PersistentVolumeClaim, error)
}

type persistentVolumeClaimGetter struct {
	informers informers.SharedInformerFactory
}

func NewPersistentVolumeClaimGetter(informers informers.SharedInformerFactory) PersistentVolumeClaimGetter {
	return &persistentVolumeClaimGetter{informers: informers}
}

func (c *persistentVolumeClaimGetter) GetPersistentVolumeClaimByStorageClass(scName string) ([]*v1.PersistentVolumeClaim, error) {
	persistentVolumeClaimLister := c.informers.Core().V1().PersistentVolumeClaims().Lister()
	all, err := persistentVolumeClaimLister.List(labels.Everything())

	if err != nil {
		return nil, err
	}

	result := make([]*v1.PersistentVolumeClaim, 0)

	for _, item := range all {
		if item.Spec.StorageClassName != nil {
			if *item.Spec.StorageClassName == scName {
				result = append(result, item.DeepCopy())
			}
		} else if item.GetAnnotations()[v1.BetaStorageClassAnnotation] == scName {
			result = append(result, item.DeepCopy())
		}
	}
	return result, nil
}

// Get info of metrics
func (c *persistentVolumeClaimGetter) GetScMetrics(scName string) (*ScMetrics, error) {
	persistentVolumeLister := c.informers.Core().V1().PersistentVolumes().Lister()
	pvList, err := persistentVolumeLister.List(labels.Everything())
	if err != nil {
		return nil, err
	}
	// Get PVC
	pvcList, err := c.GetPersistentVolumeClaimByStorageClass(scName)

	if err != nil {
		return nil, err
	}

	// Get storage usage
	// Gathering usage of a specific StorageClass
	var total resource.Quantity
	for _, volume := range pvList {
		if volume.Spec.StorageClassName != scName {
			continue
		}
		total.Add(volume.Spec.Capacity[v1.ResourceStorage])
	}
	usage := total.String()

	// Get PVC number
	pvcNum := len(pvcList)

	return &ScMetrics{Usage: usage, PvcNumber: strconv.Itoa(pvcNum)}, nil
}

// Get SC item list
func (c *persistentVolumeClaimGetter) GetScList() ([]*storageV1.StorageClass, error) {

	// Get StorageClass list
	scList, err := c.informers.Storage().V1().StorageClasses().Lister().List(labels.Everything())

	if err != nil {
		return nil, err
	}

	return scList, nil
}