/*
Copyright 2020 The CDI Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package datavolume

import (
	"context"
	"fmt"
	"math"
	"strconv"

	"github.com/go-logr/logr"
	"github.com/pkg/errors"

	v1 "k8s.io/api/core/v1"
	storagev1 "k8s.io/api/storage/v1"
	"k8s.io/apimachinery/pkg/api/resource"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/client-go/tools/cache"
	"k8s.io/client-go/tools/record"
	storagehelpers "k8s.io/component-helpers/storage/volume"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/reconcile"

	cdiv1 "kubevirt.io/containerized-data-importer-api/pkg/apis/core/v1beta1"
	cc "kubevirt.io/containerized-data-importer/pkg/controller/common"
	"kubevirt.io/containerized-data-importer/pkg/util"
)

const (
	// AnnOwnedByDataVolume annotation has the owner DataVolume name
	AnnOwnedByDataVolume = "cdi.kubevirt.io/ownedByDataVolume"
)

// renderPvcSpec creates a new PVC Spec based on either the dv.spec.pvc or dv.spec.storage section
func renderPvcSpec(client client.Client, recorder record.EventRecorder, log logr.Logger, dv *cdiv1.DataVolume) (*v1.PersistentVolumeClaimSpec, error) {
	if dv.Spec.PVC != nil {
		return dv.Spec.PVC.DeepCopy(), nil
	}

	if dv.Spec.Storage != nil {
		return pvcFromStorage(client, recorder, log, dv)
	}

	return nil, errors.Errorf("datavolume one of {pvc, storage} field is required")
}

func pvcFromStorage(client client.Client, recorder record.EventRecorder, log logr.Logger, dv *cdiv1.DataVolume) (*v1.PersistentVolumeClaimSpec, error) {
	storage := dv.Spec.Storage
	pvcSpec := copyStorageAsPvc(log, storage)

	if dv.Spec.ContentType == cdiv1.DataVolumeArchive {
		if pvcSpec.VolumeMode != nil && *pvcSpec.VolumeMode == v1.PersistentVolumeBlock {
			log.V(1).Info("DataVolume with ContentType Archive cannot have block volumeMode", "namespace", dv.Namespace, "name", dv.Name)
			recorder.Eventf(dv, v1.EventTypeWarning, cc.ErrClaimNotValid, "DataVolume with ContentType Archive cannot have block volumeMode")
			return nil, errors.Errorf("DataVolume with ContentType Archive cannot have block volumeMode")
		}
		volumeMode := v1.PersistentVolumeFilesystem
		pvcSpec.VolumeMode = &volumeMode
	}

	storageClass, err := cc.GetStorageClassByName(client, storage.StorageClassName)
	if err != nil {
		return nil, err
	}

	if storageClass == nil {
		// Not even default storageClass on the cluster, cannot apply the defaults, verify spec is ok
		if len(pvcSpec.AccessModes) == 0 {
			log.V(1).Info("Cannot set accessMode for new pvc", "namespace", dv.Namespace, "name", dv.Name)
			recorder.Eventf(dv, v1.EventTypeWarning, cc.ErrClaimNotValid, "DataVolume.storage spec is missing accessMode and no storageClass to choose profile")
			return nil, errors.Errorf("DataVolume spec is missing accessMode")
		}
	} else {
		pvcSpec.StorageClassName = &storageClass.Name
		// given storageClass we can apply defaults if needed
		if (pvcSpec.VolumeMode == nil || *pvcSpec.VolumeMode == "") && (len(pvcSpec.AccessModes) == 0) {
			accessModes, volumeMode, err := getDefaultVolumeAndAccessMode(client, storageClass)
			if err != nil {
				log.V(1).Info("Cannot set accessMode and volumeMode for new pvc", "namespace", dv.Namespace, "name", dv.Name, "Error", err)
				recorder.Eventf(dv, v1.EventTypeWarning, cc.ErrClaimNotValid,
					fmt.Sprintf("DataVolume.storage spec is missing accessMode and volumeMode, cannot get access mode from StorageProfile %s", getName(storageClass)))
				return nil, err
			}
			pvcSpec.AccessModes = append(pvcSpec.AccessModes, accessModes...)
			pvcSpec.VolumeMode = volumeMode
		} else if len(pvcSpec.AccessModes) == 0 {
			accessModes, err := getDefaultAccessModes(client, storageClass, pvcSpec.VolumeMode)
			if err != nil {
				log.V(1).Info("Cannot set accessMode for new pvc", "namespace", dv.Namespace, "name", dv.Name, "Error", err)
				recorder.Eventf(dv, v1.EventTypeWarning, cc.ErrClaimNotValid,
					fmt.Sprintf("DataVolume.storage spec is missing accessMode and cannot get access mode from StorageProfile %s", getName(storageClass)))
				return nil, err
			}
			pvcSpec.AccessModes = append(pvcSpec.AccessModes, accessModes...)
		} else if pvcSpec.VolumeMode == nil || *pvcSpec.VolumeMode == "" {
			volumeMode, err := getDefaultVolumeMode(client, storageClass, pvcSpec.AccessModes)
			if err != nil {
				return nil, err
			}
			pvcSpec.VolumeMode = volumeMode
		}
	}

	requestedVolumeSize, err := resolveVolumeSize(client, dv.Spec, pvcSpec)
	if err != nil {
		return nil, err
	}
	if pvcSpec.Resources.Requests == nil {
		pvcSpec.Resources.Requests = v1.ResourceList{}
	}
	pvcSpec.Resources.Requests[v1.ResourceStorage] = *requestedVolumeSize

	return pvcSpec, nil
}

func getName(storageClass *storagev1.StorageClass) string {
	if storageClass != nil {
		return storageClass.Name
	}
	return ""
}

func copyStorageAsPvc(log logr.Logger, storage *cdiv1.StorageSpec) *v1.PersistentVolumeClaimSpec {
	input := storage.DeepCopy()
	pvcSpec := &v1.PersistentVolumeClaimSpec{
		AccessModes:      input.AccessModes,
		Selector:         input.Selector,
		Resources:        input.Resources,
		VolumeName:       input.VolumeName,
		StorageClassName: input.StorageClassName,
		VolumeMode:       input.VolumeMode,
		DataSource:       input.DataSource,
		DataSourceRef:    input.DataSourceRef,
	}

	return pvcSpec
}

func getDefaultVolumeAndAccessMode(c client.Client, storageClass *storagev1.StorageClass) ([]v1.PersistentVolumeAccessMode, *v1.PersistentVolumeMode, error) {
	if storageClass == nil {
		return nil, nil, errors.Errorf("no accessMode defined on DV and no StorageProfile")
	}

	storageProfile := &cdiv1.StorageProfile{}
	err := c.Get(context.TODO(), types.NamespacedName{Name: storageClass.Name}, storageProfile)
	if err != nil {
		return nil, nil, errors.Wrap(err, "cannot get StorageProfile")
	}

	if len(storageProfile.Status.ClaimPropertySets) > 0 &&
		len(storageProfile.Status.ClaimPropertySets[0].AccessModes) > 0 {
		accessModes := storageProfile.Status.ClaimPropertySets[0].AccessModes
		volumeMode := storageProfile.Status.ClaimPropertySets[0].VolumeMode
		return accessModes, volumeMode, nil
	}

	// no accessMode configured on storageProfile
	return nil, nil, errors.Errorf("no accessMode defined DV nor on StorageProfile for %s StorageClass", storageClass.Name)
}

func getDefaultVolumeMode(c client.Client, storageClass *storagev1.StorageClass, pvcAccessModes []v1.PersistentVolumeAccessMode) (*v1.PersistentVolumeMode, error) {
	if storageClass == nil {
		// fallback to k8s defaults
		return nil, nil
	}

	storageProfile := &cdiv1.StorageProfile{}
	err := c.Get(context.TODO(), types.NamespacedName{Name: storageClass.Name}, storageProfile)
	if err != nil {
		return nil, errors.Wrap(err, "cannot get StorageProfile")
	}
	if len(storageProfile.Status.ClaimPropertySets) > 0 {
		volumeMode := storageProfile.Status.ClaimPropertySets[0].VolumeMode
		if len(pvcAccessModes) == 0 {
			return volumeMode, nil
		}
		// check for volume mode matching with given pvc access modes
		for _, cps := range storageProfile.Status.ClaimPropertySets {
			for _, accessMode := range cps.AccessModes {
				for _, pvcAccessMode := range pvcAccessModes {
					if accessMode == pvcAccessMode {
						return cps.VolumeMode, nil
					}
				}
			}
		}
		// if not found return default volume mode for the storage class
		return volumeMode, nil
	}

	// since volumeMode is optional - > gracefully fallback to k8s defaults,
	return nil, nil
}

func getDefaultAccessModes(c client.Client, storageClass *storagev1.StorageClass, pvcVolumeMode *v1.PersistentVolumeMode) ([]v1.PersistentVolumeAccessMode, error) {
	if storageClass == nil {
		return nil, errors.Errorf("no accessMode defined on DV, no StorageProfile ")
	}

	storageProfile := &cdiv1.StorageProfile{}
	err := c.Get(context.TODO(), types.NamespacedName{Name: storageClass.Name}, storageProfile)
	if err != nil {
		return nil, errors.Wrap(err, "no accessMode defined on DV, cannot get StorageProfile")
	}

	if len(storageProfile.Status.ClaimPropertySets) > 0 {
		// check for access modes matching with given pvc volume mode
		defaultAccessModes := []v1.PersistentVolumeAccessMode{}
		for _, cps := range storageProfile.Status.ClaimPropertySets {
			if cps.VolumeMode != nil && pvcVolumeMode != nil && *cps.VolumeMode == *pvcVolumeMode {
				if len(cps.AccessModes) > 0 {
					return cps.AccessModes, nil
				}
			} else if len(cps.AccessModes) > 0 && len(defaultAccessModes) == 0 {
				defaultAccessModes = cps.AccessModes
			}
		}
		// if not found return default access modes for the storage profile
		if len(defaultAccessModes) > 0 {
			return defaultAccessModes, nil
		}
	}

	// no accessMode configured on storageProfile
	return nil, errors.Errorf("no accessMode defined on StorageProfile for %s StorageClass", storageClass.Name)
}

func resolveVolumeSize(c client.Client, dvSpec cdiv1.DataVolumeSpec, pvcSpec *v1.PersistentVolumeClaimSpec) (*resource.Quantity, error) {
	// resources.requests[storage] - just copy it to pvc,
	requestedSize, found := dvSpec.Storage.Resources.Requests[v1.ResourceStorage]

	if !found {
		// Storage size can be empty when cloning
		isClone := dvSpec.Source.PVC != nil
		if isClone {
			return &requestedSize, nil
		}
		return nil, errors.Errorf("Datavolume Spec is not valid - missing storage size")
	}

	// disk or image size, inflate it with overhead
	requestedSize, err := inflateSizeWithOverhead(c, requestedSize.Value(), pvcSpec)

	return &requestedSize, err
}

// inflateSizeWithOverhead inflates a storage size with proper overhead calculations
func inflateSizeWithOverhead(c client.Client, imgSize int64, pvcSpec *v1.PersistentVolumeClaimSpec) (resource.Quantity, error) {
	var returnSize resource.Quantity

	if util.ResolveVolumeMode(pvcSpec.VolumeMode) == v1.PersistentVolumeFilesystem {
		fsOverhead, err := cc.GetFilesystemOverheadForStorageClass(c, pvcSpec.StorageClassName)
		if err != nil {
			return resource.Quantity{}, err
		}
		// Parse filesystem overhead (percentage) into a 64-bit float
		fsOverheadFloat, _ := strconv.ParseFloat(string(fsOverhead), 64)

		// Merge the previous values into a 'resource.Quantity' struct
		requiredSpace := GetRequiredSpace(fsOverheadFloat, imgSize)
		returnSize = *resource.NewScaledQuantity(requiredSpace, 0)
	} else {
		// Inflation is not needed with 'Block' mode
		returnSize = *resource.NewScaledQuantity(imgSize, 0)
	}

	return returnSize, nil
}

// GetRequiredSpace calculates space required taking file system overhead into account
func GetRequiredSpace(filesystemOverhead float64, requestedSpace int64) int64 {
	// the `image` has to be aligned correctly, so the space requested has to be aligned to
	// next value that is a multiple of a block size
	alignedSize := util.RoundUp(requestedSpace, util.DefaultAlignBlockSize)

	// count overhead as a percentage of the whole/new size, including aligned image
	// and the space required by filesystem metadata
	spaceWithOverhead := int64(math.Ceil(float64(alignedSize) / (1 - filesystemOverhead)))
	return spaceWithOverhead
}

func createStorageProfile(name string,
	accessModes []v1.PersistentVolumeAccessMode,
	volumeMode v1.PersistentVolumeMode) *cdiv1.StorageProfile {
	claimPropertySets := []cdiv1.ClaimPropertySet{{
		AccessModes: accessModes,
		VolumeMode:  &volumeMode,
	}}
	return createStorageProfileWithClaimPropertySets(name, claimPropertySets)
}

func createStorageProfileWithClaimPropertySets(name string,
	claimPropertySets []cdiv1.ClaimPropertySet) *cdiv1.StorageProfile {
	return createStorageProfileWithCloneStrategy(name, claimPropertySets, nil)
}

func createStorageProfileWithCloneStrategy(name string,
	claimPropertySets []cdiv1.ClaimPropertySet,
	cloneStrategy *cdiv1.CDICloneStrategy) *cdiv1.StorageProfile {

	return &cdiv1.StorageProfile{
		ObjectMeta: metav1.ObjectMeta{
			Name: name,
		},
		Status: cdiv1.StorageProfileStatus{
			StorageClass:      &name,
			ClaimPropertySets: claimPropertySets,
			CloneStrategy:     cloneStrategy,
		},
	}
}

func hasAnnOwnedByDataVolume(obj metav1.Object) bool {
	_, ok := obj.GetAnnotations()[AnnOwnedByDataVolume]
	return ok
}

func getAnnOwnedByDataVolume(obj metav1.Object) (string, string, error) {
	val := obj.GetAnnotations()[AnnOwnedByDataVolume]
	return cache.SplitMetaNamespaceKey(val)
}

func setAnnOwnedByDataVolume(dest, obj metav1.Object) error {
	key, err := cache.MetaNamespaceKeyFunc(obj)
	if err != nil {
		return err
	}

	if dest.GetAnnotations() == nil {
		dest.SetAnnotations(make(map[string]string))
	}
	dest.GetAnnotations()[AnnOwnedByDataVolume] = key

	return nil
}

// adapted from k8s.io/kubernetes/pkg/controller/volume/persistentvolume/pv_controller.go
// checkVolumeSatisfyClaim checks if the volume requested by the claim satisfies the requirements of the claim
func checkVolumeSatisfyClaim(volume *v1.PersistentVolume, claim *v1.PersistentVolumeClaim) error {
	requestedQty := claim.Spec.Resources.Requests[v1.ResourceName(v1.ResourceStorage)]
	requestedSize := requestedQty.Value()

	// check if PV's DeletionTimeStamp is set, if so, return error.
	if volume.ObjectMeta.DeletionTimestamp != nil {
		return fmt.Errorf("the volume is marked for deletion %q", volume.Name)
	}

	volumeQty := volume.Spec.Capacity[v1.ResourceStorage]
	volumeSize := volumeQty.Value()
	if volumeSize < requestedSize {
		return fmt.Errorf("requested PV is too small")
	}

	// this differs from pv_controller, be loose on storage class if not specified
	requestedClass := storagehelpers.GetPersistentVolumeClaimClass(claim)
	if requestedClass != "" && storagehelpers.GetPersistentVolumeClass(volume) != requestedClass {
		return fmt.Errorf("storageClassName does not match")
	}

	if storagehelpers.CheckVolumeModeMismatches(&claim.Spec, &volume.Spec) {
		return fmt.Errorf("incompatible volumeMode")
	}

	if !storagehelpers.CheckAccessModes(claim, volume) {
		return fmt.Errorf("incompatible accessMode")
	}

	return nil
}

func getReconcileRequest(obj client.Object) reconcile.Request {
	return reconcile.Request{NamespacedName: client.ObjectKeyFromObject(obj)}
}