/*
Copyright 2014 The Kubernetes Authors.
Copyright 2020 Authors of Arktos - file modified.

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 helper

import (
	"encoding/json"
	"fmt"
	"strings"

	"k8s.io/apimachinery/pkg/api/resource"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/conversion"
	"k8s.io/apimachinery/pkg/fields"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apimachinery/pkg/selection"
	"k8s.io/apimachinery/pkg/util/sets"
	"k8s.io/apimachinery/pkg/util/validation"
	"k8s.io/kubernetes/pkg/apis/core"
)

// IsHugePageResourceName returns true if the resource name has the huge page
// resource prefix.
func IsHugePageResourceName(name core.ResourceName) bool {
	return strings.HasPrefix(string(name), core.ResourceHugePagesPrefix)
}

// IsQuotaHugePageResourceName returns true if the resource name has the quota
// related huge page resource prefix.
func IsQuotaHugePageResourceName(name core.ResourceName) bool {
	return strings.HasPrefix(string(name), core.ResourceHugePagesPrefix) || strings.HasPrefix(string(name), core.ResourceRequestsHugePagesPrefix)
}

// HugePageResourceName returns a ResourceName with the canonical hugepage
// prefix prepended for the specified page size.  The page size is converted
// to its canonical representation.
func HugePageResourceName(pageSize resource.Quantity) core.ResourceName {
	return core.ResourceName(fmt.Sprintf("%s%s", core.ResourceHugePagesPrefix, pageSize.String()))
}

// HugePageSizeFromResourceName returns the page size for the specified huge page
// resource name.  If the specified input is not a valid huge page resource name
// an error is returned.
func HugePageSizeFromResourceName(name core.ResourceName) (resource.Quantity, error) {
	if !IsHugePageResourceName(name) {
		return resource.Quantity{}, fmt.Errorf("resource name: %s is an invalid hugepage name", name)
	}
	pageSize := strings.TrimPrefix(string(name), core.ResourceHugePagesPrefix)
	return resource.ParseQuantity(pageSize)
}

// NonConvertibleFields iterates over the provided map and filters out all but
// any keys with the "non-convertible.kubernetes.io" prefix.
func NonConvertibleFields(annotations map[string]string) map[string]string {
	nonConvertibleKeys := map[string]string{}
	for key, value := range annotations {
		if strings.HasPrefix(key, core.NonConvertibleAnnotationPrefix) {
			nonConvertibleKeys[key] = value
		}
	}
	return nonConvertibleKeys
}

// Semantic can do semantic deep equality checks for core objects.
// Example: apiequality.Semantic.DeepEqual(aPod, aPodWithNonNilButEmptyMaps) == true
var Semantic = conversion.EqualitiesOrDie(
	func(a, b resource.Quantity) bool {
		// Ignore formatting, only care that numeric value stayed the same.
		// TODO: if we decide it's important, it should be safe to start comparing the format.
		//
		// Uninitialized quantities are equivalent to 0 quantities.
		return a.Cmp(b) == 0
	},
	func(a, b metav1.MicroTime) bool {
		return a.UTC() == b.UTC()
	},
	func(a, b metav1.Time) bool {
		return a.UTC() == b.UTC()
	},
	func(a, b labels.Selector) bool {
		return a.String() == b.String()
	},
	func(a, b fields.Selector) bool {
		return a.String() == b.String()
	},
)

var standardResourceQuotaScopes = sets.NewString(
	string(core.ResourceQuotaScopeTerminating),
	string(core.ResourceQuotaScopeNotTerminating),
	string(core.ResourceQuotaScopeBestEffort),
	string(core.ResourceQuotaScopeNotBestEffort),
	string(core.ResourceQuotaScopePriorityClass),
)

// IsStandardResourceQuotaScope returns true if the scope is a standard value
func IsStandardResourceQuotaScope(str string) bool {
	return standardResourceQuotaScopes.Has(str)
}

var podObjectCountQuotaResources = sets.NewString(
	string(core.ResourcePods),
)

var podComputeQuotaResources = sets.NewString(
	string(core.ResourceCPU),
	string(core.ResourceMemory),
	string(core.ResourceLimitsCPU),
	string(core.ResourceLimitsMemory),
	string(core.ResourceRequestsCPU),
	string(core.ResourceRequestsMemory),
)

// IsResourceQuotaScopeValidForResource returns true if the resource applies to the specified scope
func IsResourceQuotaScopeValidForResource(scope core.ResourceQuotaScope, resource string) bool {
	switch scope {
	case core.ResourceQuotaScopeTerminating, core.ResourceQuotaScopeNotTerminating, core.ResourceQuotaScopeNotBestEffort, core.ResourceQuotaScopePriorityClass:
		return podObjectCountQuotaResources.Has(resource) || podComputeQuotaResources.Has(resource)
	case core.ResourceQuotaScopeBestEffort:
		return podObjectCountQuotaResources.Has(resource)
	default:
		return true
	}
}

var standardContainerResources = sets.NewString(
	string(core.ResourceCPU),
	string(core.ResourceMemory),
	string(core.ResourceEphemeralStorage),
)

// IsStandardContainerResourceName returns true if the container can make a resource request
// for the specified resource
func IsStandardContainerResourceName(str string) bool {
	return standardContainerResources.Has(str) || IsHugePageResourceName(core.ResourceName(str))
}

// IsExtendedResourceName returns true if:
// 1. the resource name is not in the default namespace;
// 2. resource name does not have "requests." prefix,
// to avoid confusion with the convention in quota
// 3. it satisfies the rules in IsQualifiedName() after converted into quota resource name
func IsExtendedResourceName(name core.ResourceName) bool {
	if IsNativeResource(name) || strings.HasPrefix(string(name), core.DefaultResourceRequestsPrefix) {
		return false
	}
	// Ensure it satisfies the rules in IsQualifiedName() after converted into quota resource name
	nameForQuota := fmt.Sprintf("%s%s", core.DefaultResourceRequestsPrefix, string(name))
	if errs := validation.IsQualifiedName(string(nameForQuota)); len(errs) != 0 {
		return false
	}
	return true
}

// IsNativeResource returns true if the resource name is in the
// *kubernetes.io/ namespace. Partially-qualified (unprefixed) names are
// implicitly in the kubernetes.io/ namespace.
func IsNativeResource(name core.ResourceName) bool {
	return !strings.Contains(string(name), "/") ||
		strings.Contains(string(name), core.ResourceDefaultNamespacePrefix)
}

// IsOvercommitAllowed returns true if the resource is in the default
// namespace and is not hugepages.
func IsOvercommitAllowed(name core.ResourceName) bool {
	return IsNativeResource(name) &&
		!IsHugePageResourceName(name)
}

var standardLimitRangeTypes = sets.NewString(
	string(core.LimitTypePod),
	string(core.LimitTypeContainer),
	string(core.LimitTypePersistentVolumeClaim),
)

// IsStandardLimitRangeType returns true if the type is Pod or Container
func IsStandardLimitRangeType(str string) bool {
	return standardLimitRangeTypes.Has(str)
}

var standardQuotaResources = sets.NewString(
	string(core.ResourceCPU),
	string(core.ResourceMemory),
	string(core.ResourceEphemeralStorage),
	string(core.ResourceRequestsCPU),
	string(core.ResourceRequestsMemory),
	string(core.ResourceRequestsStorage),
	string(core.ResourceRequestsEphemeralStorage),
	string(core.ResourceLimitsCPU),
	string(core.ResourceLimitsMemory),
	string(core.ResourceLimitsEphemeralStorage),
	string(core.ResourcePods),
	string(core.ResourceQuotas),
	string(core.ResourceServices),
	string(core.ResourceReplicationControllers),
	string(core.ResourceSecrets),
	string(core.ResourcePersistentVolumeClaims),
	string(core.ResourceConfigMaps),
	string(core.ResourceServicesNodePorts),
	string(core.ResourceServicesLoadBalancers),
)

// IsStandardQuotaResourceName returns true if the resource is known to
// the quota tracking system
func IsStandardQuotaResourceName(str string) bool {
	return standardQuotaResources.Has(str) || IsQuotaHugePageResourceName(core.ResourceName(str))
}

var standardResources = sets.NewString(
	string(core.ResourceCPU),
	string(core.ResourceMemory),
	string(core.ResourceEphemeralStorage),
	string(core.ResourceRequestsCPU),
	string(core.ResourceRequestsMemory),
	string(core.ResourceRequestsEphemeralStorage),
	string(core.ResourceLimitsCPU),
	string(core.ResourceLimitsMemory),
	string(core.ResourceLimitsEphemeralStorage),
	string(core.ResourcePods),
	string(core.ResourceQuotas),
	string(core.ResourceServices),
	string(core.ResourceReplicationControllers),
	string(core.ResourceSecrets),
	string(core.ResourceConfigMaps),
	string(core.ResourcePersistentVolumeClaims),
	string(core.ResourceStorage),
	string(core.ResourceRequestsStorage),
	string(core.ResourceServicesNodePorts),
	string(core.ResourceServicesLoadBalancers),
)

// IsStandardResourceName returns true if the resource is known to the system
func IsStandardResourceName(str string) bool {
	return standardResources.Has(str) || IsQuotaHugePageResourceName(core.ResourceName(str))
}

var integerResources = sets.NewString(
	string(core.ResourcePods),
	string(core.ResourceQuotas),
	string(core.ResourceServices),
	string(core.ResourceReplicationControllers),
	string(core.ResourceSecrets),
	string(core.ResourceConfigMaps),
	string(core.ResourcePersistentVolumeClaims),
	string(core.ResourceServicesNodePorts),
	string(core.ResourceServicesLoadBalancers),
)

// IsIntegerResourceName returns true if the resource is measured in integer values
func IsIntegerResourceName(str string) bool {
	return integerResources.Has(str) || IsExtendedResourceName(core.ResourceName(str))
}

// IsServiceIPSet aims to check if the service's ClusterIP is set or not
// the objective is not to perform validation here
func IsServiceIPSet(service *core.Service) bool {
	return service.Spec.ClusterIP != core.ClusterIPNone && service.Spec.ClusterIP != ""
}

var standardFinalizers = sets.NewString(
	string(core.FinalizerArktos),
	string(core.FinalizerKubernetes),
	metav1.FinalizerOrphanDependents,
	metav1.FinalizerDeleteDependents,
)

// IsStandardFinalizerName checks if the input string is a standard finalizer name
func IsStandardFinalizerName(str string) bool {
	return standardFinalizers.Has(str)
}

// LoadBalancerStatusEqual checks if the status of the load balancer is equal to the target status
// TODO: make method on LoadBalancerStatus?
func LoadBalancerStatusEqual(l, r *core.LoadBalancerStatus) bool {
	return ingressSliceEqual(l.Ingress, r.Ingress)
}

func ingressSliceEqual(lhs, rhs []core.LoadBalancerIngress) bool {
	if len(lhs) != len(rhs) {
		return false
	}
	for i := range lhs {
		if !ingressEqual(&lhs[i], &rhs[i]) {
			return false
		}
	}
	return true
}

func ingressEqual(lhs, rhs *core.LoadBalancerIngress) bool {
	if lhs.IP != rhs.IP {
		return false
	}
	if lhs.Hostname != rhs.Hostname {
		return false
	}
	return true
}

// GetAccessModesAsString returns a string representation of an array of access modes.
// modes, when present, are always in the same order: RWO,ROX,RWX.
func GetAccessModesAsString(modes []core.PersistentVolumeAccessMode) string {
	modes = removeDuplicateAccessModes(modes)
	modesStr := []string{}
	if containsAccessMode(modes, core.ReadWriteOnce) {
		modesStr = append(modesStr, "RWO")
	}
	if containsAccessMode(modes, core.ReadOnlyMany) {
		modesStr = append(modesStr, "ROX")
	}
	if containsAccessMode(modes, core.ReadWriteMany) {
		modesStr = append(modesStr, "RWX")
	}
	return strings.Join(modesStr, ",")
}

// GetAccessModesFromString returns an array of AccessModes from a string created by GetAccessModesAsString
func GetAccessModesFromString(modes string) []core.PersistentVolumeAccessMode {
	strmodes := strings.Split(modes, ",")
	accessModes := []core.PersistentVolumeAccessMode{}
	for _, s := range strmodes {
		s = strings.Trim(s, " ")
		switch {
		case s == "RWO":
			accessModes = append(accessModes, core.ReadWriteOnce)
		case s == "ROX":
			accessModes = append(accessModes, core.ReadOnlyMany)
		case s == "RWX":
			accessModes = append(accessModes, core.ReadWriteMany)
		}
	}
	return accessModes
}

// removeDuplicateAccessModes returns an array of access modes without any duplicates
func removeDuplicateAccessModes(modes []core.PersistentVolumeAccessMode) []core.PersistentVolumeAccessMode {
	accessModes := []core.PersistentVolumeAccessMode{}
	for _, m := range modes {
		if !containsAccessMode(accessModes, m) {
			accessModes = append(accessModes, m)
		}
	}
	return accessModes
}

func containsAccessMode(modes []core.PersistentVolumeAccessMode, mode core.PersistentVolumeAccessMode) bool {
	for _, m := range modes {
		if m == mode {
			return true
		}
	}
	return false
}

// NodeSelectorRequirementsAsSelector converts the []NodeSelectorRequirement core type into a struct that implements
// labels.Selector.
func NodeSelectorRequirementsAsSelector(nsm []core.NodeSelectorRequirement) (labels.Selector, error) {
	if len(nsm) == 0 {
		return labels.Nothing(), nil
	}
	selector := labels.NewSelector()
	for _, expr := range nsm {
		var op selection.Operator
		switch expr.Operator {
		case core.NodeSelectorOpIn:
			op = selection.In
		case core.NodeSelectorOpNotIn:
			op = selection.NotIn
		case core.NodeSelectorOpExists:
			op = selection.Exists
		case core.NodeSelectorOpDoesNotExist:
			op = selection.DoesNotExist
		case core.NodeSelectorOpGt:
			op = selection.GreaterThan
		case core.NodeSelectorOpLt:
			op = selection.LessThan
		default:
			return nil, fmt.Errorf("%q is not a valid node selector operator", expr.Operator)
		}
		r, err := labels.NewRequirement(expr.Key, op, expr.Values)
		if err != nil {
			return nil, err
		}
		selector = selector.Add(*r)
	}
	return selector, nil
}

// NodeSelectorRequirementsAsFieldSelector converts the []NodeSelectorRequirement core type into a struct that implements
// fields.Selector.
func NodeSelectorRequirementsAsFieldSelector(nsm []core.NodeSelectorRequirement) (fields.Selector, error) {
	if len(nsm) == 0 {
		return fields.Nothing(), nil
	}

	selectors := []fields.Selector{}
	for _, expr := range nsm {
		switch expr.Operator {
		case core.NodeSelectorOpIn:
			if len(expr.Values) != 1 {
				return nil, fmt.Errorf("unexpected number of value (%d) for node field selector operator %q",
					len(expr.Values), expr.Operator)
			}
			selectors = append(selectors, fields.OneTermEqualSelector(expr.Key, expr.Values[0]))

		case core.NodeSelectorOpNotIn:
			if len(expr.Values) != 1 {
				return nil, fmt.Errorf("unexpected number of value (%d) for node field selector operator %q",
					len(expr.Values), expr.Operator)
			}
			selectors = append(selectors, fields.OneTermNotEqualSelector(expr.Key, expr.Values[0]))

		default:
			return nil, fmt.Errorf("%q is not a valid node field selector operator", expr.Operator)
		}
	}

	return fields.AndSelectors(selectors...), nil
}

// GetTolerationsFromPodAnnotations gets the json serialized tolerations data from Pod.Annotations
// and converts it to the []Toleration type in core.
func GetTolerationsFromPodAnnotations(annotations map[string]string) ([]core.Toleration, error) {
	var tolerations []core.Toleration
	if len(annotations) > 0 && annotations[core.TolerationsAnnotationKey] != "" {
		err := json.Unmarshal([]byte(annotations[core.TolerationsAnnotationKey]), &tolerations)
		if err != nil {
			return tolerations, err
		}
	}
	return tolerations, nil
}

// AddOrUpdateTolerationInPod tries to add a toleration to the pod's toleration list.
// Returns true if something was updated, false otherwise.
func AddOrUpdateTolerationInPod(pod *core.Pod, toleration *core.Toleration) bool {
	podTolerations := pod.Spec.Tolerations

	var newTolerations []core.Toleration
	updated := false
	for i := range podTolerations {
		if toleration.MatchToleration(&podTolerations[i]) {
			if Semantic.DeepEqual(toleration, podTolerations[i]) {
				return false
			}
			newTolerations = append(newTolerations, *toleration)
			updated = true
			continue
		}

		newTolerations = append(newTolerations, podTolerations[i])
	}

	if !updated {
		newTolerations = append(newTolerations, *toleration)
	}

	pod.Spec.Tolerations = newTolerations
	return true
}

// GetTaintsFromNodeAnnotations gets the json serialized taints data from Pod.Annotations
// and converts it to the []Taint type in core.
func GetTaintsFromNodeAnnotations(annotations map[string]string) ([]core.Taint, error) {
	var taints []core.Taint
	if len(annotations) > 0 && annotations[core.TaintsAnnotationKey] != "" {
		err := json.Unmarshal([]byte(annotations[core.TaintsAnnotationKey]), &taints)
		if err != nil {
			return []core.Taint{}, err
		}
	}
	return taints, nil
}

// GetPersistentVolumeClass returns StorageClassName.
func GetPersistentVolumeClass(volume *core.PersistentVolume) string {
	// Use beta annotation first
	if class, found := volume.Annotations[core.BetaStorageClassAnnotation]; found {
		return class
	}

	return volume.Spec.StorageClassName
}

// GetPersistentVolumeClaimClass returns StorageClassName. If no storage class was
// requested, it returns "".
func GetPersistentVolumeClaimClass(claim *core.PersistentVolumeClaim) string {
	// Use beta annotation first
	if class, found := claim.Annotations[core.BetaStorageClassAnnotation]; found {
		return class
	}

	if claim.Spec.StorageClassName != nil {
		return *claim.Spec.StorageClassName
	}

	return ""
}

// PersistentVolumeClaimHasClass returns true if given claim has set StorageClassName field.
func PersistentVolumeClaimHasClass(claim *core.PersistentVolumeClaim) bool {
	// Use beta annotation first
	if _, found := claim.Annotations[core.BetaStorageClassAnnotation]; found {
		return true
	}

	if claim.Spec.StorageClassName != nil {
		return true
	}

	return false
}
