/*
Copyright 2015 The Kubernetes 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 pod

import (
	"strings"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	utilfeature "k8s.io/apiserver/pkg/util/feature"
	api "k8s.io/kubernetes/pkg/apis/core"
	"k8s.io/kubernetes/pkg/features"
	"k8s.io/kubernetes/pkg/security/apparmor"
)

// Visitor is called with each object name, and returns true if visiting should continue
type Visitor func(name string) (shouldContinue bool)

// VisitPodSecretNames invokes the visitor function with the name of every secret
// referenced by the pod spec. If visitor returns false, visiting is short-circuited.
// Transitive references (e.g. pod -> pvc -> pv -> secret) are not visited.
// Returns true if visiting completed, false if visiting was short-circuited.
func VisitPodSecretNames(pod *api.Pod, visitor Visitor) bool {
	for _, reference := range pod.Spec.ImagePullSecrets {
		if !visitor(reference.Name) {
			return false
		}
	}
	for i := range pod.Spec.InitContainers {
		if !visitContainerSecretNames(&pod.Spec.InitContainers[i], visitor) {
			return false
		}
	}
	for i := range pod.Spec.Containers {
		if !visitContainerSecretNames(&pod.Spec.Containers[i], visitor) {
			return false
		}
	}
	var source *api.VolumeSource
	for i := range pod.Spec.Volumes {
		source = &pod.Spec.Volumes[i].VolumeSource
		switch {
		case source.AzureFile != nil:
			if len(source.AzureFile.SecretName) > 0 && !visitor(source.AzureFile.SecretName) {
				return false
			}
		case source.CephFS != nil:
			if source.CephFS.SecretRef != nil && !visitor(source.CephFS.SecretRef.Name) {
				return false
			}
		case source.Cinder != nil:
			if source.Cinder.SecretRef != nil && !visitor(source.Cinder.SecretRef.Name) {
				return false
			}
		case source.FlexVolume != nil:
			if source.FlexVolume.SecretRef != nil && !visitor(source.FlexVolume.SecretRef.Name) {
				return false
			}
		case source.Projected != nil:
			for j := range source.Projected.Sources {
				if source.Projected.Sources[j].Secret != nil {
					if !visitor(source.Projected.Sources[j].Secret.Name) {
						return false
					}
				}
			}
		case source.RBD != nil:
			if source.RBD.SecretRef != nil && !visitor(source.RBD.SecretRef.Name) {
				return false
			}
		case source.Secret != nil:
			if !visitor(source.Secret.SecretName) {
				return false
			}
		case source.ScaleIO != nil:
			if source.ScaleIO.SecretRef != nil && !visitor(source.ScaleIO.SecretRef.Name) {
				return false
			}
		case source.ISCSI != nil:
			if source.ISCSI.SecretRef != nil && !visitor(source.ISCSI.SecretRef.Name) {
				return false
			}
		case source.StorageOS != nil:
			if source.StorageOS.SecretRef != nil && !visitor(source.StorageOS.SecretRef.Name) {
				return false
			}
		case source.CSI != nil:
			if source.CSI.NodePublishSecretRef != nil && !visitor(source.CSI.NodePublishSecretRef.Name) {
				return false
			}
		}
	}
	return true
}

func visitContainerSecretNames(container *api.Container, visitor Visitor) bool {
	for _, env := range container.EnvFrom {
		if env.SecretRef != nil {
			if !visitor(env.SecretRef.Name) {
				return false
			}
		}
	}
	for _, envVar := range container.Env {
		if envVar.ValueFrom != nil && envVar.ValueFrom.SecretKeyRef != nil {
			if !visitor(envVar.ValueFrom.SecretKeyRef.Name) {
				return false
			}
		}
	}
	return true
}

// VisitPodConfigmapNames invokes the visitor function with the name of every configmap
// referenced by the pod spec. If visitor returns false, visiting is short-circuited.
// Transitive references (e.g. pod -> pvc -> pv -> secret) are not visited.
// Returns true if visiting completed, false if visiting was short-circuited.
func VisitPodConfigmapNames(pod *api.Pod, visitor Visitor) bool {
	for i := range pod.Spec.InitContainers {
		if !visitContainerConfigmapNames(&pod.Spec.InitContainers[i], visitor) {
			return false
		}
	}
	for i := range pod.Spec.Containers {
		if !visitContainerConfigmapNames(&pod.Spec.Containers[i], visitor) {
			return false
		}
	}
	var source *api.VolumeSource
	for i := range pod.Spec.Volumes {
		source = &pod.Spec.Volumes[i].VolumeSource
		switch {
		case source.Projected != nil:
			for j := range source.Projected.Sources {
				if source.Projected.Sources[j].ConfigMap != nil {
					if !visitor(source.Projected.Sources[j].ConfigMap.Name) {
						return false
					}
				}
			}
		case source.ConfigMap != nil:
			if !visitor(source.ConfigMap.Name) {
				return false
			}
		}
	}
	return true
}

func visitContainerConfigmapNames(container *api.Container, visitor Visitor) bool {
	for _, env := range container.EnvFrom {
		if env.ConfigMapRef != nil {
			if !visitor(env.ConfigMapRef.Name) {
				return false
			}
		}
	}
	for _, envVar := range container.Env {
		if envVar.ValueFrom != nil && envVar.ValueFrom.ConfigMapKeyRef != nil {
			if !visitor(envVar.ValueFrom.ConfigMapKeyRef.Name) {
				return false
			}
		}
	}
	return true
}

// IsPodReady returns true if a pod is ready; false otherwise.
func IsPodReady(pod *api.Pod) bool {
	return IsPodReadyConditionTrue(pod.Status)
}

// IsPodReadyConditionTrue returns true if a pod is ready; false otherwise.
func IsPodReadyConditionTrue(status api.PodStatus) bool {
	condition := GetPodReadyCondition(status)
	return condition != nil && condition.Status == api.ConditionTrue
}

// GetPodReadyCondition extracts the pod ready condition from the given status and returns that.
// Returns nil if the condition is not present.
func GetPodReadyCondition(status api.PodStatus) *api.PodCondition {
	_, condition := GetPodCondition(&status, api.PodReady)
	return condition
}

// GetPodCondition extracts the provided condition from the given status and returns that.
// Returns nil and -1 if the condition is not present, and the index of the located condition.
func GetPodCondition(status *api.PodStatus, conditionType api.PodConditionType) (int, *api.PodCondition) {
	if status == nil {
		return -1, nil
	}
	for i := range status.Conditions {
		if status.Conditions[i].Type == conditionType {
			return i, &status.Conditions[i]
		}
	}
	return -1, nil
}

// UpdatePodCondition updates existing pod condition or creates a new one. Sets LastTransitionTime to now if the
// status has changed.
// Returns true if pod condition has changed or has been added.
func UpdatePodCondition(status *api.PodStatus, condition *api.PodCondition) bool {
	condition.LastTransitionTime = metav1.Now()
	// Try to find this pod condition.
	conditionIndex, oldCondition := GetPodCondition(status, condition.Type)

	if oldCondition == nil {
		// We are adding new pod condition.
		status.Conditions = append(status.Conditions, *condition)
		return true
	}
	// We are updating an existing condition, so we need to check if it has changed.
	if condition.Status == oldCondition.Status {
		condition.LastTransitionTime = oldCondition.LastTransitionTime
	}

	isEqual := condition.Status == oldCondition.Status &&
		condition.Reason == oldCondition.Reason &&
		condition.Message == oldCondition.Message &&
		condition.LastProbeTime.Equal(&oldCondition.LastProbeTime) &&
		condition.LastTransitionTime.Equal(&oldCondition.LastTransitionTime)

	status.Conditions[conditionIndex] = *condition
	// Return true if one of the fields have changed.
	return !isEqual
}

// DropDisabledTemplateFields removes disabled fields from the pod template metadata and spec.
// This should be called from PrepareForCreate/PrepareForUpdate for all resources containing a PodTemplateSpec
func DropDisabledTemplateFields(podTemplate, oldPodTemplate *api.PodTemplateSpec) {
	var (
		podSpec           *api.PodSpec
		podAnnotations    map[string]string
		oldPodSpec        *api.PodSpec
		oldPodAnnotations map[string]string
	)
	if podTemplate != nil {
		podSpec = &podTemplate.Spec
		podAnnotations = podTemplate.Annotations
	}
	if oldPodTemplate != nil {
		oldPodSpec = &oldPodTemplate.Spec
		oldPodAnnotations = oldPodTemplate.Annotations
	}
	dropDisabledFields(podSpec, podAnnotations, oldPodSpec, oldPodAnnotations)
}

// DropDisabledPodFields removes disabled fields from the pod metadata and spec.
// This should be called from PrepareForCreate/PrepareForUpdate for all resources containing a Pod
func DropDisabledPodFields(pod, oldPod *api.Pod) {
	var (
		podSpec           *api.PodSpec
		podAnnotations    map[string]string
		oldPodSpec        *api.PodSpec
		oldPodAnnotations map[string]string
	)
	if pod != nil {
		podSpec = &pod.Spec
		podAnnotations = pod.Annotations
	}
	if oldPod != nil {
		oldPodSpec = &oldPod.Spec
		oldPodAnnotations = oldPod.Annotations
	}
	dropDisabledFields(podSpec, podAnnotations, oldPodSpec, oldPodAnnotations)
}

// dropDisabledFields removes disabled fields from the pod metadata and spec.
func dropDisabledFields(
	podSpec *api.PodSpec, podAnnotations map[string]string,
	oldPodSpec *api.PodSpec, oldPodAnnotations map[string]string,
) {
	// the new spec must always be non-nil
	if podSpec == nil {
		podSpec = &api.PodSpec{}
	}

	if !utilfeature.DefaultFeatureGate.Enabled(features.TokenRequestProjection) &&
		!tokenRequestProjectionInUse(oldPodSpec) {
		for i := range podSpec.Volumes {
			if podSpec.Volumes[i].Projected != nil {
				for j := range podSpec.Volumes[i].Projected.Sources {
					podSpec.Volumes[i].Projected.Sources[j].ServiceAccountToken = nil
				}
			}

		}
	}

	if !utilfeature.DefaultFeatureGate.Enabled(features.AppArmor) && !appArmorInUse(oldPodAnnotations) {
		for k := range podAnnotations {
			if strings.HasPrefix(k, apparmor.ContainerAnnotationKeyPrefix) {
				delete(podAnnotations, k)
			}
		}
	}

	if !utilfeature.DefaultFeatureGate.Enabled(features.PodShareProcessNamespace) && !shareProcessNamespaceInUse(oldPodSpec) {
		if podSpec.SecurityContext != nil {
			podSpec.SecurityContext.ShareProcessNamespace = nil
		}
	}

	if !utilfeature.DefaultFeatureGate.Enabled(features.PodPriority) && !podPriorityInUse(oldPodSpec) {
		// Set to nil pod's priority fields if the feature is disabled and the old pod
		// does not specify any values for these fields.
		podSpec.Priority = nil
		podSpec.PriorityClassName = ""
	}

	if !utilfeature.DefaultFeatureGate.Enabled(features.Sysctls) && !sysctlsInUse(oldPodSpec) {
		if podSpec.SecurityContext != nil {
			podSpec.SecurityContext.Sysctls = nil
		}
	}

	if !utilfeature.DefaultFeatureGate.Enabled(features.LocalStorageCapacityIsolation) && !emptyDirSizeLimitInUse(oldPodSpec) {
		for i := range podSpec.Volumes {
			if podSpec.Volumes[i].EmptyDir != nil {
				podSpec.Volumes[i].EmptyDir.SizeLimit = nil
			}
		}
	}

	if !utilfeature.DefaultFeatureGate.Enabled(features.VolumeSubpath) && !subpathInUse(oldPodSpec) {
		// drop subpath from the pod if the feature is disabled and the old spec did not specify subpaths
		for i := range podSpec.Containers {
			for j := range podSpec.Containers[i].VolumeMounts {
				podSpec.Containers[i].VolumeMounts[j].SubPath = ""
			}
		}
		for i := range podSpec.InitContainers {
			for j := range podSpec.InitContainers[i].VolumeMounts {
				podSpec.InitContainers[i].VolumeMounts[j].SubPath = ""
			}
		}
	}

	if !subpathExprInUse(oldPodSpec) {
		// drop subpath env expansion from the pod if either of the subpath features is disabled and the old spec did not specify subpath env expansion
		for i := range podSpec.Containers {
			for j := range podSpec.Containers[i].VolumeMounts {
				podSpec.Containers[i].VolumeMounts[j].SubPathExpr = ""
			}
		}
		for i := range podSpec.InitContainers {
			for j := range podSpec.InitContainers[i].VolumeMounts {
				podSpec.InitContainers[i].VolumeMounts[j].SubPathExpr = ""
			}
		}
	}

	dropDisabledVolumeDevicesFields(podSpec, oldPodSpec)

	dropDisabledRunAsGroupField(podSpec, oldPodSpec)

	if !utilfeature.DefaultFeatureGate.Enabled(features.RuntimeClass) && !runtimeClassInUse(oldPodSpec) {
		// Set RuntimeClassName to nil only if feature is disabled and it is not used
		podSpec.RuntimeClassName = nil
	}

	dropDisabledProcMountField(podSpec, oldPodSpec)

	dropDisabledCSIVolumeSourceAlphaFields(podSpec, oldPodSpec)

}

// dropDisabledRunAsGroupField removes disabled fields from PodSpec related
// to RunAsGroup
func dropDisabledRunAsGroupField(podSpec, oldPodSpec *api.PodSpec) {
	if !utilfeature.DefaultFeatureGate.Enabled(features.RunAsGroup) && !runAsGroupInUse(oldPodSpec) {
		if podSpec.SecurityContext != nil {
			podSpec.SecurityContext.RunAsGroup = nil
		}
		for i := range podSpec.Containers {
			if podSpec.Containers[i].SecurityContext != nil {
				podSpec.Containers[i].SecurityContext.RunAsGroup = nil
			}
		}
		for i := range podSpec.InitContainers {
			if podSpec.InitContainers[i].SecurityContext != nil {
				podSpec.InitContainers[i].SecurityContext.RunAsGroup = nil
			}
		}
	}
}

// dropDisabledProcMountField removes disabled fields from PodSpec related
// to ProcMount only if it is not already used by the old spec
func dropDisabledProcMountField(podSpec, oldPodSpec *api.PodSpec) {
	if !procMountInUse(oldPodSpec) {
		defaultProcMount := api.DefaultProcMount
		for i := range podSpec.Containers {
			if podSpec.Containers[i].SecurityContext != nil {
				if podSpec.Containers[i].SecurityContext.ProcMount != nil {
					// The ProcMount field was improperly forced to non-nil in 1.12.
					// If the feature is disabled, and the existing object is not using any non-default values, and the ProcMount field is present in the incoming object, force to the default value.
					// Note: we cannot force the field to nil when the feature is disabled because it causes a diff against previously persisted data.
					podSpec.Containers[i].SecurityContext.ProcMount = &defaultProcMount
				}
			}
		}
		for i := range podSpec.InitContainers {
			if podSpec.InitContainers[i].SecurityContext != nil {
				if podSpec.InitContainers[i].SecurityContext.ProcMount != nil {
					// The ProcMount field was improperly forced to non-nil in 1.12.
					// If the feature is disabled, and the existing object is not using any non-default values, and the ProcMount field is present in the incoming object, force to the default value.
					// Note: we cannot force the field to nil when the feature is disabled because it causes a diff against previously persisted data.
					podSpec.InitContainers[i].SecurityContext.ProcMount = &defaultProcMount
				}
			}
		}
	}
}

// dropDisabledVolumeDevicesFields removes disabled fields from []VolumeDevice if it has not been already populated.
// This should be called from PrepareForCreate/PrepareForUpdate for all resources containing a VolumeDevice
func dropDisabledVolumeDevicesFields(podSpec, oldPodSpec *api.PodSpec) {
	if !utilfeature.DefaultFeatureGate.Enabled(features.BlockVolume) && !volumeDevicesInUse(oldPodSpec) {
		for i := range podSpec.Containers {
			podSpec.Containers[i].VolumeDevices = nil
		}
		for i := range podSpec.InitContainers {
			podSpec.InitContainers[i].VolumeDevices = nil
		}
	}
}

// dropDisabledCSIVolumeSourceAlphaFields removes disabled alpha fields from []CSIVolumeSource.
// This should be called from PrepareForCreate/PrepareForUpdate for all pod specs resources containing a CSIVolumeSource
func dropDisabledCSIVolumeSourceAlphaFields(podSpec, oldPodSpec *api.PodSpec) {
	if !csiInUse(oldPodSpec) {
		for i := range podSpec.Volumes {
			podSpec.Volumes[i].CSI = nil
		}
	}
}

// subpathInUse returns true if the pod spec is non-nil and has a volume mount that makes use of the subPath feature
func subpathInUse(podSpec *api.PodSpec) bool {
	if podSpec == nil {
		return false
	}
	for i := range podSpec.Containers {
		for j := range podSpec.Containers[i].VolumeMounts {
			if len(podSpec.Containers[i].VolumeMounts[j].SubPath) > 0 {
				return true
			}
		}
	}
	for i := range podSpec.InitContainers {
		for j := range podSpec.InitContainers[i].VolumeMounts {
			if len(podSpec.InitContainers[i].VolumeMounts[j].SubPath) > 0 {
				return true
			}
		}
	}
	return false
}

// runtimeClassInUse returns true if the pod spec is non-nil and has a RuntimeClassName set
func runtimeClassInUse(podSpec *api.PodSpec) bool {
	if podSpec == nil {
		return false
	}
	if podSpec.RuntimeClassName != nil {
		return true
	}
	return false
}

// procMountInUse returns true if the pod spec is non-nil and has a SecurityContext's ProcMount field set to a non-default value
func procMountInUse(podSpec *api.PodSpec) bool {
	if podSpec == nil {
		return false
	}
	for i := range podSpec.Containers {
		if podSpec.Containers[i].SecurityContext != nil {
			if podSpec.Containers[i].SecurityContext.ProcMount != nil {
				if *podSpec.Containers[i].SecurityContext.ProcMount != api.DefaultProcMount {
					return true
				}
			}
		}
	}
	for i := range podSpec.InitContainers {
		if podSpec.InitContainers[i].SecurityContext != nil {
			if podSpec.InitContainers[i].SecurityContext.ProcMount != nil {
				if *podSpec.InitContainers[i].SecurityContext.ProcMount != api.DefaultProcMount {
					return true
				}
			}
		}
	}
	return false
}

// appArmorInUse returns true if the pod has apparmor related information
func appArmorInUse(podAnnotations map[string]string) bool {
	for k := range podAnnotations {
		if strings.HasPrefix(k, apparmor.ContainerAnnotationKeyPrefix) {
			return true
		}
	}
	return false
}

func shareProcessNamespaceInUse(podSpec *api.PodSpec) bool {
	if podSpec == nil {
		return false
	}
	if podSpec.SecurityContext != nil && podSpec.SecurityContext.ShareProcessNamespace != nil {
		return true
	}
	return false
}

func tokenRequestProjectionInUse(podSpec *api.PodSpec) bool {
	if podSpec == nil {
		return false
	}
	for _, v := range podSpec.Volumes {
		if v.Projected == nil {
			continue
		}
		for _, s := range v.Projected.Sources {
			if s.ServiceAccountToken != nil {
				return true
			}
		}
	}
	return false
}

// podPriorityInUse returns true if the pod spec is non-nil and has Priority or PriorityClassName set.
func podPriorityInUse(podSpec *api.PodSpec) bool {
	if podSpec == nil {
		return false
	}
	if podSpec.Priority != nil || podSpec.PriorityClassName != "" {
		return true
	}
	return false
}

func sysctlsInUse(podSpec *api.PodSpec) bool {
	if podSpec == nil {
		return false
	}
	if podSpec.SecurityContext != nil && podSpec.SecurityContext.Sysctls != nil {
		return true
	}
	return false
}

// emptyDirSizeLimitInUse returns true if any pod's EptyDir volumes use SizeLimit.
func emptyDirSizeLimitInUse(podSpec *api.PodSpec) bool {
	if podSpec == nil {
		return false
	}
	for i := range podSpec.Volumes {
		if podSpec.Volumes[i].EmptyDir != nil {
			if podSpec.Volumes[i].EmptyDir.SizeLimit != nil {
				return true
			}
		}
	}
	return false
}

// volumeDevicesInUse returns true if the pod spec is non-nil and has VolumeDevices set.
func volumeDevicesInUse(podSpec *api.PodSpec) bool {
	if podSpec == nil {
		return false
	}
	for i := range podSpec.Containers {
		if podSpec.Containers[i].VolumeDevices != nil {
			return true
		}
	}
	for i := range podSpec.InitContainers {
		if podSpec.InitContainers[i].VolumeDevices != nil {
			return true
		}
	}
	return false
}

// runAsGroupInUse returns true if the pod spec is non-nil and has a SecurityContext's RunAsGroup field set
func runAsGroupInUse(podSpec *api.PodSpec) bool {
	if podSpec == nil {
		return false
	}

	if podSpec.SecurityContext != nil && podSpec.SecurityContext.RunAsGroup != nil {
		return true
	}
	for i := range podSpec.Containers {
		if podSpec.Containers[i].SecurityContext != nil && podSpec.Containers[i].SecurityContext.RunAsGroup != nil {
			return true
		}
	}
	for i := range podSpec.InitContainers {
		if podSpec.InitContainers[i].SecurityContext != nil && podSpec.InitContainers[i].SecurityContext.RunAsGroup != nil {
			return true
		}
	}
	return false
}

// subpathExprInUse returns true if the pod spec is non-nil and has a volume mount that makes use of the subPathExpr feature
func subpathExprInUse(podSpec *api.PodSpec) bool {
	if podSpec == nil {
		return false
	}
	for i := range podSpec.Containers {
		for j := range podSpec.Containers[i].VolumeMounts {
			if len(podSpec.Containers[i].VolumeMounts[j].SubPathExpr) > 0 {
				return true
			}
		}
	}
	for i := range podSpec.InitContainers {
		for j := range podSpec.InitContainers[i].VolumeMounts {
			if len(podSpec.InitContainers[i].VolumeMounts[j].SubPathExpr) > 0 {
				return true
			}
		}
	}
	return false
}

// csiInUse returns true if any pod's spec include inline CSI volumes.
func csiInUse(podSpec *api.PodSpec) bool {
	if podSpec == nil {
		return false
	}
	for i := range podSpec.Volumes {
		if podSpec.Volumes[i].CSI != nil {
			return true
		}
	}
	return false
}