/*
Copyright The Velero Contributors.

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 nodeagent

import (
	"context"
	"encoding/json"
	"fmt"

	"github.com/pkg/errors"
	corev1api "k8s.io/api/core/v1"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/client-go/kubernetes"
	ctrlclient "sigs.k8s.io/controller-runtime/pkg/client"

	"github.com/vmware-tanzu/velero/pkg/util/kube"
)

const (
	// daemonSet is the name of the Velero node agent daemonset on linux nodes.
	daemonSet = "node-agent"

	// daemonsetWindows is the name of the Velero node agent daemonset on Windows nodes.
	daemonsetWindows = "node-agent-windows"

	// nodeAgentRole marks pods with node-agent role on all nodes.
	nodeAgentRole = "node-agent"

	// HostPodVolumeMount is the name of the volume in node-agent for host-pod mount
	HostPodVolumeMount = "host-pods"

	// HostPodVolumeMountPoint is the mount point of the volume in node-agent for host-pod mount
	HostPodVolumeMountPoint = "host_pods"
)

var (
	ErrDaemonSetNotFound           = errors.New("daemonset not found")
	ErrNodeAgentLabelNotFound      = errors.New("node-agent label not found")
	ErrNodeAgentAnnotationNotFound = errors.New("node-agent annotation not found")
	ErrNodeAgentTolerationNotFound = errors.New("node-agent toleration not found")
)

type LoadConcurrency struct {
	// GlobalConfig specifies the concurrency number to all nodes for which per-node config is not specified
	GlobalConfig int `json:"globalConfig,omitempty"`

	// PerNodeConfig specifies the concurrency number to nodes matched by rules
	PerNodeConfig []RuledConfigs `json:"perNodeConfig,omitempty"`

	// PrepareQueueLength specifies the max number of loads that are under expose
	PrepareQueueLength int `json:"prepareQueueLength,omitempty"`
}

type LoadAffinity struct {
	// NodeSelector specifies the label selector to match nodes
	NodeSelector metav1.LabelSelector `json:"nodeSelector"`
}

type RuledConfigs struct {
	// NodeSelector specifies the label selector to match nodes
	NodeSelector metav1.LabelSelector `json:"nodeSelector"`

	// Number specifies the number value associated to the matched nodes
	Number int `json:"number"`
}

type BackupPVC struct {
	// StorageClass is the name of storage class to be used by the backupPVC
	StorageClass string `json:"storageClass,omitempty"`

	// ReadOnly sets the backupPVC's access mode as read only
	ReadOnly bool `json:"readOnly,omitempty"`

	// SPCNoRelabeling sets Spec.SecurityContext.SELinux.Type to "spc_t" for the pod mounting the backupPVC
	// ignored if ReadOnly is false
	SPCNoRelabeling bool `json:"spcNoRelabeling,omitempty"`
}

type RestorePVC struct {
	// IgnoreDelayBinding indicates to ignore delay binding the restorePVC when it is in WaitForFirstConsumer mode
	IgnoreDelayBinding bool `json:"ignoreDelayBinding,omitempty"`
}

type Configs struct {
	// LoadConcurrency is the config for data path load concurrency per node.
	LoadConcurrency *LoadConcurrency `json:"loadConcurrency,omitempty"`

	// LoadAffinity is the config for data path load affinity.
	LoadAffinity []*kube.LoadAffinity `json:"loadAffinity,omitempty"`

	// BackupPVCConfig is the config for backupPVC (intermediate PVC) of snapshot data movement
	BackupPVCConfig map[string]BackupPVC `json:"backupPVC,omitempty"`

	// RestoreVCConfig is the config for restorePVC (intermediate PVC) of generic restore
	RestorePVCConfig *RestorePVC `json:"restorePVC,omitempty"`

	// PodResources is the resource config for various types of pods launched by node-agent, i.e., data mover pods.
	PodResources *kube.PodResources `json:"podResources,omitempty"`

	// PriorityClassName is the priority class name for data mover pods created by the node agent
	PriorityClassName string `json:"priorityClassName,omitempty"`
}

func IsRunningOnLinux(ctx context.Context, kubeClient kubernetes.Interface, namespace string) error {
	return isRunning(ctx, kubeClient, namespace, daemonSet)
}

func IsRunningOnWindows(ctx context.Context, kubeClient kubernetes.Interface, namespace string) error {
	return isRunning(ctx, kubeClient, namespace, daemonsetWindows)
}

func isRunning(ctx context.Context, kubeClient kubernetes.Interface, namespace string, daemonset string) error {
	if _, err := kubeClient.AppsV1().DaemonSets(namespace).Get(ctx, daemonset, metav1.GetOptions{}); apierrors.IsNotFound(err) {
		return ErrDaemonSetNotFound
	} else if err != nil {
		return err
	} else {
		return nil
	}
}

// KbClientIsRunningInNode checks if the node agent pod is running properly in a specified node through kube client. If not, return the error found
func KbClientIsRunningInNode(ctx context.Context, namespace string, nodeName string, kubeClient kubernetes.Interface) error {
	return isRunningInNode(ctx, namespace, nodeName, nil, kubeClient)
}

// IsRunningInNode checks if the node agent pod is running properly in a specified node through controller client. If not, return the error found
func IsRunningInNode(ctx context.Context, namespace string, nodeName string, crClient ctrlclient.Client) error {
	return isRunningInNode(ctx, namespace, nodeName, crClient, nil)
}

func isRunningInNode(ctx context.Context, namespace string, nodeName string, crClient ctrlclient.Client, kubeClient kubernetes.Interface) error {
	if nodeName == "" {
		return errors.New("node name is empty")
	}

	pods := new(corev1api.PodList)
	parsedSelector, err := labels.Parse(fmt.Sprintf("role=%s", nodeAgentRole))
	if err != nil {
		return errors.Wrap(err, "fail to parse selector")
	}

	if crClient != nil {
		err = crClient.List(ctx, pods, &ctrlclient.ListOptions{LabelSelector: parsedSelector})
	} else {
		pods, err = kubeClient.CoreV1().Pods(namespace).List(ctx, metav1.ListOptions{LabelSelector: parsedSelector.String()})
	}

	if err != nil {
		return errors.Wrap(err, "failed to list node-agent pods")
	}

	for i := range pods.Items {
		if kube.IsPodRunning(&pods.Items[i]) != nil {
			continue
		}

		if pods.Items[i].Spec.NodeName == nodeName {
			return nil
		}
	}

	return errors.Errorf("daemonset pod not found in running state in node %s", nodeName)
}

func GetPodSpec(ctx context.Context, kubeClient kubernetes.Interface, namespace string, osType string) (*corev1api.PodSpec, error) {
	dsName := daemonSet
	if osType == kube.NodeOSWindows {
		dsName = daemonsetWindows
	}

	ds, err := kubeClient.AppsV1().DaemonSets(namespace).Get(ctx, dsName, metav1.GetOptions{})
	if err != nil {
		return nil, errors.Wrapf(err, "error to get %s daemonset", dsName)
	}

	return &ds.Spec.Template.Spec, nil
}

func GetConfigs(ctx context.Context, namespace string, kubeClient kubernetes.Interface, configName string) (*Configs, error) {
	cm, err := kubeClient.CoreV1().ConfigMaps(namespace).Get(ctx, configName, metav1.GetOptions{})
	if err != nil {
		return nil, errors.Wrapf(err, "error to get node agent configs %s", configName)
	}

	if cm.Data == nil {
		return nil, errors.Errorf("data is not available in config map %s", configName)
	}

	jsonString := ""
	for _, v := range cm.Data {
		jsonString = v
	}

	configs := &Configs{}
	err = json.Unmarshal([]byte(jsonString), configs)
	if err != nil {
		return nil, errors.Wrapf(err, "error to unmarshall configs from %s", configName)
	}

	return configs, nil
}

func GetLabelValue(ctx context.Context, kubeClient kubernetes.Interface, namespace string, key string, osType string) (string, error) {
	dsName := daemonSet
	if osType == kube.NodeOSWindows {
		dsName = daemonsetWindows
	}

	ds, err := kubeClient.AppsV1().DaemonSets(namespace).Get(ctx, dsName, metav1.GetOptions{})
	if err != nil {
		return "", errors.Wrapf(err, "error getting %s daemonset", dsName)
	}

	if ds.Spec.Template.Labels == nil {
		return "", ErrNodeAgentLabelNotFound
	}

	val, found := ds.Spec.Template.Labels[key]
	if !found {
		return "", ErrNodeAgentLabelNotFound
	}

	return val, nil
}

func GetAnnotationValue(ctx context.Context, kubeClient kubernetes.Interface, namespace string, key string, osType string) (string, error) {
	dsName := daemonSet
	if osType == kube.NodeOSWindows {
		dsName = daemonsetWindows
	}

	ds, err := kubeClient.AppsV1().DaemonSets(namespace).Get(ctx, dsName, metav1.GetOptions{})
	if err != nil {
		return "", errors.Wrapf(err, "error getting %s daemonset", dsName)
	}

	if ds.Spec.Template.Annotations == nil {
		return "", ErrNodeAgentAnnotationNotFound
	}

	val, found := ds.Spec.Template.Annotations[key]
	if !found {
		return "", ErrNodeAgentAnnotationNotFound
	}

	return val, nil
}

func GetToleration(ctx context.Context, kubeClient kubernetes.Interface, namespace string, key string, osType string) (*corev1api.Toleration, error) {
	dsName := daemonSet
	if osType == kube.NodeOSWindows {
		dsName = daemonsetWindows
	}

	ds, err := kubeClient.AppsV1().DaemonSets(namespace).Get(ctx, dsName, metav1.GetOptions{})
	if err != nil {
		return nil, errors.Wrapf(err, "error getting %s daemonset", dsName)
	}

	for i, t := range ds.Spec.Template.Spec.Tolerations {
		if t.Key == key {
			return &ds.Spec.Template.Spec.Tolerations[i], nil
		}
	}

	return nil, ErrNodeAgentTolerationNotFound
}

func GetHostPodPath(ctx context.Context, kubeClient kubernetes.Interface, namespace string, osType string) (string, error) {
	dsName := daemonSet
	if osType == kube.NodeOSWindows {
		dsName = daemonsetWindows
	}

	ds, err := kubeClient.AppsV1().DaemonSets(namespace).Get(ctx, dsName, metav1.GetOptions{})
	if err != nil {
		return "", errors.Wrapf(err, "error getting daemonset %s", dsName)
	}

	var volume *corev1api.Volume
	for _, v := range ds.Spec.Template.Spec.Volumes {
		if v.Name == HostPodVolumeMount {
			volume = &v
			break
		}
	}

	if volume == nil {
		return "", errors.New("host pod volume is not found")
	}

	if volume.HostPath == nil {
		return "", errors.New("host pod volume is not a host path volume")
	}

	if volume.HostPath.Path == "" {
		return "", errors.New("host pod volume path is empty")
	}

	return volume.HostPath.Path, nil
}

func HostPodVolumeMountPath() string {
	return "/" + HostPodVolumeMountPoint
}

func HostPodVolumeMountPathWin() string {
	return "\\" + HostPodVolumeMountPoint
}