package addons

import (
	"context"
	// For go:embed
	_ "embed"
	"errors"
	"fmt"
	"time"

	"github.com/kris-nova/logger"

	api "github.com/weaveworks/eksctl/pkg/apis/eksctl.io/v1alpha5"
	"github.com/weaveworks/eksctl/pkg/kubernetes"
	"github.com/weaveworks/eksctl/pkg/utils/instance"

	appsv1 "k8s.io/api/apps/v1"
	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/watch"
	clientappsv1 "k8s.io/client-go/kubernetes/typed/apps/v1"
)

//go:embed assets/efa-device-plugin.yaml
var efaDevicePluginYaml []byte

//go:embed assets/neuron-device-plugin.yaml
var neuronDevicePluginYaml []byte

//go:embed assets/nvidia-device-plugin.yaml
var nvidiaDevicePluginYaml []byte

func useRegionalImage(spec *corev1.PodTemplateSpec, region string, account string) error {
	imageFormat := spec.Spec.Containers[0].Image
	dnsSuffix, err := awsDNSSuffixForRegion(region)
	if err != nil {
		return err
	}
	regionalImage := fmt.Sprintf(imageFormat, account, region, dnsSuffix)
	spec.Spec.Containers[0].Image = regionalImage
	return nil
}

func watchDaemonSetReady(dsClientSet clientappsv1.DaemonSetInterface, dsName string) error {
	watcher, err := dsClientSet.Watch(context.TODO(), metav1.ListOptions{
		FieldSelector: fmt.Sprintf("metadata.name=%s", dsName),
	})

	if err != nil {
		return err
	}

	defer watcher.Stop()
	timeout := 45 * time.Second

	timer := time.NewTimer(timeout)
	defer timer.Stop()

	for {
		select {
		case event, ok := <-watcher.ResultChan():
			if !ok {
				return errors.New("failed waiting for daemon set: unexpected close of ResultChan")
			}
			switch event.Type {
			case watch.Added, watch.Modified:
				return nil
			}
		case <-timer.C:
			return fmt.Errorf("timed out (after %v) waiting for certificate", timeout)
		}

	}
}

type MkDevicePlugin func(rawClient kubernetes.RawClientInterface, region string, planMode bool, spec *api.ClusterConfig) DevicePlugin

type DevicePlugin interface {
	RawClient() kubernetes.RawClientInterface
	PlanMode() bool
	Manifest() []byte
	SetImage(t *corev1.PodTemplateSpec) error
	SetTolerations(t *corev1.PodTemplateSpec) error
	Deploy() error
}

func applyDevicePlugin(dp DevicePlugin) error {
	list, err := kubernetes.NewList(dp.Manifest())
	if err != nil {
		return fmt.Errorf("creating list from device plugin manifest: %w", err)
	}

	rawClient := dp.RawClient()
	for _, rawObj := range list.Items {
		rawResource, err := rawClient.NewRawResource(rawObj.Object)
		if err != nil {
			return fmt.Errorf("creating raw resource from list item: %w", err)
		}
		switch rawResource.GVK.Kind {
		case "DaemonSet":
			daemonSet, ok := rawResource.Info.Object.(*appsv1.DaemonSet)
			if !ok {
				return &typeAssertionError{&appsv1.DaemonSet{}, rawResource}
			}
			if err := dp.SetImage(&daemonSet.Spec.Template); err != nil {
				return fmt.Errorf("setting image of device plugin daemonset: %w", err)
			}
			if err := dp.SetTolerations(&daemonSet.Spec.Template); err != nil {
				return fmt.Errorf("adding tolerations to device plugin daemonset: %w", err)
			}
			msg, err := rawResource.CreateOrReplace(dp.PlanMode())
			if err != nil {
				return fmt.Errorf("calling create or replace on raw device plugin daemonset: %w", err)
			}
			logger.Info(msg)
			if err := watchDaemonSetReady(dp.RawClient().ClientSet().AppsV1().DaemonSets(daemonSet.Namespace), daemonSet.Name); err != nil {
				return fmt.Errorf("waiting for device plugin daemonset to become ready: %w", err)
			}
		default:
			status, err := rawResource.CreateOrReplace(dp.PlanMode())
			if err != nil {
				return fmt.Errorf("calling create or replace on raw device plugin rawResource: %w", err)
			}
			logger.Info(status)
		}
	}
	return nil
}

// NewNeuronDevicePlugin creates a new NeuronDevicePlugin
func NewNeuronDevicePlugin(rawClient kubernetes.RawClientInterface, region string, planMode bool, spec *api.ClusterConfig) DevicePlugin {
	return &NeuronDevicePlugin{
		rawClient: rawClient,
		region:    region,
		planMode:  planMode,
	}
}

// A NeuronDevicePlugin deploys the Neuron Device Plugin to a cluster
type NeuronDevicePlugin struct {
	rawClient kubernetes.RawClientInterface
	region    string
	planMode  bool
}

func (n *NeuronDevicePlugin) RawClient() kubernetes.RawClientInterface {
	return n.rawClient
}

func (n *NeuronDevicePlugin) PlanMode() bool {
	return n.planMode
}

func (n *NeuronDevicePlugin) Manifest() []byte {
	return neuronDevicePluginYaml
}

func (n *NeuronDevicePlugin) SetImage(t *corev1.PodTemplateSpec) error {
	return nil
}

func (n *NeuronDevicePlugin) SetTolerations(t *corev1.PodTemplateSpec) error {
	return nil
}

// Deploy deploys the Neuron device plugin to the specified cluster
func (n *NeuronDevicePlugin) Deploy() error {
	return applyDevicePlugin(n)
}

// NewNvidiaDevicePlugin creates a new NvidiaDevicePlugin
func NewNvidiaDevicePlugin(rawClient kubernetes.RawClientInterface, region string, planMode bool, spec *api.ClusterConfig) DevicePlugin {
	return &NvidiaDevicePlugin{
		rawClient: rawClient,
		region:    region,
		planMode:  planMode,
		spec:      spec,
	}
}

// A NvidiaDevicePlugin deploys the Nvidia Device Plugin to a cluster
type NvidiaDevicePlugin struct {
	rawClient kubernetes.RawClientInterface
	region    string
	planMode  bool
	spec      *api.ClusterConfig
}

func (n *NvidiaDevicePlugin) RawClient() kubernetes.RawClientInterface {
	return n.rawClient
}

func (n *NvidiaDevicePlugin) PlanMode() bool {
	return n.planMode
}

func (n *NvidiaDevicePlugin) SetImage(t *corev1.PodTemplateSpec) error {
	return nil
}

func (n *NvidiaDevicePlugin) Manifest() []byte {
	return nvidiaDevicePluginYaml
}

// Deploy deploys the Nvidia device plugin to the specified cluster
func (n *NvidiaDevicePlugin) Deploy() error {
	return applyDevicePlugin(n)
}

// SetTolerations sets given tolerations on the DaemonSet if they don't already exist.
// We check the taints on each node which is an NVIDIA instance type and apply
// tolerations for all the taints defined on the node.
func (n *NvidiaDevicePlugin) SetTolerations(spec *corev1.PodTemplateSpec) error {
	contains := func(list []corev1.Toleration, key string) bool {
		for _, t := range list {
			if t.Key == key {
				return true
			}
		}
		return false
	}
	// don't duplicate taints from other nodes or overwrite them with
	// different values ( shouldn't happen in general... )
	taints := make(map[string]api.NodeGroupTaint)
	for _, ng := range n.spec.NodeGroups {
		if api.HasInstanceType(ng, instance.IsNvidiaInstanceType) &&
			ng.GetAMIFamily() == api.NodeImageFamilyAmazonLinux2 {
			for _, taint := range ng.Taints {
				if _, ok := taints[taint.Key]; !ok {
					taints[taint.Key] = taint
				}
			}
		}
	}
	for _, ng := range n.spec.ManagedNodeGroups {
		if api.HasInstanceTypeManaged(ng, instance.IsNvidiaInstanceType) &&
			ng.GetAMIFamily() == api.NodeImageFamilyAmazonLinux2 {
			for _, taint := range ng.Taints {
				if _, ok := taints[taint.Key]; !ok {
					taints[taint.Key] = taint
				}
			}
		}
	}
	for _, t := range taints {
		// only add toleration if it doesn't already exist. In that case, we don't overwrite it.
		if !contains(spec.Spec.Tolerations, t.Key) {
			spec.Spec.Tolerations = append(spec.Spec.Tolerations, corev1.Toleration{
				Key:   t.Key,
				Value: t.Value,
			})
		}
	}
	return nil
}

// A EFADevicePlugin deploys the EFA Device Plugin to a cluster
type EFADevicePlugin struct {
	rawClient kubernetes.RawClientInterface
	region    string
	planMode  bool
}

func (n *EFADevicePlugin) RawClient() kubernetes.RawClientInterface {
	return n.rawClient
}

func (n *EFADevicePlugin) PlanMode() bool {
	return n.planMode
}

func (n *EFADevicePlugin) Manifest() []byte {
	return efaDevicePluginYaml
}

func (n *EFADevicePlugin) SetImage(t *corev1.PodTemplateSpec) error {
	account := api.EKSResourceAccountID(n.region)
	return useRegionalImage(t, n.region, account)
}

func (n *EFADevicePlugin) SetTolerations(spec *corev1.PodTemplateSpec) error {
	return nil
}

// NewEFADevicePlugin creates a new EFADevicePlugin
func NewEFADevicePlugin(rawClient kubernetes.RawClientInterface, region string, planMode bool, spec *api.ClusterConfig) DevicePlugin {
	return &EFADevicePlugin{
		rawClient: rawClient,
		region:    region,
		planMode:  planMode,
	}
}

// Deploy deploys the EFA device plugin to the specified cluster
func (n *EFADevicePlugin) Deploy() error {
	return applyDevicePlugin(n)
}
