package resource

import (
	"bytes"
	"path"

	"github.com/derailed/k9s/internal/k8s"
	"github.com/rs/zerolog/log"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/cli-runtime/pkg/genericclioptions/printers"
	"k8s.io/kubernetes/pkg/kubectl/describe"
	versioned "k8s.io/kubernetes/pkg/kubectl/describe/versioned"
)

type (
	// Creator can create a new resources.
	Creator interface {
		NewInstance(interface{}) Columnar
	}

	// Caller can call Kubernetes verbs on a resource.
	Caller interface {
		k8s.Res
	}

	// APIFn knows how to call K8s api server.
	APIFn func() k8s.Res

	// InstanceFn instantiates a concrete resource.
	InstanceFn func(interface{}) Columnar

	// Base resource.
	Base struct {
		path string

		caller  Caller
		creator Creator
	}
)

// Name returns the resource namespaced name.
func (b *Base) Name() string {
	return b.path
}

// Get a resource by name
func (b *Base) Get(path string) (Columnar, error) {
	ns, n := namespaced(path)
	i, err := b.caller.Get(ns, n)
	if err != nil {
		return nil, err
	}
	return b.creator.NewInstance(i), nil
}

// List all resources
func (b *Base) List(ns string) (Columnars, error) {
	ii, err := b.caller.List(ns)
	if err != nil {
		return nil, err
	}

	cc := make(Columnars, 0, len(ii))
	for i := 0; i < len(ii); i++ {
		cc = append(cc, b.creator.NewInstance(ii[i]))
	}
	return cc, nil
}

// Describe a given resource.
func (b *Base) Describe(kind, pa string) (string, error) {

	ns, n := namespaced(pa)
	mapping, err := k8s.RestMapping.Find(kind)
	if err != nil {
		return "", err
	}
	d, err := versioned.Describer(k8s.KubeConfig.Flags(), mapping)
	if err != nil {
		return "", err
	}
	opts := describe.DescriberSettings{
		ShowEvents: true,
	}
	return d.Describe(ns, n, opts)
}

// Delete a resource by name.
func (b *Base) Delete(path string) error {
	ns, n := namespaced(path)
	return b.caller.Delete(ns, n)
}

func (*Base) namespacedName(m metav1.ObjectMeta) string {
	return path.Join(m.Namespace, m.Name)
}

func (*Base) marshalObject(o runtime.Object) (string, error) {
	var (
		buff bytes.Buffer
		p    printers.YAMLPrinter
	)
	err := p.PrintObj(o, &buff)
	if err != nil {
		log.Error().Msgf("Marshal Error %v", err)
		return "", err
	}
	return buff.String(), nil
}