package clientbase

import (
	"encoding/json"

	"github.com/pkg/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/runtime/schema"
	"k8s.io/apimachinery/pkg/watch"
	"k8s.io/client-go/dynamic"
	"k8s.io/client-go/rest"
)

type ObjectFactory interface {
	Object() runtime.Object
	List() runtime.Object
}

type ObjectClient struct {
	restClient rest.Interface
	resource   *metav1.APIResource
	gvk        schema.GroupVersionKind
	ns         string
	Factory    ObjectFactory
}

func NewObjectClient(namespace string, config rest.Config, apiResource *metav1.APIResource, gvk schema.GroupVersionKind, factory ObjectFactory) (*ObjectClient, error) {
	if config.NegotiatedSerializer == nil {
		configConfig := dynamic.ContentConfig()
		config.NegotiatedSerializer = configConfig.NegotiatedSerializer
	}

	restClient, err := rest.UnversionedRESTClientFor(&config)
	if err != nil {
		return nil, err
	}

	return &ObjectClient{
		restClient: restClient,
		resource:   apiResource,
		gvk:        gvk,
		ns:         namespace,
		Factory:    factory,
	}, nil
}

func (p *ObjectClient) Create(o runtime.Object) (runtime.Object, error) {
	ns := p.ns
	if obj, ok := o.(metav1.Object); ok && obj.GetNamespace() != "" {
		ns = obj.GetNamespace()
	}
	result := p.Factory.Object()
	err := p.restClient.Post().
		Prefix("apis", p.gvk.Group, p.gvk.Version).
		NamespaceIfScoped(ns, p.resource.Namespaced).
		Resource(p.resource.Name).
		Body(o).
		Do().
		Into(result)
	return result, err
}

func (p *ObjectClient) Get(name string, opts metav1.GetOptions) (runtime.Object, error) {
	result := p.Factory.Object()
	err := p.restClient.Get().
		Prefix("apis", p.gvk.Group, p.gvk.Version).
		NamespaceIfScoped(p.ns, p.resource.Namespaced).
		Resource(p.resource.Name).
		VersionedParams(&opts, dynamic.VersionedParameterEncoderWithV1Fallback).
		Name(name).
		Do().
		Into(result)
	return result, err
}

func (p *ObjectClient) Update(name string, o runtime.Object) (runtime.Object, error) {
	ns := p.ns
	if obj, ok := o.(metav1.Object); ok && obj.GetNamespace() != "" {
		ns = obj.GetNamespace()
	}
	result := p.Factory.Object()
	if len(name) == 0 {
		return result, errors.New("object missing name")
	}
	err := p.restClient.Put().
		Prefix("apis", p.gvk.Group, p.gvk.Version).
		NamespaceIfScoped(ns, p.resource.Namespaced).
		Resource(p.resource.Name).
		Name(name).
		Body(o).
		Do().
		Into(result)
	return result, err
}

func (p *ObjectClient) Delete(name string, opts *metav1.DeleteOptions) error {
	return p.restClient.Delete().
		Prefix("apis", p.gvk.Group, p.gvk.Version).
		NamespaceIfScoped(p.ns, p.resource.Namespaced).
		Resource(p.resource.Name).
		Name(name).
		Body(opts).
		Do().
		Error()
}

func (p *ObjectClient) List(opts metav1.ListOptions) (runtime.Object, error) {
	result := p.Factory.List()
	return result, p.restClient.Get().
		Prefix("apis", p.gvk.Group, p.gvk.Version).
		NamespaceIfScoped(p.ns, p.resource.Namespaced).
		Resource(p.resource.Name).
		VersionedParams(&opts, dynamic.VersionedParameterEncoderWithV1Fallback).
		Do().
		Into(result)
}

func (p *ObjectClient) Watch(opts metav1.ListOptions) (watch.Interface, error) {
	r, err := p.restClient.Get().
		Prefix("apis", p.gvk.Group, p.gvk.Version).
		Prefix("watch").
		Namespace(p.ns).
		NamespaceIfScoped(p.ns, p.resource.Namespaced).
		Resource(p.resource.Name).
		VersionedParams(&opts, dynamic.VersionedParameterEncoderWithV1Fallback).
		Stream()
	if err != nil {
		return nil, err
	}
	return watch.NewStreamWatcher(&dynamicDecoder{
		factory: p.Factory,
		dec:     json.NewDecoder(r),
		close:   r.Close,
	}), nil
}

func (p *ObjectClient) DeleteCollection(deleteOptions *metav1.DeleteOptions, listOptions metav1.ListOptions) error {
	return p.restClient.Delete().
		Prefix("apis", p.gvk.Group, p.gvk.Version).
		NamespaceIfScoped(p.ns, p.resource.Namespaced).
		Resource(p.resource.Name).
		VersionedParams(&listOptions, dynamic.VersionedParameterEncoderWithV1Fallback).
		Body(deleteOptions).
		Do().
		Error()
}

type dynamicDecoder struct {
	factory ObjectFactory
	dec     *json.Decoder
	close   func() error
}

func (d *dynamicDecoder) Close() {
	d.close()
}

func (d *dynamicDecoder) Decode() (action watch.EventType, object runtime.Object, err error) {
	e := dynamicEvent{
		Object: holder{
			factory: d.factory,
		},
	}
	if err := d.dec.Decode(&e); err != nil {
		return watch.Error, nil, err
	}
	return e.Type, e.Object.obj, nil
}

type dynamicEvent struct {
	Type   watch.EventType
	Object holder
}

type holder struct {
	factory ObjectFactory
	obj     runtime.Object
}

func (h *holder) UnmarshalJSON(b []byte) error {
	h.obj = h.factory.Object()
	return json.Unmarshal(b, h.obj)
}