/*
Copyright 2020 The Knative 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 v1

import (
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	eventingduckv1 "knative.dev/eventing/pkg/apis/duck/v1"
	"knative.dev/pkg/apis"
	duckv1 "knative.dev/pkg/apis/duck/v1"
	"knative.dev/pkg/kmeta"
)

// +genclient
// +genreconciler
// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object

// Channel represents a generic Channel. It is normally used when we want a
// Channel, but do not need a specific Channel implementation.
type Channel struct {
	metav1.TypeMeta `json:",inline"`
	// +optional
	metav1.ObjectMeta `json:"metadata,omitempty"`

	// Spec defines the desired state of the Channel.
	Spec ChannelSpec `json:"spec,omitempty"`

	// Status represents the current state of the Channel. This data may be out
	// of date.
	// +optional
	Status ChannelStatus `json:"status,omitempty"`
}

var (
	// Check that Channel can be validated and defaulted.
	_ apis.Validatable = (*Channel)(nil)
	_ apis.Defaultable = (*Channel)(nil)

	// Check that Channel can return its spec untyped.
	_ apis.HasSpec = (*Channel)(nil)

	_ runtime.Object = (*Channel)(nil)

	// Check that we can create OwnerReferences to a Channel.
	_ kmeta.OwnerRefable = (*Channel)(nil)

	// Check that the type conforms to the duck Knative Resource shape.
	_ duckv1.KRShaped = (*Channel)(nil)
)

// ChannelSpec defines which subscribers have expressed interest in receiving
// events from this Channel. It also defines the ChannelTemplate to use in
// order to create the CRD Channel backing this Channel.
type ChannelSpec struct {
	// ChannelTemplate specifies which Channel CRD to use to create the CRD
	// Channel backing this Channel. This is immutable after creation.
	// Normally this is set by the Channel defaulter, not directly by the user.
	// +optional
	ChannelTemplate *ChannelTemplateSpec `json:"channelTemplate,omitempty"`

	// Channel conforms to ChannelableSpec
	eventingduckv1.ChannelableSpec `json:",inline"`
}

// ChannelStatus represents the current state of a Channel.
type ChannelStatus struct {
	// Channel conforms to ChannelableStatus
	eventingduckv1.ChannelableStatus `json:",inline"`

	// Channel is an KReference to the Channel CRD backing this Channel.
	// +optional
	Channel *duckv1.KReference `json:"channel,omitempty"`
}

// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object

// ChannelList is a collection of Channels.
type ChannelList struct {
	metav1.TypeMeta `json:",inline"`
	// +optional
	metav1.ListMeta `json:"metadata,omitempty"`
	Items           []Channel `json:"items"`
}

// GetStatus retrieves the status of the Channel. Implements the KRShaped
// interface.
func (t *Channel) GetStatus() *duckv1.Status {
	return &t.Status.Status
}
