/*
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 v1alpha2

import (
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	"knative.dev/pkg/apis"
	duckv1 "knative.dev/pkg/apis/duck/v1"
	duckv1alpha1 "knative.dev/pkg/apis/duck/v1alpha1"
	"knative.dev/pkg/kmeta"
)

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

// SinkBinding describes a Binding that is also a Source.
// The `sink` (from the Source duck) is resolved to a URL and
// then projected into the `subject` by augmenting the runtime
// contract of the referenced containers to have a `K_SINK`
// environment variable holding the endpoint to which to send
// cloud events.
type SinkBinding struct {
	metav1.TypeMeta   `json:",inline"`
	metav1.ObjectMeta `json:"metadata,omitempty"`

	Spec   SinkBindingSpec   `json:"spec"`
	Status SinkBindingStatus `json:"status"`
}

// Check the interfaces that SinkBinding should be implementing.
var (
	_ runtime.Object     = (*SinkBinding)(nil)
	_ kmeta.OwnerRefable = (*SinkBinding)(nil)
	_ apis.Validatable   = (*SinkBinding)(nil)
	_ apis.Defaultable   = (*SinkBinding)(nil)
	_ apis.HasSpec       = (*SinkBinding)(nil)
)

// SinkBindingSpec holds the desired state of the SinkBinding (from the client).
type SinkBindingSpec struct {
	// inherits duck/v1 SourceSpec, which currently provides:
	// * Sink - a reference to an object that will resolve to a domain name or
	//   a URI directly to use as the sink.
	// * CloudEventOverrides - defines overrides to control the output format
	//   and modifications of the event sent to the sink.
	duckv1.SourceSpec `json:",inline"`

	// inherits duck/v1alpha1 BindingSpec, which currently provides:
	// * Subject - Subject references the resource(s) whose "runtime contract"
	//   should be augmented by Binding implementations.
	duckv1alpha1.BindingSpec `json:",inline"`
}

const (
	// SinkBindingConditionReady is configured to indicate whether the Binding
	// has been configured for resources subject to its runtime contract.
	SinkBindingConditionReady = apis.ConditionReady
)

// SinkBindingStatus communicates the observed state of the SinkBinding (from the controller).
type SinkBindingStatus struct {
	// inherits duck/v1 SourceStatus, which currently provides:
	// * ObservedGeneration - the 'Generation' of the Service that was last
	//   processed by the controller.
	// * Conditions - the latest available observations of a resource's current
	//   state.
	// * SinkURI - the current active sink URI that has been configured for the
	//   Source.
	duckv1.SourceStatus `json:",inline"`
}

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

// SinkBindingList contains a list of SinkBinding
type SinkBindingList struct {
	metav1.TypeMeta `json:",inline"`
	metav1.ListMeta `json:"metadata,omitempty"`
	Items           []SinkBinding `json:"items"`
}
