/*
 * 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 v1beta1

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"
	"knative.dev/pkg/kmeta"
)

const (
	// DependencyAnnotation is the annotation key used to mark the sources that the Trigger depends on.
	// This will be used when the kn client creates a source and trigger pair for the user such that the trigger only receives events produced by the paired source.
	DependencyAnnotation = "knative.dev/dependency"
	// InjectionAnnotation is the annotation key used to enable knative eventing injection for a namespace and automatically create a default broker.
	// This will be used when the client creates a trigger paired with default broker and the default broker doesn't exist in the namespace
	InjectionAnnotation = "knative-eventing-injection"
)

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

// Trigger represents a request to have events delivered to a consumer from a
// Broker's event pool.
type Trigger struct {
	metav1.TypeMeta `json:",inline"`
	// +optional
	metav1.ObjectMeta `json:"metadata,omitempty"`

	// Spec defines the desired state of the Trigger.
	Spec TriggerSpec `json:"spec,omitempty"`

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

var (
	// Check that Trigger can be validated, can be defaulted, and has immutable fields.
	_ apis.Validatable = (*Trigger)(nil)
	_ apis.Defaultable = (*Trigger)(nil)

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

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

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

type TriggerSpec struct {
	// Broker is the broker that this trigger receives events from. If not specified, will default
	// to 'default'.
	Broker string `json:"broker,omitempty"`

	// Filter is the filter to apply against all events from the Broker. Only events that pass this
	// filter will be sent to the Subscriber. If not specified, will default to allowing all events.
	//
	// +optional
	Filter *TriggerFilter `json:"filter,omitempty"`

	// Subscriber is the addressable that receives events from the Broker that pass the Filter. It
	// is required.
	Subscriber duckv1.Destination `json:"subscriber"`
}

type TriggerFilter struct {
	// Attributes filters events by exact match on event context attributes.
	// Each key in the map is compared with the equivalent key in the event
	// context. An event passes the filter if all values are equal to the
	// specified values.
	//
	// Nested context attributes are not supported as keys. Only string values are supported.
	//
	// +optional
	Attributes TriggerFilterAttributes `json:"attributes,omitempty"`
}

// TriggerFilterAttributes is a map of context attribute names to values for
// filtering by equality. Only exact matches will pass the filter. You can use the value ''
// to indicate all strings match.
type TriggerFilterAttributes map[string]string

// TriggerStatus represents the current state of a Trigger.
type TriggerStatus struct {
	// inherits duck/v1 Status, 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.
	duckv1.Status `json:",inline"`

	// SubscriberURI is the resolved URI of the receiver for this Trigger.
	SubscriberURI *apis.URL `json:"subscriberUri,omitempty"`
}

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

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