/*
Copyright 2017 The Kubernetes 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:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object

// EgressSelectorConfiguration provides versioned configuration for egress selector clients.
type EgressSelectorConfiguration struct {
	metav1.TypeMeta `json:",inline"`

	// connectionServices contains a list of egress selection client configurations
	EgressSelections []EgressSelection `json:"egressSelections"`
}

// EgressSelection provides the configuration for a single egress selection client.
type EgressSelection struct {
	// name is the name of the egress selection.
	// Currently supported values are "Master", "Etcd" and "Cluster"
	Name string `json:"name"`

	// connection is the exact information used to configure the egress selection
	Connection Connection `json:"connection"`
}

// Connection provides the configuration for a single egress selection client.
type Connection struct {
	// Protocol is the protocol used to connect from client to the konnectivity server.
	ProxyProtocol ProtocolType `json:"proxyProtocol,omitempty"`

	// Transport defines the transport configurations we use to dial to the konnectivity server.
	// This is required if ProxyProtocol is HTTPConnect or GRPC.
	// +optional
	Transport *Transport `json:"transport,omitempty"`
}

// ProtocolType is a set of valid values for Connection.ProtocolType
type ProtocolType string

// Valid types for ProtocolType for konnectivity server
const (
	// Use HTTPConnect to connect to konnectivity server
	ProtocolHTTPConnect ProtocolType = "HTTPConnect"
	// Use grpc to connect to konnectivity server
	ProtocolGRPC ProtocolType = "GRPC"
	// Connect directly (skip konnectivity server)
	ProtocolDirect ProtocolType = "Direct"
)

// Transport defines the transport configurations we use to dial to the konnectivity server
type Transport struct {
	// TCP is the TCP configuration for communicating with the konnectivity server via TCP
	// ProxyProtocol of GRPC is not supported with TCP transport at the moment
	// Requires at least one of TCP or UDS to be set
	// +optional
	TCP *TCPTransport `json:"tcp,omitempty"`

	// UDS is the UDS configuration for communicating with the konnectivity server via UDS
	// Requires at least one of TCP or UDS to be set
	// +optional
	UDS *UDSTransport `json:"uds,omitempty"`
}

// TCPTransport provides the information to connect to konnectivity server via TCP
type TCPTransport struct {
	// URL is the location of the konnectivity server to connect to.
	// As an example it might be "https://127.0.0.1:8131"
	URL string `json:"url,omitempty"`

	// TLSConfig is the config needed to use TLS when connecting to konnectivity server
	// +optional
	TLSConfig *TLSConfig `json:"tlsConfig,omitempty"`
}

// UDSTransport provides the information to connect to konnectivity server via UDS
type UDSTransport struct {
	// UDSName is the name of the unix domain socket to connect to konnectivity server
	// This does not use a unix:// prefix. (Eg: /etc/srv/kubernetes/konnectivity-server/konnectivity-server.socket)
	UDSName string `json:"udsName,omitempty"`
}

// TLSConfig provides the authentication information to connect to konnectivity server
// Only used with TCPTransport
type TLSConfig struct {
	// caBundle is the file location of the CA to be used to determine trust with the konnectivity server.
	// Must be absent/empty if TCPTransport.URL is prefixed with http://
	// If absent while TCPTransport.URL is prefixed with https://, default to system trust roots.
	// +optional
	CABundle string `json:"caBundle,omitempty"`

	// clientKey is the file location of the client key to be used in mtls handshakes with the konnectivity server.
	// Must be absent/empty if TCPTransport.URL is prefixed with http://
	// Must be configured if TCPTransport.URL is prefixed with https://
	// +optional
	ClientKey string `json:"clientKey,omitempty"`

	// clientCert is the file location of the client certificate to be used in mtls handshakes with the konnectivity server.
	// Must be absent/empty if TCPTransport.URL is prefixed with http://
	// Must be configured if TCPTransport.URL is prefixed with https://
	// +optional
	ClientCert string `json:"clientCert,omitempty"`
}
