/*
Copyright 2016 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 rbac

import (
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
)

// Authorization is calculated against
// 1. evaluation of ClusterRoleBindings - short circuit on match
// 2. evaluation of RoleBindings in the namespace requested - short circuit on match
// 3. deny by default

// APIGroupAll and these consts are default values for rbac authorization.
const (
	APIGroupAll    = "*"
	ResourceAll    = "*"
	VerbAll        = "*"
	NonResourceAll = "*"

	GroupKind          = "Group"
	ServiceAccountKind = "ServiceAccount"
	UserKind           = "User"

	// AutoUpdateAnnotationKey is the name of an annotation which prevents reconciliation if set to "false"
	AutoUpdateAnnotationKey = "rbac.authorization.kubernetes.io/autoupdate"
)

// PolicyRule holds information that describes a policy rule, but does not contain information
// about who the rule applies to or which namespace the rule applies to.
type PolicyRule struct {
	// Verbs is a list of Verbs that apply to ALL the ResourceKinds and AttributeRestrictions contained in this rule. '*' represents all verbs.
	Verbs []string

	// APIGroups is the name of the APIGroup that contains the resources.
	// If multiple API groups are specified, any action requested against one of the enumerated resources in any API group will be allowed.
	APIGroups []string
	// Resources is a list of resources this rule applies to.  '*' represents all resources in the specified apiGroups.
	// '*/foo' represents the subresource 'foo' for all resources in the specified apiGroups.
	Resources []string
	// ResourceNames is an optional white list of names that the rule applies to.  An empty set means that everything is allowed.
	ResourceNames []string

	// NonResourceURLs is a set of partial urls that a user should have access to.  *s are allowed, but only as the full, final step in the path
	// If an action is not a resource API request, then the URL is split on '/' and is checked against the NonResourceURLs to look for a match.
	// Since non-resource URLs are not namespaced, this field is only applicable for ClusterRoles referenced from a ClusterRoleBinding.
	// Rules can either apply to API resources (such as "pods" or "secrets") or non-resource URL paths (such as "/api"),  but not both.
	NonResourceURLs []string
}

// Subject contains a reference to the object or user identities a role binding applies to.  This can either hold a direct API object reference,
// or a value for non-objects such as user and group names.
type Subject struct {
	// Kind of object being referenced. Values defined by this API group are "User", "Group", and "ServiceAccount".
	// If the Authorizer does not recognized the kind value, the Authorizer should report an error.
	Kind string
	// APIGroup holds the API group of the referenced subject.
	// Defaults to "" for ServiceAccount subjects.
	// Defaults to "rbac.authorization.k8s.io" for User and Group subjects.
	APIGroup string
	// Name of the object being referenced.
	Name string
	// Namespace of the referenced object.  If the object kind is non-namespace, such as "User" or "Group", and this value is not empty
	// the Authorizer should report an error.
	Namespace string
}

// RoleRef contains information that points to the role being used
type RoleRef struct {
	// APIGroup is the group for the resource being referenced
	APIGroup string
	// Kind is the type of resource being referenced
	Kind string
	// Name is the name of resource being referenced
	Name string
}

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

// Role is a namespaced, logical grouping of PolicyRules that can be referenced as a unit by a RoleBinding.
type Role struct {
	metav1.TypeMeta
	// Standard object's metadata.
	metav1.ObjectMeta

	// Rules holds all the PolicyRules for this Role
	Rules []PolicyRule
}

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

// RoleBinding references a role, but does not contain it.  It can reference a Role in the same namespace or a ClusterRole in the global namespace.
// It adds who information via Subjects and namespace information by which namespace it exists in.  RoleBindings in a given
// namespace only have effect in that namespace.
type RoleBinding struct {
	metav1.TypeMeta
	metav1.ObjectMeta

	// Subjects holds references to the objects the role applies to.
	Subjects []Subject

	// RoleRef can reference a Role in the current namespace or a ClusterRole in the global namespace.
	// If the RoleRef cannot be resolved, the Authorizer must return an error.
	RoleRef RoleRef
}

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

// RoleBindingList is a collection of RoleBindings
type RoleBindingList struct {
	metav1.TypeMeta
	// Standard object's metadata.
	metav1.ListMeta

	// Items is a list of roleBindings
	Items []RoleBinding
}

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

// RoleList is a collection of Roles
type RoleList struct {
	metav1.TypeMeta
	// Standard object's metadata.
	metav1.ListMeta

	// Items is a list of roles
	Items []Role
}

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

// ClusterRole is a cluster level, logical grouping of PolicyRules that can be referenced as a unit by a RoleBinding or ClusterRoleBinding.
type ClusterRole struct {
	metav1.TypeMeta
	// Standard object's metadata.
	metav1.ObjectMeta

	// Rules holds all the PolicyRules for this ClusterRole
	Rules []PolicyRule

	// AggregationRule is an optional field that describes how to build the Rules for this ClusterRole.
	// If AggregationRule is set, then the Rules are controller managed and direct changes to Rules will be
	// stomped by the controller.
	AggregationRule *AggregationRule
}

// AggregationRule describes how to locate ClusterRoles to aggregate into the ClusterRole
type AggregationRule struct {
	// ClusterRoleSelectors holds a list of selectors which will be used to find ClusterRoles and create the rules.
	// If any of the selectors match, then the ClusterRole's permissions will be added
	ClusterRoleSelectors []metav1.LabelSelector
}

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

// ClusterRoleBinding references a ClusterRole, but not contain it.  It can reference a ClusterRole in the global namespace,
// and adds who information via Subject.
type ClusterRoleBinding struct {
	metav1.TypeMeta
	// Standard object's metadata.
	metav1.ObjectMeta

	// Subjects holds references to the objects the role applies to.
	Subjects []Subject

	// RoleRef can only reference a ClusterRole in the global namespace.
	// If the RoleRef cannot be resolved, the Authorizer must return an error.
	RoleRef RoleRef
}

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

// ClusterRoleBindingList is a collection of ClusterRoleBindings
type ClusterRoleBindingList struct {
	metav1.TypeMeta
	// Standard object's metadata.
	metav1.ListMeta

	// Items is a list of ClusterRoleBindings
	Items []ClusterRoleBinding
}

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

// ClusterRoleList is a collection of ClusterRoles
type ClusterRoleList struct {
	metav1.TypeMeta
	// Standard object's metadata.
	metav1.ListMeta

	// Items is a list of ClusterRoles
	Items []ClusterRole
}
