/*
Copyright 2022-23. projectsveltos.io. All rights reserved.

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 v1alpha1

import (
	"fmt"
	"strings"

	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
)

const (
	// ClassifierFinalizer allows ClassifierReconciler to clean up resources associated with
	// Classifier before removing it from the apiserver.
	ClassifierFinalizer = "classifierfinalizer.projectsveltos.io"

	// ClassifierReportClusterNameLabel is added to each ClassifierReport
	ClassifierReportClusterNameLabel = "classifier.projectsveltos.io/cluster-name"

	// ClassifierReportClusterTypeLabel is added to each ClassifierReport
	ClassifierReportClusterTypeLabel = "classifier.projectsveltos.io/cluster-type"

	ClassifierKind = "Classifier"

	FeatureClassifier = "Classifier"
)

func GetClassifierReportName(classifierName, clusterName string, clusterType *ClusterType) string {
	// TODO: shorten this
	return fmt.Sprintf("%s--%s--%s",
		strings.ToLower(string(*clusterType)), classifierName, clusterName)
}

func GetClassifierReportLabels(classifierName, clusterName string, clusterType *ClusterType) map[string]string {
	return map[string]string{
		ClassifierlNameLabel:             classifierName,
		ClassifierReportClusterNameLabel: clusterName,
		ClassifierReportClusterTypeLabel: strings.ToLower(string(*clusterType)),
	}
}

func GetClusterInfo(clusterNamespace, clusterName string) string {
	return fmt.Sprintf("%s--%s", clusterNamespace, clusterName)
}

type ClassifierLabel struct {
	// Key is the label key
	Key string `json:"key"`

	// Value is the label value
	Value string `json:"value"`
}

type DeployedResourceConstraint struct {
	// ResourceSelectors identifies what resources to select
	// If no AggregatedClassification is specified, a cluster is
	// a match for Classifier instance, if all ResourceSelectors returns at
	// least one match.
	ResourceSelectors []ResourceSelector `json:"resourceSelectors"`

	// AggregatedClassification is optional and can be used to specify a Lua function
	// that will be used to further detect whether the subset of the resources
	// selected using the ResourceSelector field are a match for this Classifier.
	// The function will receive the array of resources selected by ResourceSelectors.
	// If this field is not specified, a cluster is a match for Classifier instance,
	// if all ResourceSelectors returns at least one match.
	// This field allows to perform more complex evaluation  on the resources, looking
	// at all resources together.
	// This can be useful for more sophisticated tasks, such as identifying resources
	// that are related to each other or that have similar properties.
	// The Lua function must return a struct with:
	// - "matching" field: boolean indicating whether cluster is a match;
	// - "message" field: (optional) message.
	// +optional
	AggregatedClassification string `json:"aggregatedClassification,omitempty"`
}

type KubernetesComparison string

// Define the Action constants.
const (
	ComparisonEqual                KubernetesComparison = "Equal"
	ComparisonNotEqual             KubernetesComparison = "NotEqual"
	ComparisonGreaterThan          KubernetesComparison = "GreaterThan"
	ComparisonLessThan             KubernetesComparison = "LessThan"
	ComparisonGreaterThanOrEqualTo KubernetesComparison = "GreaterThanOrEqualTo"
	ComparisonLessThanOrEqualTo    KubernetesComparison = "LessThanOrEqualTo"
)

type KubernetesVersionConstraint struct {
	// Version is the kubernetes version
	Version string `json:"version"`

	// Comparison indicate how to compare cluster kubernetes version with the specified version
	// +kubebuilder:validation:Enum=Equal;NotEqual;GreaterThan;LessThan;GreaterThanOrEqualTo;LessThanOrEqualTo
	Comparison string `json:"comparison"`
}

// ClassifierSpec defines the desired state of Classifier
type ClassifierSpec struct {
	// DeployedResourceConstraint allows to classify based on current deployed resources
	// +optional
	DeployedResourceConstraint *DeployedResourceConstraint `json:"deployedResourceConstraint,omitempty"`

	// KubernetesVersionConstraints allows to classify based on current kubernetes version
	// +optional
	KubernetesVersionConstraints []KubernetesVersionConstraint `json:"kubernetesVersionConstraints,omitempty"`

	// ClassifierLabels is set of labels, key,value pair, that will be added to each
	// cluster matching Classifier instance
	ClassifierLabels []ClassifierLabel `json:"classifierLabels"`
}

type UnManagedLabel struct {
	// Key represents a label Classifier would like to manage
	// but cannot because currently managed by different instance
	Key string `json:"key"`

	// FailureMessage is a human consumable message explaining the
	// misconfiguration
	// +optional
	FailureMessage *string `json:"failureMessage,omitempty"`
}

type MachingClusterStatus struct {
	// ClusterRef references the matching Cluster
	ClusterRef corev1.ObjectReference `json:"clusterRef"`

	// ManagedLabels indicates the labels being managed on
	// the cluster by this Classifier instance
	// +optional
	ManagedLabels []string `json:"managedLabels,omitempty"`

	// UnManagedLabel indicates the labels this Classifier instance
	// would like to manage but cannot because different instance is
	// already managing it
	// +optional
	UnManagedLabels []UnManagedLabel `json:"unManagedLabels,omitempty"`
}

// ClassifierStatus defines the observed state of Classifier
type ClassifierStatus struct {
	// MatchingClusterRefs reference all the cluster-api Cluster currently matching
	// Classifier
	MachingClusterStatuses []MachingClusterStatus `json:"machingClusterStatuses,omitempty"`

	// ClusterInfo reference all the cluster-api Cluster where Classifier
	// has been/is being deployed
	ClusterInfo []ClusterInfo `json:"clusterInfo,omitempty"`
}

//+kubebuilder:object:root=true
//+kubebuilder:resource:path=classifiers,scope=Cluster
//+kubebuilder:subresource:status

// Classifier is the Schema for the classifiers API
type Classifier struct {
	metav1.TypeMeta   `json:",inline"`
	metav1.ObjectMeta `json:"metadata,omitempty"`

	Spec   ClassifierSpec   `json:"spec,omitempty"`
	Status ClassifierStatus `json:"status,omitempty"`
}

//+kubebuilder:object:root=true

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

func init() {
	SchemeBuilder.Register(&Classifier{}, &ClassifierList{})
}