v1alpha1

type Field struct {
	// Path defines the json path of the object.
	// Example: For deployment spec replica count, the path will be .spec.replicas
	Path string `json:"path"`

	// Type defines the type of the value in the given Path
	// Type can be "Integer" for integer value like .spec.replicas,
	// "DateTime" for time stamp value like .metadata.creationTimestamp
	// "Array" for array field like .spec.containers
	// "String" for string field like .statue.phase (for pod status)
	// +kubebuilder:validation:Enum=Integer;DateTime;Array;String
	Type FieldType `json:"type"`
}

type FieldType string

type Label struct {
	// Key defines the label key
	Key string `json:"key"`

	// Value defines the hard coded label value.
	// Example:
	// labels:
	//   - key: unit
	//     value: byte
	//   - key: environment
	//     value: production
	//
	// +optional
	Value string `json:"value,omitempty"`

	// ValuePath defines the label value path.
	// Example: To add deployment's resource version as labels,
	// labels:
	//   - key: version
	//     valuePath: .metadata.resourceVersion
	//
	// +optional
	ValuePath string `json:"valuePath"`
}

type MetricValue struct {
	// Value contains the metric value. It is always equal to 1.
	// It is defined when some information of the object is
	// collected as labels but there is no specific metric value.
	//
	// Example: For metrics "kube_pod_info", there are some information
	// like host_ip, pod_ip, node name is collected as labels.
	// As there must be a metric value, metric value is kept as 1.
	// The metric will look like `kube_pod_info{host_ip="172.18.0.2", pod_ip="10.244.0.14", node="kind-control-plane" .....}  1`
	// +optional
	Value *float64 `json:"value,omitempty"`

	// ValueFromPath contains the field path of the manifest file of a object.
	// ValueFromPath is used when the metric value is coming from
	// any specific json path of the object.
	//
	// Example: For metrics "kube_deployment_spec_replicas",
	// the metricValue is coming from a specific path .spec.replicas
	// In this case, valueFromPath: .spec.replicas
	// Some example of json path: .metadata.observedGeneration, .spec.restartPolicy, .status.startTime
	//
	// Some example of json path
	// which is coming from an element of an array: .spec.containers[*].image, .status.containerStatuses[*].restartCount
	// +optional
	ValueFromPath string `json:"valueFromPath,omitempty"`

	// ValueFromExpression contains an expression for the metric value
	// expression can be a function as well. Parameters is used in the expression string
	//
	// Available expression evaluation functions are:
	//
	// int() returns 1 if the expression is true otherwise 0,
	// example: int(phase == 'Running')
	//
	// percentage(percent, total, roundUp) returns the value of (percent * total%) when `percent` contains the percent(%) value.
	// If percent represents an Integer value, then it will simply return it.
	// roundUp is an optional field. By default, its value is false. If roundUp is set as `true`, the resultant value will be rounded up.
	// example: (i) percentage("25%", 4) will return 1.
	//         (ii) percentage("25%", 1 , true) will return 1 as roundUp is set as true.
	//        (iii) percentage(2, 4) will return 2 as percent is representing an Integer value.
	//
	// cpu_cores() returns the cpu in unit core
	// example: cpu_cores(cpu), for cpu value 150m, it will return 0.15
	//
	// bytes() returns the memory size in byte
	// example: bytes(memory), for memory value 1 ki, it will return 1024
	//
	// unix() returns the DateTime string into unix format.
	// example: unix(dateTime) will return the corresponding unix value for the given dateTime
	//
	// in above examples phase, replicas, maxUnavailable, cpu, memory, dateTime are Parameter's key
	// those values will come from corresponding Parameter's value
	//
	// Some expression evaluation functions are used for calculating resource requests and limits.
	// Those functions are stated here: https://github.com/kmodules/resource-metrics/blob/master/eval.go
	// +optional
	ValueFromExpression string `json:"valueFromExpression,omitempty"`
}

type Metrics struct {
	// Name defines the metrics name. Name should be in snake case.
	// Example: kube_deployment_spec_replicas
	Name string `json:"name"`

	// Help is used to describe the metrics.
	// Example: For kube_deployment_spec_replicas, help string can be "Number of desired pods for a deployment."
	Help string `json:"help"`

	// Type defines the metrics type.
	// For kubernetes based object, types can only be "gauge"
	// +kubebuilder:validation:Enum=gauge;
	Type string `json:"type"`

	// Field defines the metric value path of the manifest file and the type of that value
	// +optional
	Field Field `json:"field,omitempty"`

	// Labels defines the metric labels as a key-value pair
	// +optional
	Labels []Label `json:"labels,omitempty"`

	// Params is list of parameters configuration used in expression evaluation
	// +optional
	Params []Parameter `json:"params,omitempty"`

	// States handle metrics with label cardinality.
	// States specify the possible states for a label
	// and their corresponding MetricValue configuration.
	//
	// Metrics must contain either States or MetricValue.
	// If both are specified, MetricValue will be ignored.
	// +optional
	States *State `json:"states,omitempty"`

	// MetricValue defines the configuration to obtain metric value.
	//
	// Metrics must contain either States or MetricValue.
	// If both are specified, MetricValue will be ignored.
	// +optional
	MetricValue MetricValue `json:"metricValue,omitempty"`
}

type MetricsConfiguration struct {
	metav1.TypeMeta   `json:",inline"`
	metav1.ObjectMeta `json:"metadata,omitempty"`
	Spec              MetricsConfigurationSpec `json:"spec,omitempty"`
}

type MetricsConfigurationList struct {
	metav1.TypeMeta `json:",inline"`
	metav1.ListMeta `json:"metadata,omitempty"`
	Items           []MetricsConfiguration `json:"items,omitempty"`
}

type MetricsConfigurationSpec struct {
	// TargetRef defines the object for which metrics will be collected
	TargetRef TargetRef `json:"targetRef"`

	// CommonLabels defines the common labels added to all the exported metrics
	// +optional
	CommonLabels []Label `json:"commonLabels,omitempty"`

	// List of Metrics configuration for the resource object defined in TargetRef
	Metrics []Metrics `json:"metrics"`
}

type Parameter struct {
	// Key defines the parameter's key
	Key string `json:"key"`

	// Value defines user defined parameter's value.
	// +optional
	Value string `json:"value,omitempty"`

	// ValuePath defines the manifest field path for the parameter's value.
	// Example: To add deployment's spec replica count as parameter,
	// params:
	//   - key: replica
	//     valuePath: .spec.replicas
	// +optional
	ValuePath string `json:"valuePath,omitempty"`
}

type State struct {
	// LabelKey defines an user defined label key of the label
	// which label cardinality is greater than one.
	// Example: For metric "kube_pod_status_phase", the LabelKey can be "phase"
	LabelKey string `json:"labelKey"`

	// Values contains the list of state values.
	// The size of the list is always equal to the cardinality of that label.
	// Example: "kube_pod_statue_phase" metric has a label "phase"
	// which cardinality is equal to 5. So Values should have StateValues config for all of them.
	Values []StateValues `json:"values"`
}

type StateValues struct {
	// LabelValue defines the value of the label.
	// Example: For labelKey "phase" (metric: kube_pod_status_phase path: .status.phase )
	// label value can be "Running", "Succeeded", "Failed", "Unknown" and "Pending"
	LabelValue string `json:"labelValue"`

	// MetricValue defines the configuration of the metric value for the corresponding LabelValue
	MetricValue MetricValue `json:"metricValue"`
}

type TargetRef struct {
	// APIVersion defines the versioned schema of this representation of an object.
	APIVersion string `json:"apiVersion"`

	// Kind is a string value representing the REST resource this object represents.
	// In CamelCase.
	Kind string `json:"kind"`
}