metric

type FireflyDefaultLabels struct {
	Namespace string
}

type MetricsManager interface {
	// functions for defining metrics
	NewCounterMetric(ctx context.Context, metricName string, helpText string, withDefaultLabels bool)
	NewCounterMetricWithLabels(ctx context.Context, metricName string, helpText string, labelNames []string, withDefaultLabels bool)
	NewGaugeMetric(ctx context.Context, metricName string, helpText string, withDefaultLabels bool)
	NewGaugeMetricWithLabels(ctx context.Context, metricName string, helpText string, labelNames []string, withDefaultLabels bool)
	NewHistogramMetric(ctx context.Context, metricName string, helpText string, buckets []float64, withDefaultLabels bool)
	NewHistogramMetricWithLabels(ctx context.Context, metricName string, helpText string, buckets []float64, labelNames []string, withDefaultLabels bool)
	NewSummaryMetric(ctx context.Context, metricName string, helpText string, withDefaultLabels bool)
	NewSummaryMetricWithLabels(ctx context.Context, metricName string, helpText string, labelNames []string, withDefaultLabels bool)

	// functions for emitting metrics
	SetGaugeMetric(ctx context.Context, metricName string, number float64, defaultLabels *FireflyDefaultLabels)
	SetGaugeMetricWithLabels(ctx context.Context, metricName string, number float64, labels map[string]string, defaultLabels *FireflyDefaultLabels)
	IncGaugeMetric(ctx context.Context, metricName string, defaultLabels *FireflyDefaultLabels)
	IncGaugeMetricWithLabels(ctx context.Context, metricName string, labels map[string]string, defaultLabels *FireflyDefaultLabels)
	DecGaugeMetric(ctx context.Context, metricName string, defaultLabels *FireflyDefaultLabels)
	DecGaugeMetricWithLabels(ctx context.Context, metricName string, labels map[string]string, defaultLabels *FireflyDefaultLabels)

	IncCounterMetric(ctx context.Context, metricName string, defaultLabels *FireflyDefaultLabels)
	IncCounterMetricWithLabels(ctx context.Context, metricName string, labels map[string]string, defaultLabels *FireflyDefaultLabels)
	ObserveHistogramMetric(ctx context.Context, metricName string, number float64, defaultLabels *FireflyDefaultLabels)
	ObserveHistogramMetricWithLabels(ctx context.Context, metricName string, number float64, labels map[string]string, defaultLabels *FireflyDefaultLabels)
	ObserveSummaryMetric(ctx context.Context, metricName string, number float64, defaultLabels *FireflyDefaultLabels)
	ObserveSummaryMetricWithLabels(ctx context.Context, metricName string, number float64, labels map[string]string, defaultLabels *FireflyDefaultLabels)
}

type MetricsRegistry interface {
	// NewMetricsManagerForSubsystem returns a MetricsManager which can be used to add custom metrics
	NewMetricsManagerForSubsystem(ctx context.Context, subsystem string) (MetricsManager, error)

	// HTTPHandler returns the HTTP handler of this metrics registry
	HTTPHandler(ctx context.Context, handlerOpts promhttp.HandlerOpts) (http.Handler, error)

	// Predefined HTTP Metrics  Instrumentations
	// NewHTTPMetricsInstrumentationsForSubsystem adds predefined HTTP metrics to a subsystem
	NewHTTPMetricsInstrumentationsForSubsystem(ctx context.Context, subsystem string, useRouteTemplate bool, reqDurationBuckets []float64, labels map[string]string) error
	// GetHTTPMetricsInstrumentationsMiddlewareForSubsystem returns the HTTP middleware of a subsystem that used predefined HTTP metrics
	GetHTTPMetricsInstrumentationsMiddlewareForSubsystem(ctx context.Context, subsystem string) (func(next http.Handler) http.Handler, error)

	MustRegisterCollector(collector prometheus.Collector)
}

type Options struct {
	MetricsPrefix string
}