// Copyright 2025 TiKV 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 metrics

import "github.com/prometheus/client_golang/prometheus"

// Histogram is an interface for histogram metrics that can observe values.
//
// It is intentionally small so we can swap underlying implementations via build tags.
type Histogram interface {
	prometheus.Metric
	prometheus.Observer
	prometheus.Collector
}

// HistogramVec is an interface for histogram vector metrics that can create labeled histograms.
//
// It returns a prometheus.Observer so existing call sites and shortcuts stay unchanged.
type HistogramVec interface {
	WithLabelValues(lvs ...string) prometheus.Observer
	With(labels prometheus.Labels) prometheus.Observer
	prometheus.Collector
}