// Copyright 2015 The Prometheus 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 promhttp

import (
	"net/http"

	"github.com/prometheus/client_golang/prometheus/registry"
)

// Constants relevant to the HTTP interface.
const (
	// APIVersion is the version of the format of the exported data.  This
	// will match this library's version, which subscribes to the Semantic
	// Versioning scheme.
	APIVersion = "0.0.4"

	// DelimitedTelemetryContentType is the content type set on telemetry
	// data responses in delimited protobuf format.
	DelimitedTelemetryContentType = `application/vnd.google.protobuf; proto=io.prometheus.client.MetricFamily; encoding=delimited`
	// TextTelemetryContentType is the content type set on telemetry data
	// responses in text format.
	TextTelemetryContentType = `text/plain; version=` + APIVersion
	// ProtoTextTelemetryContentType is the content type set on telemetry
	// data responses in protobuf text format.  (Only used for debugging.)
	ProtoTextTelemetryContentType = `application/vnd.google.protobuf; proto=io.prometheus.client.MetricFamily; encoding=text`
	// ProtoCompactTextTelemetryContentType is the content type set on
	// telemetry data responses in protobuf compact text format.  (Only used
	// for debugging.)
	ProtoCompactTextTelemetryContentType = `application/vnd.google.protobuf; proto=io.prometheus.client.MetricFamily; encoding=compact-text`

	contentTypeHeader     = "Content-Type"
	contentLengthHeader   = "Content-Length"
	contentEncodingHeader = "Content-Encoding"

	acceptEncodingHeader = "Accept-Encoding"
	acceptHeader         = "Accept"
)

func Handler(r registry.Registry) http.Handler {
	return nil // TODO
}