// Copyright 2013 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 mapper

import "fmt"

type ObserverType string

const (
	ObserverTypeHistogram ObserverType = "histogram"
	ObserverTypeSummary   ObserverType = "summary"
	ObserverTypeDefault   ObserverType = ""
)

func (t *ObserverType) UnmarshalYAML(unmarshal func(interface{}) error) error {
	var v string
	if err := unmarshal(&v); err != nil {
		return err
	}

	switch ObserverType(v) {
	case ObserverTypeHistogram:
		*t = ObserverTypeHistogram
	case ObserverTypeSummary, ObserverTypeDefault:
		*t = ObserverTypeSummary
	default:
		return fmt.Errorf("invalid observer type '%s'", v)
	}
	return nil
}
