// Copyright © 2020 Attestant Limited.
// 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 prometheus

import (
	"time"

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

func (s *Service) setupClientMetrics() error {
	s.clientOperationCounter = prometheus.NewCounterVec(prometheus.CounterOpts{
		Namespace: "vouch",
		Subsystem: "client_operation",
		Name:      "requests_total",
	}, []string{"provider", "operation", "result"})
	if err := prometheus.Register(s.clientOperationCounter); err != nil {
		return err
	}
	s.clientOperationTimer = prometheus.NewHistogramVec(prometheus.HistogramOpts{
		Namespace: "vouch",
		Subsystem: "client_operation",
		Name:      "duration_seconds",
		Help:      "The time vouch spends in client operations.",
		Buckets: []float64{
			0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0,
			1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0,
			2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0,
			3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0,
		},
	}, []string{"provider", "operation"})
	if err := prometheus.Register(s.clientOperationTimer); err != nil {
		return err
	}

	return nil
}

// ClientOperation registers an operation.
func (s *Service) ClientOperation(provider string, operation string, succeeded bool, duration time.Duration) {
	if succeeded {
		s.clientOperationCounter.WithLabelValues(provider, operation, "succeeded").Add(1)
		s.clientOperationTimer.WithLabelValues(provider, operation).Observe(duration.Seconds())
	} else {
		s.clientOperationCounter.WithLabelValues(provider, operation, "failed").Add(1)
	}
}