// Copyright 2019 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.

// +build !nothermalzone

package collector

import (
	"fmt"

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

type thermalZoneCollector struct {
	fs       sysfs.FS
	zoneTemp *prometheus.Desc
}

func init() {
	registerCollector("thermal_zone", defaultEnabled, NewThermalZoneCollector)
}

// NewThermalZoneCollector returns a new Collector exposing kernel/system statistics.
func NewThermalZoneCollector() (Collector, error) {
	fs, err := sysfs.NewFS(*sysPath)
	if err != nil {
		return nil, fmt.Errorf("failed to open sysfs: %v", err)
	}

	return &thermalZoneCollector{
		fs: fs,
		zoneTemp: prometheus.NewDesc(
			prometheus.BuildFQName(namespace, "thermal_zone", "temp"),
			"Zone temperature in Celsius",
			[]string{"zone", "type"}, nil,
		),
	}, nil
}

func (c *thermalZoneCollector) Update(ch chan<- prometheus.Metric) error {
	thermalZones, err := c.fs.ClassThermalZoneStats()
	if err != nil {
		return err
	}

	for _, stats := range thermalZones {
		ch <- prometheus.MustNewConstMetric(
			c.zoneTemp,
			prometheus.GaugeValue,
			float64(stats.Temp)/1000.0,
			stats.Name,
			stats.Type,
		)
	}

	return nil
}