package main

import (
	"math"
	"strconv"

	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/common/log"

	"github.com/soundcloud/ipmi_exporter/freeipmi"
)

const (
	IPMICollectorName CollectorName = "ipmi"
)

var (
	sensorStateDesc = prometheus.NewDesc(
		prometheus.BuildFQName(namespace, "sensor", "state"),
		"Indicates the severity of the state reported by an IPMI sensor (0=nominal, 1=warning, 2=critical).",
		[]string{"id", "name", "type"},
		nil,
	)

	sensorValueDesc = prometheus.NewDesc(
		prometheus.BuildFQName(namespace, "sensor", "value"),
		"Generic data read from an IPMI sensor of unknown type, relying on labels for context.",
		[]string{"id", "name", "type"},
		nil,
	)

	fanSpeedDesc = prometheus.NewDesc(
		prometheus.BuildFQName(namespace, "fan_speed", "rpm"),
		"Fan speed in rotations per minute.",
		[]string{"id", "name"},
		nil,
	)

	fanSpeedStateDesc = prometheus.NewDesc(
		prometheus.BuildFQName(namespace, "fan_speed", "state"),
		"Reported state of a fan speed sensor (0=nominal, 1=warning, 2=critical).",
		[]string{"id", "name"},
		nil,
	)

	temperatureDesc = prometheus.NewDesc(
		prometheus.BuildFQName(namespace, "temperature", "celsius"),
		"Temperature reading in degree Celsius.",
		[]string{"id", "name"},
		nil,
	)

	temperatureStateDesc = prometheus.NewDesc(
		prometheus.BuildFQName(namespace, "temperature", "state"),
		"Reported state of a temperature sensor (0=nominal, 1=warning, 2=critical).",
		[]string{"id", "name"},
		nil,
	)

	voltageDesc = prometheus.NewDesc(
		prometheus.BuildFQName(namespace, "voltage", "volts"),
		"Voltage reading in Volts.",
		[]string{"id", "name"},
		nil,
	)

	voltageStateDesc = prometheus.NewDesc(
		prometheus.BuildFQName(namespace, "voltage", "state"),
		"Reported state of a voltage sensor (0=nominal, 1=warning, 2=critical).",
		[]string{"id", "name"},
		nil,
	)

	currentDesc = prometheus.NewDesc(
		prometheus.BuildFQName(namespace, "current", "amperes"),
		"Current reading in Amperes.",
		[]string{"id", "name"},
		nil,
	)

	currentStateDesc = prometheus.NewDesc(
		prometheus.BuildFQName(namespace, "current", "state"),
		"Reported state of a current sensor (0=nominal, 1=warning, 2=critical).",
		[]string{"id", "name"},
		nil,
	)

	powerDesc = prometheus.NewDesc(
		prometheus.BuildFQName(namespace, "power", "watts"),
		"Power reading in Watts.",
		[]string{"id", "name"},
		nil,
	)

	powerStateDesc = prometheus.NewDesc(
		prometheus.BuildFQName(namespace, "power", "state"),
		"Reported state of a power sensor (0=nominal, 1=warning, 2=critical).",
		[]string{"id", "name"},
		nil,
	)
)

type IPMICollector struct{}

func (c IPMICollector) Name() CollectorName {
	return IPMICollectorName
}

func (c IPMICollector) Cmd() string {
	return "ipmimonitoring"
}

func (c IPMICollector) Args() []string {
	return []string{
		"-Q",
		"--ignore-unrecognized-events",
		"--comma-separated-output",
		"--no-header-output",
		"--sdr-cache-recreate",
		"--output-event-bitmask",
	}
}

func (c IPMICollector) Collect(result freeipmi.Result, ch chan<- prometheus.Metric, target ipmiTarget) (int, error) {
	excludeIds := target.config.ExcludeSensorIDs
	results, err := freeipmi.GetSensorData(result, excludeIds)
	if err != nil {
		log.Errorf("Failed to collect sensor data from %s: %s", targetName(target.host), err)
		return 0, err
	}
	for _, data := range results {
		var state float64

		switch data.State {
		case "Nominal":
			state = 0
		case "Warning":
			state = 1
		case "Critical":
			state = 2
		case "N/A":
			state = math.NaN()
		default:
			log.Errorf("Unknown sensor state: '%s'\n", data.State)
			state = math.NaN()
		}

		log.Debugf("Got values: %v\n", data)

		switch data.Unit {
		case "RPM":
			collectTypedSensor(ch, fanSpeedDesc, fanSpeedStateDesc, state, data)
		case "C":
			collectTypedSensor(ch, temperatureDesc, temperatureStateDesc, state, data)
		case "A":
			collectTypedSensor(ch, currentDesc, currentStateDesc, state, data)
		case "V":
			collectTypedSensor(ch, voltageDesc, voltageStateDesc, state, data)
		case "W":
			collectTypedSensor(ch, powerDesc, powerStateDesc, state, data)
		default:
			collectGenericSensor(ch, state, data)
		}
	}
	return 1, nil
}

func (c IPMICollector) Describe(ch chan<- *prometheus.Desc) {
	ch <- sensorStateDesc
	ch <- sensorValueDesc
	ch <- fanSpeedDesc
	ch <- fanSpeedStateDesc
	ch <- temperatureDesc
	ch <- temperatureStateDesc
	ch <- voltageDesc
	ch <- voltageStateDesc
	ch <- currentDesc
	ch <- currentStateDesc
	ch <- powerDesc
	ch <- powerStateDesc
}

func collectTypedSensor(ch chan<- prometheus.Metric, desc, stateDesc *prometheus.Desc, state float64, data freeipmi.SensorData) {
	ch <- prometheus.MustNewConstMetric(
		desc,
		prometheus.GaugeValue,
		data.Value,
		strconv.FormatInt(data.ID, 10),
		data.Name,
	)
	ch <- prometheus.MustNewConstMetric(
		stateDesc,
		prometheus.GaugeValue,
		state,
		strconv.FormatInt(data.ID, 10),
		data.Name,
	)
}

func collectGenericSensor(ch chan<- prometheus.Metric, state float64, data freeipmi.SensorData) {
	ch <- prometheus.MustNewConstMetric(
		sensorValueDesc,
		prometheus.GaugeValue,
		data.Value,
		strconv.FormatInt(data.ID, 10),
		data.Name,
		data.Type,
	)
	ch <- prometheus.MustNewConstMetric(
		sensorStateDesc,
		prometheus.GaugeValue,
		state,
		strconv.FormatInt(data.ID, 10),
		data.Name,
		data.Type,
	)
}