// 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.

// +build openbsd
// +build !norcctl

package collector

import (
	"github.com/go-kit/kit/log"
	"github.com/go-kit/kit/log/level"
	"github.com/prometheus/client_golang/prometheus"
	"os/exec"
	"strings"
)

var (
	specialSvcs = map[string]struct{}{
		"accounting":   struct{}{},
		"check_quotas": struct{}{},
		"ipsec":        struct{}{},
		"library_aslr": struct{}{},
		"multicast":    struct{}{},
		"pf":           struct{}{},
		"spamd_black":  struct{}{},
	}
)

const (
	rcctl = "/usr/sbin/rcctl"
	rcdir = "/etc/rc.d"
)

type rcctlCollector struct {
	state, stateDesired typedDesc
	logger              log.Logger
}

func init() {
	registerCollector("rcctl", defaultDisabled, NewRcctlCollector)
}

// NewRunitCollector returns a new Collector exposing runit statistics.
func NewRcctlCollector(logger log.Logger) (Collector, error) {
	var (
		subsystem   = "service"
		constLabels = prometheus.Labels{"supervisor": "rcctl"}
		labelNames  = []string{"service"}
	)

	return &rcctlCollector{
		state: typedDesc{prometheus.NewDesc(
			prometheus.BuildFQName(namespace, subsystem, "state"),
			"State of rcctl service.",
			labelNames, constLabels,
		), prometheus.GaugeValue},
		stateDesired: typedDesc{prometheus.NewDesc(
			prometheus.BuildFQName(namespace, subsystem, "desired_state"),
			"Desired state of rcctl service.",
			labelNames, constLabels,
		), prometheus.GaugeValue},
		logger: logger,
	}, nil
}

func (rcctlCollector) check(service string) (status int) {
	cmd := exec.Command(rcdir+"/"+service, "check")
	err := cmd.Run()
	if err != nil {
		return
	}
	if cmd.ProcessState.ExitCode() == 0 {
		status = 1
	}
	return
}

func (c *rcctlCollector) Update(ch chan<- prometheus.Metric) error {
	cmd := exec.Command(rcctl, "ls", "on")
	on, err := cmd.Output()
	if err != nil {
		return err
	}
	for _, s := range strings.Split(string(on), "\n") {
		if s == "" {
			continue
		}
		if _, ok := specialSvcs[s]; ok {
			continue
		}
		status := c.check(s)
		level.Debug(c.logger).Log("msg", "Current status", "Service", s, "Status", status)
		ch <- c.state.mustNewConstMetric(float64(status), s)
		ch <- c.stateDesired.mustNewConstMetric(float64(1), s)
	}
	return nil
}