// (C) 2022 by Harald Welte <laforge@gnumonks.org>
// SPDX-License-Identifier: Apache-2.0

package main

/*
#include <dahdi/user.h>
 */
import "C"

import (
	"fmt"
	"flag"
	"unsafe"
	"syscall"
	"acln.ro/ioctl"

	"net/http"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promauto"
	"github.com/prometheus/client_golang/prometheus/promhttp"
)

var (
	listen_http = flag.String("http",":2113", "local HTTP listen host:port")
	dahdi_ctl int

	spanno = promauto.NewGaugeVec(
		prometheus.GaugeOpts {
			Subsystem:	"dahdi",
			Name: 		"spaninfo_span_number",
			Help:		"span number of this span",
		},
		[]string{
			"span_name",
		})

	txlevel = promauto.NewGaugeVec(
		prometheus.GaugeOpts {
			Subsystem:	"dahdi",
			Name: 		"spaninfo_txlevel",
			Help:		"current Tx Level",
		},
		[]string{
			"span_name",
		})

	rxlevel = promauto.NewGaugeVec(
		prometheus.GaugeOpts {
			Subsystem:	"dahdi",
			Name: 		"spaninfo_rxlevel",
			Help:		"current Rx Level",
		},
		[]string{
			"span_name",
		})

	bpvcount = promauto.NewGaugeVec(
		prometheus.GaugeOpts {
			Subsystem:	"dahdi",
			Name: 		"spaninfo_bpv_error_total",
			Help:		"current BPV (bi-polar violation) count",
		},
		[]string{
			"span_name",
		})

	crc4count = promauto.NewGaugeVec(
		prometheus.GaugeOpts {
			Subsystem:	"dahdi",
			Name: 		"spaninfo_crc4_error_total",
			Help:		"current CRC4 error count",
		},
		[]string{
			"span_name",
		})

	ebitcount = promauto.NewGaugeVec(
		prometheus.GaugeOpts {
			Subsystem:	"dahdi",
			Name: 		"spaninfo_ebit_error_total",
			Help:		"current E-bit error count",
		},
		[]string{
			"span_name",
		})

	fascount = promauto.NewGaugeVec(
		prometheus.GaugeOpts {
			Subsystem:	"dahdi",
			Name: 		"spaninfo_fas_error_total",
			Help:		"current FAS error count",
		},
		[]string{
			"span_name",
		})

	fecount = promauto.NewGaugeVec(
		prometheus.GaugeOpts {
			Subsystem:	"dahdi",
			Name: 		"spaninfo_framing_error_total",
			Help:		"current framing error count",
		},
		[]string{
			"span_name",
		})

	cvcount = promauto.NewGaugeVec(
		prometheus.GaugeOpts {
			Subsystem:	"dahdi",
			Name: 		"spaninfo_coding_violation_total",
			Help:		"current coding violation error count",
		},
		[]string{
			"span_name",
		})

	becount = promauto.NewGaugeVec(
		prometheus.GaugeOpts {
			Subsystem:	"dahdi",
			Name: 		"spaninfo_bit_error_total",
			Help:		"current bit error count",
		},
		[]string{
			"span_name",
		})

	prbs = promauto.NewGaugeVec(
		prometheus.GaugeOpts {
			Subsystem:	"dahdi",
			Name: 		"spaninfo_prbs",
			Help:		"current PRBS detected pattern",
		},
		[]string{
			"span_name",
		})

	errsec = promauto.NewGaugeVec(
		prometheus.GaugeOpts {
			Subsystem:	"dahdi",
			Name: 		"spaninfo_errored_seconds",
			Help:		"errored seconds",
		},
		[]string{
			"span_name",
		})

	irqmisses = promauto.NewGaugeVec(
		prometheus.GaugeOpts {
			Subsystem:	"dahdi",
			Name: 		"spaninfo_irq_misses_total",
			Help:		"current IRQ misses",
		},
		[]string{
			"span_name",
		})

	syncsrc = promauto.NewGaugeVec(
		prometheus.GaugeOpts {
			Subsystem:	"dahdi",
			Name: 		"spaninfo_sync_source_span",
			Help:		"span number of current sync source",
		},
		[]string{
			"span_name",
		})

	numchans = promauto.NewGaugeVec(
		prometheus.GaugeOpts {
			Subsystem:	"dahdi",
			Name: 		"spaninfo_channels_configured_total",
			Help:		"number of configured channels in this span",
		},
		[]string{
			"span_name",
		})


	totalchans = promauto.NewGaugeVec(
		prometheus.GaugeOpts {
			Subsystem:	"dahdi",
			Name: 		"spaninfo_channels_total",
			Help:		"number of channels in this span",
		},
		[]string{
			"span_name",
		})
)

/* report one span to prometheus */
func report_span(spaninfo *C.struct_dahdi_spaninfo) {
	name := C.GoString(&spaninfo.name[0])
	spanno.WithLabelValues(name).Set(float64(spaninfo.spanno))
	txlevel.WithLabelValues(name).Set(float64(spaninfo.txlevel))
	rxlevel.WithLabelValues(name).Set(float64(spaninfo.rxlevel))
	bpvcount.WithLabelValues(name).Set(float64(spaninfo.bpvcount))
	crc4count.WithLabelValues(name).Set(float64(spaninfo.crc4count))
	ebitcount.WithLabelValues(name).Set(float64(spaninfo.ebitcount))
	fascount.WithLabelValues(name).Set(float64(spaninfo.fascount))
	fecount.WithLabelValues(name).Set(float64(spaninfo.fecount))
	cvcount.WithLabelValues(name).Set(float64(spaninfo.cvcount))
	becount.WithLabelValues(name).Set(float64(spaninfo.becount))
	prbs.WithLabelValues(name).Set(float64(spaninfo.prbs))
	errsec.WithLabelValues(name).Set(float64(spaninfo.errsec))
	irqmisses.WithLabelValues(name).Set(float64(spaninfo.irqmisses))
	syncsrc.WithLabelValues(name).Set(float64(spaninfo.syncsrc))
	numchans.WithLabelValues(name).Set(float64(spaninfo.numchans))
	totalchans.WithLabelValues(name).Set(float64(spaninfo.totalchans))
}

/* read spanstat of one span */
func read_span(spaninfo *C.struct_dahdi_spaninfo) {
	var spanstat ioctl.WR
	//var spaninfo C.struct_dahdi_spaninfo
	var err error

	spanstat.Name = "DAHDI Spaninfo"
	spanstat.Type = 0xDA
	spanstat.Nr = 10
	spanstat.Size = uint16(unsafe.Sizeof(*spaninfo))

	fmt.Println("SPANSTAT ioctl on span ", spaninfo)
	if err = spanstat.Exec(dahdi_ctl, unsafe.Pointer(spaninfo)); err != nil {
		fmt.Println("spaninfo ", spaninfo)
		panic(fmt.Sprintf("Failed to execute ioctl: %s", err))
	}
}

/* iterate over all spans, read + report each of them */
func read_spans() {
	var spaninfo C.struct_dahdi_spaninfo
	//var err error

	/* first obtain the total number of spans */
	spaninfo.spanno = 1
	read_span(&spaninfo)
	report_span(&spaninfo)
	total_spans := int(spaninfo.totalspans)

	/* then iterate over the remainder of them */
	for i := 2; i <= total_spans; i++ {
		spaninfo.spanno = C.int(i)
		read_span(&spaninfo)
		report_span(&spaninfo)
	}

}

func main() {
	var err error

	flag.Parse()

	if dahdi_ctl, err = syscall.Open("/dev/dahdi/ctl", syscall.O_RDWR, 0775); err != nil {
		panic(fmt.Sprintf("Failed to open DAHDI ctl: %s", err))
	}

	read_spans()

	fmt.Println("Listening to HTTP requests at", *listen_http)
	http.Handle("/metrics", promhttp.Handler())
	http.ListenAndServe(*listen_http, nil)


}