package main

import (
	"flag"
	"fmt"
	"log"
	"net/http"
	"os"
	"path/filepath"
	"strings"
	"time"

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

const VERSION = "0.2.0"

const LISTEN_ADDR = ":9403"
const INTERVAL = 30 * time.Minute

var backupDir = flag.String("backup-dir", "/srv/backups", "Directory where the backups are located")
var version_flag = flag.Bool("version", false, "Shows the program version")
var logfile = flag.String("logfile", "-", "Where to write the logs")

func main() {
	flag.Parse()

	if *logfile != "-" {
		f, err := os.OpenFile(*logfile, os.O_CREATE|os.O_RDWR|os.O_APPEND, 0664)
		if err != nil {
			log.Fatalf("Could not open logfile: %v\n", err)
		}
		defer f.Close()
		log.SetOutput(f)
	}

	if *version_flag {
		fmt.Printf("%v\n", VERSION)
		os.Exit(0)
	}

	reg := prometheus.NewRegistry()

	log.Printf("Backup directory is: %v\n", *backupDir)

	m := NewMetrics(reg)

	go RecordMetrics(*m)

	http.Handle("/metrics", promhttp.HandlerFor(reg, promhttp.HandlerOpts{Registry: reg}))

	log.Printf("Listening on %v ...\n", LISTEN_ADDR)

	log.Fatal(http.ListenAndServe(LISTEN_ADDR, nil))
}

func RecordMetrics(m Metrics) {
	for {
		m.Reset()

		entries, err := os.ReadDir(*backupDir)
		if err != nil {
			log.Fatalln(err)
		}

		for _, entry := range entries {
			if !entry.IsDir() || strings.HasPrefix(entry.Name(), ".") {
				log.Printf(">> Ignoring %v\n", entry.Name())
				continue
			}

			path := filepath.Join(*backupDir, entry.Name())

			info, err := GetInfo(path)
			if err != nil {
				log.Printf(">> Could not get info about %v: %v\n", path, err)
				continue
			}
			list, err := GetList(path)
			if err != nil {
				log.Printf(">> Could not get archive list from %v: %v\n", path, err)
				continue
			}

			stats := info.Cache.Stats

			log.Printf("> Got info for: %v\n", path)
			m.ArchiveCount.With(prometheus.Labels{"repo_name": entry.Name()}).Set(float64(len(list.Archives)))
			m.LastArchiveTime.With(prometheus.Labels{"repo_name": entry.Name()}).Set(list.LastArchiveUnix())
			m.LastModified.With(prometheus.Labels{"repo_name": entry.Name()}).Set(info.LastmodUnix())
			m.TotalChunks.With(prometheus.Labels{"repo_name": entry.Name()}).Set(stats.Total_chunks)
			m.TotalCsize.With(prometheus.Labels{"repo_name": entry.Name()}).Set(stats.Total_csize)
			m.TotalSize.With(prometheus.Labels{"repo_name": entry.Name()}).Set(stats.Total_size)
			m.TotalUniqueChunks.With(prometheus.Labels{"repo_name": entry.Name()}).Set(stats.Total_unique_chunks)
			m.UniqueCsize.With(prometheus.Labels{"repo_name": entry.Name()}).Set(stats.Unique_csize)
			m.UniqueSize.With(prometheus.Labels{"repo_name": entry.Name()}).Set(stats.Unique_size)
		}

		log.Printf("> Waiting %v\n", INTERVAL)
		time.Sleep(INTERVAL)
	}
}