package main

import (
	"fmt"
	"io/ioutil"
	"local/args"
	"local/storage"
	"log"
	"os"
	"os/exec"
	"path"
	"path/filepath"
	"sort"
	"time"
)

type Config struct {
	n      int
	conf   string
	rclone string
	ns     string
	root   string
	store  string
}

func main() {
	conf := config()
	log.Println(conf)
	store, err := storage.New(storage.TypeFromString(conf.store), conf.conf, path.Join(conf.rclone+":", conf.ns))
	if err != nil {
		panic(err)
	}
	if err := push(conf.root, store); err != nil {
		panic(err)
	}
	if err := clean(conf.n, store); err != nil {
		panic(err)
	}
}

func config() Config {
	as := args.NewArgSet()
	as.Append(args.INT, "n", "number of backups to retain", 5)
	as.Append(args.STRING, "conf", "path to rclone conf", path.Join(os.Getenv("HOME"), "/.config/rclone/rclone.conf"))
	as.Append(args.STRING, "root", "path to root", "./public")
	as.Append(args.STRING, "ns", "ns for backups", path.Join("lastn", "dev"))
	as.Append(args.STRING, "rclone", "rclone backend name", "blapointe-drive-enc")
	as.Append(args.STRING, "store", "type of store, like [map rclone]", "map")
	if err := as.Parse(); err != nil {
		panic(err)
	}
	return Config{
		n:      as.Get("n").GetInt(),
		conf:   as.Get("conf").GetString(),
		rclone: as.Get("rclone").GetString(),
		root:   as.Get("root").GetString(),
		ns:     as.Get("ns").GetString(),
		store:  as.Get("store").GetString(),
	}
}

func push(root string, store storage.DB) error {
	root, err := filepath.Abs(root)
	if err != nil {
		return err
	}
	archive := path.Join(
		os.TempDir(),
		fmt.Sprintf(
			"%s.tar",
			time.Now().Format("2006.01.02.15.04.05"),
		),
	)
	cmd := exec.Command(
		"tar",
		"-C",
		path.Dir(root),
		"-czf",
		archive,
		root,
	)
	out, err := cmd.CombinedOutput()
	if err != nil {
		return fmt.Errorf("%v: %s", err, out)
	}
	b, err := ioutil.ReadFile(archive)
	if err != nil {
		return err
	}
	log.Println("Created backup", path.Base(archive))
	return store.Set(path.Base(archive), b)
}

func clean(n int, store storage.DB) error {
	backups, err := store.List(nil)
	if err != nil {
		return err
	}
	sort.Strings(backups)
	for i := 0; i < len(backups)-n; i++ {
		log.Println("Pruning old backup", backups[i])
		err := store.Set(backups[i], nil)
		if err != nil {
			return err
		}
	}
	return nil
}