// Bamboo is the site agent: run it inside a private network to expose services from there.
package main

import (
	"context"
	"flag"
	"log"
	"os"
	"os/signal"
	"path/filepath"
	"strconv"
	"strings"

	"git.veillax.com/Veillax/bamboo"
	"git.veillax.com/Veillax/bamboo/discover"
	"git.veillax.com/Veillax/bamboo/sshd"
	"git.veillax.com/Veillax/reef/dotenv"
	"git.veillax.com/Veillax/reef/selfupdate"
)

// version is set at build time (deploy/build.sh).
var version = "dev"

func env(k, def string) string {
	if v := os.Getenv(k); v != "" {
		return v
	}
	return def
}

func envFloat(k string, def float64) float64 {
	if f, err := strconv.ParseFloat(os.Getenv(k), 64); err == nil && f > 0 {
		return f
	}
	return def
}

func main() {
	// secrets (tokens, DNS-provider credentials) can live in a .env file instead of the command line
	envFile := dotenv.ArgPath(os.Args[1:], ".env")
	if _, err := dotenv.Load(envFile); err != nil {
		log.Fatalf("read %s: %v", envFile, err)
	}
	hh := flag.String("hammerhead", env("BAMBOO_HAMMERHEAD", ""), "URL of hammerhead")
	token := flag.String("token", env("BAMBOO_TOKEN", ""), "site token from the hammerhead UI")
	data := flag.String("data", env("BAMBOO_DATA", "./bamboo-data"), "directory for this agent's WireGuard key")
	dockerOn := flag.Bool("docker", os.Getenv("BAMBOO_DOCKER") == "1", "report local Docker containers so they can be picked as targets in the UI")
	discoverOn := flag.Bool("discover", os.Getenv("BAMBOO_DISCOVER") == "1", "report services listening on this machine as suggested targets in the UI (Linux)")
	discoverSubnets := flag.String("discover-subnets", os.Getenv("BAMBOO_DISCOVER_SUBNETS"), "comma-separated private subnets to scan for services, e.g. 192.168.1.0/24 (at most /22 each; off by default)")
	discoverPorts := flag.String("discover-ports", os.Getenv("BAMBOO_DISCOVER_PORTS"), "TCP ports to try on scanned addresses, e.g. 22,80,443,8000-8010 (default: a short list of common ones)")
	discoverRate := flag.Float64("discover-rate", envFloat("BAMBOO_DISCOVER_RATE", discover.DefaultRate), "most connection attempts per second discovery may make")
	sshOn := flag.Bool("ssh", os.Getenv("BAMBOO_SSH") == "1", "run a built-in SSH server (public keys only) so this machine can be reached through a tunnelled port")
	sshListen := flag.String("ssh-listen", env("BAMBOO_SSH_LISTEN", sshd.DefaultListen), "address the SSH server listens on; point a Hammerhead port at it from this site")
	sshKeys := flag.String("ssh-keys", os.Getenv("BAMBOO_SSH_KEYS"), "authorized_keys file listing who may sign in (default: authorized_keys in the data folder)")
	flag.String("env", ".env", "file to read secrets and settings from")
	autoUpdate := flag.Bool("auto-update", os.Getenv("BAMBOO_AUTO_UPDATE") == "1", "check for new releases every few hours and update and restart by itself (Linux and macOS)")
	showVersion := flag.Bool("version", false, "print the version and exit")
	flag.Parse()
	if *showVersion {
		os.Stdout.WriteString("bamboo " + version + "\n")
		return
	}
	if *hh == "" || *token == "" {
		flag.Usage()
		os.Exit(2)
	}
	log.Printf("bamboo %s starting", version)
	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
	defer stop()
	upd := selfupdate.Config{Server: "https://git.veillax.com", Repo: "Veillax/bamboo", App: "bamboo", Current: version, Logf: log.Printf}
	if *autoUpdate {
		go selfupdate.Run(ctx, upd)
	}
	dc := discover.Config{Local: *discoverOn || *discoverSubnets != "", Rate: *discoverRate}
	var err error
	if dc.Subnets, err = discover.ParseSubnets(*discoverSubnets); err != nil {
		log.Fatalf("-discover-subnets: %v", err)
	}
	if dc.Ports, err = discover.ParsePorts(*discoverPorts); err != nil {
		log.Fatalf("-discover-ports: %v", err)
	}
	sshAddr := "" // reported to Hammerhead, so its terminal can reach the server through this agent
	if *sshOn {
		if !sshd.Supported {
			log.Fatal("-ssh: the SSH server is not available on this platform")
		}
		keys := *sshKeys
		if keys == "" {
			keys = filepath.Join(*data, "authorized_keys")
		}
		srv, err := sshd.New(sshd.Config{Listen: *sshListen, AuthorizedKeys: keys, HostKey: filepath.Join(*data, "ssh_host_ed25519_key"), Logf: log.Printf})
		if err != nil {
			log.Fatalf("-ssh: %v", err)
		}
		sshAddr = *sshListen
		log.Printf("ssh: listening on %s, host key %s", *sshListen, srv.Fingerprint())
		go func() {
			if err := srv.Run(ctx); err != nil {
				log.Printf("ssh: stopped: %v", err)
			}
		}()
	}
	b, err := bamboo.New(bamboo.Config{Hammerhead: strings.TrimRight(*hh, "/"), Token: *token, DataDir: *data, Docker: *dockerOn, Discover: dc, SSH: sshAddr,
		Version: version, AutoUpdate: *autoUpdate,
		UpdateNow: func(ctx context.Context, progress func(string, int, string)) (string, error) {
			c := upd
			c.Progress = func(e selfupdate.Event) { progress(e.Stage, e.Pct, e.Line) }
			return selfupdate.CheckOnce(ctx, c)
		}})
	if err != nil {
		log.Fatal(err)
	}
	b.Run(ctx)
}