// clip-sync — bidirectional LAN clipboard synchronization daemon.
//
// Usage:
//
//	clip-sync [flags]                 # run the daemon
//	clip-sync history                 # print local clipboard history
//	clip-sync send-file <path>        # send a file to all peers
//	clip-sync --one-shot [text]       # send the clipboard (or text) once, then exit
//
// Flags:
//
//	--config path       config file (default ~/.config/clip-sync/peers.toml)
//	--version           print version and exit
//	--generate-key      generate a shared key and exit
//	--generate-cert     generate a self-signed TLS cert/key and exit
package main

import (
	"context"
	"flag"
	"fmt"
	"log"
	"os"
	"os/signal"
	"strings"
	"syscall"
	"time"

	"git.dracodev.net/Projets/clip-sync/internal/clipboard"
	"git.dracodev.net/Projets/clip-sync/internal/config"
	"git.dracodev.net/Projets/clip-sync/internal/daemon"
	"git.dracodev.net/Projets/clip-sync/internal/history"
	"git.dracodev.net/Projets/clip-sync/internal/peer"
	"git.dracodev.net/Projets/clip-sync/internal/security"
	"git.dracodev.net/Projets/clip-sync/internal/transfer"
)

// version is overridden at build time via -ldflags "-X main.version=...".
var version = "0.2.0"

func main() {
	log.SetFlags(log.LstdFlags | log.Lshortfile)
	log.SetPrefix("")

	fs := flag.NewFlagSet("clip-sync", flag.ExitOnError)
	configPath := fs.String("config", "", "config file path")
	showVersion := fs.Bool("version", false, "print version and exit")
	generateKey := fs.Bool("generate-key", false, "generate a shared key and exit")
	generateCert := fs.Bool("generate-cert", false, "generate a self-signed TLS certificate and exit")
	oneShot := fs.Bool("one-shot", false, "send the clipboard once and exit")
	fs.Usage = func() {
		fmt.Fprintf(os.Stderr, "Usage:\n  clip-sync [flags]\n  clip-sync history\n\nFlags:\n")
		fs.PrintDefaults()
	}
	_ = fs.Parse(os.Args[1:])

	// Subcommand: history
	if fs.NArg() > 0 && fs.Arg(0) == "history" {
		runHistory()
		return
	}

	if *showVersion {
		fmt.Printf("clip-sync %s\n", version)
		return
	}

	if *generateKey {
		key, err := security.GenerateKey()
		if err != nil {
			log.Fatalf("clip-sync: generate key: %v", err)
		}
		fmt.Println(key)
		return
	}

	if *generateCert {
		runGenerateCert()
		return
	}

	cfg, err := loadConfig(*configPath)
	if err != nil {
		log.Fatalf("clip-sync: config: %v", err)
	}

	if *oneShot {
		runOneShot(cfg, fs.Arg(0))
		return
	}

	// Subcommand: send-file <path>
	if fs.NArg() > 0 && fs.Arg(0) == "send-file" {
		path := ""
		if fs.NArg() > 1 {
			path = fs.Arg(1)
		}
		runSendFile(cfg, path)
		return
	}

	runDaemon(cfg)
}

func loadConfig(path string) (*config.Config, error) {
	if path != "" {
		return config.LoadFrom(path)
	}
	return config.Load()
}

func runDaemon(cfg *config.Config) {
	d, err := daemon.New(cfg)
	if err != nil {
		log.Fatalf("clip-sync: init: %v", err)
	}

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	sigCh := make(chan os.Signal, 1)
	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)

	go func() {
		sig := <-sigCh
		log.Printf("clip-sync: received %v, shutting down...", sig)
		cancel()
	}()

	if err := d.Run(ctx); err != nil && err != context.Canceled {
		log.Fatalf("clip-sync: %v", err)
	}

	log.Println("clip-sync: stopped")
}

func runOneShot(cfg *config.Config, textArg string) {
	origin, err := os.Hostname()
	if err != nil {
		log.Fatalf("clip-sync: hostname: %v", err)
	}

	b := peer.NewBroadcaster(cfg.Peers, origin, peer.Options{
		SharedKey:          cfg.Security.SharedKey,
		TLS:                cfg.Security.TLS,
		CertFile:           cfg.Security.CertFile,
		InsecureSkipVerify: cfg.Security.InsecureSkipVerify,
	})

	text := textArg
	if text == "" {
		cb, err := clipboard.New()
		if err != nil {
			log.Fatalf("clip-sync: clipboard: %v", err)
		}
		text, err = cb.Read()
		if err != nil {
			log.Fatalf("clip-sync: clipboard read: %v", err)
		}
	}

	if text == "" {
		log.Fatal("clip-sync: nothing to send (clipboard is empty)")
	}

	b.BroadcastSync(text)
	fmt.Printf("clip-sync: sent %d bytes to %d peer(s)\n", len(text), b.PeerCount())
}

func runSendFile(cfg *config.Config, path string) {
	if path == "" {
		log.Fatal("clip-sync: usage: clip-sync send-file <path>")
	}

	origin, err := os.Hostname()
	if err != nil {
		log.Fatalf("clip-sync: hostname: %v", err)
	}

	f, err := transfer.ReadFile(path, origin)
	if err != nil {
		log.Fatalf("clip-sync: read file: %v", err)
	}

	b := peer.NewBroadcaster(cfg.Peers, origin, peer.Options{
		SharedKey:          cfg.Security.SharedKey,
		TLS:                cfg.Security.TLS,
		CertFile:           cfg.Security.CertFile,
		InsecureSkipVerify: cfg.Security.InsecureSkipVerify,
	})

	b.SendFileSync(*f)
	fmt.Printf("clip-sync: sent %q (%s) to %d peer(s)\n", f.Name, f.Mime, b.PeerCount())
}

func runHistory() {
	path, err := history.DefaultPath()
	if err != nil {
		log.Fatalf("clip-sync: history: %v", err)
	}
	entries := history.New(path, 0).List()
	if len(entries) == 0 {
		fmt.Println("clip-sync: no history yet")
		return
	}
	for _, e := range entries {
		ts := time.Unix(0, e.Ts).Format("2006-01-02 15:04:05")
		text := strings.ReplaceAll(e.Text, "\n", "\\n")
		if len(text) > 80 {
			text = text[:80] + "…"
		}
		fmt.Printf("%s  [%s]  %s\n", ts, e.Origin, text)
	}
}

func runGenerateCert() {
	certFile, err := config.DefaultCertFile()
	if err != nil {
		log.Fatalf("clip-sync: cert path: %v", err)
	}
	keyFile, err := config.DefaultKeyFile()
	if err != nil {
		log.Fatalf("clip-sync: key path: %v", err)
	}
	host, _ := os.Hostname()

	if err := security.GenerateSelfSignedCert(certFile, keyFile, []string{host, "localhost"}); err != nil {
		log.Fatalf("clip-sync: generate cert: %v", err)
	}
	fmt.Printf("clip-sync: certificate written to %s and %s\n", certFile, keyFile)
	fmt.Println("Set [security] tls = true and cert_file/key_file in peers.toml, and share these files with your peers.")
}