// Package mount provides FUSE-based 9P mount functionality.
// Used by `olliesrv mount` for network-transparent access to remote servers.
package mount

import (
	"fmt"
	"os"
	"os/signal"
	"syscall"

	"9fans.net/go/plan9/client"
	"github.com/hanwen/go-fuse/v2/fs"
	"github.com/hanwen/go-fuse/v2/fuse"
)

// Config configures a FUSE mount.
type Config struct {
	Network    string // "unix" or "tcp"
	Address    string // server address
	Mountpoint string // local mountpoint
	Uname      string // uname for Tattach (default: $USER)
}

// Run mounts the remote 9P server and blocks until unmounted or signaled.
func Run(cfg Config) error {
	if cfg.Uname == "" {
		cfg.Uname = os.Getenv("USER")
	}
	if cfg.Uname == "" {
		cfg.Uname = "none"
	}

	conn, err := client.Dial(cfg.Network, cfg.Address)
	if err != nil {
		return fmt.Errorf("dial %s!%s: %w", cfg.Network, cfg.Address, err)
	}
	fsys, err := conn.Attach(nil, cfg.Uname, "")
	if err != nil {
		conn.Close()
		return fmt.Errorf("attach: %w", err)
	}

	root := &p9Dir{fsys: fsys, path: "/"}
	server, err := fs.Mount(cfg.Mountpoint, root, &fs.Options{
		MountOptions: fuse.MountOptions{
			FsName:        "ollie",
			Name:          "ollie9p",
			DisableXAttrs: true,
			MaxBackground: 32,
		},
	})
	if err != nil {
		return fmt.Errorf("mount %s: %w", cfg.Mountpoint, err)
	}

	sigCh := make(chan os.Signal, 1)
	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
	go func() {
		<-sigCh
		server.Unmount()
	}()

	server.Wait()
	return nil
}