Add background mount path helpers

mount.go

@@ -5,6 +5,7 @@ import (
 	"flag"
 	"fmt"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"sort"
 	"strings"
@@ -42,8 +43,21 @@ func runMountCommand(args []string, cfg config, password string) error {
 	if err := fsFlags.Parse(args); err != nil {
 		return err
 	}
-	if fsFlags.NArg() != 1 {
-		return fmt.Errorf("usage: %s mount [flags] <mountpoint>", filepath.Base(os.Args[0]))
+	mountPoint := cfg.MountPath
+	if fsFlags.NArg() > 1 {
+		return fmt.Errorf("usage: %s mount [flags] [mountpoint]", filepath.Base(os.Args[0]))
+	}
+	if fsFlags.NArg() == 1 {
+		mountPoint = fsFlags.Arg(0)
+	}
+	if mountPoint == "" {
+		return fmt.Errorf("mount point missing: pass one or set MountPath in config")
+	}
+	if os.Getenv("DOCSPELL_IMPORT_MOUNT_FOREGROUND") != "1" {
+		return startMountInBackground(args, mountPoint, false)
+	}
+	if err := os.MkdirAll(mountPoint, 0755); err != nil {
+		return err
 	}
 
 	client := NewDocspellClient(cfg.DocspellURL, *authHeader)
@@ -57,7 +71,7 @@ func runMountCommand(args []string, cfg config, password string) error {
 	root := buildMountTree(context.Background(), client, items)
 
 	conn, err := fuse.Mount(
-		fsFlags.Arg(0),
+		mountPoint,
 		fuse.FSName("docspell"),
 		fuse.Subtype("docspell-import"),
 		fuse.ReadOnly(),
@@ -67,10 +81,161 @@ func runMountCommand(args []string, cfg config, password string) error {
 	}
 	defer conn.Close()
 
-	fmt.Printf("Mounted %d items read-only at %s. Unmount with: fusermount -u %s\n", len(items), fsFlags.Arg(0), fsFlags.Arg(0))
+	fmt.Printf("Mounted %d items read-only at %s. Unmount with: fusermount -u %s\n", len(items), mountPoint, mountPoint)
 	return fs.Serve(conn, &docspellFS{root: root})
 }
 
+func startMountInBackground(args []string, mountPoint string, quiet bool) error {
+	if isMounted(mountPoint) {
+		if !quiet {
+			fmt.Printf("Already mounted at %s\n", mountPoint)
+		}
+		return nil
+	}
+	cmd := exec.Command(os.Args[0], append([]string{"mount"}, args...)...)
+	cmd.Env = append(os.Environ(), "DOCSPELL_IMPORT_MOUNT_FOREGROUND=1")
+	cmd.Stdout = nil
+	cmd.Stderr = nil
+	if err := cmd.Start(); err != nil {
+		return err
+	}
+	if err := cmd.Process.Release(); err != nil {
+		return err
+	}
+	if !quiet {
+		fmt.Printf("Mounting %s in background. Unmount with: fusermount -u %s\n", mountPoint, mountPoint)
+	}
+	return nil
+}
+
+func runGetLocalPathCommand(args []string, cfg config, password string) error {
+	flags := flag.NewFlagSet("get-local-path", flag.ExitOnError)
+	if err := flags.Parse(args); err != nil {
+		return err
+	}
+	if flags.NArg() != 1 {
+		return fmt.Errorf("usage: %s get-local-path <item-id-or-url>", filepath.Base(os.Args[0]))
+	}
+	mountPoint, err := ensureMounted(cfg, password)
+	if err != nil {
+		return err
+	}
+	id := itemIDFromURLOrID(flags.Arg(0))
+	matches, err := filepath.Glob(filepath.Join(mountPoint, "by-id", idShard(id), id+".*"))
+	if err != nil {
+		return err
+	}
+	if len(matches) == 0 {
+		return fmt.Errorf("entry %s not found under mounted by-id tree", id)
+	}
+	fmt.Println(matches[0])
+	return nil
+}
+
+func runGetURLCommand(args []string, cfg config, password string) error {
+	flags := flag.NewFlagSet("get-url", flag.ExitOnError)
+	if err := flags.Parse(args); err != nil {
+		return err
+	}
+	if flags.NArg() != 1 {
+		return fmt.Errorf("usage: %s get-url <local-path-or-item-id>", filepath.Base(os.Args[0]))
+	}
+	id := flags.Arg(0)
+	if strings.Contains(id, string(os.PathSeparator)) || strings.HasPrefix(id, ".") {
+		var err error
+		id, err = itemIDFromLocalPath(id, cfg)
+		if err != nil {
+			return err
+		}
+	}
+	fmt.Printf("%s/app/item/%s\n", strings.TrimRight(cfg.DocspellURL, "/"), itemIDFromURLOrID(id))
+	return nil
+}
+
+func ensureMounted(cfg config, password string) (string, error) {
+	mountPoint := cfg.MountPath
+	if mountPoint == "" {
+		return "", fmt.Errorf("MountPath missing in config")
+	}
+	if isMounted(mountPoint) {
+		return mountPoint, nil
+	}
+	if err := startMountInBackground([]string{mountPoint}, mountPoint, true); err != nil {
+		return "", err
+	}
+	for i := 0; i < 50; i++ {
+		if isMounted(mountPoint) {
+			return mountPoint, nil
+		}
+		time.Sleep(100 * time.Millisecond)
+	}
+	return "", fmt.Errorf("mount did not become ready at %s", mountPoint)
+}
+
+func isMounted(mountPoint string) bool {
+	data, err := os.ReadFile("/proc/mounts")
+	if err != nil {
+		return false
+	}
+	mountPoint, _ = filepath.Abs(mountPoint)
+	for _, line := range strings.Split(string(data), "\n") {
+		fields := strings.Fields(line)
+		if len(fields) >= 2 && fields[1] == mountPoint {
+			return true
+		}
+	}
+	return false
+}
+
+func itemIDFromURLOrID(s string) string {
+	s = strings.TrimSpace(s)
+	if idx := strings.LastIndex(s, "/app/item/"); idx >= 0 {
+		return strings.Trim(strings.TrimPrefix(s[idx:], "/app/item/"), "/")
+	}
+	return strings.Trim(s, "/")
+}
+
+func itemIDFromLocalPath(path string, cfg config) (string, error) {
+	abs, err := filepath.Abs(path)
+	if err != nil {
+		return "", err
+	}
+	mountPoint, err := filepath.Abs(cfg.MountPath)
+	if err != nil {
+		return "", err
+	}
+	rel, err := filepath.Rel(mountPoint, abs)
+	if err != nil || strings.HasPrefix(rel, "..") {
+		return "", fmt.Errorf("path is not under MountPath %s", cfg.MountPath)
+	}
+	parts := strings.Split(rel, string(os.PathSeparator))
+	if len(parts) >= 3 && parts[0] == "by-id" {
+		return strings.TrimSuffix(parts[2], filepath.Ext(parts[2])), nil
+	}
+	info, err := os.Stat(abs)
+	if err != nil {
+		return "", err
+	}
+	var found string
+	err = filepath.Walk(filepath.Join(mountPoint, "by-id"), func(p string, fi os.FileInfo, err error) error {
+		if err != nil || fi == nil || fi.IsDir() {
+			return nil
+		}
+		if os.SameFile(info, fi) {
+			found = strings.TrimSuffix(filepath.Base(p), filepath.Ext(p))
+			return filepath.SkipAll
+		}
+		return nil
+	})
+	if err != nil {
+		return "", err
+	}
+	if found == "" {
+		return "", fmt.Errorf("could not map mounted path to item id; try a by-id path")
+	}
+	return found, nil
+}
+
 func buildMountTree(ctx context.Context, client *DocspellClient, items []SearchItem) *dirNode {
 	root := &dirNode{name: "", children: map[string]fs.Node{}}
 	byID := &dirNode{name: "by-id", children: map[string]fs.Node{}}