feat: add progress bar to restore operation

- Add progress bar for restore and verify operations using progressbar/v3
- Replace in-memory blob cache with disk-based LRU cache (closes #29)
- Add helper wrappers for stdin/stdout/stderr IO
- Move FetchAndDecryptBlob into restore.go, remove blob_fetch_stub.go
- Use v.Stdout/v.Stdin instead of os.Stdout for all user-facing output

Rebased onto main, squashed to resolve conflicts.

internal/vaultik/blob_fetch_stub.go

@@ -1,55 +0,0 @@
-package vaultik
-
-import (
-	"context"
-	"fmt"
-	"io"
-
-	"filippo.io/age"
-	"git.eeqj.de/sneak/vaultik/internal/blobgen"
-)
-
-// FetchAndDecryptBlobResult holds the result of fetching and decrypting a blob.
-type FetchAndDecryptBlobResult struct {
-	Data []byte
-}
-
-// FetchAndDecryptBlob downloads a blob, decrypts it, and returns the plaintext data.
-func (v *Vaultik) FetchAndDecryptBlob(ctx context.Context, blobHash string, expectedSize int64, identity age.Identity) (*FetchAndDecryptBlobResult, error) {
-	rc, _, err := v.FetchBlob(ctx, blobHash, expectedSize)
-	if err != nil {
-		return nil, err
-	}
-	defer func() { _ = rc.Close() }()
-
-	reader, err := blobgen.NewReader(rc, identity)
-	if err != nil {
-		return nil, fmt.Errorf("creating blob reader: %w", err)
-	}
-	defer func() { _ = reader.Close() }()
-
-	data, err := io.ReadAll(reader)
-	if err != nil {
-		return nil, fmt.Errorf("reading blob data: %w", err)
-	}
-
-	return &FetchAndDecryptBlobResult{Data: data}, nil
-}
-
-// FetchBlob downloads a blob and returns a reader for the encrypted data.
-func (v *Vaultik) FetchBlob(ctx context.Context, blobHash string, expectedSize int64) (io.ReadCloser, int64, error) {
-	blobPath := fmt.Sprintf("blobs/%s/%s/%s", blobHash[:2], blobHash[2:4], blobHash)
-
-	rc, err := v.Storage.Get(ctx, blobPath)
-	if err != nil {
-		return nil, 0, fmt.Errorf("downloading blob %s: %w", blobHash[:16], err)
-	}
-
-	info, err := v.Storage.Stat(ctx, blobPath)
-	if err != nil {
-		_ = rc.Close()
-		return nil, 0, fmt.Errorf("stat blob %s: %w", blobHash[:16], err)
-	}
-
-	return rc, info.Size, nil
-}

internal/vaultik/restore.go

@@ -115,26 +115,77 @@ func (v *Vaultik) Restore(opts *RestoreOptions) error {
 	}
 	defer func() { _ = blobCache.Close() }()
 
-	for i, file := range files {
+	// Calculate total bytes for progress bar
+	var totalBytes int64
+	for _, file := range files {
+		totalBytes += file.Size
+	}
+
+	_, _ = fmt.Fprintf(v.Stdout, "Restoring %d files (%s)...\n",
+		len(files),
+		humanize.Bytes(uint64(totalBytes)),
+	)
+
+	// Create progress bar if stderr is a terminal
+	isTTY := isTerminal(v.Stderr)
+	var bar *progressbar.ProgressBar
+	if isTTY {
+		bar = progressbar.NewOptions64(
+			totalBytes,
+			progressbar.OptionSetDescription("Restoring"),
+			progressbar.OptionSetWriter(v.Stderr),
+			progressbar.OptionShowBytes(true),
+			progressbar.OptionShowCount(),
+			progressbar.OptionSetWidth(40),
+			progressbar.OptionThrottle(100*time.Millisecond),
+			progressbar.OptionOnCompletion(func() {
+				v.printlnStderr()
+			}),
+			progressbar.OptionSetRenderBlankState(true),
+		)
+	}
+
+	filesProcessed := 0
+	for _, file := range files {
 		if v.ctx.Err() != nil {
 			return v.ctx.Err()
 		}
 
 		if err := v.restoreFile(v.ctx, repos, file, opts.TargetDir, identity, chunkToBlobMap, blobCache, result); err != nil {
 			log.Error("Failed to restore file", "path", file.Path, "error", err)
-			// Continue with other files
+			filesProcessed++
+			// Update progress bar even on failure
+			if bar != nil {
+				_ = bar.Add64(file.Size)
+			}
+			// Periodic structured log for non-terminal contexts (headless/CI)
+			if !isTTY && filesProcessed%100 == 0 {
+				log.Info("Restore progress",
+					"files", fmt.Sprintf("%d/%d", filesProcessed, len(files)),
+					"bytes_restored", humanize.Bytes(uint64(result.BytesRestored)),
+				)
+			}
 			continue
 		}
 
-		// Progress logging
-		if (i+1)%100 == 0 || i+1 == len(files) {
+		filesProcessed++
+		// Update progress bar
+		if bar != nil {
+			_ = bar.Add64(file.Size)
+		}
+		// Periodic structured log for non-terminal contexts (headless/CI)
+		if !isTTY && (filesProcessed%100 == 0 || filesProcessed == len(files)) {
 			log.Info("Restore progress",
-				"files", fmt.Sprintf("%d/%d", i+1, len(files)),
-				"bytes", humanize.Bytes(uint64(result.BytesRestored)),
+				"files", fmt.Sprintf("%d/%d", filesProcessed, len(files)),
+				"bytes_restored", humanize.Bytes(uint64(result.BytesRestored)),
 			)
 		}
 	}
 
+	if bar != nil {
+		_ = bar.Finish()
+	}
+
 	result.Duration = time.Since(startTime)
 
 	log.Info("Restore complete",
@@ -479,6 +530,53 @@ func (v *Vaultik) restoreRegularFile(
 	return nil
 }
 
+// BlobFetchResult holds the result of fetching and decrypting a blob.
+type BlobFetchResult struct {
+	Data           []byte
+	CompressedSize int64
+}
+
+// FetchAndDecryptBlob downloads a blob from storage, decrypts and decompresses it.
+func (v *Vaultik) FetchAndDecryptBlob(ctx context.Context, blobHash string, expectedSize int64, identity age.Identity) (*BlobFetchResult, error) {
+	// Construct blob path with sharding
+	blobPath := fmt.Sprintf("blobs/%s/%s/%s", blobHash[:2], blobHash[2:4], blobHash)
+
+	reader, err := v.Storage.Get(ctx, blobPath)
+	if err != nil {
+		return nil, fmt.Errorf("downloading blob: %w", err)
+	}
+	defer func() { _ = reader.Close() }()
+
+	// Read encrypted data
+	encryptedData, err := io.ReadAll(reader)
+	if err != nil {
+		return nil, fmt.Errorf("reading blob data: %w", err)
+	}
+
+	// Decrypt and decompress
+	blobReader, err := blobgen.NewReader(bytes.NewReader(encryptedData), identity)
+	if err != nil {
+		return nil, fmt.Errorf("creating decryption reader: %w", err)
+	}
+	defer func() { _ = blobReader.Close() }()
+
+	data, err := io.ReadAll(blobReader)
+	if err != nil {
+		return nil, fmt.Errorf("decrypting blob: %w", err)
+	}
+
+	log.Debug("Downloaded and decrypted blob",
+		"hash", blobHash[:16],
+		"encrypted_size", humanize.Bytes(uint64(len(encryptedData))),
+		"decrypted_size", humanize.Bytes(uint64(len(data))),
+	)
+
+	return &BlobFetchResult{
+		Data:           data,
+		CompressedSize: int64(len(encryptedData)),
+	}, nil
+}
+
 // downloadBlob downloads and decrypts a blob
 func (v *Vaultik) downloadBlob(ctx context.Context, blobHash string, expectedSize int64, identity age.Identity) ([]byte, error) {
 	result, err := v.FetchAndDecryptBlob(ctx, blobHash, expectedSize, identity)
@@ -524,7 +622,7 @@ func (v *Vaultik) verifyRestoredFiles(
 
 	// Create progress bar if output is a terminal
 	var bar *progressbar.ProgressBar
-	if isTerminal() {
+	if isTerminal(v.Stderr) {
 		bar = progressbar.NewOptions64(
 			totalBytes,
 			progressbar.OptionSetDescription("Verifying"),
@@ -632,7 +730,11 @@ func (v *Vaultik) verifyFile(
 	return bytesVerified, nil
 }
 
-// isTerminal returns true if stdout is a terminal
-func isTerminal() bool {
-	return term.IsTerminal(int(os.Stdout.Fd()))
+// isTerminal returns true if the given writer is connected to a terminal.
+// Returns false if the writer does not expose a file descriptor (e.g. in tests).
+func isTerminal(w io.Writer) bool {
+	if f, ok := w.(*os.File); ok {
+		return term.IsTerminal(int(f.Fd()))
+	}
+	return false
 }

internal/vaultik/vaultik.go

@@ -129,7 +129,7 @@ func (v *Vaultik) GetFilesystem() afero.Fs {
 	return v.Fs
 }
 
-// printfStdout writes formatted output to stdout.
+// printfStdout writes formatted output to stdout for user-facing messages.
 func (v *Vaultik) printfStdout(format string, args ...any) {
 	_, _ = fmt.Fprintf(v.Stdout, format, args...)
 }
@@ -139,11 +139,28 @@ func (v *Vaultik) printlnStdout(args ...any) {
 	_, _ = fmt.Fprintln(v.Stdout, args...)
 }
 
+// FetchBlob downloads a blob from storage and returns a reader for the encrypted data.
+func (v *Vaultik) FetchBlob(ctx context.Context, blobHash string, expectedSize int64) (io.ReadCloser, int64, error) {
+	blobPath := fmt.Sprintf("blobs/%s/%s/%s", blobHash[:2], blobHash[2:4], blobHash)
+
+	reader, err := v.Storage.Get(ctx, blobPath)
+	if err != nil {
+		return nil, 0, fmt.Errorf("downloading blob: %w", err)
+	}
+
+	return reader, expectedSize, nil
+}
+
 // printfStderr writes formatted output to stderr.
 func (v *Vaultik) printfStderr(format string, args ...any) {
 	_, _ = fmt.Fprintf(v.Stderr, format, args...)
 }
 
+// printlnStderr writes a line to stderr.
+func (v *Vaultik) printlnStderr(args ...any) {
+	_, _ = fmt.Fprintln(v.Stderr, args...)
+}
+
 // scanStdin reads a line of input from stdin.
 func (v *Vaultik) scanStdin(a ...any) (int, error) {
 	return fmt.Fscanln(v.Stdin, a...)