Moved generic archive abstraction into separate package

pkg/listenbrainz/archive.go

@@ -22,19 +22,16 @@ THE SOFTWARE.
 package listenbrainz
 
 import (
-	"archive/zip"
 	"encoding/json"
-	"fmt"
 	"io"
 	"iter"
-	"os"
-	"path/filepath"
 	"regexp"
 	"sort"
 	"strconv"
 	"time"
 
 	"github.com/simonfrey/jsonl"
+	"go.uploadedlobster.com/scotty/internal/archive"
 )
 
 // Represents a ListenBrainz export archive.
@@ -42,7 +39,17 @@ import (
 // The export contains the user's listen history, favorite tracks and
 // user information.
 type Archive struct {
-	backend archiveBackend
+	backend archive.Archive
+}
+
+// Open a ListenBrainz archive from file path.
+func OpenArchive(path string) (*Archive, error) {
+	backend, err := archive.OpenArchive(path)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Archive{backend: backend}, nil
 }
 
 // Close the archive and release any resources.
@@ -137,166 +144,27 @@ func (a *Archive) IterListens(minTimestamp time.Time) iter.Seq2[Listen, error] {
 	}
 }
 
-// Open a ListenBrainz archive from file path.
-func OpenArchive(path string) (*Archive, error) {
-	fi, err := os.Stat(path)
-	if err != nil {
-		return nil, err
-	}
-	switch mode := fi.Mode(); {
-	case mode.IsRegular():
-		backend := &zipArchive{}
-		err := backend.Open(path)
-		if err != nil {
-			return nil, err
-		}
-		return &Archive{backend: backend}, nil
-	case mode.IsDir():
-		backend := &dirArchive{}
-		err := backend.Open(path)
-		if err != nil {
-			return nil, err
-		}
-		return &Archive{backend: backend}, nil
-	default:
-		return nil, fmt.Errorf("unsupported file mode: %s", mode)
-	}
-}
-
 type UserInfo struct {
 	ID   string `json:"user_id"`
 	Name string `json:"username"`
 }
 
-type archiveBackend interface {
-	Close() error
-	OpenFile(path string) (io.ReadCloser, error)
-	Glob(pattern string) ([]FileInfo, error)
-}
-
 type timeRange struct {
 	Start time.Time
 	End   time.Time
 }
 
-type OpenableFile interface {
-	Open() (io.ReadCloser, error)
-}
-
-type FileInfo struct {
-	Name string
-	File OpenableFile
-}
-
-type FilesystemFile struct {
-	path string
-}
-
-func (f *FilesystemFile) Open() (io.ReadCloser, error) {
-	return os.Open(f.path)
-}
-
 type ListenExportFileInfo struct {
 	Name      string
 	TimeRange timeRange
-	f         OpenableFile
-}
-
-// An implementation of the archiveBackend interface for zip files.
-type zipArchive struct {
-	zip *zip.ReadCloser
-}
-
-func (a *zipArchive) Open(path string) error {
-	zip, err := zip.OpenReader(path)
-	if err != nil {
-		return err
-	}
-	a.zip = zip
-	return nil
-}
-
-func (a *zipArchive) Close() error {
-	if a.zip == nil {
-		return nil
-	}
-	return a.zip.Close()
-}
-
-func (a *zipArchive) Glob(pattern string) ([]FileInfo, error) {
-	result := make([]FileInfo, 0)
-	for _, file := range a.zip.File {
-		if matched, err := filepath.Match(pattern, file.Name); matched {
-			if err != nil {
-				return nil, err
-			}
-			info := FileInfo{
-				Name: file.Name,
-				File: file,
-			}
-			result = append(result, info)
-		}
-	}
-
-	return result, nil
-}
-
-func (a *zipArchive) OpenFile(path string) (io.ReadCloser, error) {
-	file, err := a.zip.Open(path)
-	if err != nil {
-		return nil, err
-	}
-	return file, nil
-}
-
-// An implementation of the archiveBackend interface for directories.
-type dirArchive struct {
-	dir string
-}
-
-func (a *dirArchive) Open(path string) error {
-	a.dir = filepath.Clean(path)
-	return nil
-}
-
-func (a *dirArchive) Close() error {
-	return nil
-}
-
-func (a *dirArchive) OpenFile(path string) (io.ReadCloser, error) {
-	file, err := os.Open(filepath.Join(a.dir, path))
-	if err != nil {
-		return nil, err
-	}
-	return file, nil
-}
-
-func (a *dirArchive) Glob(pattern string) ([]FileInfo, error) {
-	files, err := filepath.Glob(filepath.Join(a.dir, pattern))
-	if err != nil {
-		return nil, err
-	}
-	result := make([]FileInfo, 0)
-	for _, filename := range files {
-		name, err := filepath.Rel(a.dir, filename)
-		if err != nil {
-			return nil, err
-		}
-		info := FileInfo{
-			Name: name,
-			File: &FilesystemFile{path: filename},
-		}
-		result = append(result, info)
-	}
-
-	return result, nil
+	f         archive.OpenableFile
 }
 
 type ListenExportFile struct {
-	file OpenableFile
+	file archive.OpenableFile
 }
 
-func NewExportFile(f OpenableFile) ListenExportFile {
+func NewExportFile(f archive.OpenableFile) ListenExportFile {
 	return ListenExportFile{file: f}
 }