fix(importer): normalize multi-volume archives with duplicate obfuscated names

internal/importer/archive/rar/processor.go

@@ -71,13 +71,24 @@ func (rh *rarProcessor) AnalyzeRarContentFromNzb(ctx context.Context, rarFiles [
 	}
 
 	// Normalize RAR part filenames (e.g., part010 -> part10) for consistent processing
-	// Check if ALL files have no extension - if so, we'll add .partXX.rar extensions
-	allFilesNoExt := true
+	// Check if any files have no extension or if there are duplicate filenames - if so, we'll treat it as allFilesNoExt and add extensions
+	// seenNames detects obfuscated archives where every volume has the same name (or no extension).
+	// We break on the first duplicate found — that's sufficient to identify the obfuscated case.
+	allFilesNoExt := false
+	seenNames := make(map[string]struct{})
 	for _, file := range rarFiles {
-		if archive.HasExtension(file.Filename) {
-			allFilesNoExt = false
+		if !archive.HasExtension(file.Filename) {
+			allFilesNoExt = true
 			break
 		}
+		// Duplicate filename detected: this is an obfuscated multi-volume set where
+		// all parts share the same name. Treat as no-extension so we assign synthetic
+		// partXX.rar names to distinguish each volume.
+		if _, exists := seenNames[file.Filename]; exists {
+			allFilesNoExt = true
+			break
+		}
+		seenNames[file.Filename] = struct{}{}
 	}
 
 	// Get base filename from first file if all files have no extension
@@ -86,9 +97,12 @@ func (rh *rarProcessor) AnalyzeRarContentFromNzb(ctx context.Context, rarFiles [
 		slices.SortFunc(rarFiles, func(a, b parser.ParsedFile) int {
 			return strings.Compare(a.Filename, b.Filename)
 		})
-		// Use the first file's name as the base for all parts
+		// Use the first file's name as the base for all parts (stripping any added extension)
 		if len(rarFiles) > 0 {
 			baseFilename = rarFiles[0].Filename
+			if ext := filepath.Ext(baseFilename); ext != "" {
+				baseFilename = strings.TrimSuffix(baseFilename, ext)
+			}
 		}
 	}
 

internal/importer/archive/rar/utils.go

@@ -483,7 +483,7 @@ func normalizeRarPartFilename(filename string, index int, allFilesNoExt bool, to
 	// If all files have no extension, use baseFilename with .rXX extension
 	// This ensures all parts of the same archive have the same base filename
 	// Using RAR multi-volume convention: .r00, .r01, .r02, etc. (0-based)
-	if allFilesNoExt && !archive.HasExtension(filename) && baseFilename != "" {
+	if allFilesNoExt && (!archive.HasExtension(filename) || strings.HasSuffix(filename, ".rar")) && baseFilename != "" {
 		// Calculate padding width based on total number of files (0-based, so totalFiles-1)
 		width := len(strconv.Itoa(totalFiles - 1))
 		// Format with zero-padding (index is already 0-based from OriginalIndex)

internal/importer/archive/rar/utils_test.go

@@ -231,3 +231,44 @@ func oldRollSetSkip(base string, sCount int, skip string) []string {
 	}
 	return out
 }
+
+func TestNormalizeRarPartFilenameMix(t *testing.T) {
+	tests := []struct {
+		name         string
+		filename     string
+		index        int
+		allNoExt     bool
+		totalFiles   int
+		baseFilename string
+		want         string
+	}{
+		{
+			name:         "first file with .rar extension gets normalized to .r00",
+			filename:     "my_show.rar",
+			index:        0,
+			allNoExt:     true,
+			totalFiles:   46,
+			baseFilename: "my_show",
+			want:         "my_show.r00",
+		},
+		{
+			name:         "continuation file with no extension gets normalized to .r01",
+			filename:     "my_show",
+			index:        1,
+			allNoExt:     true,
+			totalFiles:   46,
+			baseFilename: "my_show",
+			want:         "my_show.r01",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := normalizeRarPartFilename(tt.filename, tt.index, tt.allNoExt, tt.totalFiles, tt.baseFilename)
+			if got != tt.want {
+				t.Errorf("normalizeRarPartFilename(%q) = %q; want %q", tt.filename, got, tt.want)
+			}
+		})
+	}
+}
+

internal/importer/archive/sevenzip/processor.go

@@ -533,13 +533,19 @@ func extractBaseFilenameSevenZip(filename string) string {
 
 // renameSevenZipFilesAndSort renames all 7z files to have the same base name and sorts them
 func renameSevenZipFilesAndSort(sevenZipFiles []parser.ParsedFile) []parser.ParsedFile {
-	// Check if ALL files have no extension - if so, we'll add .XXX extensions
-	allFilesNoExt := true
+	// Check if any files have no extension or if there are duplicate filenames - if so, we'll treat it as allFilesNoExt and add extensions
+	allFilesNoExt := false
+	seenNames := make(map[string]struct{})
 	for _, file := range sevenZipFiles {
-		if archive.HasExtension(file.Filename) {
-			allFilesNoExt = false
+		if !archive.HasExtension(file.Filename) {
+			allFilesNoExt = true
 			break
 		}
+		if _, exists := seenNames[file.Filename]; exists {
+			allFilesNoExt = true
+			break
+		}
+		seenNames[file.Filename] = struct{}{}
 	}
 
 	// Get base filename from first file if all files have no extension
@@ -549,9 +555,12 @@ func renameSevenZipFilesAndSort(sevenZipFiles []parser.ParsedFile) []parser.Pars
 		sort.Slice(sevenZipFiles, func(i, j int) bool {
 			return sevenZipFiles[i].Filename < sevenZipFiles[j].Filename
 		})
-		// Use the first file's name as the base for all parts
+		// Use the first file's name as the base for all parts (stripping any added extension)
 		if len(sevenZipFiles) > 0 {
 			baseFilename = sevenZipFiles[0].Filename
+			if ext := filepath.Ext(baseFilename); ext != "" {
+				baseFilename = strings.TrimSuffix(baseFilename, ext)
+			}
 		}
 	} else {
 		// Sort files by part number BEFORE extracting base filename

internal/importer/archive/sevenzip/utils.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"regexp"
 	"strconv"
+	"strings"
 
 	"github.com/javi11/altmount/internal/importer/archive"
 )
@@ -30,7 +31,7 @@ func normalize7zPartFilename(filename string, index int, allFilesNoExt bool, tot
 	// If all files have no extension, use baseFilename with .XXX extension
 	// This ensures all parts of the same archive have the same base filename
 	// Using 7zip multi-volume convention: .001, .002, .003, etc. (1-based)
-	if allFilesNoExt && !archive.HasExtension(filename) && baseFilename != "" {
+	if allFilesNoExt && (!archive.HasExtension(filename) || strings.HasSuffix(filename, ".7z")) && baseFilename != "" {
 		// Calculate padding width based on total number of files (1-based, so totalFiles)
 		width := len(strconv.Itoa(totalFiles))
 		// Format with zero-padding (convert 0-based index to 1-based: index+1)