fix: use unique filenames in Anki exports by prefixing with card ID

- Fixed issue where all cards used the same filenames (audio.mp3, image.jpg)
- Now prefixes media files with card ID (directory name) in Anki exports
- Updated both CSV and APKG generators to use unique names
- Ensures Anki properly associates correct media with each card
- Files in directories remain unchanged, only Anki references are prefixed

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

2 files changed, 53 insertions, 20 deletions

diff --git a/internal/anki/apkg_generator.go b/internal/anki/apkg_generator.go
index 6f0043f..6da0cfb 100644
--- a/internal/anki/apkg_generator.go
+++ b/internal/anki/apkg_generator.go
@@ -504,19 +504,29 @@ func (g *APKGGenerator) insertNotesAndCards(db *sql.DB) error {
 		
 		imageField := ""
 		if card.ImageFile != "" && fileExists(card.ImageFile) {
-			basename := filepath.Base(card.ImageFile)
-			if _, ok := g.mediaFiles[basename]; ok {
-				// Use the original filename in the card content
-				imageField = fmt.Sprintf(`<img src="%s">`, basename)
+			// Get card ID from the source path (parent directory name)
+			cardID := filepath.Base(filepath.Dir(card.ImageFile))
+			originalFilename := filepath.Base(card.ImageFile)
+			// Create unique filename with card ID prefix
+			uniqueFilename := fmt.Sprintf("%s_%s", cardID, originalFilename)
+			
+			if _, ok := g.mediaFiles[uniqueFilename]; ok {
+				// Use the unique filename in the card content
+				imageField = fmt.Sprintf(`<img src="%s">`, uniqueFilename)
 			}
 		}
 		
 		audioField := ""
 		if card.AudioFile != "" && fileExists(card.AudioFile) {
-			basename := filepath.Base(card.AudioFile)
-			if _, ok := g.mediaFiles[basename]; ok {
-				// Use the original filename in the card content
-				audioField = fmt.Sprintf("[sound:%s]", basename)
+			// Get card ID from the source path (parent directory name)
+			cardID := filepath.Base(filepath.Dir(card.AudioFile))
+			originalFilename := filepath.Base(card.AudioFile)
+			// Create unique filename with card ID prefix
+			uniqueFilename := fmt.Sprintf("%s_%s", cardID, originalFilename)
+			
+			if _, ok := g.mediaFiles[uniqueFilename]; ok {
+				// Use the unique filename in the card content
+				audioField = fmt.Sprintf("[sound:%s]", uniqueFilename)
 			}
 		}
 		
@@ -588,26 +598,36 @@ func (g *APKGGenerator) copyMediaFiles(tempDir string) error {
 	for _, card := range g.cards {
 		// Copy audio file
 		if card.AudioFile != "" && fileExists(card.AudioFile) {
-			filename := filepath.Base(card.AudioFile)
-			if _, exists := g.mediaFiles[filename]; !exists {
+			// Get card ID from the source path (parent directory name)
+			cardID := filepath.Base(filepath.Dir(card.AudioFile))
+			originalFilename := filepath.Base(card.AudioFile)
+			// Create unique filename with card ID prefix
+			uniqueFilename := fmt.Sprintf("%s_%s", cardID, originalFilename)
+			
+			if _, exists := g.mediaFiles[uniqueFilename]; !exists {
 				targetPath := filepath.Join(tempDir, fmt.Sprintf("%d", g.mediaCounter))
 				if err := copyFile(card.AudioFile, targetPath); err != nil {
 					return fmt.Errorf("failed to copy audio file %s: %w", card.AudioFile, err)
 				}
-				g.mediaFiles[filename] = g.mediaCounter
+				g.mediaFiles[uniqueFilename] = g.mediaCounter
 				g.mediaCounter++
 			}
 		}
 		
 		// Copy image file
 		if card.ImageFile != "" && fileExists(card.ImageFile) {
-			filename := filepath.Base(card.ImageFile)
-			if _, exists := g.mediaFiles[filename]; !exists {
+			// Get card ID from the source path (parent directory name)
+			cardID := filepath.Base(filepath.Dir(card.ImageFile))
+			originalFilename := filepath.Base(card.ImageFile)
+			// Create unique filename with card ID prefix
+			uniqueFilename := fmt.Sprintf("%s_%s", cardID, originalFilename)
+			
+			if _, exists := g.mediaFiles[uniqueFilename]; !exists {
 				targetPath := filepath.Join(tempDir, fmt.Sprintf("%d", g.mediaCounter))
 				if err := copyFile(card.ImageFile, targetPath); err != nil {
 					return fmt.Errorf("failed to copy image file %s: %w", card.ImageFile, err)
 				}
-				g.mediaFiles[filename] = g.mediaCounter
+				g.mediaFiles[uniqueFilename] = g.mediaCounter
 				g.mediaCounter++
 			}
 		}
diff --git a/internal/anki/generator.go b/internal/anki/generator.go
index 0682d94..0b393f3 100644
--- a/internal/anki/generator.go
+++ b/internal/anki/generator.go
@@ -109,8 +109,12 @@ func (g *Generator) formatAudioField(audioFile string) string {
 		return ""
 	}
 	
-	// Get just the filename
-	filename := filepath.Base(audioFile)
+	// Get card ID from the source path (parent directory name)
+	cardID := filepath.Base(filepath.Dir(audioFile))
+	originalFilename := filepath.Base(audioFile)
+	
+	// Create filename with card ID prefix for uniqueness in Anki
+	filename := fmt.Sprintf("%s_%s", cardID, originalFilename)
 	
 	// Anki audio format: [sound:filename.mp3]
 	return fmt.Sprintf("[sound:%s]", filename)
@@ -122,8 +126,13 @@ func (g *Generator) formatImageField(imageFile string) string {
 		return ""
 	}
 	
-	// Get just the filename
-	filename := filepath.Base(imageFile)
+	// Get card ID from the source path (parent directory name)
+	cardID := filepath.Base(filepath.Dir(imageFile))
+	originalFilename := filepath.Base(imageFile)
+	
+	// Create filename with card ID prefix for uniqueness in Anki
+	filename := fmt.Sprintf("%s_%s", cardID, originalFilename)
+	
 	return fmt.Sprintf(`<img src="%s">`, filename)
 }
 
@@ -279,8 +288,12 @@ func (g *Generator) copyMediaFile(src, destDir string) (string, error) {
 		return "", err
 	}
 	
-	// Create destination path
-	filename := filepath.Base(src)
+	// Get the card ID from the source path (parent directory name)
+	cardID := filepath.Base(filepath.Dir(src))
+	
+	// Create destination filename with card ID prefix
+	originalFilename := filepath.Base(src)
+	filename := fmt.Sprintf("%s_%s", cardID, originalFilename)
 	destPath := filepath.Join(destDir, filename)
 	
 	// Check if file already exists