feat: implement multiple folder ebook scanner and API handlers

- Create EbookScanner service with multiple folder support
- Update scanner to handle array of folder paths instead of single path
- Add EPUB metadata extraction for rich ebook information
- Implement folder monitoring with fsnotify for real-time updates
- Add API endpoints for folder management:
  - POST /api/auth/ebook-folders (add folder)
  - GET /api/auth/ebook-folders (list folders)
  - DELETE /api/auth/ebook-folders/:folderPath (remove folder)
- Update scanner endpoints to accept folder_paths array
- Add go-epub and fsnotify dependencies for metadata extraction and file watching

backend/go.mod

@@ -3,9 +3,10 @@ module bookmann
 go 1.25
 
 require (
+	github.com/ArcadiaLin/go-epub v0.1.1
+	github.com/fsnotify/fsnotify v1.9.0
 	github.com/go-playground/validator/v10 v10.30.1
-
+	github.com/golang-jwt/jwt v3.2.2+incompatible
-
 	github.com/google/uuid v1.4.0
 	github.com/jackc/pgx/v5 v5.4.3
 	github.com/labstack/echo/v4 v4.11.3
@@ -16,7 +17,6 @@ require (
 	github.com/gabriel-vasile/mimetype v1.4.12 // indirect
 	github.com/go-playground/locales v0.14.1 // indirect
 	github.com/go-playground/universal-translator v0.18.1 // indirect
-	github.com/golang-jwt/jwt v3.2.2+incompatible // indirect
 	github.com/jackc/pgpassfile v1.0.0 // indirect
 	github.com/jackc/pgservicefile v0.0.0-20221227161230-091c0ba34f0a // indirect
 	github.com/jackc/puddle/v2 v2.2.1 // indirect

backend/go.sum

@@ -1,6 +1,10 @@
+github.com/ArcadiaLin/go-epub v0.1.1 h1:13roe62tarrZ1Y1QTxE+Bzd/NKlChhRzegLVmU5Hgws=
+github.com/ArcadiaLin/go-epub v0.1.1/go.mod h1:GY09AG6jnEbsYytkw6VeICLOt25F1GQDGXjYS7cxNhU=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/fsnotify/fsnotify v1.9.0 h1:2Ml+OJNzbYCTzsxtv8vKSFD9PbJjmhYF14k/jKC7S9k=
+github.com/fsnotify/fsnotify v1.9.0/go.mod h1:8jBTzvmWwFyi3Pb8djgCCO5IBqzKJ/Jwo8TRcHyHii0=
 github.com/gabriel-vasile/mimetype v1.4.12 h1:e9hWvmLYvtp846tLHam2o++qitpguFiYCKbn0w9jyqw=
 github.com/gabriel-vasile/mimetype v1.4.12/go.mod h1:d+9Oxyo1wTzWdyVUPMmXFvp4F9tea18J8ufA774AB3s=
 github.com/go-playground/assert/v2 v2.2.0 h1:JvknZsQTYeFEAhQwI4qEt9cyV5ONwRHC+lYKSsYSR8s=
@@ -13,8 +17,6 @@ github.com/go-playground/validator/v10 v10.30.1 h1:f3zDSN/zOma+w6+1Wswgd9fLkdwy0
 github.com/go-playground/validator/v10 v10.30.1/go.mod h1:oSuBIQzuJxL//3MelwSLD5hc2Tu889bF0Idm9Dg26cM=
 github.com/golang-jwt/jwt v3.2.2+incompatible h1:IfV12K8xAKAnZqdXVzCZ+TOjboZ2keLg81eXfW3O+oY=
 github.com/golang-jwt/jwt v3.2.2+incompatible/go.mod h1:8pz2t5EyA70fFQQSrl6XZXzqecmYZeUEB8OUGHkxJ+I=
-github.com/golang-jwt/jwt/v5 v5.3.0 h1:pv4AsKCKKZuqlgs5sUmn4x8UlGa0kEVt/puTpKx9vvo=
-github.com/golang-jwt/jwt/v5 v5.3.0/go.mod h1:fxCRLWMO43lRc8nhHWY6LGqRcf+1gQWArsqaEUEa5bE=
 github.com/google/uuid v1.4.0 h1:MtMxsa51/r9yyhkyLsVeVt0B+BGQZzpQiTQ4eHZ8bc4=
 github.com/google/uuid v1.4.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/jackc/pgpassfile v1.0.0 h1:/6Hmqy13Ss2zCq62VdNG8tM1wchn8zjSGOBJ6icpsIM=

backend/internal/handlers/auth.go

@@ -315,6 +315,99 @@ func (h *AuthHandler) ListUsers(c echo.Context) error {
 	return c.JSON(http.StatusOK, userList)
 }
 
+type AddEbookFolderRequest struct {
+	FolderPath string `json:"folder_path" validate:"required"`
+}
+
+type EbookFolderResponse struct {
+	ID         string `json:"id"`
+	UserID     string `json:"user_id"`
+	FolderPath string `json:"folder_path"`
+	CreatedAt  string `json:"created_at"`
+}
+
+// AddEbookFolder handles POST /api/auth/ebook-folders
+func (h *AuthHandler) AddEbookFolder(c echo.Context) error {
+	userID := c.Get("user_id").(string)
+	userUUID, err := uuid.Parse(userID)
+	if err != nil {
+		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid user id"})
+	}
+
+	var req AddEbookFolderRequest
+	if err := c.Bind(&req); err != nil {
+		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid request"})
+	}
+	if err := c.Validate(&req); err != nil {
+		return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
+	}
+
+	folder, err := h.db.AddUserEbookFolder(c.Request().Context(), database.AddUserEbookFolderParams{
+		UserID:     pgtype.UUID{Bytes: userUUID, Valid: true},
+		FolderPath: req.FolderPath,
+	})
+	if err != nil {
+		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
+	}
+
+	return c.JSON(http.StatusCreated, EbookFolderResponse{
+		ID:         uuid.UUID(folder.ID.Bytes).String(),
+		UserID:     uuid.UUID(folder.UserID.Bytes).String(),
+		FolderPath: folder.FolderPath,
+		CreatedAt:  folder.CreatedAt.Time.Format("2006-01-02T15:04:05Z07:00"),
+	})
+}
+
+// GetEbookFolders handles GET /api/auth/ebook-folders
+func (h *AuthHandler) GetEbookFolders(c echo.Context) error {
+	userID := c.Get("user_id").(string)
+	userUUID, err := uuid.Parse(userID)
+	if err != nil {
+		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid user id"})
+	}
+
+	folders, err := h.db.GetUserEbookFolders(c.Request().Context(), pgtype.UUID{Bytes: userUUID, Valid: true})
+	if err != nil {
+		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
+	}
+
+	var response []EbookFolderResponse
+	for _, folder := range folders {
+		response = append(response, EbookFolderResponse{
+			ID:         uuid.UUID(folder.ID.Bytes).String(),
+			UserID:     uuid.UUID(folder.UserID.Bytes).String(),
+			FolderPath: folder.FolderPath,
+			CreatedAt:  folder.CreatedAt.Time.Format("2006-01-02T15:04:05Z07:00"),
+		})
+	}
+
+	return c.JSON(http.StatusOK, response)
+}
+
+// DeleteEbookFolder handles DELETE /api/auth/ebook-folders/:folderPath
+func (h *AuthHandler) DeleteEbookFolder(c echo.Context) error {
+	userID := c.Get("user_id").(string)
+	userUUID, err := uuid.Parse(userID)
+	if err != nil {
+		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid user id"})
+	}
+
+	folderPath := c.Param("folderPath")
+	if folderPath == "" {
+		return c.JSON(http.StatusBadRequest, map[string]string{"error": "folder path is required"})
+	}
+
+	err = h.db.DeleteUserEbookFolder(c.Request().Context(), database.DeleteUserEbookFolderParams{
+		UserID:     pgtype.UUID{Bytes: userUUID, Valid: true},
+		FolderPath: folderPath,
+	})
+	if err != nil {
+		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
+	}
+
+	return c.JSON(http.StatusOK, map[string]string{"message": "ebook folder removed"})
+}
+
 func (h *AuthHandler) generateJWT(userID string) (string, error) {
 	claims := jwtgo.MapClaims{
 		"user_id": userID,

backend/internal/handlers/ebook.go

@@ -2,8 +2,11 @@ package handlers
 
 import (
 	"bookmann/internal/database"
+	"bookmann/internal/services"
+	"context"
 	"net/http"
 	"strconv"
+	"sync"
 	"time"
 
 	"github.com/google/uuid"
@@ -12,12 +15,20 @@ import (
 )
 
 type Handler struct {
-	db *database.Queries
+	db      *database.Queries
+	scanner *services.EbookScanner
+	ctx     context.Context
+	cancel  context.CancelFunc
+	mu      sync.Mutex
 }
 
 func NewHandler(db *database.Queries) *Handler {
+	ctx, cancel := context.WithCancel(context.Background())
 	return &Handler{
-		db: db,
+		db:      db,
+		scanner: services.NewEbookScanner(db),
+		ctx:     ctx,
+		cancel:  cancel,
 	}
 }
 
@@ -49,6 +60,11 @@ func SetupRoutes(g *echo.Group, db *database.Queries) {
 	g.PUT("/ebooks/:id/rating", h.CreateOrUpdateEbookRating)
 	g.DELETE("/ebooks/:id/rating", h.DeleteEbookRating)
 	g.GET("/ebooks/:id/ratings", h.GetEbookRatings)
+
+	// Scanner routes
+	g.POST("/scanner/scan", h.ScanEbooks)
+	g.POST("/scanner/start", h.StartScanner)
+	g.POST("/scanner/stop", h.StopScanner)
 }
 
 // ListEbooks handles GET /api/ebooks
@@ -407,3 +423,66 @@ func (h *Handler) GetEbookRatings(c echo.Context) error {
 
 	return c.JSON(http.StatusOK, ratings)
 }
+
+// ScanEbooksRequest represents the request for scanning ebooks
+type ScanEbooksRequest struct {
+	FolderPaths []string `json:"folder_paths" validate:"required,min=1"`
+}
+
+// ScanEbooks handles POST /api/scanner/scan
+func (h *Handler) ScanEbooks(c echo.Context) error {
+	var req ScanEbooksRequest
+	if err := c.Bind(&req); err != nil {
+		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid request"})
+	}
+	if err := c.Validate(&req); err != nil {
+		return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
+	}
+
+	// Set the folder paths for scanning
+	if err := h.scanner.SetFolders(req.FolderPaths); err != nil {
+		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid folder paths: " + err.Error()})
+	}
+
+	// Perform the scan
+	if err := h.scanner.ScanFolders(h.ctx); err != nil {
+		return c.JSON(http.StatusInternalServerError, map[string]string{"error": "scan failed: " + err.Error()})
+	}
+
+	return c.JSON(http.StatusOK, map[string]string{"message": "scan completed"})
+}
+
+// StartScanner handles POST /api/scanner/start
+func (h *Handler) StartScanner(c echo.Context) error {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+
+	var req ScanEbooksRequest
+	if err := c.Bind(&req); err != nil {
+		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid request"})
+	}
+	if err := c.Validate(&req); err != nil {
+		return c.JSON(http.StatusBadRequest, map[string]string{"error": err.Error()})
+	}
+
+	// Set the folder paths
+	if err := h.scanner.SetFolders(req.FolderPaths); err != nil {
+		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid folder paths: " + err.Error()})
+	}
+
+	// Start watching for changes
+	h.scanner.WatchChanges(h.ctx)
+
+	return c.JSON(http.StatusOK, map[string]string{"message": "scanner started"})
+}
+
+// StopScanner handles POST /api/scanner/stop
+func (h *Handler) StopScanner(c echo.Context) error {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+
+	h.cancel()
+	h.ctx, h.cancel = context.WithCancel(context.Background())
+
+	return c.JSON(http.StatusOK, map[string]string{"message": "scanner stopped"})
+}

backend/internal/services/ebook_scanner.go

@@ -0,0 +1,312 @@
+package services
+
+import (
+	"bookmann/internal/database"
+	"context"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	epub "github.com/ArcadiaLin/go-epub"
+	"github.com/fsnotify/fsnotify"
+	"github.com/jackc/pgx/v5/pgtype"
+)
+
+type EbookMetadata struct {
+	Title        string
+	Author       string
+	Description  string
+	Series       string
+	SeriesNumber int32
+	Publisher    string
+	PublishDate  time.Time
+	Contributors string
+	CoverPath    string
+}
+
+type EbookScanner struct {
+	db      *database.Queries
+	watcher *fsnotify.Watcher
+	folders []string
+}
+
+func NewEbookScanner(db *database.Queries) *EbookScanner {
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		panic(fmt.Sprintf("Failed to create file watcher: %v", err))
+	}
+
+	return &EbookScanner{
+		db:      db,
+		watcher: watcher,
+	}
+}
+
+func (s *EbookScanner) SetFolders(folders []string) error {
+	s.folders = folders
+
+	// Remove old watch if exists
+	if s.watcher != nil {
+		s.watcher.Close()
+	}
+
+	// Create new watcher
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		return fmt.Errorf("failed to create watcher: %v", err)
+	}
+	s.watcher = watcher
+
+	// Add all folders to watch
+	for _, folder := range folders {
+		if err := s.watcher.Add(folder); err != nil {
+			fmt.Printf("Warning: failed to watch folder %s: %v\n", folder, err)
+		}
+	}
+
+	return nil
+}
+
+func (s *EbookScanner) ScanFolders(ctx context.Context) error {
+	if len(s.folders) == 0 {
+		return fmt.Errorf("no folders set")
+	}
+
+	for _, folder := range s.folders {
+		err := filepath.WalkDir(folder, func(path string, d fs.DirEntry, err error) error {
+			if err != nil {
+				return err
+			}
+
+			if d.IsDir() {
+				// Also watch subdirectories
+				if err := s.watcher.Add(path); err != nil {
+					fmt.Printf("Warning: failed to watch subdirectory %s: %v\n", path, err)
+				}
+				return nil
+			}
+
+			// Check if it's an ebook file
+			if s.isEbookFile(path) {
+				if err := s.processEbookFile(ctx, path); err != nil {
+					fmt.Printf("Error processing ebook %s: %v\n", path, err)
+				}
+			}
+
+			return nil
+		})
+		if err != nil {
+			return fmt.Errorf("failed to scan folder %s: %v", folder, err)
+		}
+	}
+
+	return nil
+}
+
+func (s *EbookScanner) isEbookFile(path string) bool {
+	ext := strings.ToLower(filepath.Ext(path))
+	switch ext {
+	case ".epub", ".pdf", ".mobi", ".azw3", ".fb2", ".txt":
+		return true
+	default:
+		return false
+	}
+}
+
+func (s *EbookScanner) processEbookFile(ctx context.Context, path string) error {
+	// Get file info
+	info, err := os.Stat(path)
+	if err != nil {
+		return fmt.Errorf("failed to get file info: %v", err)
+	}
+
+	// Check if ebook already exists in database
+	existingEbook, err := s.getEbookByFilePath(ctx, path)
+	if err == nil {
+		// Ebook exists, check if file has changed (by size)
+		if existingEbook.FileSize.Int64 != info.Size() {
+			return s.updateEbook(ctx, existingEbook.ID, path, info)
+		}
+		return nil // Skip if already exists and size matches
+	} else if err.Error() != "sql: no rows in result set" {
+		// Some other error occurred
+		return fmt.Errorf("failed to check if ebook exists: %v", err)
+	}
+	// Ebook doesn't exist, continue with creation
+
+	// Extract metadata
+	metadata, err := s.extractMetadata(path)
+	if err != nil {
+		fmt.Printf("Warning: failed to extract metadata from %s: %v\n", path, err)
+		// Continue with basic metadata
+		metadata = &EbookMetadata{
+			Title:  filepath.Base(path),
+			Author: "Unknown",
+		}
+	}
+
+	// Create ebook in database
+	_, err = s.db.CreateEbook(ctx, database.CreateEbookParams{
+		Title:          metadata.Title,
+		Author:         pgtype.Text{String: metadata.Author, Valid: metadata.Author != ""},
+		Description:    pgtype.Text{String: metadata.Description, Valid: metadata.Description != ""},
+		FilePath:       path,
+		FileSize:       pgtype.Int8{Int64: info.Size(), Valid: true},
+		MimeType:       pgtype.Text{String: s.getMimeType(path), Valid: true},
+		CoverImagePath: pgtype.Text{String: metadata.CoverPath, Valid: metadata.CoverPath != ""},
+		Series:         pgtype.Text{String: metadata.Series, Valid: metadata.Series != ""},
+		SeriesNumber:   pgtype.Int4{Int32: metadata.SeriesNumber, Valid: metadata.SeriesNumber > 0},
+		Publisher:      pgtype.Text{String: metadata.Publisher, Valid: metadata.Publisher != ""},
+		DatePublished:  pgtype.Date{Time: metadata.PublishDate, Valid: !metadata.PublishDate.IsZero()},
+		Contributors:   pgtype.Text{String: metadata.Contributors, Valid: metadata.Contributors != ""},
+	})
+
+	return err
+}
+
+func (s *EbookScanner) extractMetadata(path string) (*EbookMetadata, error) {
+	ext := strings.ToLower(filepath.Ext(path))
+
+	switch ext {
+	case ".epub":
+		return s.extractEPUBMetadata(path)
+	default:
+		// For other formats, return basic metadata
+		return &EbookMetadata{
+			Title: filepath.Base(path),
+		}, nil
+	}
+}
+
+func (s *EbookScanner) extractEPUBMetadata(path string) (*EbookMetadata, error) {
+	book, err := epub.ReadBook(path)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open EPUB: %v", err)
+	}
+
+	metadata := &EbookMetadata{}
+
+	// Title
+	if title, err := book.Title(); err == nil && title != "" {
+		metadata.Title = title
+	}
+
+	// Author
+	if authors, err := book.MetadataByKey("creator"); err == nil && len(authors) > 0 {
+		metadata.Author = authors[0]
+	}
+
+	// Description
+	if descriptions, err := book.MetadataByKey("description"); err == nil && len(descriptions) > 0 {
+		metadata.Description = descriptions[0]
+	}
+
+	// Publisher
+	if publishers, err := book.MetadataByKey("publisher"); err == nil && len(publishers) > 0 {
+		metadata.Publisher = publishers[0]
+	}
+
+	// Publish date
+	if dates, err := book.MetadataByKey("date"); err == nil && len(dates) > 0 {
+		if date, err := time.Parse("2006-01-02", dates[0]); err == nil {
+			metadata.PublishDate = date
+		}
+	}
+
+	// Contributors
+	if contributors, err := book.MetadataByKey("contributor"); err == nil && len(contributors) > 0 {
+		metadata.Contributors = strings.Join(contributors, ", ")
+	}
+
+	return metadata, nil
+}
+
+func (s *EbookScanner) updateEbook(ctx context.Context, ebookID pgtype.UUID, filePath string, info os.FileInfo) error {
+	metadata, err := s.extractMetadata(filePath)
+	if err != nil {
+		fmt.Printf("Warning: failed to extract metadata from %s: %v\n", filePath, err)
+		metadata = &EbookMetadata{
+			Title: filepath.Base(filePath),
+		}
+	}
+
+	_, err = s.db.UpdateEbook(ctx, database.UpdateEbookParams{
+		ID:             ebookID,
+		Title:          metadata.Title,
+		Author:         pgtype.Text{String: metadata.Author, Valid: metadata.Author != ""},
+		Isbn:           pgtype.Text{}, // Keep existing ISBN
+		Description:    pgtype.Text{String: metadata.Description, Valid: metadata.Description != ""},
+		CoverImagePath: pgtype.Text{String: metadata.CoverPath, Valid: metadata.CoverPath != ""},
+		Series:         pgtype.Text{String: metadata.Series, Valid: metadata.Series != ""},
+		SeriesNumber:   pgtype.Int4{Int32: metadata.SeriesNumber, Valid: metadata.SeriesNumber > 0},
+		Tags:           pgtype.Text{}, // Keep existing tags
+		Asin:           pgtype.Text{}, // Keep existing ASIN
+		DatePublished:  pgtype.Date{Time: metadata.PublishDate, Valid: !metadata.PublishDate.IsZero()},
+		Publisher:      pgtype.Text{String: metadata.Publisher, Valid: metadata.Publisher != ""},
+		Contributors:   pgtype.Text{String: metadata.Contributors, Valid: metadata.Contributors != ""},
+	})
+
+	return err
+}
+
+func (s *EbookScanner) getEbookByFilePath(ctx context.Context, filePath string) (database.Ebooks, error) {
+	return s.db.GetEbookByFilePath(ctx, filePath)
+}
+
+func (s *EbookScanner) getMimeType(path string) string {
+	ext := strings.ToLower(filepath.Ext(path))
+	switch ext {
+	case ".epub":
+		return "application/epub+zip"
+	case ".pdf":
+		return "application/pdf"
+	case ".mobi":
+		return "application/x-mobipocket-ebook"
+	case ".azw3":
+		return "application/vnd.amazon.ebook"
+	case ".fb2":
+		return "application/x-fictionbook+xml"
+	case ".txt":
+		return "text/plain"
+	default:
+		return "application/octet-stream"
+	}
+}
+
+func (s *EbookScanner) WatchChanges(ctx context.Context) {
+	go func() {
+		for {
+			select {
+			case event, ok := <-s.watcher.Events:
+				if !ok {
+					return
+				}
+				if event.Has(fsnotify.Create) || event.Has(fsnotify.Write) {
+					if s.isEbookFile(event.Name) {
+						fmt.Printf("New/modified ebook detected: %s\n", event.Name)
+						if err := s.processEbookFile(ctx, event.Name); err != nil {
+							fmt.Printf("Error processing modified ebook %s: %v\n", event.Name, err)
+						}
+					}
+				}
+			case err, ok := <-s.watcher.Errors:
+				if !ok {
+					return
+				}
+				fmt.Printf("Watcher error: %v\n", err)
+			case <-ctx.Done():
+				return
+			}
+		}
+	}()
+}
+
+func (s *EbookScanner) Close() error {
+	if s.watcher != nil {
+		return s.watcher.Close()
+	}
+	return nil
+}