feat: image gallery (#2)

Reviewed-on: #2

internal/components/gallery/image.go

@@ -0,0 +1,113 @@
+package gallery
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"hash/fnv"
+	"log/slog"
+	"os"
+	"path"
+	"strings"
+	"time"
+
+	"github.com/valkey-io/valkey-go"
+)
+
+type Image struct {
+	UID    string
+	X      int
+	Y      int
+	Width  int
+	Height int
+}
+
+const (
+	imagesKey = "gallery:images:list"
+	hashKey   = "gallery:images:hash"
+)
+
+func (s *Service) autoRefresh() {
+	t := time.NewTicker(time.Minute)
+	for {
+		ctx, cancle := context.WithTimeout(context.Background(), time.Minute)
+
+		if err := s.assembleImageList(ctx); err != nil {
+			slog.Error("error while refreshing gallery", "err", err)
+		}
+		cancle()
+		<-t.C
+	}
+}
+
+func (s *Service) assembleImageList(ctx context.Context) error {
+	files, err := s.readDirRecursive(s.cfg.Path)
+	if err != nil {
+		return fmt.Errorf("could not read contents of %s: %w", s.cfg.Path, err)
+	}
+	slog.Debug("loaded files", "files", files)
+
+	savedHash, _ := s.cache.Do(ctx, s.cache.B().Get().Key(hashKey).Build()).AsBytes()
+
+	newHash := hashImageList(files)
+
+	if bytes.Equal(savedHash, newHash) {
+		slog.Debug("images up to date no refreshing of gallery", "savedHash", savedHash, "newHash", newHash)
+		return nil
+	}
+
+	slog.Info("starting gallery refresh")
+	defer slog.Info("gallery refresh completed")
+
+	imgs := make([]Image, 0, len(files))
+	for _, file := range files {
+		if strings.HasSuffix(file.Name(), ".md") {
+			continue
+		}
+
+		imagePath := path.Join(s.cfg.Path, file.Name())
+		img, err := s.img.GetImage(imagePath)
+		if err != nil || img.Image == nil {
+			slog.Warn("could not get image for gallery", "err", err, "img", img)
+			continue
+		}
+
+		uid, err := img.UID()
+		if err != nil {
+			continue
+		}
+
+		imgs = append(imgs, Image{
+			UID:    uid,
+			Width:  img.Bounds().Dx(),
+			Height: img.Bounds().Dy(),
+		})
+	}
+
+	if err = s.cache.Do(ctx, s.cache.B().Set().Key(hashKey).Value(valkey.BinaryString(newHash)).Build()).Error(); err != nil {
+		return err
+	}
+
+	if err = s.cache.Do(ctx, s.cache.B().Set().Key(imagesKey).Value(valkey.JSON(imgs)).Build()).Error(); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func hashImageList(files []os.FileInfo) []byte {
+	h := fnv.New128()
+
+	for _, file := range files {
+		fmt.Fprint(h, file.ModTime())
+		fmt.Fprint(h, file.Size())
+		fmt.Fprint(h, file.Name())
+	}
+
+	return h.Sum([]byte{})
+}
+
+func (s *Service) GetImages(ctx context.Context) (images []Image, err error) {
+	err = s.cache.Do(ctx, s.cache.B().Get().Key(imagesKey).Build()).DecodeJSON(&images)
+	return
+}