feat: image gallery (#2)

Reviewed-on: #2

internal/components/gallery/controller.go

@@ -0,0 +1,86 @@
+package gallery
+
+import (
+	"context"
+	"math"
+
+	"github.com/InfinityTools/go-binpack2d"
+)
+
+type Gallery struct {
+	GridWith   int
+	GridHeight int
+	Images     []Image
+}
+type Set struct {
+	SM  Gallery
+	LG  Gallery
+	XLG Gallery
+}
+
+func (s *Service) GetGallerySet(ctx context.Context) (gallerySet Set, err error) {
+	gallerySet.SM, err = s.GetGallery(ctx, 50)
+	if err != nil {
+		return
+	}
+	gallerySet.LG, err = s.GetGallery(ctx, 80)
+	if err != nil {
+		return
+	}
+
+	gallerySet.XLG, err = s.GetGallery(ctx, 120)
+	if err != nil {
+		return
+	}
+
+	return
+}
+
+func (s *Service) GetGallery(ctx context.Context, width int) (gallery Gallery, err error) {
+	imgs, err := s.GetImages(ctx)
+	if err != nil {
+		return
+	}
+
+	packer := binpack2d.Create(width, 999999)
+
+	for len(imgs) > 0 {
+		unused := make([]Image, 0, len(imgs))
+		for _, img := range imgs {
+			adjustImageSize(&img, 200)
+			rect, ok := packer.Insert(img.Width, img.Height, binpack2d.RULE_BEST_SHORT_SIDE_FIT)
+			if !ok {
+				unused = append(unused, img)
+				continue
+			}
+
+			img.X = rect.X
+			img.Y = rect.Y
+
+			gallery.Images = append(gallery.Images, img)
+		}
+		imgs = unused
+	}
+
+	packer.ShrinkBin(false)
+
+	gallery.GridHeight = packer.GetHeight()
+	gallery.GridWith = packer.GetWidth()
+
+	return
+}
+
+// adjustImageSize adjusts the image size so that the aspect ratio stays the same
+// but the image area is the given parameter.
+func adjustImageSize(img *Image, area int) {
+	// Calculate the original aspect ratio (W / H)
+	aspectRatio := float64(img.Width) / float64(img.Height)
+
+	// Calculate new height and width using the derived formulas
+	newHeight := math.Sqrt(float64(area) / aspectRatio)
+	newWidth := newHeight * aspectRatio
+
+	// Round to the nearest integer to minimize precision loss
+	img.Width = int(math.Round(newWidth))
+	img.Height = int(math.Round(newHeight))
+}