Add GTK application implementation

internal/gui/coverloader.go

@@ -0,0 +1,188 @@
+package gui
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"strconv"
+	"sync"
+
+	"github.com/diamondburned/gotk4/pkg/core/gerror"
+	"github.com/diamondburned/gotk4/pkg/gdkpixbuf/v2"
+	"github.com/diamondburned/gotk4/pkg/glib/v2"
+	"suruatoel.xyz/mcg/internal/client"
+	"suruatoel.xyz/mcg/internal/common"
+)
+
+type CoverLoader struct {
+	hostDir string
+	size    int
+	mutex   sync.Mutex
+}
+
+func NewCoverLoader(host string) *CoverLoader {
+	loader := CoverLoader{}
+	loader.hostDir = loader.getHostDir(host)
+	loader.size = loader.readCacheSize()
+
+	return &loader
+}
+
+func (l *CoverLoader) SetSize(size int) {
+	if l.size != size {
+		log.Println("cache size has changed from", l.size, "to", size)
+		l.clearCache()
+		l.writeCacheSize(size)
+		l.size = size
+	}
+}
+
+func (l *CoverLoader) LoadThumbnail(album *common.Album) *gdkpixbuf.Pixbuf {
+	// Load cover from cache
+	pixbuf := l.getCached(album)
+	if pixbuf != nil {
+		return pixbuf
+	}
+
+	// Load cover from server
+	albumart := client.Instance().LoadAlbumartNow(album)
+	if albumart != nil {
+		pixbuf = l.loadImage(albumart)
+	}
+	if pixbuf != nil {
+		pixbuf = pixbuf.ScaleSimple(l.size, l.size, gdkpixbuf.InterpHyper)
+		if pixbuf != nil {
+			l.setCached(album, pixbuf)
+		}
+	}
+
+	return pixbuf
+}
+
+func (l *CoverLoader) getHostDir(host string) string {
+	cacheDir, cacheDirErr := os.UserCacheDir()
+	if cacheDirErr != nil {
+		log.Println("failed to detect user cache directory:", cacheDirErr)
+		return ""
+	}
+
+	hostDir := filepath.Join(cacheDir, "mcg", host)
+
+	return hostDir
+}
+
+func (l *CoverLoader) ensureHostDir() {
+	hostDirErr := os.MkdirAll(l.hostDir, 0o750)
+	if hostDirErr != nil {
+		log.Println("failed to create cache folder for host", l.hostDir, ":", hostDirErr)
+	}
+}
+
+func (l *CoverLoader) readCacheSize() int {
+	sizeFile := l.getCacheSizeFile()
+	if sizeFile == "" {
+		return 100
+	}
+
+	l.mutex.Lock()
+	defer l.mutex.Unlock()
+
+	content, readErr := os.ReadFile(sizeFile)
+	if readErr != nil {
+		log.Println("failed to read cache size file for host", l.hostDir, ":", readErr)
+		return 100
+	}
+
+	size, sizeErr := strconv.Atoi(string(content[:]))
+	if sizeErr != nil {
+		log.Println("invalid content of cache size file for host", l.hostDir, ":", readErr)
+	}
+
+	return size
+}
+
+func (l *CoverLoader) writeCacheSize(size int) {
+	l.ensureHostDir()
+	sizeFile := l.getCacheSizeFile()
+	if sizeFile == "" {
+		return
+	}
+
+	writeErr := os.WriteFile(sizeFile, []byte(fmt.Sprintf("%d", size)), 0o644)
+	if writeErr != nil {
+		log.Println("failed to write cache size file for host", l.hostDir, ":", writeErr)
+	}
+}
+
+func (l *CoverLoader) getCacheFile(album *common.Album) string {
+	if l.hostDir == "" {
+		return ""
+	}
+
+	return filepath.Join(l.hostDir, album.ID())
+}
+
+func (l *CoverLoader) getCacheSizeFile() string {
+	if l.hostDir == "" {
+		return ""
+	}
+
+	return filepath.Join(l.hostDir, "size")
+}
+
+func (l *CoverLoader) clearCache() {
+	if l.hostDir == "" {
+		return
+	}
+
+	removeErr := os.RemoveAll(l.hostDir)
+	if removeErr != nil {
+		log.Println("failed to clear cache folder for host", l.hostDir, ":", removeErr)
+	}
+}
+
+func (l *CoverLoader) getCached(album *common.Album) *gdkpixbuf.Pixbuf {
+	cacheFile := l.getCacheFile(album)
+	if cacheFile == "" {
+		return nil
+	}
+
+	pixbuf, pixbufErr := gdkpixbuf.NewPixbufFromFile(cacheFile)
+	if pixbufErr != nil {
+		if !isFileNotFoundError(pixbufErr) {
+			log.Println("failed to read cached thumbnail for host", l.hostDir, ":", pixbufErr)
+		}
+		return nil
+	}
+
+	return pixbuf
+}
+
+func isFileNotFoundError(err error) bool {
+	if gerr, isGerror := err.(*gerror.GError); isGerror {
+		return gerr.Quark() == uint32(glib.FileErrorQuark()) && gerr.ErrorCode() == int(glib.FileErrorNoent)
+	}
+
+	return false
+}
+
+func (l *CoverLoader) setCached(album *common.Album, pixbuf *gdkpixbuf.Pixbuf) {
+	cacheFile := l.getCacheFile(album)
+	if cacheFile == "" {
+		return
+	}
+
+	l.ensureHostDir()
+	pixbuf.Savev(cacheFile, "jpeg", []string{}, []string{})
+}
+
+func (l *CoverLoader) loadImage(file []byte) *gdkpixbuf.Pixbuf {
+	pixbufLoader, loaderErr := loadPixbuf(file)
+	if loaderErr != nil {
+		log.Println("failed to load image:", loaderErr)
+		return nil
+	}
+
+	return pixbufLoader.Pixbuf()
+}