1 files changed, 158 insertions, 0 deletions
diff --git a/internal/notify/icons.go b/internal/notify/icons.go
new file mode 100644
index 0000000..b874581
--- /dev/null
+++ b/internal/notify/icons.go
@@ -0,0 +1,158 @@
+// Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 2 as
+// published by the Free Software Foundation.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+package notify
+
+import (
+	"os"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+// IconThemeName reads the desktop's current icon theme: qt6ct is the truth on
+// this desktop, then the GTK3 setting, then hicolor. A missing or empty value
+// falls through.
+func IconThemeName() string {
+	if v := iniValue(filepath.Join(homeDir(), ".config", "qt6ct", "qt6ct.conf"), "icon_theme"); v != "" {
+		return v
+	}
+	if v := iniValue(filepath.Join(homeDir(), ".config", "gtk-3.0", "settings.ini"), "gtk-icon-theme-name"); v != "" {
+		return v
+	}
+	return "hicolor"
+}
+
+// ResolveIcon turns an app_icon or image-path value into a file path. A URI is
+// trimmed, a path is returned unchanged, and a bare name is looked up in the
+// icon theme. Nothing found is an empty string, which renders no image.
+func ResolveIcon(value string) string {
+	if value == "" {
+		return ""
+	}
+	if strings.HasPrefix(value, "file://") {
+		return strings.TrimPrefix(value, "file://")
+	}
+	if strings.Contains(value, "/") {
+		return value
+	}
+	return lookupThemeIcon(value, IconThemeName())
+}
+
+// XDGIconDirs is the icon search path: the user's dir then each data dir.
+func XDGIconDirs() []string {
+	home := os.Getenv("XDG_DATA_HOME")
+	if home == "" {
+		home = filepath.Join(homeDir(), ".local", "share")
+	}
+	dirs := []string{filepath.Join(home, "icons")}
+	for _, d := range filepath.SplitList(os.Getenv("XDG_DATA_DIRS")) {
+		if d != "" {
+			dirs = append(dirs, filepath.Join(d, "icons"))
+		}
+	}
+	if len(dirs) == 1 {
+		dirs = append(dirs, "/usr/local/share/icons", "/usr/share/icons")
+	}
+	return dirs
+}
+
+// lookupThemeIcon searches the theme, then its Inherits chain, then hicolor.
+func lookupThemeIcon(name, theme string) string {
+	seen := map[string]bool{}
+	for theme != "" && !seen[theme] {
+		seen[theme] = true
+		found, next := "", ""
+		for _, root := range XDGIconDirs() {
+			base := filepath.Join(root, theme)
+			if p := findInTheme(base, name); p != "" {
+				found = p
+				break
+			}
+			if next == "" {
+				next = inheritsOf(base)
+			}
+		}
+		if found != "" {
+			return found
+		}
+		theme = next
+	}
+	for _, root := range XDGIconDirs() {
+		if p := findInTheme(filepath.Join(root, "hicolor"), name); p != "" {
+			return p
+		}
+	}
+	return ""
+}
+
+// findInTheme prefers scalable then the largest raster under apps/.
+func findInTheme(base, name string) string {
+	sizes := []string{"scalable"}
+	matches, _ := filepath.Glob(filepath.Join(base, "apps", "[0-9]*"))
+	for _, m := range matches {
+		sizes = append(sizes, filepath.Base(m))
+	}
+	numeric := sizes[1:]
+	sort.Slice(numeric, func(i, j int) bool {
+		a, _ := strconv.Atoi(strings.TrimSuffix(numeric[i], "@2x"))
+		b, _ := strconv.Atoi(strings.TrimSuffix(numeric[j], "@2x"))
+		return a > b
+	})
+	for _, size := range sizes {
+		for _, ext := range []string{"svg", "png", "xpm"} {
+			p := filepath.Join(base, "apps", size, name+"."+ext)
+			if fileExists(p) {
+				return p
+			}
+		}
+	}
+	return ""
+}
+
+func inheritsOf(base string) string {
+	v := iniValue(filepath.Join(base, "index.theme"), "Inherits")
+	if i := strings.IndexByte(v, ','); i >= 0 {
+		v = v[:i]
+	}
+	return strings.TrimSpace(v)
+}
+
+func iniValue(path, key string) string {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return ""
+	}
+	for _, line := range strings.Split(string(data), "\n") {
+		line = strings.TrimSpace(line)
+		if strings.HasPrefix(line, "#") || !strings.Contains(line, "=") {
+			continue
+		}
+		k, v, _ := strings.Cut(line, "=")
+		if strings.TrimSpace(k) == key {
+			return strings.TrimSpace(v)
+		}
+	}
+	return ""
+}
+
+func homeDir() string {
+	if h := os.Getenv("HOME"); h != "" {
+		return h
+	}
+	return os.TempDir()
+}
+
+func fileExists(path string) bool {
+	info, err := os.Stat(path)
+	return err == nil && !info.IsDir()
+}