feat: Add composable to fetch app icon as SVG for inline use

Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>

apps/settings/src/composables/useAppIcon.ts

@@ -0,0 +1,52 @@
+import type { Ref } from 'vue'
+import type { IAppstoreApp } from '../app-types.ts'
+
+import { mdiCog } from '@mdi/js'
+import { computed, ref, watchEffect } from 'vue'
+import AppstoreCategoryIcons from '../constants/AppstoreCategoryIcons.ts'
+import logger from '../logger.ts'
+
+/**
+ * Get the app icon raw SVG for use with `NcIconSvgWrapper` (do never use without sanitizing)
+ * It has a fallback to the categroy icon.
+ *
+ * @param app The app to get the icon for
+ */
+export function useAppIcon(app: Ref<IAppstoreApp>) {
+	const appIcon = ref<string|null>(null)
+
+	/**
+	 * Fallback value if no app icon available
+	 */
+	const categoryIcon = computed(() => {
+		const path = [app.value?.category ?? []].flat()
+			.map((name) => AppstoreCategoryIcons[name])
+			.filter((icon) => !!icon)
+			.at(0)
+			?? mdiCog
+		return path ? `<svg viewBox="0 0 24 24" xmlns="http://www.w3.org/2000/svg"><path d="${path}" /></svg>` : null
+	})
+
+	watchEffect(async () => {
+		// Note: Only variables until the first `await` will be watched!
+		if (!app.value?.preview) {
+			appIcon.value = categoryIcon.value
+		} else {
+			appIcon.value = null
+			// Now try to load the real app icon
+			try {
+				const response = await window.fetch(app.value.preview)
+				const blob = await response.blob()
+				const rawSvg = await blob.text()
+				appIcon.value = rawSvg.replaceAll(/fill="#(fff|ffffff)([a-z0-9]{1,2})?"/ig, 'fill="currentColor"')
+			} catch (error) {
+				appIcon.value = categoryIcon.value
+				logger.error('Could not load app icon', { error })
+			}
+		}
+	})
+
+	return {
+		appIcon,
+	}
+}