feat(ComparisonSlider): rewrite slider labels to include selects for compared fonts

src/widgets/ComparisonSlider/ui/ComparisonSlider/components/Labels.svelte

@@ -1,37 +1,110 @@
-<script lang="ts">
+<!--
-import type { Snippet } from 'svelte';
+    Component: Labels
+    Displays labels for font selection in the comparison slider.
+-->
+<script lang="ts" generics="T extends { name: string; id: string }">
+import {
+    FontVirtualList,
+    type UnifiedFont,
+} from '$entities/Font';
+import FontApplicator from '$entities/Font/ui/FontApplicator/FontApplicator.svelte';
+import { displayedFontsStore } from '$features/DisplayFont';
+import { buttonVariants } from '$shared/shadcn/ui/button';
+import {
+    Content as SelectContent,
+    Item as SelectItem,
+    Root as SelectRoot,
+    Trigger as SelectTrigger,
+} from '$shared/shadcn/ui/select';
+import { cn } from '$shared/shadcn/utils/shadcn-utils';
 
-interface Props {
+interface Props<T> {
-    fontA: { name: string; id: string };
+    /**
-    fontB: { name: string; id: string };
+     * First font to compare
+     */
+    fontA: T;
+    /**
+     * Second font to compare
+     */
+    fontB: T;
+    /**
+     * Position of the slider
+     */
     sliderPos: number;
 }
-let { fontA, fontB, sliderPos }: Props = $props();
+let { fontA, fontB, sliderPos }: Props<T> = $props();
+
+const fontList = $derived(
+    displayedFontsStore.fonts.filter(font => font.name !== fontA.name && font.name !== fontB.name),
+);
+
+function selectFontA(fontId: string) {
+    const newFontA = displayedFontsStore.getById(fontId);
+    if (!newFontA) return;
+    displayedFontsStore.fontA = newFontA;
+}
+
+function selectFontB(fontId: string) {
+    const newFontB = displayedFontsStore.getById(fontId);
+    if (!newFontB) return;
+    displayedFontsStore.fontB = newFontB;
+}
 </script>
 
-<!-- Bottom Labels -->
+{#snippet fontSelector(
-<div class="absolute bottom-6 inset-x-8 sm:inset-x-12 flex justify-between items-center pointer-events-none z-20">
+    name: string,
-    <!-- Left Label (Font A) -->
+    id: string,
+    fonts: UnifiedFont[],
+    handleChange: (value: string) => void,
+)}
     <div
-        class="flex flex-col gap-1 transition-opacity duration-300"
+        class="z-50 pointer-events-auto **:bg-transparent"
-        style:opacity={sliderPos < 10 ? 0 : 1}
+        onpointerdown={(e => e.stopPropagation())}
     >
-        <span class="text-[0.5rem] font-mono uppercase tracking-widest text-indigo-400"
+        <SelectRoot type="single" onValueChange={handleChange}>
-        >Baseline</span>
+            <SelectTrigger
-        <span class="text-xs sm:text-sm font-bold text-indigo-600">
+                class={cn(buttonVariants({ variant: 'ghost' }), 'border-none, hover:bg-indigo-100')}
-            {fontB.name}
+                disabled={!fontList.length}
-        </span>
+            >
+                <FontApplicator name={name} id={id}>
+                    {name}
+                </FontApplicator>
+            </SelectTrigger>
+            <SelectContent
+                class="h-60 bg-transparent **:bg-transparent backdrop-blur-0 data-[state=open]:backdrop-blur-lg transition-[backdrop-filter] duration-200"
+                scrollYThreshold={100}
+                side="top"
+            >
+                <FontVirtualList items={fonts}>
+                    {#snippet children({ item: font })}
+                        <SelectItem value={font.id} class="data-[highlighted]:bg-indigo-100">
+                            <FontApplicator name={font.name} id={font.id}>
+                                {font.name}
+                            </FontApplicator>
+                        </SelectItem>
+                    {/snippet}
+                </FontVirtualList>
+            </SelectContent>
+        </SelectRoot>
+    </div>
+{/snippet}
+
+<div class="absolute bottom-6 inset-x-6 sm:inset-x-6 flex justify-between items-end pointer-events-none z-20">
+    <div
+        class="flex flex-col gap-0.5 transition-opacity duration-300 items-start"
+        style:opacity={sliderPos < 15 ? 0 : 1}
+    >
+        <span class="text-[0.5rem] font-mono uppercase tracking-widest text-indigo-400">
+            Baseline</span>
+        {@render fontSelector(fontB.name, fontB.id, fontList, selectFontB)}
     </div>
 
-    <!-- Right Label (Font B) -->
     <div
         class="flex flex-col items-end text-right gap-1 transition-opacity duration-300"
-        style:opacity={sliderPos > 90 ? 0 : 1}
+        style:opacity={sliderPos > 85 ? 0 : 1}
     >
-        <span class="text-[0.5rem] font-mono uppercase tracking-widest text-slate-400"
+        <span class="text-[0.5rem] font-mono uppercase tracking-widest text-slate-400">
-        >Comparison</span>
+            Comparison</span>
-        <span class="text-xs sm:text-sm font-bold text-slate-900">
+        {@render fontSelector(fontA.name, fontA.id, fontList, selectFontA)}
-            {fontA.name}
-        </span>
     </div>
 </div>