Add post-processing audio effects system

app/src/components/Effects/EffectsChainEditor.tsx

@@ -0,0 +1,377 @@
+import {
+  closestCenter,
+  DndContext,
+  type DragEndEvent,
+  KeyboardSensor,
+  PointerSensor,
+  useSensor,
+  useSensors,
+} from '@dnd-kit/core';
+import {
+  arrayMove,
+  SortableContext,
+  sortableKeyboardCoordinates,
+  useSortable,
+  verticalListSortingStrategy,
+} from '@dnd-kit/sortable';
+import { CSS } from '@dnd-kit/utilities';
+import { useQuery } from '@tanstack/react-query';
+import { ChevronDown, ChevronRight, GripVertical, Plus, Power, Trash2 } from 'lucide-react';
+import { useCallback, useMemo, useRef, useState } from 'react';
+import { Button } from '@/components/ui/button';
+import { Label } from '@/components/ui/label';
+import {
+  Select,
+  SelectContent,
+  SelectItem,
+  SelectTrigger,
+  SelectValue,
+} from '@/components/ui/select';
+import { Slider } from '@/components/ui/slider';
+import { apiClient } from '@/lib/api/client';
+import type { AvailableEffect, EffectConfig, EffectPresetResponse } from '@/lib/api/types';
+import { cn } from '@/lib/utils/cn';
+
+// Each effect in the chain gets a stable ID for dnd-kit
+interface EffectWithId extends EffectConfig {
+  _id: string;
+}
+
+let nextId = 0;
+function makeId() {
+  return `fx-${++nextId}`;
+}
+
+interface EffectsChainEditorProps {
+  value: EffectConfig[];
+  onChange: (chain: EffectConfig[]) => void;
+  compact?: boolean;
+  showPresets?: boolean;
+}
+
+export function EffectsChainEditor({
+  value,
+  onChange,
+  compact = false,
+  showPresets = true,
+}: EffectsChainEditorProps) {
+  const [expandedId, setExpandedId] = useState<string | null>(null);
+
+  // Maintain stable IDs for each effect across renders.
+  // We use a ref to map value items to IDs, rebuilding when length changes.
+  const idsRef = useRef<string[]>([]);
+  const items: EffectWithId[] = useMemo(() => {
+    // Grow ID array if effects were added
+    while (idsRef.current.length < value.length) {
+      idsRef.current.push(makeId());
+    }
+    // Shrink if effects were removed
+    if (idsRef.current.length > value.length) {
+      idsRef.current = idsRef.current.slice(0, value.length);
+    }
+    return value.map((e, i) => ({ ...e, _id: idsRef.current[i] }));
+  }, [value]);
+
+  const sensors = useSensors(
+    useSensor(PointerSensor, { activationConstraint: { distance: 5 } }),
+    useSensor(KeyboardSensor, { coordinateGetter: sortableKeyboardCoordinates }),
+  );
+
+  const { data: availableEffects } = useQuery({
+    queryKey: ['available-effects'],
+    queryFn: () => apiClient.getAvailableEffects(),
+    staleTime: Infinity,
+  });
+
+  const { data: presets } = useQuery({
+    queryKey: ['effect-presets'],
+    queryFn: () => apiClient.listEffectPresets(),
+    staleTime: 30_000,
+  });
+
+  const effectsMap = useMemo(() => {
+    const m = new Map<string, AvailableEffect>();
+    if (availableEffects) {
+      for (const e of availableEffects.effects) {
+        m.set(e.type, e);
+      }
+    }
+    return m;
+  }, [availableEffects]);
+
+  function addEffect(type: string) {
+    const def = effectsMap.get(type);
+    if (!def) return;
+    const params: Record<string, number> = {};
+    for (const [key, p] of Object.entries(def.params)) {
+      params[key] = p.default;
+    }
+    const newEffect: EffectConfig = { type, enabled: true, params };
+    const newId = makeId();
+    idsRef.current = [...idsRef.current, newId];
+    onChange([...value, newEffect]);
+    setExpandedId(newId);
+  }
+
+  const removeEffect = useCallback(
+    (index: number) => {
+      const removedId = idsRef.current[index];
+      idsRef.current = idsRef.current.filter((_, i) => i !== index);
+      onChange(value.filter((_, i) => i !== index));
+      if (expandedId === removedId) setExpandedId(null);
+    },
+    [value, onChange, expandedId],
+  );
+
+  const toggleEnabled = useCallback(
+    (index: number) => {
+      onChange(value.map((e, i) => (i === index ? { ...e, enabled: !e.enabled } : e)));
+    },
+    [value, onChange],
+  );
+
+  const updateParam = useCallback(
+    (index: number, paramName: string, paramValue: number) => {
+      onChange(
+        value.map((e, i) =>
+          i === index ? { ...e, params: { ...e.params, [paramName]: paramValue } } : e,
+        ),
+      );
+    },
+    [value, onChange],
+  );
+
+  function loadPreset(preset: EffectPresetResponse) {
+    idsRef.current = preset.effects_chain.map(() => makeId());
+    onChange(preset.effects_chain);
+    setExpandedId(null);
+  }
+
+  function clearAll() {
+    idsRef.current = [];
+    onChange([]);
+    setExpandedId(null);
+  }
+
+  function handleDragEnd(event: DragEndEvent) {
+    const { active, over } = event;
+    if (!over || active.id === over.id) return;
+
+    const oldIndex = idsRef.current.indexOf(active.id as string);
+    const newIndex = idsRef.current.indexOf(over.id as string);
+    if (oldIndex === -1 || newIndex === -1) return;
+
+    idsRef.current = arrayMove(idsRef.current, oldIndex, newIndex);
+    onChange(arrayMove([...value], oldIndex, newIndex));
+  }
+
+  return (
+    <div className={cn('space-y-2', compact && 'text-sm')}>
+      {/* Preset selector row */}
+      {showPresets && (
+        <div className="flex items-center gap-2">
+          <Select
+            onValueChange={(id) => {
+              const preset = presets?.find((p) => p.id === id);
+              if (preset) loadPreset(preset);
+            }}
+          >
+            <SelectTrigger className="h-8 flex-1 text-xs focus:ring-0 focus:ring-offset-0">
+              <SelectValue placeholder="Load preset..." />
+            </SelectTrigger>
+            <SelectContent>
+              {presets?.map((p) => (
+                <SelectItem key={p.id} value={p.id}>
+                  {p.name}
+                  {p.description && (
+                    <span className="ml-1 text-muted-foreground">- {p.description}</span>
+                  )}
+                </SelectItem>
+              ))}
+            </SelectContent>
+          </Select>
+
+          {value.length > 0 && (
+            <Button
+              variant="ghost"
+              size="sm"
+              className="h-8 px-2 text-xs text-muted-foreground"
+              onClick={clearAll}
+            >
+              Clear
+            </Button>
+          )}
+        </div>
+      )}
+
+      {/* Sortable effects chain */}
+      <DndContext sensors={sensors} collisionDetection={closestCenter} onDragEnd={handleDragEnd}>
+        <SortableContext items={items.map((i) => i._id)} strategy={verticalListSortingStrategy}>
+          {items.map((effect, index) => (
+            <SortableEffectItem
+              key={effect._id}
+              id={effect._id}
+              effect={effect}
+              index={index}
+              effectDef={effectsMap.get(effect.type)}
+              isExpanded={expandedId === effect._id}
+              onToggleExpand={() => setExpandedId(expandedId === effect._id ? null : effect._id)}
+              onRemove={() => removeEffect(index)}
+              onToggleEnabled={() => toggleEnabled(index)}
+              onUpdateParam={(paramName, paramValue) => updateParam(index, paramName, paramValue)}
+            />
+          ))}
+        </SortableContext>
+      </DndContext>
+
+      {/* Add effect */}
+      {availableEffects && (
+        <Select onValueChange={addEffect}>
+          <SelectTrigger className="h-8 border-dashed text-xs text-muted-foreground focus:ring-0 focus:ring-offset-0">
+            <Plus className="mr-1 h-3.5 w-3.5" />
+            <SelectValue placeholder="Add effect..." />
+          </SelectTrigger>
+          <SelectContent>
+            {availableEffects.effects.map((e) => (
+              <SelectItem key={e.type} value={e.type}>
+                {e.label}
+              </SelectItem>
+            ))}
+          </SelectContent>
+        </Select>
+      )}
+    </div>
+  );
+}
+
+// ---------------------------------------------------------------------------
+// Sortable effect item
+// ---------------------------------------------------------------------------
+
+interface SortableEffectItemProps {
+  id: string;
+  effect: EffectConfig;
+  index: number;
+  effectDef?: AvailableEffect;
+  isExpanded: boolean;
+  onToggleExpand: () => void;
+  onRemove: () => void;
+  onToggleEnabled: () => void;
+  onUpdateParam: (paramName: string, paramValue: number) => void;
+}
+
+function SortableEffectItem({
+  id,
+  effect,
+  effectDef,
+  isExpanded,
+  onToggleExpand,
+  onRemove,
+  onToggleEnabled,
+  onUpdateParam,
+}: SortableEffectItemProps) {
+  const { attributes, listeners, setNodeRef, transform, transition, isDragging } = useSortable({
+    id,
+  });
+
+  const style = {
+    transform: CSS.Transform.toString(transform),
+    transition,
+    zIndex: isDragging ? 10 : undefined,
+  };
+
+  const label = effectDef?.label ?? effect.type;
+
+  return (
+    <div
+      ref={setNodeRef}
+      style={style}
+      className={cn(
+        'rounded-md border',
+        effect.enabled ? 'border-border bg-card' : 'border-border/50 bg-muted/30',
+        isDragging && 'opacity-80 shadow-lg',
+      )}
+    >
+      {/* Header */}
+      <div className="flex items-center gap-1 px-2 py-1.5">
+        <button
+          type="button"
+          className="p-0.5 text-muted-foreground hover:text-foreground"
+          onClick={onToggleExpand}
+        >
+          {isExpanded ? (
+            <ChevronDown className="h-3.5 w-3.5" />
+          ) : (
+            <ChevronRight className="h-3.5 w-3.5" />
+          )}
+        </button>
+
+        <button
+          type="button"
+          className="p-0.5 text-muted-foreground/50 hover:text-muted-foreground cursor-grab active:cursor-grabbing touch-none"
+          {...attributes}
+          {...listeners}
+        >
+          <GripVertical className="h-3.5 w-3.5" />
+        </button>
+
+        <span
+          className={cn('flex-1 text-xs font-medium', !effect.enabled && 'text-muted-foreground')}
+        >
+          {label}
+        </span>
+
+        <button
+          type="button"
+          className={cn(
+            'p-0.5 transition-colors',
+            effect.enabled ? 'text-primary' : 'text-muted-foreground hover:text-foreground',
+          )}
+          onClick={onToggleEnabled}
+          title={effect.enabled ? 'Disable' : 'Enable'}
+        >
+          <Power className="h-3.5 w-3.5" />
+        </button>
+
+        <button
+          type="button"
+          className="p-0.5 text-muted-foreground hover:text-destructive"
+          onClick={onRemove}
+          title="Remove"
+        >
+          <Trash2 className="h-3.5 w-3.5" />
+        </button>
+      </div>
+
+      {/* Params */}
+      {isExpanded && effectDef && (
+        <div className="space-y-3 border-t px-3 py-2.5">
+          {Object.entries(effectDef.params).map(([paramName, paramDef]) => {
+            const currentValue = effect.params[paramName] ?? paramDef.default;
+            return (
+              <div key={paramName} className="space-y-1">
+                <div className="flex items-center justify-between">
+                  <Label className="text-[11px] text-muted-foreground">
+                    {paramDef.description}
+                  </Label>
+                  <span className="text-[11px] font-mono tabular-nums text-foreground">
+                    {currentValue.toFixed(
+                      paramDef.step < 1 ? Math.max(1, -Math.floor(Math.log10(paramDef.step))) : 0,
+                    )}
+                  </span>
+                </div>
+                <Slider
+                  min={paramDef.min}
+                  max={paramDef.max}
+                  step={paramDef.step}
+                  value={[currentValue]}
+                  onValueChange={([v]) => onUpdateParam(paramName, v)}
+                />
+              </div>
+            );
+          })}
+        </div>
+      )}
+    </div>
+  );
+}