initial commit

frontend/src/lib/project.ts

@@ -0,0 +1,56 @@
+import type { Project } from './types';
+import { app, setActiveSwitch, setMarkers, setSelectedIds } from './store.svelte';
+
+export function buildProject(): Project {
+  return {
+    version: 1,
+    switch: app.activeSwitch,
+    markers: app.markers.map((m) => ({ ...m })),
+  };
+}
+
+export function downloadProject(filename = 'project.json') {
+  const project = buildProject();
+  const blob = new Blob([JSON.stringify(project, null, 2)], { type: 'application/json' });
+  const url = URL.createObjectURL(blob);
+  const anchor = document.createElement('a');
+  anchor.href = url;
+  anchor.download = filename;
+  anchor.click();
+  URL.revokeObjectURL(url);
+}
+
+export function loadProject(data: Project) {
+  if (data.version !== 1) {
+    throw new Error(`Unsupported project version: ${data.version}`);
+  }
+  setMarkers(data.markers.map((m) => ({ ...m })));
+  setActiveSwitch(data.switch);
+  setSelectedIds(new Set());
+}
+
+export async function exportAudio(duration: number) {
+  const project = buildProject();
+  const response = await fetch('/api/export/audio', {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({
+      duration,
+      switch: project.switch,
+      markers: project.markers,
+    }),
+  });
+
+  if (!response.ok) {
+    const detail = await response.text();
+    throw new Error(detail || 'Audio export failed');
+  }
+
+  const blob = await response.blob();
+  const url = URL.createObjectURL(blob);
+  const anchor = document.createElement('a');
+  anchor.href = url;
+  anchor.download = 'keyboard_track.wav';
+  anchor.click();
+  URL.revokeObjectURL(url);
+}