feat: can now load disk samples via samples

+ encapsulate file logic from FilesTab

website/src/repl/files.mjs

@@ -0,0 +1,104 @@
+import {
+  processSampleMap,
+  registerSamplesPrefix,
+  registerSound,
+  onTriggerSample,
+  getAudioContext,
+  loadBuffer,
+} from '@strudel.cycles/webaudio';
+
+const TAURI = window.__TAURI__;
+export const { BaseDirectory, readDir, readBinaryFile, writeTextFile, readTextFile, exists } = TAURI?.fs || {};
+
+export const dir = BaseDirectory?.Audio; // https://tauri.app/v1/api/js/path#audiodir
+const prefix = '~/music/';
+
+async function hasStrudelJson(subpath) {
+  return exists(subpath + '/strudel.json', { dir });
+}
+
+async function loadStrudelJson(subpath) {
+  const contents = await readTextFile(subpath + '/strudel.json', { dir });
+  const sampleMap = JSON.parse(contents);
+  processSampleMap(sampleMap, (key, value) => {
+    registerSound(key, (t, hapValue, onended) => onTriggerSample(t, hapValue, onended, value, fileResolver(subpath)), {
+      type: 'sample',
+      samples: value,
+      fileSystem: true,
+      tag: 'local',
+    });
+  });
+}
+
+async function writeStrudelJson(subpath) {
+  const children = await readDir(subpath, { dir, recursive: true });
+  const name = subpath.split('/').slice(-1)[0];
+  const tree = { name, children };
+
+  let samples = {};
+  let count = 0;
+  walkFileTree(tree, (entry, parent) => {
+    if (['wav', 'mp3'].includes(entry.name.split('.').slice(-1)[0])) {
+      samples[parent.name] = samples[parent.name] || [];
+      count += 1;
+      samples[parent.name].push(entry.subpath.slice(1).concat([entry.name]).join('/'));
+    }
+  });
+  const json = JSON.stringify(samples, null, 2);
+  const filepath = subpath + '/strudel.json';
+  await writeTextFile(filepath, json, { dir });
+  console.log(`wrote strudel.json with ${count} samples to ${subpath}!`);
+}
+
+registerSamplesPrefix(prefix, async (path) => {
+  const subpath = path.replace(prefix, '');
+  const hasJson = await hasStrudelJson(subpath);
+  if (!hasJson) {
+    await writeStrudelJson(subpath);
+  }
+  return loadStrudelJson(subpath);
+});
+
+export const walkFileTree = (node, fn) => {
+  if (!Array.isArray(node?.children)) {
+    return;
+  }
+  for (const entry of node.children) {
+    entry.subpath = (node.subpath || []).concat([node.name]);
+    fn(entry, node);
+    if (entry.children) {
+      walkFileTree(entry, fn);
+    }
+  }
+};
+
+export const isAudioFile = (filename) => ['wav', 'mp3'].includes(filename.split('.').slice(-1)[0]);
+
+function uint8ArrayToDataURL(uint8Array) {
+  const blob = new Blob([uint8Array], { type: 'audio/*' });
+  const dataURL = URL.createObjectURL(blob);
+  return dataURL;
+}
+
+const loadCache = {}; // caches local urls to data urls
+export async function resolveFileURL(url) {
+  if (loadCache[url]) {
+    return loadCache[url];
+  }
+  loadCache[url] = (async () => {
+    const contents = await readBinaryFile(url, { dir });
+    return uint8ArrayToDataURL(contents);
+  })();
+  return loadCache[url];
+}
+
+const fileResolver = (subpath) => (url) => resolveFileURL(subpath.endsWith('/') ? subpath + url : subpath + '/' + url);
+
+export async function playFile(path) {
+  const url = await resolveFileURL(path);
+  const ac = getAudioContext();
+  const bufferSource = ac.createBufferSource();
+  bufferSource.buffer = await loadBuffer(url, ac);
+  bufferSource.connect(ac.destination);
+  bufferSource.start(ac.currentTime);
+}