Add MAX Mini App frontend flow

app/composables/useMessengerMiniAppStart.ts

@@ -0,0 +1,125 @@
+const MESSENGER_MINI_APP_PATH_PREFIX = 'path_';
+
+function getBuffer() {
+  return (globalThis as typeof globalThis & {
+    Buffer?: {
+      from(input: string | Uint8Array, encoding?: string): {
+        toString(encoding?: string): string;
+      };
+    };
+  }).Buffer;
+}
+
+function encodeUtf8(value: string) {
+  if (typeof TextEncoder !== 'undefined') {
+    return new TextEncoder().encode(value);
+  }
+
+  const buffer = getBuffer();
+  if (buffer) {
+    return Uint8Array.from(buffer.from(value, 'utf8'));
+  }
+
+  return Uint8Array.from(value.split('').map((char) => char.charCodeAt(0)));
+}
+
+function decodeUtf8(bytes: Uint8Array) {
+  if (typeof TextDecoder !== 'undefined') {
+    return new TextDecoder().decode(bytes);
+  }
+
+  const buffer = getBuffer();
+  if (buffer) {
+    return buffer.from(bytes).toString('utf8');
+  }
+
+  return String.fromCharCode(...bytes);
+}
+
+function toBase64(bytes: Uint8Array) {
+  const buffer = getBuffer();
+  if (buffer) {
+    return buffer.from(bytes).toString('base64');
+  }
+
+  let binary = '';
+  for (const byte of bytes) {
+    binary += String.fromCharCode(byte);
+  }
+  return btoa(binary);
+}
+
+function fromBase64(value: string) {
+  const buffer = getBuffer();
+  if (buffer) {
+    return Uint8Array.from(buffer.from(value, 'base64'));
+  }
+
+  const binary = atob(value);
+  return Uint8Array.from(binary, (char) => char.charCodeAt(0));
+}
+
+function normalizePath(value: string) {
+  const normalizedPath = String(value || '').trim();
+  return normalizedPath.startsWith('/') ? normalizedPath : '';
+}
+
+function toBase64Url(value: string) {
+  return toBase64(encodeUtf8(value))
+    .replace(/\+/g, '-')
+    .replace(/\//g, '_')
+    .replace(/=+$/g, '');
+}
+
+function fromBase64Url(value: string) {
+  const normalizedValue = value.replace(/-/g, '+').replace(/_/g, '/');
+  const padding = normalizedValue.length % 4 === 0 ? '' : '='.repeat(4 - (normalizedValue.length % 4));
+  return decodeUtf8(fromBase64(`${normalizedValue}${padding}`));
+}
+
+function readWindowStartParam() {
+  if (!import.meta.client) {
+    return '';
+  }
+
+  const telegramStartParam = String(window.Telegram?.WebApp?.initDataUnsafe?.start_param || '').trim();
+  if (telegramStartParam) {
+    return telegramStartParam;
+  }
+
+  return String(window.WebApp?.initDataUnsafe?.start_param || '').trim();
+}
+
+export function encodeMessengerMiniAppPath(path: string) {
+  const normalizedPath = normalizePath(path);
+  if (!normalizedPath) {
+    return '';
+  }
+
+  return `${MESSENGER_MINI_APP_PATH_PREFIX}${toBase64Url(normalizedPath)}`;
+}
+
+export function decodeMessengerMiniAppStartParam(startParam: string) {
+  const normalizedStartParam = String(startParam || '').trim();
+  if (!normalizedStartParam) {
+    return '';
+  }
+
+  if (normalizedStartParam.startsWith('/')) {
+    return normalizePath(normalizedStartParam);
+  }
+
+  if (!normalizedStartParam.startsWith(MESSENGER_MINI_APP_PATH_PREFIX)) {
+    return '';
+  }
+
+  try {
+    return normalizePath(fromBase64Url(normalizedStartParam.slice(MESSENGER_MINI_APP_PATH_PREFIX.length)));
+  } catch {
+    return '';
+  }
+}
+
+export function readMessengerMiniAppStartPath() {
+  return decodeMessengerMiniAppStartParam(readWindowStartParam());
+}