/** Extract literal Minimal API routes and their receiver-specific MapGroup prefix. */
export function extractRoutesFromSource(source, file) {
  const prefixes = new Map([["app", ""]]);
  const groupPattern = /\b(?:var|const|RouteGroupBuilder)\s+(\w+)\s*=\s*(\w+)\.MapGroup\(\s*"([^"]+)"\s*\)/g;
  for (const match of source.matchAll(groupPattern)) {
    const parent = prefixes.get(match[2]);
    if (parent === undefined) throw new Error(`Unknown MapGroup receiver ${match[2]} in ${file}`);
    prefixes.set(match[1], parent + match[3]);
  }
  const routes = [];
  const mapPattern = /\b(\w+)\.Map(Get|Post|Put|Delete|Patch)\(\s*"([^"]*)"/g;
  for (const match of source.matchAll(mapPattern)) {
    const prefix = prefixes.get(match[1]);
    if (prefix === undefined) throw new Error(`Unknown route receiver ${match[1]} in ${file}`);
    const path = (prefix + match[3]).replace(/\{([a-zA-Z0-9_]+)(:[a-zA-Z]+)?\}/g, "{$1}");
    if (!path.startsWith("/api/v1")) {
      if (!path.startsWith("/health")) throw new Error(`Unexpected non-API route ${path} in ${file}`);
      continue;
    }
    routes.push({ method: match[2].toUpperCase(), path: path.slice("/api/v1".length) || "/", file });
  }
  return routes;
}