import { MCP_APPS_SHELL_STABLE_ASSET_PATH } from "./shell-asset-path"; let shellHtmlCache: string | undefined; /** * The self-contained shell HTML served as the MCP-Apps `ui://` resource, read * from the local filesystem. * * Hosts inject this through `SharedMcpServerConfig.loadAppShellHtml` rather * than the MCP host package importing it directly: the shell drags React, * Recharts and Tailwind into whatever graph imports it, and the MCP host also * runs on Workers where none of that belongs. * * This loader is for hosts WITH a filesystem: the local CLI/desktop binary * (shell copied next to the executable by `apps/cli/src/build.ts`), dev runs * from the repo, and the self-host image (the stable-named copy its SPA build * emits into `dist/assets/`). Workers hosts use `makeAssetsShellHtmlLoader` * from `@executor-js/mcp-apps-shell/worker` instead — `fs.readFile` can never * succeed there. * * A missing shell REJECTS, deliberately. This used to degrade to a "Shell not * built" placeholder, which is the worst possible failure mode: the resource * read succeeds, the client loads an inert document that never starts the * MCP-Apps handshake, and every artifact spins on its loading state forever * with no error anywhere in the chain — which is exactly how production * served the placeholder unnoticed. A rejected read surfaces as a JSON-RPC * error naming the missing file and the command that produces it. */export const loadMcpAppsShellHtml = async (): Promise<string> => {  if (shellHtmlCache) return shellHtmlCache;   const fs = await import("node:fs/promises");  const path = await import("node:path");  const candidates = [    // `bun build --compile` can't bundle this runtime `fs.readFile`, so the    // binary build (apps/cli/src/build.ts) copies `mcp-app.html` next to the    // executable. We find it via `process.execPath`, the same colocation    // trick native-bindings.ts uses for `libsql.node` / `keyring.node`.    path.join(path.dirname(process.execPath), "mcp-app.html"),    // Dev / package-resolved (`bun run`, vitest): the package's own dist.    path.join(import.meta.dirname, "../dist/mcp-app.html"),    path.join(import.meta.dirname, "../../dist/mcp-app.html"),    // The self-host runtime image. Its server is bundled to    // `apps/host-selfhost/dist-server/serve.js`, and the sibling `dist/` is    // the SPA build, whose `mcpAppsShellAsset` emits the stable-named copy of    // the shell into `dist/assets/`. The package-dist candidates above can't    // hit there — the image carries no `packages/` tree at all.    path.join(import.meta.dirname, "../dist", MCP_APPS_SHELL_STABLE_ASSET_PATH),  ];   for (const candidate of candidates) {    // oxlint-disable-next-line executor/no-try-catch-or-throw -- boundary: try each possible emitted shell path before failing    try {      shellHtmlCache = await fs.readFile(candidate, "utf-8");      return shellHtmlCache;    } catch {      // Try the next candidate path.    }  }   // oxlint-disable-next-line executor/no-try-catch-or-throw, executor/no-error-constructor -- boundary: a host without the built shell must fail the resource read loudly; a placeholder document hangs every MCP-Apps client silently  throw new Error(    "MCP-Apps shell document not found. Tried:\n" +      candidates.map((candidate) => `  ${candidate}`).join("\n") +      "\nBuild it with: bun run --cwd packages/hosts/mcp-apps-shell build:shell",  );};