import { describe, expect, test } from "bun:test";
import { existsSync, readFileSync } from "node:fs";
import { join } from "node:path";

/**
 * Tripwires for the patched, pinned Transformers.js runtime (D-WS1a).
 * `@huggingface/transformers` carries a `bun patch` (D-027/D-028) keyed by
 * its exact version; a bump that forgets to regenerate the patch would leave
 * the app working but silently bring back the mobile OOM. These checks fail
 * the fast suite instead.
 */

const ROOT = join(import.meta.dir, "..");
const PKG_DIR = join(ROOT, "node_modules/@huggingface/transformers");
const PINNED_VERSION = "4.3.2";

function read(path: string): string {
  return readFileSync(path, "utf8");
}

/** Source text of `async function <name>(…) { … }` in a bundled file. */
function functionSource(source: string, name: string): string {
  const start = source.indexOf(`async function ${name}(`);
  if (start < 0) throw new Error(`${name} not found`);
  const end = source.indexOf("\nfunction ", start + 1);
  const endAsync = source.indexOf("\nasync function ", start + 1);
  const stops = [end, endAsync].filter((i) => i > 0);
  return source.slice(start, stops.length ? Math.min(...stops) : undefined);
}

describe("@huggingface/transformers runtime", () => {
  test("installed version is the pinned 4.3.2", () => {
    const installed = JSON.parse(read(join(PKG_DIR, "package.json"))).version;
    expect(installed).toBe(PINNED_VERSION);
  });

  test("patchedDependencies points at an existing patch for the installed version", () => {
    const rootPkg = JSON.parse(read(join(ROOT, "package.json")));
    const patchPath = rootPkg.patchedDependencies?.[`@huggingface/transformers@${PINNED_VERSION}`];
    expect(typeof patchPath).toBe("string");
    expect(existsSync(join(ROOT, patchPath))).toBe(true);
  });

  test("web bundle's constructSessions carries the sequential-load patch (D-027/D-028)", () => {
    const body = functionSource(read(join(PKG_DIR, "dist/transformers.web.js")), "constructSessions");
    expect(body).toContain("options?.sequentialSessionLoad");
    expect(body).toContain("Promise.all(");
    expect(body).toContain("for (const name of Object.keys(names))");
  });

  test("Whisper generate still takes the seek loop when max_new_tokens is unset (D-021, D-WS1b)", () => {
    // The worker's `max_new_tokens: 440` exists only to dodge this branch.
    // If upstream changes the condition, re-measure D-021 before touching it.
    const source = read(join(PKG_DIR, "src/models/whisper/modeling_whisper.js"));
    expect(source).toContain("if (generation_config.return_timestamps && !kwargs.max_new_tokens)");
  });

  test("onnxruntime-web is the build D-WS1c re-tested 8-bit decoders on at the default optimization level", () => {
    // D-014's "basic" cap was dropped because this build loads the q8 merged
    // decoders at every graphOptimizationLevel. A different build needs the
    // D-WS1c session-creation check re-run before it ships.
    const ortWeb = JSON.parse(read(join(ROOT, "node_modules/onnxruntime-web/package.json"))).version;
    expect(ortWeb).toBe("1.31.0-dev.20260914-8d85527a0");
  });

  test("worker leaves WASM sessions at the default graph optimization level (D-WS1c)", () => {
    const worker = read(join(ROOT, "src/worker/inference.worker.ts"));
    expect(worker).not.toContain("graphOptimizationLevel");
  });
});