import assert from "node:assert/strict";
import { readdirSync, readFileSync, statSync } from "node:fs";
import { join, relative } from "node:path";
import { fileURLToPath } from "node:url";
import test from "node:test";

// BUG-1140: deploy/railway-web.Dockerfile copies frontend/src and frontend/scripts but not
// frontend/tests, and `next build` type-checks every *.ts under frontend/. A runtime or script
// file that imports from tests/ builds locally and then fails the staging image build.
const frontend = fileURLToPath(new URL("..", import.meta.url));
const roots = ["src", "scripts"];
const importsTests = /(?:from\s+|import\s*\(\s*|new URL\(\s*)["'](?:\.\.?\/)+(?:[^"']*\/)?tests\//;

function sources(directory: string): string[] {
  return readdirSync(directory).flatMap((name) => {
    const path = join(directory, name);
    if (statSync(path).isDirectory()) return sources(path);
    return /\.(?:ts|tsx|mts|mjs|js)$/.test(name) ? [path] : [];
  });
}

test("files copied into the web image never import from frontend/tests", () => {
  const offenders = roots
    .flatMap((root) => sources(join(frontend, root)))
    .filter((path) => importsTests.test(readFileSync(path, "utf8")))
    .map((path) => relative(frontend, path));
  assert.deepEqual(offenders, []);
});

test("the guard recognises the shapes that broke the build", () => {
  for (const line of [
    'import { startPostgresFixture } from "../tests/helpers/postgres-fixture.ts";',
    "const fixture = await import('../../tests/helpers/postgres-fixture.ts');",
    'new URL("../tests/fixtures/x.json", import.meta.url)',
  ]) assert.ok(importsTests.test(line), line);
  assert.equal(importsTests.test('import { x } from "../src/lib/tests-helpers.ts";'), false);
});