import { afterEach, expect, test } from "bun:test";
import { mkdirSync, mkdtempSync, readFileSync, rmSync, writeFileSync } from "node:fs";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { updateApp } from "../src/update.ts";

const roots: string[] = [];
afterEach(() => {
  for (const root of roots.splice(0)) rmSync(root, { recursive: true, force: true });
});

const CONFIG = `export default {
  compatibilityDate: "2026-08-02",
  frameworkBehaviour: 1,
  functions: { legacyDefaultRuntime: "current" },
  compatibility: { legacyEmit: false, stringLayouts: false },
  observability: { sampleRate: 1 },
};
`;

const NESTED_CONFIG = `export default {
  compatibilityDate: "2026-08-02",
  frameworkBehaviour: 1,
  functions: { legacyDefaultRuntime: "current", overrides: { a: { b: 1 } } },
  compatibility: { legacyEmit: false, nested: { deeper: { value: true } } },
  observability: { sampleRate: 1 },
};
`;

function project(config = CONFIG): string {
  const root = mkdtempSync(join(tmpdir(), "wrnexus-migrate-"));
  roots.push(root);
  mkdirSync(join(root, "app"), { recursive: true });
  writeFileSync(
    join(root, "package.json"),
    JSON.stringify({
      name: "config-migrate-app",
      dependencies: { "@wrnexus/core": "^0.8.0" },
      wrnexus: { version: "0.8.0" },
    }),
  );
  writeFileSync(join(root, "wrnexus.config.ts"), config);
  return root;
}

test("the removed keys are deleted and the rest is kept", () => {
  const root = project();
  updateApp(root, "0.9.0", false);
  const config = readFileSync(join(root, "wrnexus.config.ts"), "utf8");

  expect(config).not.toContain("compatibilityDate");
  expect(config).not.toContain("frameworkBehaviour");
  expect(config).not.toContain("legacyDefaultRuntime");
  expect(config).not.toContain("legacyEmit");
  expect(config).toContain("observability");
});

test("running it twice changes nothing the second time", () => {
  const root = project();
  updateApp(root, "0.9.0", false);
  const once = readFileSync(join(root, "wrnexus.config.ts"), "utf8");
  updateApp(root, "0.9.0", false);

  expect(readFileSync(join(root, "wrnexus.config.ts"), "utf8")).toBe(once);
});

test("a dry run writes nothing", () => {
  const root = project();
  updateApp(root, "0.9.0", true);

  expect(readFileSync(join(root, "wrnexus.config.ts"), "utf8")).toBe(CONFIG);
});

test("a nested object value under a removed key does not corrupt the file", () => {
  const root = project(NESTED_CONFIG);
  updateApp(root, "0.9.0", false);
  const config = readFileSync(join(root, "wrnexus.config.ts"), "utf8");

  expect(config).not.toContain("compatibilityDate");
  expect(config).not.toContain("frameworkBehaviour");
  expect(config).not.toContain("legacyDefaultRuntime");
  expect(config).not.toContain("legacyEmit");
  expect(config).not.toContain("overrides");
  expect(config).not.toContain("nested");
  expect(config).toContain("observability");

  // The file must remain valid, balanced TypeScript: an equal number of
  // opening and closing braces, and it must still be parseable as a module.
  const opens = (config.match(/\{/g) ?? []).length;
  const closes = (config.match(/\}/g) ?? []).length;
  expect(opens).toBe(closes);
});