import { describe, expect, test, beforeEach, afterEach } from 'bun:test';
import { NpmError, forgetToken, normaliseUrl, npmRequest, probe } from './npm-client';

/**
 * The client, against a stubbed `fetch`.
 *
 * Two behaviours here are worth a test more than anything else in the plugin, because both are invisible
 * when they break: **a 404 means the credential, not a missing route**, and **a stale token is re-minted
 * once before anything is concluded**. Neither throws, neither logs, and a plausible refactor of either
 * turns a working panel into one that says "not found" forever.
 *
 * The token cache is module state keyed on `url + identity`, so every test uses its own credential and
 * clears it afterwards. Sharing one would let an earlier test's cached token satisfy a later one, and the
 * test that then passes for the wrong reason is the retry test.
 */

type StubbedCall = { url: string; init: RequestInit | undefined };

const realFetch = globalThis.fetch;
let calls: StubbedCall[] = [];

/** Queue one Response per expected call, in order. A call past the end of the queue fails loudly. */
const stubFetch = (responses: (() => Response | Promise<Response>)[]): void => {
  let index = 0;
  calls = [];
  globalThis.fetch = (async (input: RequestInfo | URL, init?: RequestInit) => {
    calls.push({ url: String(input), init });
    const next = responses[index++];
    if (!next) throw new Error(`unexpected fetch #${index} to ${String(input)}`);
    return next();
  }) as typeof fetch;
};

const json = (body: unknown, status = 200) =>
  new Response(JSON.stringify(body), { status, headers: { 'content-type': 'application/json' } });

const token = (value: string, expires?: string) => () => json({ token: value, expires });
const npmNotFound = (path: string) => () => json({ error: { code: 404, message: `Not Found - ${path}` } }, 404);

let counter = 0;
const freshCredentials = () => ({ url: 'http://npm.test', identity: `admin${counter++}@test`, secret: 'pw' });

let used: ReturnType<typeof freshCredentials>[] = [];
const credentials = () => {
  const c = freshCredentials();
  used.push(c);
  return c;
};

beforeEach(() => {
  used = [];
});

afterEach(() => {
  globalThis.fetch = realFetch;
  for (const c of used) forgetToken(c);
});

describe('normaliseUrl', () => {
  test('strips trailing slashes and surrounding space', () => {
    expect(normaliseUrl('  http://npm.test/  ')).toBe('http://npm.test');
    expect(normaliseUrl('http://npm.test///')).toBe('http://npm.test');
    expect(normaliseUrl('http://npm.test')).toBe('http://npm.test');
  });

  // The base is concatenated with `/api${path}`, so a surviving slash produces `//api/...`, which NPM
  // answers with — of course — a 404, and then the 404 rule blames the credential.
  test('a normalised url produces exactly one slash before /api', async () => {
    const c = { ...credentials(), url: 'http://npm.test/' };
    stubFetch([token('t'), () => json([])]);
    await npmRequest(c, { path: '/nginx/proxy-hosts' });
    expect(calls[1]?.url).toBe('http://npm.test/api/nginx/proxy-hosts');
  });
});

describe('tokens', () => {
  test('mints once and reuses the cached token', async () => {
    const c = credentials();
    stubFetch([token('t1'), () => json([]), () => json([])]);

    await npmRequest(c, { path: '/nginx/proxy-hosts' });
    await npmRequest(c, { path: '/nginx/certificates' });

    expect(calls).toHaveLength(3);
    expect(calls[0]?.url).toBe('http://npm.test/api/tokens');
    expect(calls[1]?.init?.headers).toMatchObject({ authorization: 'Bearer t1' });
    expect(calls[2]?.init?.headers).toMatchObject({ authorization: 'Bearer t1' });
  });

  test('the cache is keyed on identity, so a changed credential cannot reuse a token', async () => {
    const first = credentials();
    const second = { ...credentials(), url: first.url };

    stubFetch([token('t1'), () => json([]), token('t2'), () => json([])]);
    await npmRequest(first, { path: '/nginx/proxy-hosts' });
    await npmRequest(second, { path: '/nginx/proxy-hosts' });

    expect(calls[1]?.init?.headers).toMatchObject({ authorization: 'Bearer t1' });
    expect(calls[3]?.init?.headers).toMatchObject({ authorization: 'Bearer t2' });
  });

  test('forgetToken forces a fresh mint', async () => {
    const c = credentials();
    stubFetch([token('t1'), () => json([]), token('t2'), () => json([])]);

    await npmRequest(c, { path: '/nginx/proxy-hosts' });
    forgetToken(c);
    await npmRequest(c, { path: '/nginx/proxy-hosts' });

    expect(calls[3]?.init?.headers).toMatchObject({ authorization: 'Bearer t2' });
  });

  // A token cached right up to its stated expiry fails mid-flight as a 404, which reads as a missing
  // route. The client keeps a minute of headroom; an already-expired one must never be served.
  test('an expiry inside the headroom window is not cached', async () => {
    const c = credentials();
    const soon = new Date(Date.now() + 30_000).toISOString();
    stubFetch([token('t1', soon), () => json([]), token('t2', soon), () => json([])]);

    await npmRequest(c, { path: '/nginx/proxy-hosts' });
    await npmRequest(c, { path: '/nginx/proxy-hosts' });

    expect(calls[2]?.url).toBe('http://npm.test/api/tokens');
    expect(calls[3]?.init?.headers).toMatchObject({ authorization: 'Bearer t2' });
  });

  test('a bad credential is reported as auth, not as a 400', async () => {
    const c = credentials();
    stubFetch([() => json({ error: { message: 'Invalid email or password' } }, 400)]);

    const error = (await npmRequest(c, { path: '/nginx/proxy-hosts' }).catch((e) => e)) as NpmError;
    expect(error).toBeInstanceOf(NpmError);
    expect(error.status).toBe(400);
    expect(error.likelyAuth).toBe(true);
  });

  test('a token response with no token is an error rather than a bearer of undefined', async () => {
    const c = credentials();
    stubFetch([() => json({ expires: '2030-01-01T00:00:00Z' })]);

    const error = (await npmRequest(c, { path: '/nginx/proxy-hosts' }).catch((e) => e)) as NpmError;
    expect(error).toBeInstanceOf(NpmError);
    expect(error.message).toMatch(/no token/i);
  });
});

describe('the 404 quirk', () => {
  // The whole reason this client exists in the shape it does. NPM registers a resource only once the
  // request carries a token, so unauthenticated and non-existent are the same response.
  test('a stale token is re-minted once and the request retried', async () => {
    const c = credentials();
    stubFetch([token('stale'), npmNotFound('/nginx/proxy-hosts'), token('fresh'), () => json([{ id: 1 }])]);

    const hosts = await npmRequest<{ id: number }[]>(c, { path: '/nginx/proxy-hosts' });

    expect(hosts).toEqual([{ id: 1 }]);
    expect(calls).toHaveLength(4);
    expect(calls[1]?.init?.headers).toMatchObject({ authorization: 'Bearer stale' });
    expect(calls[3]?.init?.headers).toMatchObject({ authorization: 'Bearer fresh' });
  });

  test('401 gets the same retry as 404', async () => {
    const c = credentials();
    stubFetch([token('stale'), () => json({ error: { message: 'nope' } }, 401), token('fresh'), () => json([])]);

    await npmRequest(c, { path: '/nginx/proxy-hosts' });
    expect(calls[3]?.init?.headers).toMatchObject({ authorization: 'Bearer fresh' });
  });

  test('a 404 that survives the retry blames the credential, not the route', async () => {
    const c = credentials();
    stubFetch([token('t1'), npmNotFound('/nginx/proxy-hosts'), token('t2'), npmNotFound('/nginx/proxy-hosts')]);

    const error = (await npmRequest(c, { path: '/nginx/proxy-hosts' }).catch((e) => e)) as NpmError;
    expect(error.status).toBe(404);
    expect(error.likelyAuth).toBe(true);
    expect(error.message).toMatch(/credential/i);
  });

  test('retries exactly once — a second 404 does not mint a third token', async () => {
    const c = credentials();
    stubFetch([token('t1'), npmNotFound('/x'), token('t2'), npmNotFound('/x')]);

    await npmRequest(c, { path: '/x' }).catch(() => undefined);
    expect(calls.filter((call) => call.url.endsWith('/api/tokens'))).toHaveLength(2);
  });
});

describe('requests', () => {
  test('a body is sent as JSON with a content-type; a bodyless request has neither', async () => {
    const c = credentials();
    stubFetch([token('t'), () => json({ ok: true }), () => json({ ok: true })]);

    await npmRequest(c, { path: '/x', method: 'POST', body: { a: 1 } });
    await npmRequest(c, { path: '/y' });

    expect(calls[1]?.init?.method).toBe('POST');
    expect(calls[1]?.init?.headers).toMatchObject({ 'content-type': 'application/json' });
    expect(calls[1]?.init?.body).toBe('{"a":1}');
    expect(calls[2]?.init?.body).toBeUndefined();
    expect(calls[2]?.init?.headers).not.toMatchObject({ 'content-type': 'application/json' });
  });

  // NPM answers 204 to some writes. `response.json()` on an empty body throws, and that throw would
  // surface as an unshaped 500 rather than a success.
  test('204 resolves to undefined instead of failing to parse', async () => {
    const c = credentials();
    stubFetch([token('t'), () => new Response(null, { status: 204 })]);
    expect(await npmRequest(c, { path: '/x', method: 'POST' })).toBeUndefined();
  });

  test('an unreachable server is status 0, not a raw fetch error', async () => {
    const c = credentials();
    stubFetch([
      () => {
        throw new Error('connect ECONNREFUSED');
      },
    ]);

    const error = (await npmRequest(c, { path: '/x' }).catch((e) => e)) as NpmError;
    expect(error).toBeInstanceOf(NpmError);
    expect(error.status).toBe(0);
    expect(error.message).toMatch(/Cannot reach/);
  });

  test("an error body's message is preferred over the status text", async () => {
    const c = credentials();
    stubFetch([token('t'), () => json({ error: { message: 'Access list not found' } }, 400)]);

    const error = (await npmRequest(c, { path: '/x' }).catch((e) => e)) as NpmError;
    expect(error.message).toBe('Access list not found');
    expect(error.likelyAuth).toBe(false);
  });

  test('a non-JSON error body falls back to the status rather than throwing', async () => {
    const c = credentials();
    stubFetch([token('t'), () => new Response('<html>502</html>', { status: 502 })]);

    const error = (await npmRequest(c, { path: '/x' }).catch((e) => e)) as NpmError;
    expect(error).toBeInstanceOf(NpmError);
    expect(error.status).toBe(502);
  });
});

describe('probe', () => {
  test('reads the version from GET /api/ and sends no token', async () => {
    stubFetch([() => json({ status: 'OK', setup: true, version: { major: 2, minor: 15, revision: 1 } })]);

    expect(await probe('http://npm.test/')).toEqual({ version: '2.15.1', setup: true });
    expect(calls[0]?.url).toBe('http://npm.test/api/');
    expect(calls[0]?.init?.headers).toBeUndefined();
  });

  test('setup defaults to false when NPM omits it', async () => {
    stubFetch([() => json({ version: { major: 2, minor: 15, revision: 1 } })]);
    expect((await probe('http://npm.test')).setup).toBe(false);
  });

  test('something that answers but is not an NPM is rejected', async () => {
    stubFetch([() => json({ hello: 'world' })]);

    const error = (await probe('http://npm.test').catch((e) => e)) as NpmError;
    expect(error).toBeInstanceOf(NpmError);
    expect(error.message).toMatch(/not like an Nginx Proxy Manager/);
  });

  test('a non-200 names the url rather than reporting a parse failure', async () => {
    stubFetch([() => new Response('nope', { status: 500 })]);

    const error = (await probe('http://npm.test').catch((e) => e)) as NpmError;
    expect(error.status).toBe(500);
    expect(error.message).toMatch(/is that an Nginx Proxy Manager/);
  });

  test('unreachable is status 0', async () => {
    stubFetch([
      () => {
        throw new Error('ETIMEDOUT');
      },
    ]);

    const error = (await probe('http://npm.test').catch((e) => e)) as NpmError;
    expect(error.status).toBe(0);
  });
});