import test from 'node:test';
import assert from 'node:assert/strict';
import http from 'node:http';
import { once } from 'node:events';
import { validateBaseUrl, validateGeneration, listModels, generateImages } from '../lib/engine.mjs';

const apiKey = 'secret-do-not-echo';
const input = { model: 'explicit-third-party-model', prompt: 'a blue bird' };
const png = Buffer.from('iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mP8/x8AAwMCAO+jRZkAAAAASUVORK5CYII=', 'base64');
const json = (res, value) => { res.setHeader('Content-Type', 'application/json'); res.end(JSON.stringify(value)); };

async function server(t, handler) {
  const failures = [];
  const instance = http.createServer((req, res) => {
    Promise.resolve().then(() => handler(req, res)).catch(error => { failures.push(error); res.destroy(); });
  });
  instance.listen(0, '127.0.0.1');
  await once(instance, 'listening');
  t.after(async () => {
    const closed = new Promise(resolve => instance.close(resolve));
    instance.closeAllConnections();
    await closed;
    if (failures.length) throw failures[0];
  });
  return `http://127.0.0.1:${instance.address().port}`;
}

async function requestJson(req) {
  const chunks = [];
  for await (const chunk of req) chunks.push(chunk);
  return JSON.parse(Buffer.concat(chunks).toString());
}

test('base URL normalization preserves API prefix and rejects unsafe parts', () => {
  assert.equal(validateBaseUrl(' HTTPS://EXAMPLE.COM/v1/// '), 'https://example.com/v1');
  for (const value of ['', null, '/v1', 'ftp://example.com', 'https://a:b@example.com', 'https://example.com?x=1', 'https://example.com#x', 'https://example.com?', 'https://example.com#']) {
    assert.throws(() => validateBaseUrl(value));
  }
});

test('generation requires explicit fields and sends only specified supported options', () => {
  assert.deepEqual(validateGeneration({ ...input, ignored: true }), { ...input, n: 1 });
  const options = { ...input, n: 4, size: '1536x1024', quality: 'high', background: 'transparent', output_format: 'webp' };
  assert.deepEqual(validateGeneration(options), options);
  assert.equal(validateGeneration({ ...input, size: 'auto' }).size, 'auto');
  for (const change of [{ model: undefined }, { model: ' ' }, { model: 'x'.repeat(201) }, { prompt: '' }, { prompt: 'x'.repeat(32001) }, { n: 0 }, { n: 5 }, { n: 1.5 }, { n: '1' }, { n: null }, { size: '1024X1024' }, { quality: 'best' }, { background: null }, { output_format: 'gif' }]) {
    assert.throws(() => validateGeneration({ ...input, ...change }));
  }
  assert.throws(() => validateGeneration(null));
  assert.equal(validateGeneration({ model: 'm'.repeat(200), prompt: 'p'.repeat(32000) }).n, 1);
});

test('listModels uses exact API prefix, GET and bearer authentication', async t => {
  const base = await server(t, (req, res) => {
    assert.equal(req.method, 'GET');
    assert.equal(req.url, '/custom/v1/models');
    assert.equal(req.headers.authorization, `Bearer ${apiKey}`);
    json(res, { data: [{ id: 'model-b' }, { id: 'model-a' }] });
  });
  assert.deepEqual(await listModels({ baseUrl: `${base}/custom/v1///`, apiKey }), ['model-b', 'model-a']);
});

test('generation posts explicit model, omits optional defaults and decodes base64', async t => {
  let requests = 0;
  const baseUrl = await server(t, async (req, res) => {
    requests++;
    assert.equal(req.url, '/images/generations');
    assert.equal(req.method, 'POST');
    assert.equal(req.headers.authorization, `Bearer ${apiKey}`);
    assert.equal(req.headers['content-type'], 'application/json');
    assert.deepEqual(await requestJson(req), { ...input, n: 1 });
    json(res, { model: 'provider-model', data: [{ b64_json: png.toString('base64'), revised_prompt: 'revised bird' }] });
  });
  const result = await generateImages({ baseUrl, apiKey, input });
  assert.deepEqual(result, { ...input, images: [{ data: png, mediaType: 'image/png', revisedPrompt: 'revised bird' }] });
  assert.equal(requests, 1);
});

test('URL images never receive bearer auth and bytes determine media type', async t => {
  let downloads = 0;
  const imageBase = await server(t, (req, res) => {
    downloads++;
    assert.equal(req.url, '/asset?signature=public-token');
    assert.equal(req.headers.authorization, undefined);
    res.setHeader('Content-Type', 'text/html');
    res.end(png);
  });
  const baseUrl = await server(t, (req, res) => json(res, { data: [{ url: `${imageBase}/asset?signature=public-token` }] }));
  const result = await generateImages({ baseUrl, apiKey, input });
  assert.deepEqual(result.images, [{ data: png, mediaType: 'image/png' }]);
  assert.equal(downloads, 1);
});

test('recognizes JPEG, WebP and GIF signatures', async t => {
  const fixtures = [Buffer.from([255, 216, 255, 224, 0, 0]), Buffer.from('RIFF\x04\0\0\0WEBP', 'latin1'), Buffer.from('GIF89a\x01\0\x01\0', 'latin1')];
  const baseUrl = await server(t, (req, res) => json(res, { data: fixtures.map(data => ({ b64_json: data.toString('base64') })) }));
  const result = await generateImages({ baseUrl, apiKey, input: { ...input, n: 3 } });
  assert.deepEqual(result.images.map(image => image.mediaType), ['image/jpeg', 'image/webp', 'image/gif']);
});

test('HTTP errors expose status but never provider payload or key, with no retries', async t => {
  let count = 0;
  const baseUrl = await server(t, (req, res) => { count++; res.writeHead(429); res.end(`provider-private ${apiKey}`); });
  await assert.rejects(generateImages({ baseUrl, apiKey, input }), error => {
    assert.match(error.message, /HTTP 429/);
    assert.doesNotMatch(error.message, /secret-do-not-echo|provider-private/);
    assert.equal(error.cause, undefined);
    return true;
  });
  assert.equal(count, 1);
});

test('API redirects are rejected without contacting redirect destination', async t => {
  let redirected = 0;
  const target = await server(t, (req, res) => { redirected++; json(res, { data: [] }); });
  const baseUrl = await server(t, (req, res) => { res.writeHead(302, { Location: `${target}/models` }); res.end(); });
  await assert.rejects(listModels({ baseUrl, apiKey }), /network request failed/);
  assert.equal(redirected, 0);
});

test('malformed JSON and model lists are rejected without raw response echo', async t => {
  let payload = 'private-provider-body';
  const baseUrl = await server(t, (req, res) => res.end(payload));
  await assert.rejects(listModels({ baseUrl, apiKey }), /malformed JSON/);
  for (const value of [null, {}, { data: [null] }, { data: [{ id: 4 }] }, { data: [{ id: ' ' }] }]) {
    payload = JSON.stringify(value);
    await assert.rejects(listModels({ baseUrl, apiKey }), /malformed model list/);
  }
});

test('invalid base64, invalid bytes and malformed image responses fail', async t => {
  let payload;
  const baseUrl = await server(t, (req, res) => json(res, payload));
  for (const value of [null, {}, { data: [] }, { data: [null] }, { data: [{}] }, { data: [{ revised_prompt: 1, b64_json: png.toString('base64') }] }]) {
    payload = value;
    await assert.rejects(generateImages({ baseUrl, apiKey, input }));
  }
  for (const value of ['', '!!!!', 'aGk', 'aGk=\n', 'Zh==', 123, null]) {
    payload = { data: [{ b64_json: value }] };
    await assert.rejects(generateImages({ baseUrl, apiKey, input }), /invalid base64/);
  }
  payload = { data: [{ b64_json: Buffer.from('<html>not an image</html>').toString('base64') }] };
  await assert.rejects(generateImages({ baseUrl, apiKey, input }), /not a supported/);
  for (const url of ['file:///secret', 'http://user:password@localhost/image', '/relative']) {
    payload = { data: [{ url }] };
    await assert.rejects(generateImages({ baseUrl, apiKey, input }), /invalid image URL/);
  }
});

test('response Content-Length above 64 MB is rejected before buffering', async t => {
  const baseUrl = await server(t, (req, res) => { res.writeHead(200, { 'Content-Length': 64 * 1024 * 1024 + 1 }); res.flushHeaders(); });
  await assert.rejects(listModels({ baseUrl, apiKey }), /64 MB response limit/);
});

test('streamed responses enforce 64 MB even without Content-Length', async t => {
  const block = Buffer.alloc(1024 * 1024, 32);
  const baseUrl = await server(t, async (req, res) => {
    for (let i = 0; i < 65; i++) {
      if (res.destroyed) return;
      if (!res.write(block)) {
        await new Promise(resolve => {
          const done = () => { res.off('drain', done); res.off('close', done); resolve(); };
          res.once('drain', done);
          res.once('close', done);
        });
      }
    }
    res.end();
  });
  await assert.rejects(listModels({ baseUrl, apiKey }), /64 MB response limit/);
});

test('caller abort interrupts pending API request and sanitizes abort reason', async t => {
  const controller = new AbortController();
  const baseUrl = await server(t, () => controller.abort(new Error(apiKey)));
  await assert.rejects(listModels({ baseUrl, apiKey, signal: controller.signal }), /^Error: Request aborted\.$/);
});

test('caller abort also interrupts image download', async t => {
  const controller = new AbortController();
  const imageBase = await server(t, (req, res) => { res.writeHead(200); res.write(png.subarray(0, 4)); controller.abort(); });
  const baseUrl = await server(t, (req, res) => json(res, { data: [{ url: `${imageBase}/slow` }] }));
  await assert.rejects(generateImages({ baseUrl, apiKey, input, signal: controller.signal }), /Request aborted/);
});

test('specified generation options are preserved on the wire', async t => {
  const specified = { ...input, n: 2, size: 'auto', quality: 'hd', background: 'opaque', output_format: 'jpeg' };
  const baseUrl = await server(t, async (req, res) => {
    assert.deepEqual(await requestJson(req), specified);
    json(res, { data: [{ b64_json: png.toString('base64') }] });
  });
  await generateImages({ baseUrl, apiKey, input: specified });
});

test('180 second timeout aborts a stalled request', async t => {
  const baseUrl = await server(t, () => {});
  const original = globalThis.setTimeout;
  let configuredTimeout;
  t.mock.method(globalThis, 'setTimeout', (callback, milliseconds, ...args) => {
    if (milliseconds === 180_000) {
      configuredTimeout = milliseconds;
      return original(callback, 20, ...args);
    }
    return original(callback, milliseconds, ...args);
  });
  await assert.rejects(listModels({ baseUrl, apiKey }), /timed out after 180 seconds/);
  assert.equal(configuredTimeout, 180_000);
});

test('pre-aborted signal does not send an API request', async t => {
  let count = 0;
  const baseUrl = await server(t, (req, res) => { count++; json(res, { data: [] }); });
  await assert.rejects(listModels({ baseUrl, apiKey, signal: AbortSignal.abort(apiKey) }), /Request aborted/);
  assert.equal(count, 0);
});