/**
 * The Studio page image reaching the model, per provider kind, end to end:
 * the whole app (buildApp, every global guard, the Zod pipe, the response
 * contracts, the real MCP registry, the real agent and vision, the renders
 * route and its registry) with the provider's own adapter (Anthropic
 * Messages, Chat Completions, the Responses API of a ChatGPT plan) talking to
 * a scripted fetch instead of the network.
 *
 * What is stood in for, and why: the connection the turn resolves names the
 * kind under test (an instance can only point a `custom` connection at
 * loopback, so the kind, model and host are put on the saved one), and the
 * client is that kind's real adapter on the scripted fetch. The Studio tab is
 * the test reading the turn's stream as it comes: each render request it
 * reads is answered at once with a page image uploaded to the renders route,
 * as the tab does after drawing the page. The user's acknowledgement of page
 * images goes through its own route. Everything between, from the look to
 * the request on the wire, is the real code.
 *
 * Pinned: a model that reads images gets the uploaded page, byte for byte,
 * where its provider reads it (inside the tool_result for Anthropic, a user
 * message after the step's tool answers for Chat Completions and the
 * Responses API); the turn streams one render request and keeps the image's
 * size, never its bytes, in the stream and in the stored thread. A kind that
 * cannot be told to read images (OpenRouter) and a connection the user did
 * not acknowledge for page images ask for no image and check the page on its
 * description.
 */
import { buildApp } from '../../src/bootstrap';
import { AiChatClientService } from '../../src/nest/ai-connections/ai-chat-client.service';
import { aiHostOf } from '../../src/nest/ai-connections/ai-connections.constants';
import { AiConnectionsService } from '../../src/nest/ai-connections/ai-connections.service';
import type { ResolvedAiConnection } from '../../src/nest/ai-connections/ai-connections.types';
import { AnthropicMessagesClient } from '../../src/nest/ai-connections/providers/anthropic-messages.client';
import { OpenAiChatClient } from '../../src/nest/ai-connections/providers/openai-chat.client';
import { OpenAiResponsesClient } from '../../src/nest/ai-connections/providers/openai-responses.client';
import type { AiFetch } from '../../src/nest/ai-connections/providers/provider-http';
import { withRequestContext } from '../../src/nest/database/request-context';
import { JourneyBookEditService } from '../../src/nest/journey/journey-book-edit.service';
import { makeJourney } from '../helpers/factories/journeys';
import { setAddonEnabled } from '../helpers/factories/settings';
import { makeUser } from '../helpers/factories/users';
import { resetRateLimits } from '../helpers/test-db';
import { sessionCookie } from './harness';
import { MikroORM } from '@mikro-orm/core';
import type { INestApplication } from '@nestjs/common';
import type { AiConnectionKind, UiStreamChunk } from '@trek/shared';

import { createServer, type IncomingMessage, type Server as HttpServer, type ServerResponse } from 'node:http';
import type { AddressInfo } from 'node:net';
import request from 'supertest';
import { afterAll, beforeAll, beforeEach, describe, expect, it, vi } from 'vitest';

// ── The page the Studio tab draws ────────────────────────────────────────────

/**
 * A JPEG of 1280 x 640 as far as the renders route reads one (its frame
 * header), with a body of its own, so its bytes are told apart from anything
 * else in a request.
 */
function drawnPage(): Buffer {
  const header = Buffer.alloc(16);
  Buffer.from([0xff, 0xd8, 0xff, 0xc0, 0x00, 0x11, 0x08]).copy(header, 0);
  header.writeUInt16BE(640, 7);
  header.writeUInt16BE(1280, 9);
  return Buffer.concat([header, Buffer.from('the studio page as drawn, '.repeat(3))]);
}

const PAGE = drawnPage();
const BASE64 = PAGE.toString('base64');
const DATA_URL = `data:image/jpeg;base64,${BASE64}`;

// ── The provider, per kind: what each adapter streams back ───────────────────

/** An SSE answer from whole events, as the adapters read it. */
function sse(events: unknown[]): Response {
  const text = events.map((e) => `data: ${typeof e === 'string' ? e : JSON.stringify(e)}\n\n`).join('');
  return new Response(text, { status: 200, headers: { 'content-type': 'text/event-stream' } });
}

type Wire = 'anthropic' | 'chat' | 'responses';

const PREVIEW = 'preview_book_page';

/** The model looks at a page with one call, as each provider streams a tool call. */
function lookAt(wire: Wire, args: Record<string, unknown>): Response {
  const json = JSON.stringify(args);
  if (wire === 'anthropic') {
    return sse([
      { type: 'message_start', message: { usage: { input_tokens: 10, output_tokens: 1 } } },
      {
        type: 'content_block_start',
        index: 0,
        content_block: { type: 'tool_use', id: 'call_look', name: PREVIEW },
      },
      { type: 'content_block_delta', index: 0, delta: { type: 'input_json_delta', partial_json: json } },
      { type: 'content_block_stop', index: 0 },
      { type: 'message_delta', delta: { stop_reason: 'tool_use' }, usage: { output_tokens: 20 } },
      { type: 'message_stop' },
    ]);
  }
  if (wire === 'chat') {
    const call = { index: 0, id: 'call_look', type: 'function', function: { name: PREVIEW, arguments: json } };
    return sse([
      { choices: [{ index: 0, delta: { tool_calls: [call] } }] },
      { choices: [{ index: 0, delta: {}, finish_reason: 'tool_calls' }] },
      { choices: [], usage: { prompt_tokens: 12, completion_tokens: 4 } },
      '[DONE]',
    ]);
  }
  const item = { type: 'function_call', id: 'fc_1', call_id: 'call_look', name: PREVIEW, arguments: json };
  return sse([
    { type: 'response.created', response: {} },
    { type: 'response.output_item.done', item: { ...item, namespace: 'trek' } },
    { type: 'response.completed', response: { usage: { input_tokens: 50, output_tokens: 6 } } },
  ]);
}

/** The model's last words, as each provider streams text. */
function says(wire: Wire, text: string): Response {
  if (wire === 'anthropic') {
    return sse([
      { type: 'message_start', message: { usage: { input_tokens: 10, output_tokens: 1 } } },
      { type: 'content_block_start', index: 0, content_block: { type: 'text', text: '' } },
      { type: 'content_block_delta', index: 0, delta: { type: 'text_delta', text } },
      { type: 'content_block_stop', index: 0 },
      { type: 'message_delta', delta: { stop_reason: 'end_turn' }, usage: { output_tokens: 4 } },
      { type: 'message_stop' },
    ]);
  }
  if (wire === 'chat') {
    return sse([
      { choices: [{ index: 0, delta: { content: text } }] },
      { choices: [{ index: 0, delta: {}, finish_reason: 'stop' }] },
      { choices: [], usage: { prompt_tokens: 12, completion_tokens: 4 } },
      '[DONE]',
    ]);
  }
  return sse([
    { type: 'response.created', response: {} },
    { type: 'response.output_text.delta', delta: text },
    { type: 'response.completed', response: { usage: { input_tokens: 50, output_tokens: 6 } } },
  ]);
}

/** What the adapters sent, request by request, and what they are answered next. */
const wire = { bodies: [] as Array<Record<string, unknown>>, answers: [] as Response[] };

const scripted: AiFetch = async (_url, init) => {
  wire.bodies.push(JSON.parse(String(init.body)) as Record<string, unknown>);
  const next = wire.answers.shift();
  if (!next) throw new Error('the scripted provider has no answer left');
  return next;
};

/** The real adapter of a kind, on the scripted fetch. */
function adapterFor(kind: AiConnectionKind, model: string) {
  if (kind === 'anthropic') return new AnthropicMessagesClient(model, 'sk-ant-test', scripted);
  if (kind === 'chatgpt') return new OpenAiResponsesClient(model, async () => 'at-test', scripted);
  return new OpenAiChatClient(kind, model, 'https://provider.invalid/v1', 'sk-test', scripted);
}

// ── A loopback server, only so the instance connection can be saved ─────────

async function answerModels(req: IncomingMessage, res: ServerResponse): Promise<void> {
  if (req.method === 'GET' && req.url?.startsWith('/api/tags')) {
    res.writeHead(200, { 'content-type': 'application/json' });
    res.end(JSON.stringify({ models: [{ name: 'fake-model', size: 1 }] }));
    return;
  }
  res.writeHead(404).end();
}

// ── The app ──────────────────────────────────────────────────────────────────

let nestApp: INestApplication;
let orm: MikroORM;
let fake: HttpServer;
let books: JourneyBookEditService;
let connections: AiConnectionsService;
let chatClients: AiChatClientService;

beforeAll(async () => {
  fake = createServer((req, res) => {
    answerModels(req, res).catch(() => res.destroy());
  });
  await new Promise<void>((resolve) => fake.listen(0, '127.0.0.1', resolve));
  nestApp = await buildApp();
  orm = nestApp.get(MikroORM);
  books = nestApp.get(JourneyBookEditService);
  connections = nestApp.get(AiConnectionsService);
  chatClients = nestApp.get(AiChatClientService);
  await setAddonEnabled(orm, 'ai_assistant', true);
  await setAddonEnabled(orm, 'journey', true);
  const adminId = (await makeUser(orm, { role: 'admin' })).user.id;
  const { port } = fake.address() as AddressInfo;
  const res = await request(nestApp.getHttpServer())
    .put('/api/admin/ai/connection')
    .set('Cookie', sessionCookie(adminId))
    .send({ kind: 'custom', baseUrl: `http://127.0.0.1:${port}/v1`, model: 'fake-model' });
  expect(res.status).toBe(200);
});

beforeEach(async () => {
  await resetRateLimits(nestApp);
  vi.restoreAllMocks();
  wire.bodies = [];
  wire.answers = [];
});

afterAll(async () => {
  vi.restoreAllMocks();
  await nestApp.close();
  await new Promise<void>((resolve) => fake.close(() => resolve()));
});

// ── Helpers ──────────────────────────────────────────────────────────────────

const CTX = { locale: 'en', timeZone: 'Europe/Lisbon' };

const ofType = <T extends UiStreamChunk['type']>(chunks: UiStreamChunk[], type: T) =>
  chunks.filter((chunk): chunk is Extract<UiStreamChunk, { type: T }> => chunk.type === type);

/**
 * A turn's stream, read as it arrives: `onChunk` sees every chunk the moment
 * it comes, as the Studio tab holding the stream does.
 */
async function stream(
  path: string,
  userId: number,
  body: object,
  onChunk: (chunk: UiStreamChunk) => void,
): Promise<UiStreamChunk[]> {
  const chunks: UiStreamChunk[] = [];
  const res = await request(nestApp.getHttpServer())
    .post(path)
    .set('Cookie', sessionCookie(userId))
    .send(body)
    .buffer(true)
    .parse((s, done) => {
      let pending = '';
      s.setEncoding('utf8');
      s.on('data', (text: string) => {
        pending += text;
        const events = pending.split('\n\n');
        pending = events.pop() ?? '';
        for (const event of events) {
          if (!event.startsWith('data: ') || event === 'data: [DONE]') continue;
          const chunk = JSON.parse(event.slice('data: '.length)) as UiStreamChunk;
          chunks.push(chunk);
          onChunk(chunk);
        }
      });
      s.on('end', () => done(null, ''));
    });
  expect(res.status).toBe(200);
  return chunks;
}

/**
 * The Studio tab of a turn: every render request it reads is answered at
 * once with the drawn page, uploaded to the renders route with the page and
 * the version it was asked for. `uploads` holds each upload's status.
 */
function studioTab(journeyId: number, userId: number) {
  const uploads: Array<Promise<number>> = [];
  const onChunk = (chunk: UiStreamChunk) => {
    const [asked] = ofType([chunk], 'data-trek-render-request');
    if (!asked) return;
    const { threadId, requestId, spreadId, bookVersion } = asked.data;
    const upload = request(nestApp.getHttpServer())
      .post(`/api/journeys/${journeyId}/assistant/threads/${threadId}/renders/${requestId}`)
      .set('Cookie', sessionCookie(userId))
      .field('bookVersion', String(bookVersion))
      .field('spreadId', spreadId)
      .attach('image', PAGE, { filename: 'page.jpg', contentType: 'image/jpeg' });
    uploads.push(upload.then((res) => res.status));
  };
  return { onChunk, uploads };
}

/** A user with a journey of their own and a blank book in it: its double page is `inner`. */
async function ownerWithBook() {
  const { user } = await makeUser(orm);
  const journey = await makeJourney(orm, user.id, { title: 'Portugal by train' });
  // A service called from the test, not through a route, needs the request context a route gets.
  const created = await withRequestContext(orm, () => books.createBook(journey.id, user.id, {}));
  const inner = created.pages.find((page) => page.role === 'inner')?.id ?? 'no inner page';
  return { userId: user.id, journeyId: journey.id, inner, base: `/api/journeys/${journey.id}/assistant` };
}

/**
 * The turn runs on `kind`'s real adapter as if the user's connection were of
 * that kind, model and host; with `acked` the user let it receive page images
 * first, through the route the Studio's notice calls.
 */
async function runOn(kind: AiConnectionKind, model: string, userId: number, acked: boolean) {
  const host = aiHostOf(kind, null);
  const resolve = connections.resolveForUser.bind(connections);
  vi.spyOn(connections, 'resolveForUser').mockImplementation(async (id: number): Promise<ResolvedAiConnection> => ({
    ...(await resolve(id)),
    kind,
    model,
    host,
  }));
  vi.spyOn(chatClients, 'create').mockImplementation(() => adapterFor(kind, model));
  if (!acked) return;
  const ack = await request(nestApp.getHttpServer())
    .post('/api/ai/privacy-ack')
    .set('Cookie', sessionCookie(userId))
    .send({ kind, host, scope: 'studio_images' });
  expect(ack.status).toBe(200);
}

/** One Studio turn on `kind`: the model previews warmer paper on the inner page, then answers. */
async function lookTurn(kind: AiConnectionKind, model: string, via: Wire, acked = true) {
  const j = await ownerWithBook();
  await runOn(kind, model, j.userId, acked);
  const tab = studioTab(j.journeyId, j.userId);
  const warmer = { spreadId: j.inner, ops: [{ op: 'background', color: '#f4efe6' }] };
  wire.answers = [lookAt(via, warmer), says(via, 'Fine.')];
  const body = { ...CTX, threadId: null, text: 'Warmer?', renders: true };
  const turn = await stream(`${j.base}/chat`, j.userId, body, tab.onChunk);
  expect(wire.bodies).toHaveLength(2);
  return { j, turn, uploads: await Promise.all(tab.uploads), sent: wire.bodies[1] ?? {} };
}

/** A list in a request body, empty when that key holds none. */
const listIn = (body: Record<string, unknown>, key: string): Array<Record<string, unknown>> => {
  const value = body[key];
  return Array.isArray(value) ? (value as Array<Record<string, unknown>>) : [];
};

/** The look's answer as the model read it, in either shape (a tool message, a tool_result block), as JSON. */
function lookAnswer(sent: Record<string, unknown>): string {
  const messages = listIn(sent, 'messages');
  const blocks = messages.flatMap((message) =>
    Array.isArray(message.content) ? (message.content as Array<Record<string, unknown>>) : [],
  );
  const answer = [...messages, ...blocks].find(
    (item) => item.tool_call_id === 'call_look' || (item.type === 'tool_result' && item.tool_use_id === 'call_look'),
  );
  return JSON.stringify(answer?.content ?? null);
}

/** The Studio turn as the test drove it: whose it is and where. */
interface Studio {
  userId: number;
  inner: string;
  base: string;
}

/**
 * The turn asked the Studio once for the page, the tab's upload was taken,
 * and the image's size was kept, never its bytes: not in the stream, not in
 * the thread as stored.
 */
async function expectOneImage(j: Studio, turn: UiStreamChunk[], uploads: number[]) {
  const [asked, ...more] = ofType(turn, 'data-trek-render-request');
  expect(more).toEqual([]);
  expect(asked?.data).toMatchObject({ spreadId: j.inner, bookVersion: 1, hiddenPhotoIds: [] });
  expect(uploads).toEqual([200]);
  const [view] = ofType(turn, 'data-trek-page-view');
  expect(view?.data).toMatchObject({ spreadId: j.inner, bookVersion: 1, width: 1280, height: 640, bytes: PAGE.length });
  expect(JSON.stringify(ofType(turn, 'tool-output-available'))).toContain('is attached');
  expect(JSON.stringify(turn)).not.toContain(BASE64);
  const threadId = ofType(turn, 'data-trek-thread')[0]?.data.threadId ?? 0;
  const stored = await request(nestApp.getHttpServer())
    .get(`${j.base}/threads/${threadId}`)
    .set('Cookie', sessionCookie(j.userId));
  expect(stored.status).toBe(200);
  expect(JSON.stringify(stored.body)).toContain(`"bytes":${PAGE.length}`);
  expect(JSON.stringify(stored.body)).not.toContain(BASE64);
}

/** The turn asked for no image, and the model checked the page on its description and findings. */
function expectWordsOnly(inner: string, turn: UiStreamChunk[], uploads: number[], sent: Record<string, unknown>) {
  expect(ofType(turn, 'data-trek-render-request')).toEqual([]);
  expect(uploads).toEqual([]);
  const [view] = ofType(turn, 'data-trek-page-view');
  expect(view?.data).toMatchObject({ spreadId: inner, width: null, height: null, bytes: null });
  expect(JSON.stringify(sent)).not.toContain(BASE64);
  expect(lookAnswer(sent)).toContain('Findings');
  expect(lookAnswer(sent)).not.toContain('is attached');
}

// ── Cases ────────────────────────────────────────────────────────────────────

describe('the Studio page image per provider kind', () => {
  it('ASTIMGE2E-001: Anthropic gets the uploaded page as an image block inside the tool_result', async () => {
    const { j, turn, uploads, sent } = await lookTurn('anthropic', 'claude-sonnet-4-5', 'anthropic');
    await expectOneImage(j, turn, uploads);
    const results = listIn(sent, 'messages').flatMap((message) =>
      Array.isArray(message.content) ? (message.content as Array<Record<string, unknown>>) : [],
    );
    const result = results.find((block) => block.type === 'tool_result' && block.tool_use_id === 'call_look');
    expect(result?.content).toEqual([
      { type: 'text', text: expect.stringContaining('is attached') },
      { type: 'image', source: { type: 'base64', media_type: 'image/jpeg', data: BASE64 } },
    ]);
  });

  /** Chat Completions: the tool answer stays text, the page follows in a user message of its own. */
  async function expectChatImage(kind: AiConnectionKind, model: string) {
    const { j, turn, uploads, sent } = await lookTurn(kind, model, 'chat');
    await expectOneImage(j, turn, uploads);
    const messages = listIn(sent, 'messages');
    const answer = messages.findIndex((m) => m.role === 'tool' && m.tool_call_id === 'call_look');
    expect(answer).toBeGreaterThan(0);
    expect(typeof messages[answer]?.content).toBe('string');
    expect(messages[answer + 1]).toEqual({
      role: 'user',
      content: [
        { type: 'text', text: 'The image the call preview_book_page (call_look) produced:' },
        { type: 'image_url', image_url: { url: DATA_URL, detail: 'high' } },
      ],
    });
  }

  it('ASTIMGE2E-002: OpenAI keeps the tool answer text and sends the page in a user message after it', async () => {
    await expectChatImage('openai', 'gpt-4o');
  });

  it('ASTIMGE2E-003: a ChatGPT plan (Responses API) gets the output as text, then the page as an image', async () => {
    const { j, turn, uploads, sent } = await lookTurn('chatgpt', 'gpt-5', 'responses');
    await expectOneImage(j, turn, uploads);
    const input = listIn(sent, 'input');
    const output = input.findIndex((item) => item.type === 'function_call_output' && item.call_id === 'call_look');
    expect(output).toBeGreaterThan(0);
    expect(typeof input[output]?.output).toBe('string');
    expect(input[output + 1]).toEqual({
      type: 'message',
      role: 'user',
      content: [
        { type: 'input_text', text: 'The image the call preview_book_page (call_look) produced:' },
        { type: 'input_image', image_url: DATA_URL, detail: 'high' },
      ],
    });
  });

  it('ASTIMGE2E-004: OpenRouter (vision unknown by id) asks for no image and reads the page in words', async () => {
    const { j, turn, uploads, sent } = await lookTurn('openrouter', 'some-lab/some-model', 'chat');
    expectWordsOnly(j.inner, turn, uploads, sent);
    expect(JSON.stringify(listIn(sent, 'messages'))).not.toContain('image_url');
  });

  it('ASTIMGE2E-005: Gemini, on the same Chat Completions shape, gets the page the same way', async () => {
    await expectChatImage('gemini', 'gemini-2.5-flash');
  });

  it('ASTIMGE2E-006: a model that reads images gets none while the user has not acknowledged page images', async () => {
    const { j, turn, uploads, sent } = await lookTurn('anthropic', 'claude-sonnet-4-5', 'anthropic', false);
    expectWordsOnly(j.inner, turn, uploads, sent);
    expect(JSON.stringify(listIn(sent, 'messages'))).not.toContain('"type":"image"');
  });
});