import { describe, it, expect, beforeAll, afterAll } from 'vitest';
import { WebSocket } from 'ws';
import Fastify from 'fastify';
import websocketPlugin from '@fastify/websocket';
import {
  activeGameCount, chooseSide, createGame, attachBotDriver,
} from '../../src/games.js';
import { attachSocket } from '../../src/ws.js';
import { createGameSchema } from '../../src/validation.js';
import { CasualBrain, BotDriver } from '../../src/bot/index.js';
import type { ServerMessage } from '@blind-chess/shared';

let app: ReturnType<typeof Fastify>;
let baseUrl = '';

beforeAll(async () => {
  app = Fastify({ logger: false });
  await app.register(websocketPlugin);
  app.get('/api/health', async () => ({ ok: true, activeGames: activeGameCount() }));
  app.post('/api/games', async (req, reply) => {
    const parsed = createGameSchema.safeParse(req.body);
    if (!parsed.success) { reply.code(400); return { error: 'malformed' }; }
    const { mode, side, highlightingEnabled, vsAi } = parsed.data;
    if (vsAi && vsAi.brain === 'recon') {
      reply.code(503); return { error: 'ai_offline' };
    }
    const creatorSide = chooseSide(side);
    const { game, creatorToken } = createGame({ mode, creatorSide, highlightingEnabled, vsAi });
    if (vsAi && game.aiOpponent) {
      const brain = new CasualBrain({ seed: 1 });
      const driver = new BotDriver({ game, brain, color: game.aiOpponent.color });
      await driver.init();
      attachBotDriver(game.id, driver);
    }
    const joinUrl = vsAi ? null : `http://placeholder/g/${game.id}`;
    return { gameId: game.id, creatorToken, creatorColor: creatorSide, joinUrl };
  });
  app.get('/ws', { websocket: true }, (socket) => {
    const raw = (socket as unknown as { socket?: unknown }).socket ?? socket;
    attachSocket(raw as never);
  });
  await app.listen({ port: 0, host: '127.0.0.1' });
  const addr = app.server.address();
  if (typeof addr !== 'object' || !addr) throw new Error('no address');
  baseUrl = `http://127.0.0.1:${addr.port}`;
});

afterAll(async () => { await app.close(); });

interface Client {
  ws: WebSocket;
  msgs: ServerMessage[];
  waitFor: (pred: (m: ServerMessage) => boolean, timeoutMs?: number) => Promise<ServerMessage>;
  send: (m: unknown) => void;
  close: () => void;
}

function makeClient(gameId: string): Promise<Client> {
  return new Promise((resolve, reject) => {
    const ws = new WebSocket(baseUrl.replace('http', 'ws') + `/ws?game=${gameId}`);
    const msgs: ServerMessage[] = [];
    const waiters: Array<{ pred: (m: ServerMessage) => boolean;
                          resolve: (m: ServerMessage) => void;
                          reject: (e: Error) => void;
                          timer: NodeJS.Timeout }> = [];
    ws.on('message', (data) => {
      const m = JSON.parse(data.toString()) as ServerMessage;
      msgs.push(m);
      for (const w of [...waiters]) {
        if (w.pred(m)) {
          clearTimeout(w.timer);
          waiters.splice(waiters.indexOf(w), 1);
          w.resolve(m);
        }
      }
    });
    ws.on('open', () => resolve({
      ws, msgs,
      waitFor: (pred, timeoutMs = 2000) => new Promise<ServerMessage>((res, rej) => {
        const existing = msgs.find(pred);
        if (existing) return res(existing);
        const timer = setTimeout(() => rej(new Error('waitFor timeout')), timeoutMs);
        waiters.push({ pred, resolve: res, reject: rej, timer });
      }),
      send: (m) => ws.send(JSON.stringify(m)),
      close: () => ws.close(),
    }));
    ws.on('error', reject);
  });
}

async function createAiGame(side: 'w' | 'b', mode: 'blind' | 'vanilla' = 'vanilla'): Promise<{ gameId: string; creatorToken: string }> {
  const res = await fetch(`${baseUrl}/api/games`, {
    method: 'POST',
    headers: { 'content-type': 'application/json' },
    body: JSON.stringify({ mode, side, highlightingEnabled: false, vsAi: { brain: 'casual' } }),
  });
  return await res.json();
}

describe('AI game / Casual', () => {
  it('human as black: bot moves first as white', async () => {
    const { gameId, creatorToken } = await createAiGame('b');
    const human = await makeClient(gameId);
    human.send({ type: 'hello', gameId, token: creatorToken });
    const joined = await human.waitFor((m) => m.type === 'joined');
    expect(joined.type === 'joined' && joined.you).toBe('b');
    if (joined.type === 'joined') {
      expect(joined.aiOpponent).toEqual({ color: 'w', brain: 'casual' });
    }

    // Bot's opening move should arrive as an update (bot moves first as white).
    const botMoved = await human.waitFor((m) =>
      m.type === 'update' && m.newAnnouncements.some((a) => a.text === 'white_moved'),
      2000,
    );
    expect(botMoved.type).toBe('update');
    human.close();
  });

  it('human as white: human moves first, bot replies', async () => {
    const { gameId, creatorToken } = await createAiGame('w');
    const human = await makeClient(gameId);
    human.send({ type: 'hello', gameId, token: creatorToken });
    await human.waitFor((m) => m.type === 'joined');

    // Human plays e2e4 (arm + commit).
    human.send({ type: 'commit', from: 'e2' });
    await human.waitFor((m) => m.type === 'update' && m.touchedPiece === 'e2');
    human.send({ type: 'commit', from: 'e2', to: 'e4' });

    // Bot replies as black.
    const botMoved = await human.waitFor((m) =>
      m.type === 'update' && m.newAnnouncements.some((a) => a.text === 'black_moved'),
    );
    expect(botMoved.type).toBe('update');

    // After bot reply, it's white's turn again.
    if (botMoved.type === 'update') {
      expect(botMoved.view.toMove).toBe('w');
    }
    human.close();
  });

  it('bot alternate exchanges: game doesn\'t end prematurely', async () => {
    // One human-bot exchange: human plays white e2-e4, bot replies as black.
    const { gameId, creatorToken } = await createAiGame('w');
    const human = await makeClient(gameId);
    human.send({ type: 'hello', gameId, token: creatorToken });
    const joined = await human.waitFor((m) => m.type === 'joined');
    expect(joined.type === 'joined' && joined.gameStatus).toBe('active');

    human.send({ type: 'commit', from: 'e2' });
    await human.waitFor((m) => m.type === 'update' && m.touchedPiece === 'e2');
    human.send({ type: 'commit', from: 'e2', to: 'e4' });
    const botReplied = await human.waitFor((m) =>
      m.type === 'update' &&
      (m.gameStatus === 'finished' || m.view.toMove === 'w'),
      2000,
    );
    // Game should still be active after one exchange.
    expect(botReplied.type === 'update' && botReplied.gameStatus).toBe('active');
    human.close();
  });

  it('joinUrl is null for AI games', async () => {
    const res = await fetch(`${baseUrl}/api/games`, {
      method: 'POST',
      headers: { 'content-type': 'application/json' },
      body: JSON.stringify({ mode: 'blind', side: 'w', highlightingEnabled: false, vsAi: { brain: 'casual' } }),
    });
    const json = await res.json() as { joinUrl: string | null };
    expect(json.joinUrl).toBeNull();
  });

  it('recon brain returns 503 in Phase 1', async () => {
    const res = await fetch(`${baseUrl}/api/games`, {
      method: 'POST',
      headers: { 'content-type': 'application/json' },
      body: JSON.stringify({ mode: 'blind', side: 'w', highlightingEnabled: false, vsAi: { brain: 'recon' } }),
    });
    expect(res.status).toBe(503);
  });
});