/**
 * The HTTP layer, driven end to end over a real socket. `startServer` binds port 0 on a temp data
 * directory; nothing here reads the built site, so `distDir` is a directory with nothing in it.
 *
 * Added in v0.8.4, when four faults in `http.ts` turned out to be uncovered because no test had ever
 * stood the server up: a leaver's token surviving the leave, an unbounded body, a torn save under
 * concurrent moves, and a crash on an error after the SSE head was sent.
 */

import { describe, it, after, before } from 'node:test';
import assert from 'node:assert/strict';
import { mkdtemp, readFile, rm } from 'node:fs/promises';
import { tmpdir } from 'node:os';
import { join } from 'node:path';
import type { Server } from 'node:http';

import type { GameConfig } from '../../src/engine/state.ts';
import { startServer } from '../../src/server/http.ts';

const SECRET = 'test-secret';
const config: GameConfig = {
  mode: 'competitive',
  days: 5,
  minCombinedRevenue: 0,
  maxCollisionsPerDay: 0,
  maxCollisionsTotal: 0,
  pvpCardsAllowed: false,
  houseRules: { startingOffice: 'whistlePost' },
  optionalRules: { reducedVisibility: false, employeeRotation: false, emergencyToolbox: false },
};

let server: Server;
let base = '';
let dataDir = '';

before(async () => {
  dataDir = await mkdtemp(join(tmpdir(), 'station-master-http-'));
  server = startServer({
    port: 0,
    bindAddress: '127.0.0.1',
    joinSecret: SECRET,
    distDir: dataDir,
    dataDir,
    engineVersion: 'test',
    initialGames: new Map(),
    initialLobbies: new Map(),
    initialSessions: new Map(),
  });
  await new Promise<void>((resolve) => server.once('listening', resolve));
  const addr = server.address();
  if (!addr || typeof addr === 'string') throw new Error('no port');
  base = `http://127.0.0.1:${addr.port}`;
});

after(async () => {
  server.closeAllConnections();
  await new Promise<void>((resolve) => server.close(() => resolve()));
  // A write queued behind the last move may still be landing; retry rather than race it.
  await rm(dataDir, { recursive: true, force: true, maxRetries: 10, retryDelay: 50 });
});

const post = async (path: string, body: unknown): Promise<{ status: number; json: Record<string, unknown> }> => {
  const res = await fetch(base + path, { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify(body) });
  return { status: res.status, json: (await res.json()) as Record<string, unknown> };
};
const get = async (path: string): Promise<number> => (await fetch(base + path)).status;

/** The first SSE message on a stream, then the stream is dropped. */
async function firstPush(path: string): Promise<Record<string, unknown>> {
  const res = await fetch(base + path);
  assert.equal(res.status, 200, `${path} answered ${res.status}`);
  const reader = res.body!.getReader();
  const decoder = new TextDecoder();
  let buffer = '';
  for (;;) {
    const { value, done } = await reader.read();
    if (done) throw new Error('stream ended before a push');
    buffer += decoder.decode(value, { stream: true });
    const m = /data: (.*)\n\n/.exec(buffer);
    if (m) {
      await reader.cancel();
      return JSON.parse(m[1]!) as Record<string, unknown>;
    }
  }
}

type Seat = { token: string; player: number; gameId: string; gameCode: string };

async function table(): Promise<{ host: Seat; guest: Seat }> {
  const created = await post('/api/lobby/create', { secret: SECRET, config, displayName: 'Host', players: 2 });
  assert.equal(created.status, 200, JSON.stringify(created.json));
  const host = created.json as unknown as Seat;
  const joined = await post('/api/lobby/join', { secret: SECRET, gameCode: host.gameCode, displayName: 'Guest' });
  assert.equal(joined.status, 200, JSON.stringify(joined.json));
  return { host, guest: joined.json as unknown as Seat };
}

describe('the HTTP layer (v0.8.4)', () => {
  it('revokes the token of a player who leaves, so it cannot play the seat the next arrival takes', async () => {
    const { host, guest } = await table();
    const left = await post('/api/lobby/leave', { token: guest.token });
    assert.equal(left.status, 200);
    // The leaver's token is dead at once — for the lobby and for the game that follows.
    assert.equal(await get(`/api/lobby/stream?token=${guest.token}`), 404, 'a leaver can still watch the lobby');
    const again = await post('/api/lobby/join', { secret: SECRET, gameCode: host.gameCode, displayName: 'Newcomer' });
    assert.equal(again.status, 200);
    assert.equal(again.json['player'], guest.player, 'the vacated chair was not the one re-offered');
    const started = await post('/api/lobby/start', { token: host.token });
    assert.equal(started.status, 200, JSON.stringify(started.json));
    assert.equal(await get(`/api/session?token=${guest.token}`), 404, 'the leaver still holds a seat in the running game');
    assert.equal(await get(`/api/stream?token=${guest.token}`), 404, "the leaver can read the newcomer's stream");
    const move = await post(`/api/intent?token=${guest.token}`, { seq: 1, intent: { type: 'localOps.choose', option: 'draw' } });
    assert.equal(move.status, 404, 'the leaver can move for the newcomer');
    // And the newcomer's own token works.
    assert.equal(await get(`/api/session?token=${again.json['token'] as string}`), 200);
    // On disk too, so a restart does not hand the seat back.
    const onDisk = JSON.parse(await readFile(join(dataDir, 'games', host.gameId, 'sessions.json'), 'utf8')) as { token: string }[];
    assert.ok(!onDisk.some((s) => s.token === guest.token), 'the revoked token is still in sessions.json');
  });

  it('lets the host remove a player, revoking that token the same way', async () => {
    const { host, guest } = await table();
    const removed = await post('/api/lobby/leave', { token: host.token, seat: guest.player });
    assert.equal(removed.status, 200, JSON.stringify(removed.json));
    assert.equal(await get(`/api/lobby/stream?token=${guest.token}`), 404);
    assert.equal(await get(`/api/lobby/stream?token=${host.token}`), 200, 'the host lost their own seat');
  });

  it('refuses an oversized body before reading it, and a malformed one with 400', async () => {
    const big = await fetch(base + '/api/claim', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ code: 'x'.repeat(200_000) }),
    });
    assert.equal(big.status, 413);
    const bad = await fetch(base + '/api/lobby/join', { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: '{not json' });
    assert.equal(bad.status, 400);
    const notObject = await fetch(base + '/api/lobby/join', { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: 'null' });
    assert.equal(notObject.status, 400);
  });

  it('tells a connecting seat where its intent count stands', async () => {
    const { host, guest } = await table();
    assert.equal((await post('/api/lobby/start', { token: host.token })).status, 200);
    const hostPush = await firstPush(`/api/stream?token=${host.token}`);
    const actor = hostPush['menu'] !== null ? host : guest;
    assert.equal(hostPush['lastSeq'], 0);
    const move = await post(`/api/intent?token=${actor.token}`, { seq: 1, intent: { type: 'localOps.choose', option: 'draw' } });
    assert.deepEqual(move.json, { ok: true });
    const reconnect = await firstPush(`/api/stream?token=${actor.token}`);
    assert.equal(reconnect['lastSeq'], 1, 'the reconnect push does not carry the count');
  });

  it('applies a burst of concurrent moves one at a time and leaves the save readable', async () => {
    const { host, guest } = await table();
    assert.equal((await post('/api/lobby/start', { token: host.token })).status, 200);
    const hostPush = await firstPush(`/api/stream?token=${host.token}`);
    const actor = hostPush['menu'] !== null ? host : guest;
    // Three moves that are legal only in this order, fired together.
    const intents = [
      { type: 'localOps.choose', option: 'draw' },
      { type: 'draw.fromHomeOffice' },
      { type: 'draw.end' },
    ];
    const results = await Promise.all(intents.map((intent, i) => post(`/api/intent?token=${actor.token}`, { seq: i + 1, intent })));
    assert.ok(results.every((r) => r.status === 200), 'a concurrent move was answered with an error');
    const save = JSON.parse(await readFile(join(dataDir, 'games', host.gameId, 'game.json'), 'utf8')) as { history: unknown[] };
    assert.ok(save.history.length >= 1, 'no move reached the save');
    assert.equal(save.history.length, results.filter((r) => r.json['ok'] === true).length, 'the save and the answers disagree');
  });
});