/**
 * Stress scenario — rapid short games with chaos injection.
 *
 * Partitions sessions into N rooms (default 4), runs gamesPerRoom
 * short 1-hole games per room in parallel. While each game plays,
 * a background loop injects chaos events (rapid clicks, tab blur,
 * brief offline) with 5% per-turn probability to hunt race
 * conditions and recovery bugs.
 */

import type {
  Scenario,
  ScenarioContext,
  ScenarioResult,
  ScenarioError,
  Session,
} from '../core/types';
import { runOneMultiplayerGame } from './shared/multiplayer-game';
import { maybeInjectChaos } from './shared/chaos';

interface StressConfig {
  gamesPerRoom: number;
  holes: number;
  decks: number;
  rooms: number;
  cpusPerRoom: number;
  thinkTimeMs: [number, number];
  interGamePauseMs: number;
  chaosChance: number;
}

function chunk<T>(arr: T[], size: number): T[][] {
  const out: T[][] = [];
  for (let i = 0; i < arr.length; i += size) out.push(arr.slice(i, i + size));
  return out;
}

async function sleep(ms: number): Promise<void> {
  return new Promise((r) => setTimeout(r, ms));
}

async function runStressRoom(
  ctx: ScenarioContext,
  cfg: StressConfig,
  roomIdx: number,
  sessions: Session[],
): Promise<{ completed: number; errors: ScenarioError[]; chaosFired: number }> {
  const roomId = `room-${roomIdx}`;
  let completed = 0;
  let chaosFired = 0;
  const errors: ScenarioError[] = [];

  for (let gameNum = 0; gameNum < cfg.gamesPerRoom; gameNum++) {
    if (ctx.signal.aborted) break;

    ctx.dashboard.update(roomId, { game: gameNum + 1, totalGames: cfg.gamesPerRoom });

    // Background chaos loop — runs concurrently with the game turn loop.
    // Delay the first tick by 3 seconds so room creation + joiners + game
    // start have time to complete without chaos interference (rapid clicks
    // or brief_offline during lobby setup can prevent #create-room-btn
    // from becoming stable).
    let chaosActive = true;
    const chaosLoop = (async () => {
      await sleep(3000);
      while (chaosActive && !ctx.signal.aborted) {
        await sleep(500);
        for (const session of sessions) {
          const e = await maybeInjectChaos(
            session,
            cfg.chaosChance,
            ctx.logger,
            roomId,
          );
          if (e) chaosFired++;
        }
      }
    })();

    const result = await runOneMultiplayerGame(ctx, sessions, {
      roomId,
      holes: cfg.holes,
      decks: cfg.decks,
      cpusPerRoom: cfg.cpusPerRoom,
      thinkTimeMs: cfg.thinkTimeMs,
    });

    chaosActive = false;
    await chaosLoop;

    if (result.completed) {
      completed++;
      ctx.logger.info('game_complete', {
        room: roomId,
        game: gameNum + 1,
        turns: result.turns,
      });
    } else {
      errors.push({
        room: roomId,
        reason: 'game_failed',
        detail: result.error,
        timestamp: Date.now(),
      });
      ctx.logger.error('game_failed', { room: roomId, error: result.error });
    }

    await sleep(cfg.interGamePauseMs);
  }

  return { completed, errors, chaosFired };
}

const stress: Scenario = {
  name: 'stress',
  description: 'Rapid short games for stability & race condition hunting',
  needs: { accounts: 16, rooms: 4, cpusPerRoom: 2 },
  defaultConfig: {
    gamesPerRoom: 50,
    holes: 1,
    decks: 1,
    rooms: 4,
    cpusPerRoom: 2,
    thinkTimeMs: [50, 150],
    interGamePauseMs: 200,
    chaosChance: 0.05,
  },

  async run(ctx: ScenarioContext): Promise<ScenarioResult> {
    const start = Date.now();
    const cfg = ctx.config as unknown as StressConfig;
    const perRoom = Math.floor(ctx.sessions.length / cfg.rooms);
    if (perRoom * cfg.rooms !== ctx.sessions.length) {
      throw new Error(
        `stress: ${ctx.sessions.length} sessions does not divide evenly into ${cfg.rooms} rooms`,
      );
    }
    const roomSessions = chunk(ctx.sessions, perRoom);

    const results = await Promise.allSettled(
      roomSessions.map((s, idx) => runStressRoom(ctx, cfg, idx, s)),
    );

    let gamesCompleted = 0;
    let chaosFired = 0;
    const errors: ScenarioError[] = [];
    results.forEach((r, idx) => {
      if (r.status === 'fulfilled') {
        gamesCompleted += r.value.completed;
        chaosFired += r.value.chaosFired;
        errors.push(...r.value.errors);
      } else {
        errors.push({
          room: `room-${idx}`,
          reason: 'room_threw',
          detail: r.reason instanceof Error ? r.reason.message : String(r.reason),
          timestamp: Date.now(),
        });
      }
    });

    return {
      gamesCompleted,
      errors,
      durationMs: Date.now() - start,
      customMetrics: { chaos_fired: chaosFired },
    };
  },
};

export default stress;