/**
 * runOneMultiplayerGame — the shared "play one game in one room" loop.
 *
 * Host creates the room, announces the code via RoomCoordinator,
 * joiners wait for the code and join concurrently, host adds CPUs and
 * starts the game, then every session loops on isMyTurn/playTurn until
 * the game ends (or the abort signal fires, or maxDurationMs elapses).
 *
 * Used by both the populate and stress scenarios so the turn loop
 * lives in exactly one place.
 */

import type { Session, ScenarioContext } from '../../core/types';

export interface MultiplayerGameOptions {
  roomId: string;
  holes: number;
  decks: number;
  cpusPerRoom: number;
  cpuPersonality?: string;
  /** Per-turn think time in [min, max] ms. */
  thinkTimeMs: [number, number];
  /** Max wall-clock time before giving up on the game (ms). */
  maxDurationMs?: number;
}

export interface MultiplayerGameResult {
  completed: boolean;
  turns: number;
  durationMs: number;
  error?: string;
}

function randomInt(min: number, max: number): number {
  return Math.floor(Math.random() * (max - min + 1)) + min;
}

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

export async function runOneMultiplayerGame(
  ctx: ScenarioContext,
  sessions: Session[],
  opts: MultiplayerGameOptions,
): Promise<MultiplayerGameResult> {
  const start = Date.now();
  const [host, ...joiners] = sessions;
  const maxDuration = opts.maxDurationMs ?? 5 * 60_000;

  try {
    // Reset every session back to the lobby before starting.
    // After the first game ends each session is parked on the
    // game_over screen, which hides the lobby's Create Room button.
    // goto('/') bounces them back; localStorage-cached auth persists.
    await Promise.all(sessions.map((s) => s.bot.goto('/')));

    // Host creates game and announces the code
    const code = await host.bot.createGame(host.account.username);
    ctx.coordinator.announce(opts.roomId, code);
    ctx.heartbeat(opts.roomId);
    ctx.dashboard.update(opts.roomId, { phase: 'lobby' });
    ctx.logger.info('room_created', { room: opts.roomId, code });

    // Joiners join concurrently
    await Promise.all(
      joiners.map(async (joiner) => {
        const awaited = await ctx.coordinator.await(opts.roomId);
        await joiner.bot.joinGame(awaited, joiner.account.username);
      }),
    );
    ctx.heartbeat(opts.roomId);

    // Host adds CPUs (if any) and starts
    for (let i = 0; i < opts.cpusPerRoom; i++) {
      await host.bot.addCPU(opts.cpuPersonality);
    }
    await host.bot.startGame({ holes: opts.holes, decks: opts.decks });
    ctx.heartbeat(opts.roomId);
    ctx.dashboard.update(opts.roomId, { phase: 'playing', totalHoles: opts.holes });

    // Concurrent turn loops — one per session
    const turnCounts = new Array(sessions.length).fill(0);

    async function sessionLoop(sessionIdx: number): Promise<void> {
      const session = sessions[sessionIdx];
      while (true) {
        if (ctx.signal.aborted) return;
        if (Date.now() - start > maxDuration) return;

        const phase = await session.bot.getGamePhase();
        if (phase === 'game_over' || phase === 'round_over') return;

        if (await session.bot.isMyTurn()) {
          await session.bot.playTurn();
          turnCounts[sessionIdx]++;
          ctx.heartbeat(opts.roomId);
          ctx.dashboard.update(opts.roomId, {
            currentPlayer: session.account.username,
            moves: turnCounts.reduce((a, b) => a + b, 0),
          });
          const thinkMs = randomInt(opts.thinkTimeMs[0], opts.thinkTimeMs[1]);
          await sleep(thinkMs);
        } else {
          await sleep(200);
        }
      }
    }

    await Promise.all(sessions.map((_, i) => sessionLoop(i)));

    const totalTurns = turnCounts.reduce((a, b) => a + b, 0);
    ctx.dashboard.update(opts.roomId, { phase: 'round_over' });
    return {
      completed: true,
      turns: totalTurns,
      durationMs: Date.now() - start,
    };
  } catch (err) {
    return {
      completed: false,
      turns: 0,
      durationMs: Date.now() - start,
      error: err instanceof Error ? err.message : String(err),
    };
  }
}