/**
 * Chaos injector — occasionally fires unexpected UI events while a
 * game is playing, to hunt race conditions and recovery bugs.
 *
 * Called from the stress scenario's background chaos loop. Each call
 * has `probability` of firing; when it fires it picks one random
 * event type and runs it against one session.
 */

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

export type ChaosEvent = 'rapid_clicks' | 'tab_blur' | 'brief_offline';

const ALL_EVENTS: ChaosEvent[] = ['rapid_clicks', 'tab_blur', 'brief_offline'];

function pickEvent(): ChaosEvent {
  return ALL_EVENTS[Math.floor(Math.random() * ALL_EVENTS.length)];
}

export async function maybeInjectChaos(
  session: Session,
  probability: number,
  logger: Logger,
  roomId: string,
): Promise<ChaosEvent | null> {
  if (Math.random() >= probability) return null;

  const event = pickEvent();
  logger.info('chaos_injected', { room: roomId, session: session.key, event });
  try {
    switch (event) {
      case 'rapid_clicks': {
        // Fire 5 rapid clicks at the player's own cards
        for (let i = 0; i < 5; i++) {
          await session.page
            .locator(`#player-cards .card:nth-child(${(i % 6) + 1})`)
            .click({ timeout: 300 })
            .catch(() => {});
        }
        break;
      }
      case 'tab_blur': {
        // Briefly dispatch blur then focus — simulates user tabbing away
        await session.page.evaluate(() => {
          window.dispatchEvent(new Event('blur'));
          setTimeout(() => window.dispatchEvent(new Event('focus')), 200);
        });
        break;
      }
      case 'brief_offline': {
        // 300ms network outage — should trigger client reconnect logic
        await session.context.setOffline(true);
        await new Promise((r) => setTimeout(r, 300));
        await session.context.setOffline(false);
        break;
      }
    }
  } catch (err) {
    logger.warn('chaos_error', {
      event,
      error: err instanceof Error ? err.message : String(err),
    });
  }
  return event;
}