import { useState, useEffect, useRef } from 'react';

export interface ArcadeCountdown {
  /** Total milliseconds remaining */
  totalMs: number;
  /** Days remaining */
  days: number;
  /** Hours remaining (0-23) */
  hours: number;
  /** Minutes remaining (0-59) */
  minutes: number;
  /** Seconds remaining (0-59) */
  seconds: number;
  /** Formatted string e.g. "2d 5h 30m" or "5m 12s" */
  formatted: string;
  /** True when countdown has reached zero */
  isExpired: boolean;
}

function formatCountdown(ms: number): string {
  if (ms <= 0) return 'Ended';
  const s = Math.floor(ms / 1000);
  const m = Math.floor(s / 60);
  const h = Math.floor(m / 60);
  const d = Math.floor(h / 24);

  if (d > 0) return `${d}d ${h % 24}h ${m % 60}m`;
  if (h > 0) return `${h}h ${m % 60}m ${s % 60}s`;
  if (m > 0) return `${m}m ${s % 60}s`;
  return `${s}s`;
}

/**
 * Countdown hook for arcade pool resolution time.
 * Pass the `next_resolution` ISO string from the pool object.
 * Ticks every second automatically.
 */
export function useArcadeCountdown(nextResolution: string | null | undefined): ArcadeCountdown {
  const [now, setNow] = useState(Date.now());
  const intervalRef = useRef<ReturnType<typeof setInterval> | null>(null);

  useEffect(() => {
    if (!nextResolution) return;
    intervalRef.current = setInterval(() => setNow(Date.now()), 1000);
    return () => {
      if (intervalRef.current) clearInterval(intervalRef.current);
    };
  }, [nextResolution]);

  if (!nextResolution) {
    return { totalMs: 0, days: 0, hours: 0, minutes: 0, seconds: 0, formatted: '--', isExpired: false };
  }

  const target = new Date(nextResolution).getTime();
  const totalMs = Math.max(0, target - now);
  const totalSec = Math.floor(totalMs / 1000);
  const days = Math.floor(totalSec / 86400);
  const hours = Math.floor((totalSec % 86400) / 3600);
  const minutes = Math.floor((totalSec % 3600) / 60);
  const seconds = totalSec % 60;

  return {
    totalMs,
    days,
    hours,
    minutes,
    seconds,
    formatted: formatCountdown(totalMs),
    isExpired: totalMs <= 0,
  };
}