import { useEffect, useState } from "react";
import { useEvent } from "@/hooks/use-event";

export const EXIT_DELAY_MS = 5000;
export const EXIT_TICK_MS = 100;

type PlaybackStatus = "idle" | "playing" | "ended";

/**
 * Returns the remaining ms when the stream has ended, or null otherwise.
 * Pauses while `paused` is true (compose, hold-to-pause, swipe-down…).
 */
export function useExitCountdown(
  status: PlaybackStatus,
  paused: boolean,
  onExit: () => void,
): number | null {
  const [remainingMs, setRemainingMs] = useState<number | null>(null);
  const handleExit = useEvent(onExit);

  useEffect(() => {
    if (status === "ended") {
      setRemainingMs(EXIT_DELAY_MS);
    } else {
      setRemainingMs(null);
    }
  }, [status]);

  useEffect(() => {
    if (remainingMs === null || remainingMs <= 0 || paused) return;
    const interval = setInterval(() => {
      setRemainingMs((prev) => {
        if (prev === null) return null;
        const next = prev - EXIT_TICK_MS;
        return next <= 0 ? 0 : next;
      });
    }, EXIT_TICK_MS);
    return () => clearInterval(interval);
  }, [remainingMs !== null && remainingMs > 0, paused, remainingMs]);

  useEffect(() => {
    if (remainingMs !== null && remainingMs <= 0) {
      handleExit();
    }
  }, [remainingMs, handleExit]);

  return remainingMs;
}