import { useCallback, useEffect, useRef } from 'react';
import { CallMembership } from 'matrix-js-sdk/lib/matrixrtc/CallMembership';
import { CallEmbed } from '../plugins/call';
import { useSetting } from '../state/hooks/settings';
import { settingsAtom } from '../state/settings';
import { useMatrixClient } from './useMatrixClient';
import { useCallMembersChange, useCallSession } from './useCall';
import { useCallJoined } from './useCallEmbed';
import { playCallJoinSound, playCallLeaveSound } from '../utils/callSounds';

const membershipKey = (m: CallMembership): string => `${m.sender}|${m.deviceId}`;

/**
 * Plays a local sound effect when another participant joins or leaves
 * the call you are in. Style (or off) is configured in Settings → Calls.
 */
export function useCallJoinLeaveSounds(embed: CallEmbed): void {
  const mx = useMatrixClient();
  const [style] = useSetting(settingsAtom, 'callJoinLeaveSound');
  const joined = useCallJoined(embed);
  const session = useCallSession(embed.room);

  const prevKeysRef = useRef<Set<string> | null>(null);

  // Snapshot current members when the session (re)starts so we never play
  // sounds for participants who were already present.
  useEffect(() => {
    prevKeysRef.current = new Set(session.memberships.map(membershipKey));
  }, [session]);

  useCallMembersChange(
    session,
    useCallback(
      (members: CallMembership[]) => {
        const next = new Set(members.map(membershipKey));
        const prev = prevKeysRef.current ?? next;
        prevKeysRef.current = next;

        if (!joined || style === 'off') return;

        const myPrefix = `${mx.getSafeUserId()}|`;
        let someoneJoined = false;
        let someoneLeft = false;
        next.forEach((key) => {
          if (!prev.has(key) && !key.startsWith(myPrefix)) someoneJoined = true;
        });
        prev.forEach((key) => {
          if (!next.has(key) && !key.startsWith(myPrefix)) someoneLeft = true;
        });

        if (someoneJoined) playCallJoinSound(style);
        if (someoneLeft) playCallLeaveSound(style);
      },
      [joined, style, mx],
    ),
  );
}
