import { router } from '@inertiajs/vue3';
import { onScopeDispose, watch } from 'vue';

import { getEcho } from '@/lib/echo';
import type { RoomStateChangedPayload } from '@/types/room';

const ROOM_EVENT = '.room.state.changed';

export function useRoomRealtime(
    roomId: () => string,
    stateVersion: () => number,
): void {
    let reloadInProgress = false;
    let pendingVersion = 0;
    let disposed = false;

    function reloadRoom(): void {
        if (reloadInProgress || disposed) {
            return;
        }

        reloadInProgress = true;

        router.reload({
            only: ['room', 'currentPlayer'],
            onFinish: () => {
                reloadInProgress = false;

                if (disposed) {
                    return;
                }

                if (pendingVersion > stateVersion()) {
                    reloadRoom();

                    return;
                }

                pendingVersion = stateVersion();
            },
        });
    }

    function handleRoomChange(payload: RoomStateChangedPayload): void {
        if (
            typeof payload.version !== 'number' ||
            payload.version <= Math.max(stateVersion(), pendingVersion)
        ) {
            return;
        }

        pendingVersion = payload.version;

        if (payload.change === 'room_deleted') {
            router.visit('/', { replace: true });

            return;
        }

        reloadRoom();
    }

    const stopWatchingRoom = watch(
        roomId,
        (nextRoomId, _previousRoomId, onCleanup) => {
            const echo = getEcho();
            const channelName = `rooms.${nextRoomId}`;

            pendingVersion = stateVersion();
            echo.channel(channelName).listen(ROOM_EVENT, handleRoomChange);

            onCleanup(() => {
                echo.leaveChannel(channelName);
            });
        },
        { immediate: true },
    );

    const stopWatchingVersion = watch(
        stateVersion,
        (version) => {
            if (!reloadInProgress) {
                pendingVersion = Math.max(pendingVersion, version);
            }
        },
        { flush: 'sync' },
    );

    onScopeDispose(() => {
        disposed = true;
        stopWatchingRoom();
        stopWatchingVersion();
    });
}