import { BuffType } from '../plugins/currency/prop/inventory/inventory';
import { Item } from '../plugins/currency/prop/item_mapping';
import { Context, Session } from 'koishi';
export declare function useBuffItem(session: Session, ctx: Context, item: Item): Promise<string>;
export declare function decreaseItemQuantity(ctx: Context, userId: string, channelId: string, itemId: string): Promise<boolean>;
export declare function addOrUpdateBuffEffect(ctx: Context, userId: string, buffType: BuffType, durationDays: number, data?: Record<string, any>): Promise<Date>;
export declare function getBuffRemainingDays(ctx: Context, userId: string, buffType: BuffType): Promise<number>;
export declare function hasActiveBuff(ctx: Context, userId: string, buffType: BuffType): Promise<boolean>;