import DataLoader from 'dataloader';
import { BatchLoadFn } from './batch-loader.interface.js';
import { KeyFunc } from './typeorm-loader-handler.interface.js';
import { TypeormLoaderOptions } from './typeorm-loader.interface.js';
import { TYPEORM_DATALOADER_EXTENSION_FIELD, CUSTOM_DATALOADER_EXTENSION_FIELD } from '../constants/extension-field.constants.js';

/**
 * A generic type to extend from for nestjs extensions.
 */
interface ExtensionType<T> {
    args: T;
    key: string | symbol;
    target: Function | object;
}
/**
 * Extension field definition for nest.js to store metadata of decorators.
 */
interface Extensions {
    [key: string]: any;
    [TYPEORM_DATALOADER_EXTENSION_FIELD]: ExtensionType<{
        keyFunc: KeyFunc;
        options?: TypeormLoaderOptions;
    }>;
    [CUSTOM_DATALOADER_EXTENSION_FIELD]: ExtensionType<{
        batchLoadFn: BatchLoadFn<any, any>;
        options?: DataLoader.Options<any, any, any>;
    }>;
}

export { Extensions };