import type { GraphQLTaggedNode, IEnvironment, Observable } from "../..";
import type { ArrayKeyType, ArrayKeyTypeData, FragmentState, KeyType, KeyTypeData } from "./FragmentTypes";

/**
 * EXPERIMENTAL: This API is experimental and does not yet support all Relay
 * features. Notably, it does not correctly handle some features of Relay Resolvers.
 *
 * Given a fragment and a fragment reference, returns an observable that emits
 * the state of the fragment over time. The observable will emit the following
 * values:
 * - 'ok': The fragment has a value
 * - 'error': The fragment has an error, this could be due to a network error or
 *  a field error due to @required(action: THROW) or @throwOnFieldError
 * - 'loading': The fragment is still in flight and is still expected to resolver.
 */
export function observeFragment<TKey extends KeyType>(
    environment: IEnvironment,
    fragmentInput: GraphQLTaggedNode,
    fragmentRef: TKey,
): Observable<FragmentState<KeyTypeData<TKey>>>;

/**
 * EXPERIMENTAL: This API is experimental and does not yet support all Relay
 * features. Notably, it does not correctly handle some features of Relay Resolvers.
 *
 * Given a fragment and a fragment reference, returns an observable that emits
 * the state of the fragment over time. The observable will emit the following
 * values:
 * - 'ok': The fragment has a value
 * - 'error': The fragment has an error, this could be due to a network error or
 *  a field error due to @required(action: THROW) or @throwOnFieldError
 * - 'loading': The fragment is still in flight and is still expected to resolver.
 */
export function observeFragment<TKey extends ArrayKeyType>(
    environment: IEnvironment,
    fragmentInput: GraphQLTaggedNode,
    fragmentRef: TKey,
): Observable<FragmentState<ArrayKeyTypeData<TKey>>>;