import { Field, ID, InputType, InterfaceType, ObjectType, type TypeResolver } from 'type-graphql';

export { runRelayClientMutation } from './runRelayClientMutation';

export type RelayConnectionCursor = string;

/*
https://github.com/graphql/graphql-relay-js/blob/main/src/connection/connection.ts
 */

@InterfaceType('Node', {
	autoRegisterImplementations: false,
	description: 'An object with a global ID.',
	resolveType: (...args) => {
		return RelayNode.resolveType(...args);
	},
})
export abstract class RelayNode {
	@Field((_type) => ID)
	id!: string;

	static resolvers: TypeResolver<any, any>[] = [];

	static resolveType: TypeResolver<any, any> = async (...args) => {
		for (const resolver of RelayNode.resolvers) {
			const resolved = await resolver(...args);
			if (resolved) {
				return resolved;
			}
		}
		const [value] = args;
		throw new Error(`Unknown node type ${value}`);
	};
}

@InputType()
export abstract class RelayMutationInput {
	@Field(() => String, { nullable: true })
	clientMutationId?: string;
}

@ObjectType()
export abstract class RelayMutationPayload {
	@Field(() => String, { nullable: true })
	clientMutationId?: string;
}

@ObjectType('PageInfo', { description: 'Information about pagination in a connection.' })
export class RelayPageInfo {
	@Field(() => String, { nullable: true, description: 'When paginating backwards, the cursor to continue.' })
	readonly startCursor?: RelayConnectionCursor | null;

	@Field(() => String, { nullable: true, description: 'When paginating forwards, the cursor to continue.' })
	readonly endCursor?: RelayConnectionCursor | null;

	@Field(() => Boolean, { nullable: true, description: 'When paginating backwards, are there more items?' })
	readonly hasPreviousPage!: boolean;

	@Field(() => Boolean, { nullable: true, description: 'When paginating forwards, are there more items?' })
	readonly hasNextPage!: boolean;
}

/**
 * A type designed to be exposed as a `Connection` over GraphQL.
 */
export interface RelayConnection<T> {
	edges: Array<RelayEdge<T>>;
	pageInfo: RelayPageInfo;
}

/**
 * A type designed to be exposed as a `Edge` over GraphQL.
 */
export interface RelayEdge<T> {
	node: T;
	cursor: RelayConnectionCursor;
}