/**
 * # Query Header
 * Messages that comprise a header sent with each query request.
 *
 * ### Keywords
 * The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
 * "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
 * document are to be interpreted as described in
 * [RFC2119](https://www.ietf.org/rfc/rfc2119) and clarified in
 * [RFC8174](https://www.ietf.org/rfc/rfc8174).
 */
syntax = "proto3";

package proto;

// SPDX-License-Identifier: Apache-2.0
option java_package = "com.hederahashgraph.api.proto.java";
// <<<pbj.java_package = "com.hedera.hapi.node.base">>> This comment is special code for setting PBJ Compiler java package
option java_multiple_files = true;

import "services_transaction.proto";

/**
 * The type of query response.<br/>
 *
 * This SHALL be answer-only as a default.<br/>
 * This value SHALL support an "estimated cost" type.<br/>
 * This value SHOULD support a "state proof" type, when available.
 */
enum ResponseType {
    /**
     * A response with the query answer.
     */
    ANSWER_ONLY = 0;

    /**
     * A response with both the query answer and a state proof.
     */
    ANSWER_STATE_PROOF = 1;

    /**
     * A response with the estimated cost to answer the query.
     */
    COST_ANSWER = 2;

    /**
     * A response with the estimated cost to answer and a state proof.
     */
    COST_ANSWER_STATE_PROOF = 3;
}

/**
 * A standard query header.<br/>
 * Each query from the client to the node must contain a QueryHeader, which
 * specifies the desired response type, and includes a payment transaction
 * that will compensate the network for responding to the query.
 * The payment may be blank if the query is free.
 *
 * The payment transaction MUST be a `cryptoTransfer` from the payer account
 * to the account of the node where the query is submitted.<br/>
 * If the payment is sufficient, the network SHALL respond with the response
 * type requested.<br/>
 * If the response type is `COST_ANSWER` the payment MUST be unset.
 * A state proof SHALL be available for some types of information.<br/>
 * A state proof SHALL be available for a Record, but not a receipt, and the
 * response entry for each supported "get info" query.
 */
message QueryHeader {
    /**
     * A signed `CryptoTransferTransaction` to pay query fees.
     * <p>
     * This MUST transfer HBAR from the "payer" to the responding node account
     * sufficient to pay the query fees.
     */
    Transaction payment = 1;

    /**
     * A type of query response requested.
     */
    ResponseType responseType = 2;
}