syntax = "proto3";

import "github.com/lightningnetwork/lnd/lnrpc/signrpc/signer.proto";

package walletrpc;

message KeyReq {
    /**
    Is the key finger print of the root pubkey that this request is targeting.
    This allows the WalletKit to possibly serve out keys for multiple HD chains
    via public derivation.
    */
    int32 key_finger_print = 1;

    /**
    The target key family to derive a key from. In other contexts, this is
    known as the "account".
    */
    int32 key_family = 2;
}

message AddrRequest{
    // No fields, as we always give out a p2wkh address.
}
message AddrResponse {
    /**
    The address encoded using a bech32 format.
    */
    string addr = 1;
}

message Transaction {
    /**
    The raw serialized transaction.
    */
    bytes tx_hex = 1;
}
message PublishResponse {
    /**
    If blank, then no error occurred and the transaction was successfully
    published. If not the empty string, then a string representation of the
    broadcast error.

    TODO(roasbeef): map to a proper enum type
    */
    string publish_error = 1;
}

message SendOutputsRequest {
    /**
    The number of satoshis per kilo weight that should be used when crafting
    this transaction.
    */
    int64 sat_per_kw = 1;

    /**
    A slice of the outputs that should be created in the transaction produced.
    */
    repeated signrpc.TxOut outputs = 2;
}
message SendOutputsResponse {
    /**
    The serialized transaction sent out on the network.
    */
    bytes raw_tx = 1;
}

message EstimateFeeRequest {
    /**
    The number of confirmations to shoot for when estimating the fee.
    */
    int32 conf_target = 1;
}
message EstimateFeeResponse {
    /**
    The amount of satoshis per kw that should be used in order to reach the
    confirmation target in the request.
    */
    int64 sat_per_kw = 1;
}

service WalletKit {
    /**
    DeriveNextKey attempts to derive the *next* key within the key family
    (account in BIP43) specified. This method should return the next external
    child within this branch.
    */
    rpc DeriveNextKey(KeyReq) returns (signrpc.KeyDescriptor);

    /**
    DeriveKey attempts to derive an arbitrary key specified by the passed
    KeyLocator. 
    */
    rpc DeriveKey(signrpc.KeyLocator) returns (signrpc.KeyDescriptor);

    /**
    NextAddr returns the next unused address within the wallet.
    */
    rpc NextAddr(AddrRequest) returns (AddrResponse);

    /**
    PublishTransaction attempts to publish the passed transaction to the
    network. Once this returns without an error, the wallet will continually
    attempt to re-broadcast the transaction on start up, until it enters the
    chain.
    */
    rpc PublishTransaction(Transaction) returns (PublishResponse);

    /**
    SendOutputs is similar to the existing sendmany call in Bitcoind, and
    allows the caller to create a transaction that sends to several outputs at
    once. This is ideal when wanting to batch create a set of transactions.
    */
    rpc SendOutputs(SendOutputsRequest) returns (SendOutputsResponse);

    /**
    EstimateFee attempts to query the internal fee estimator of the wallet to
    determine the fee (in sat/kw) to attach to a transaction in order to
    achieve the confirmation target.
    */
    rpc EstimateFee(EstimateFeeRequest) returns (EstimateFeeResponse);
}