grin-node/wallet/src/types.rs

// Copyright 2018 The Grin Developers
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use blake2;
use rand::{thread_rng, Rng};
use std::fmt;
use std::fmt::Display;
use uuid::Uuid;
use std::convert::From;
use std::fs::{self, File, OpenOptions};
use std::io::{Read, Write};
use std::path::Path;
use std::path::MAIN_SEPARATOR;
use std::collections::HashMap;
use std::cmp::min;

use serde;
use serde_json;
use tokio_core::reactor;
use tokio_retry::Retry;
use tokio_retry::strategy::FibonacciBackoff;

use failure::{Backtrace, Context, Fail, ResultExt};

use core::consensus;
use core::core::Transaction;
use core::core::hash::Hash;
use core::core::pmmr::MerkleProof;
use core::ser;
use keychain;
use keychain::BlindingFactor;
use util;
use util::secp;
use util::secp::Signature;
use util::secp::key::PublicKey;
use util::LOGGER;

const DAT_FILE: &'static str = "wallet.dat";
const LOCK_FILE: &'static str = "wallet.lock";
const SEED_FILE: &'static str = "wallet.seed";

const DEFAULT_BASE_FEE: u64 = consensus::MILLI_GRIN;

/// Transaction fee calculation
pub fn tx_fee(input_len: usize, output_len: usize, base_fee: Option<u64>) -> u64 {
	let use_base_fee = match base_fee {
		Some(bf) => bf,
		None => DEFAULT_BASE_FEE,
	};
	let mut tx_weight = -1 * (input_len as i32) + 4 * (output_len as i32) + 1;
	if tx_weight < 1 {
		tx_weight = 1;
	}

	(tx_weight as u64) * use_base_fee
}

#[derive(Debug)]
pub struct Error {
	inner: Context<ErrorKind>,
}

/// Wallet errors, mostly wrappers around underlying crypto or I/O errors.
#[derive(Copy, Clone, Eq, PartialEq, Debug, Fail)]
pub enum ErrorKind {
	#[fail(display = "Not enough funds")] NotEnoughFunds(u64),

	#[fail(display = "Fee dispute: sender fee {}, recipient fee {}", sender_fee, recipient_fee)]
	FeeDispute {
		sender_fee: u64,
		recipient_fee: u64,
	},

	#[fail(display = "Fee exceeds amount: sender amount {}, recipient fee {}", sender_amount,
	       recipient_fee)]
	FeeExceedsAmount {
		sender_amount: u64,
		recipient_fee: u64,
	},

	#[fail(display = "Keychain error")] Keychain,

	#[fail(display = "Transaction error")] Transaction,

	#[fail(display = "Secp error")] Secp,

	#[fail(display = "Wallet data error: {}", _0)] WalletData(&'static str),

	/// An error in the format of the JSON structures exchanged by the wallet
	#[fail(display = "JSON format error")]
	Format,

	#[fail(display = "I/O error")] IO,

	/// Error when contacting a node through its API
	#[fail(display = "Node API error")]
	Node,

	/// Error originating from hyper.
	#[fail(display = "Hyper error")]
	Hyper,

	/// Error originating from hyper uri parsing.
	#[fail(display = "Uri parsing error")]
	Uri,

	#[fail(display = "Signature error")] Signature(&'static str),

	/// Attempt to use duplicate transaction id in separate transactions
	#[fail(display = "Duplicate transaction ID error")]
	DuplicateTransactionId,

	/// Wallet seed already exists
	#[fail(display = "Wallet seed exists error")]
	WalletSeedExists,

	#[fail(display = "Generic error: {}", _0)] GenericError(&'static str),
}

impl Fail for Error {
	fn cause(&self) -> Option<&Fail> {
		self.inner.cause()
	}

	fn backtrace(&self) -> Option<&Backtrace> {
		self.inner.backtrace()
	}
}

impl Display for Error {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
		Display::fmt(&self.inner, f)
	}
}

impl Error {
	pub fn kind(&self) -> ErrorKind {
		*self.inner.get_context()
	}
}

impl From<ErrorKind> for Error {
	fn from(kind: ErrorKind) -> Error {
		Error {
			inner: Context::new(kind),
		}
	}
}

impl From<Context<ErrorKind>> for Error {
	fn from(inner: Context<ErrorKind>) -> Error {
		Error { inner: inner }
	}
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct WalletConfig {
	// Right now the decision to run or not a wallet is based on the command.
	// This may change in the near-future.
	// pub enable_wallet: bool,

	// The api interface/ip_address that this api server (i.e. this wallet) will run
	// by default this is 127.0.0.1 (and will not accept connections from external clients)
	pub api_listen_interface: String,
	// The port this wallet will run on
	pub api_listen_port: String,
	// The api address of a running server node against which transaction inputs
	// will be checked during send
	pub check_node_api_http_addr: String,
	// The directory in which wallet files are stored
	pub data_file_dir: String,
}

impl Default for WalletConfig {
	fn default() -> WalletConfig {
		WalletConfig {
			// enable_wallet: false,
			api_listen_interface: "127.0.0.1".to_string(),
			api_listen_port: "13415".to_string(),
			check_node_api_http_addr: "http://127.0.0.1:13413".to_string(),
			data_file_dir: ".".to_string(),
		}
	}
}

impl WalletConfig {
	pub fn api_listen_addr(&self) -> String {
		format!("{}:{}", self.api_listen_interface, self.api_listen_port)
	}
}

/// Status of an output that's being tracked by the wallet. Can either be
/// unconfirmed, spent, unspent, or locked (when it's been used to generate
/// a transaction but we don't have confirmation that the transaction was
/// broadcasted or mined).
#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, Ord, PartialOrd)]
pub enum OutputStatus {
	Unconfirmed,
	Unspent,
	Locked,
	Spent,
}

impl fmt::Display for OutputStatus {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
		match *self {
			OutputStatus::Unconfirmed => write!(f, "Unconfirmed"),
			OutputStatus::Unspent => write!(f, "Unspent"),
			OutputStatus::Locked => write!(f, "Locked"),
			OutputStatus::Spent => write!(f, "Spent"),
		}
	}
}

#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord)]
pub struct MerkleProofWrapper(pub MerkleProof);

impl MerkleProofWrapper {
	pub fn merkle_proof(&self) -> MerkleProof {
		self.0.clone()
	}
}

impl serde::ser::Serialize for MerkleProofWrapper {
	fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
	where
		S: serde::ser::Serializer,
	{
		serializer.serialize_str(&self.0.to_hex())
	}
}

impl<'de> serde::de::Deserialize<'de> for MerkleProofWrapper {
	fn deserialize<D>(deserializer: D) -> Result<MerkleProofWrapper, D::Error>
	where
		D: serde::de::Deserializer<'de>,
	{
		deserializer.deserialize_str(MerkleProofWrapperVisitor)
	}
}

struct MerkleProofWrapperVisitor;

impl<'de> serde::de::Visitor<'de> for MerkleProofWrapperVisitor {
	type Value = MerkleProofWrapper;

	fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
		formatter.write_str("a merkle proof")
	}

	fn visit_str<E>(self, s: &str) -> Result<Self::Value, E>
	where
		E: serde::de::Error,
	{
		let merkle_proof = MerkleProof::from_hex(s).unwrap();
		Ok(MerkleProofWrapper(merkle_proof))
	}
}

#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord)]
pub struct BlockIdentifier(Hash);

impl BlockIdentifier {
	pub fn hash(&self) -> Hash {
		self.0
	}

	pub fn from_hex(hex: &str) -> Result<BlockIdentifier, Error> {
		let hash = Hash::from_hex(hex).context(ErrorKind::GenericError("Invalid hex"))?;
		Ok(BlockIdentifier(hash))
	}
}

impl serde::ser::Serialize for BlockIdentifier {
	fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
	where
		S: serde::ser::Serializer,
	{
		serializer.serialize_str(&self.0.to_hex())
	}
}

impl<'de> serde::de::Deserialize<'de> for BlockIdentifier {
	fn deserialize<D>(deserializer: D) -> Result<BlockIdentifier, D::Error>
	where
		D: serde::de::Deserializer<'de>,
	{
		deserializer.deserialize_str(BlockIdentifierVisitor)
	}
}

struct BlockIdentifierVisitor;

impl<'de> serde::de::Visitor<'de> for BlockIdentifierVisitor {
	type Value = BlockIdentifier;

	fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
		formatter.write_str("a block hash")
	}

	fn visit_str<E>(self, s: &str) -> Result<Self::Value, E>
	where
		E: serde::de::Error,
	{
		let block_hash = Hash::from_hex(s).unwrap();
		Ok(BlockIdentifier(block_hash))
	}
}

/// Information about an output that's being tracked by the wallet. Must be
/// enough to reconstruct the commitment associated with the ouput when the
/// root private key is known.
#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, PartialOrd, Eq, Ord)]
pub struct OutputData {
	/// Root key_id that the key for this output is derived from
	pub root_key_id: keychain::Identifier,
	/// Derived key for this output
	pub key_id: keychain::Identifier,
	/// How many derivations down from the root key
	pub n_child: u32,
	/// Value of the output, necessary to rebuild the commitment
	pub value: u64,
	/// Current status of the output
	pub status: OutputStatus,
	/// Height of the output
	pub height: u64,
	/// Height we are locked until
	pub lock_height: u64,
	/// Is this a coinbase output? Is it subject to coinbase locktime?
	pub is_coinbase: bool,
	/// Hash of the block this output originated from.
	pub block: Option<BlockIdentifier>,
	pub merkle_proof: Option<MerkleProofWrapper>,
}

impl OutputData {
	/// Lock a given output to avoid conflicting use
	fn lock(&mut self) {
		self.status = OutputStatus::Locked;
	}

	/// How many confirmations has this output received?
	/// If height == 0 then we are either Unconfirmed or the output was
	/// cut-through
	/// so we do not actually know how many confirmations this output had (and
	/// never will).
	pub fn num_confirmations(&self, current_height: u64) -> u64 {
		if self.status == OutputStatus::Unconfirmed {
			0
		} else if self.height == 0 {
			0
		} else {
			// if an output has height n and we are at block n
			// then we have a single confirmation (the block it originated in)
			1 + (current_height - self.height)
		}
	}

	/// Check if output is eligible to spend based on state and height and
	/// confirmations
	pub fn eligible_to_spend(&self, current_height: u64, minimum_confirmations: u64) -> bool {
		if [OutputStatus::Spent, OutputStatus::Locked].contains(&self.status) {
			return false;
		} else if self.status == OutputStatus::Unconfirmed && self.is_coinbase {
			return false;
		} else if self.is_coinbase && self.block.is_none() {
			// if we do not have a block hash for coinbase output we cannot spent it
			// block index got compacted before we refreshed our wallet?
			return false;
		} else if self.is_coinbase && self.merkle_proof.is_none() {
			// if we do not have a Merkle proof for coinbase output we cannot spent it
			// block index got compacted before we refreshed our wallet?
			return false;
		} else if self.lock_height > current_height {
			return false;
		} else if self.status == OutputStatus::Unspent
			&& self.num_confirmations(current_height) >= minimum_confirmations
		{
			return true;
		} else if self.status == OutputStatus::Unconfirmed && minimum_confirmations == 0 {
			return true;
		} else {
			return false;
		}
	}
}

#[derive(Clone, PartialEq)]
pub struct WalletSeed([u8; 32]);

impl WalletSeed {
	pub fn from_bytes(bytes: &[u8]) -> WalletSeed {
		let mut seed = [0; 32];
		for i in 0..min(32, bytes.len()) {
			seed[i] = bytes[i];
		}
		WalletSeed(seed)
	}

	fn from_hex(hex: &str) -> Result<WalletSeed, Error> {
		let bytes =
			util::from_hex(hex.to_string()).context(ErrorKind::GenericError("Invalid hex"))?;
		Ok(WalletSeed::from_bytes(&bytes))
	}

	pub fn to_hex(&self) -> String {
		util::to_hex(self.0.to_vec())
	}

	pub fn derive_keychain(&self, password: &str) -> Result<keychain::Keychain, Error> {
		let seed = blake2::blake2b::blake2b(64, &password.as_bytes(), &self.0);
		let result = keychain::Keychain::from_seed(seed.as_bytes()).context(ErrorKind::Keychain)?;
		Ok(result)
	}

	pub fn init_new() -> WalletSeed {
		let seed: [u8; 32] = thread_rng().gen();
		WalletSeed(seed)
	}

	pub fn init_file(wallet_config: &WalletConfig) -> Result<WalletSeed, Error> {
		// create directory if it doesn't exist
		fs::create_dir_all(&wallet_config.data_file_dir).context(ErrorKind::IO)?;

		let seed_file_path = &format!(
			"{}{}{}",
			wallet_config.data_file_dir, MAIN_SEPARATOR, SEED_FILE,
		);

		debug!(LOGGER, "Generating wallet seed file at: {}", seed_file_path,);

		if Path::new(seed_file_path).exists() {
			Err(ErrorKind::WalletSeedExists)?
		} else {
			let seed = WalletSeed::init_new();
			let mut file = File::create(seed_file_path).context(ErrorKind::IO)?;
			file.write_all(&seed.to_hex().as_bytes())
				.context(ErrorKind::IO)?;
			Ok(seed)
		}
	}

	pub fn from_file(wallet_config: &WalletConfig) -> Result<WalletSeed, Error> {
		// create directory if it doesn't exist
		fs::create_dir_all(&wallet_config.data_file_dir).context(ErrorKind::IO)?;

		let seed_file_path = &format!(
			"{}{}{}",
			wallet_config.data_file_dir, MAIN_SEPARATOR, SEED_FILE,
		);

		debug!(LOGGER, "Using wallet seed file at: {}", seed_file_path,);

		if Path::new(seed_file_path).exists() {
			let mut file = File::open(seed_file_path).context(ErrorKind::IO)?;
			let mut buffer = String::new();
			file.read_to_string(&mut buffer).context(ErrorKind::IO)?;
			let wallet_seed = WalletSeed::from_hex(&buffer)?;
			Ok(wallet_seed)
		} else {
			error!(
				LOGGER,
				"Run: \"grin wallet init\" to initialize a new wallet.",
			);
			panic!(format!(
				"wallet seed file {} could not be opened (grin wallet init)",
				seed_file_path
			));
		}
	}
}

/// Wallet information tracking all our outputs. Based on HD derivation and
/// avoids storing any key data, only storing output amounts and child index.
#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct WalletData {
	pub outputs: HashMap<String, OutputData>,
}

impl WalletData {
	/// Allows for reading wallet data (without needing to acquire the write
	/// lock).
	pub fn read_wallet<T, F>(data_file_dir: &str, f: F) -> Result<T, Error>
	where
		F: FnOnce(&WalletData) -> Result<T, Error>,
	{
		// open the wallet readonly and do what needs to be done with it
		let data_file_path = &format!("{}{}{}", data_file_dir, MAIN_SEPARATOR, DAT_FILE);
		let wdat = WalletData::read_or_create(data_file_path)?;
		f(&wdat)
	}

	/// Allows the reading and writing of the wallet data within a file lock.
	/// Just provide a closure taking a mutable WalletData. The lock should
	/// be held for as short a period as possible to avoid contention.
	/// Note that due to the impossibility to do an actual file lock easily
	/// across operating systems, this just creates a lock file with a "should
	/// not exist" option.
	pub fn with_wallet<T, F>(data_file_dir: &str, f: F) -> Result<T, Error>
	where
		F: FnOnce(&mut WalletData) -> T,
	{
		// create directory if it doesn't exist
		fs::create_dir_all(data_file_dir).unwrap_or_else(|why| {
			info!(LOGGER, "! {:?}", why.kind());
		});

		let data_file_path = &format!("{}{}{}", data_file_dir, MAIN_SEPARATOR, DAT_FILE);
		let lock_file_path = &format!("{}{}{}", data_file_dir, MAIN_SEPARATOR, LOCK_FILE);

		info!(LOGGER, "Acquiring wallet lock ...");

		let action = || {
			debug!(LOGGER, "Attempting to acquire wallet lock");
			OpenOptions::new()
				.write(true)
				.create_new(true)
				.open(lock_file_path)
		};

		// use tokio_retry to cleanly define some retry logic
		let mut core = reactor::Core::new().unwrap();
		let retry_strategy = FibonacciBackoff::from_millis(10).take(10);
		let retry_future = Retry::spawn(core.handle(), retry_strategy, action);
		let retry_result = core.run(retry_future);

		match retry_result {
			Ok(_) => {}
			Err(e) => {
				error!(
					LOGGER,
					"Failed to acquire wallet lock file (multiple retries)",
				);
				return Err(
					e.context(ErrorKind::WalletData("Failed to acquire lock file"))
						.into(),
				);
			}
		}

		// We successfully acquired the lock - so do what needs to be done.
		let mut wdat = WalletData::read_or_create(data_file_path)?;
		let res = f(&mut wdat);
		wdat.write(data_file_path)?;

		// delete the lock file
		fs::remove_file(lock_file_path).context(ErrorKind::WalletData(
			"Could not remove wallet lock file. Maybe insufficient rights?",
		))?;

		info!(LOGGER, "... released wallet lock");

		Ok(res)
	}

	/// Read the wallet data or created a brand new one if it doesn't exist yet
	fn read_or_create(data_file_path: &str) -> Result<WalletData, Error> {
		if Path::new(data_file_path).exists() {
			WalletData::read(data_file_path)
		} else {
			// just create a new instance, it will get written afterward
			Ok(WalletData {
				outputs: HashMap::new(),
			})
		}
	}

	/// Read output_data vec from disk.
	fn read_outputs(data_file_path: &str) -> Result<Vec<OutputData>, Error> {
		let data_file = File::open(data_file_path)
			.context(ErrorKind::WalletData(&"Could not open wallet file"))?;
		serde_json::from_reader(data_file).map_err(|e| {
			e.context(ErrorKind::WalletData(&"Error reading wallet file "))
				.into()
		})
	}

	/// Populate wallet_data with output_data from disk.
	fn read(data_file_path: &str) -> Result<WalletData, Error> {
		let outputs = WalletData::read_outputs(data_file_path)?;
		let mut wallet_data = WalletData {
			outputs: HashMap::new(),
		};
		for out in outputs {
			wallet_data.add_output(out);
		}
		Ok(wallet_data)
	}

	/// Write the wallet data to disk.
	fn write(&self, data_file_path: &str) -> Result<(), Error> {
		let mut data_file = File::create(data_file_path)
			.map_err(|e| e.context(ErrorKind::WalletData(&"Could not create ")))?;
		let mut outputs = self.outputs.values().collect::<Vec<_>>();
		outputs.sort();
		let res_json = serde_json::to_vec_pretty(&outputs)
			.map_err(|e| e.context(ErrorKind::WalletData("Error serializing wallet data")))?;
		data_file
			.write_all(res_json.as_slice())
			.context(ErrorKind::WalletData(&"Error writing wallet file"))
			.map_err(|e| e.into())
	}

	/// Append a new output data to the wallet data.
	/// TODO - we should check for overwriting here - only really valid for
	/// unconfirmed coinbase
	pub fn add_output(&mut self, out: OutputData) {
		self.outputs.insert(out.key_id.to_hex(), out.clone());
	}

	// TODO - careful with this, only for Unconfirmed (maybe Locked)?
	pub fn delete_output(&mut self, id: &keychain::Identifier) {
		self.outputs.remove(&id.to_hex());
	}

	/// Lock an output data.
	/// TODO - we should track identifier on these outputs (not just n_child)
	pub fn lock_output(&mut self, out: &OutputData) {
		if let Some(out_to_lock) = self.outputs.get_mut(&out.key_id.to_hex()) {
			if out_to_lock.value == out.value {
				out_to_lock.lock()
			}
		}
	}

	pub fn get_output(&self, key_id: &keychain::Identifier) -> Option<&OutputData> {
		self.outputs.get(&key_id.to_hex())
	}

	/// Select spendable coins from the wallet.
	/// Default strategy is to spend the maximum number of outputs (up to max_outputs).
	/// Alternative strategy is to spend smallest outputs first but only as many as necessary.
	/// When we introduce additional strategies we should pass something other than a bool in.
	pub fn select_coins(
		&self,
		root_key_id: keychain::Identifier,
		amount: u64,
		current_height: u64,
		minimum_confirmations: u64,
		max_outputs: usize,
		select_all: bool,
	) -> Vec<OutputData> {
		// first find all eligible outputs based on number of confirmations
		let mut eligible = self.outputs
			.values()
			.filter(|out| {
				out.root_key_id == root_key_id
					&& out.eligible_to_spend(current_height, minimum_confirmations)
			})
			.cloned()
			.collect::<Vec<OutputData>>();

		// sort eligible outputs by increasing value
		eligible.sort_by_key(|out| out.value);

		// use a sliding window to identify potential sets of possible outputs to spend
		// Case of amount > total amount of max_outputs(500):
		// The limit exists because by default, we always select as many inputs as
		// possible in a transaction, to reduce both the Output set and the fees.
		// But that only makes sense up to a point, hence the limit to avoid being too
		// greedy. But if max_outputs(500) is actually not enought to cover the whole
		// amount, the wallet should allow going over it to satisfy what the user
		// wants to send. So the wallet considers max_outputs more of a soft limit.
		if eligible.len() > max_outputs {
			for window in eligible.windows(max_outputs) {
				let windowed_eligibles = window.iter().cloned().collect::<Vec<_>>();
				if let Some(outputs) = self.select_from(amount, select_all, windowed_eligibles) {
					return outputs;
				}
			}
			// Not exist in any window of which total amount >= amount.
			// Then take coins from the smallest one up to the total amount of selected
			// coins = the amount.
			if let Some(outputs) = self.select_from(amount, false, eligible.clone()) {
				debug!(
					LOGGER,
					"Extending maximum number of outputs. {} outputs selected.",
					outputs.len()
				);
				return outputs;
			}
		} else {
			if let Some(outputs) = self.select_from(amount, select_all, eligible.clone()) {
				return outputs;
			}
		}

		// we failed to find a suitable set of outputs to spend,
		// so return the largest amount we can so we can provide guidance on what is
		// possible
		eligible.reverse();
		eligible.iter().take(max_outputs).cloned().collect()
	}

	// Select the full list of outputs if we are using the select_all strategy.
	// Otherwise select just enough outputs to cover the desired amount.
	fn select_from(
		&self,
		amount: u64,
		select_all: bool,
		outputs: Vec<OutputData>,
	) -> Option<Vec<OutputData>> {
		let total = outputs.iter().fold(0, |acc, x| acc + x.value);
		if total >= amount {
			if select_all {
				return Some(outputs.iter().cloned().collect());
			} else {
				let mut selected_amount = 0;
				return Some(
					outputs
						.iter()
						.take_while(|out| {
							let res = selected_amount < amount;
							selected_amount += out.value;
							res
						})
						.cloned()
						.collect(),
				);
			}
		} else {
			None
		}
	}

	/// Next child index when we want to create a new output.
	pub fn next_child(&self, root_key_id: keychain::Identifier) -> u32 {
		let mut max_n = 0;
		for out in self.outputs.values() {
			if max_n < out.n_child && out.root_key_id == root_key_id {
				max_n = out.n_child;
			}
		}
		max_n + 1
	}
}

/// Define the stages of a transaction
#[derive(Serialize, Deserialize, Debug, Clone)]
pub enum PartialTxPhase {
	SenderInitiation,
	ReceiverInitiation,
	SenderConfirmation,
	ReceiverConfirmation,
}

/// Helper in serializing the information required during an interactive aggsig
/// transaction
#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct PartialTx {
	pub phase: PartialTxPhase,
	pub id: Uuid,
	pub amount: u64,
	pub public_blind_excess: String,
	pub public_nonce: String,
	pub kernel_offset: String,
	pub part_sig: String,
	pub tx: String,
}

/// Builds a PartialTx
/// aggsig_tx_context should contain the private key/nonce pair
/// the resulting partial tx will contain the corresponding public keys
pub fn build_partial_tx(
	transaction_id: &Uuid,
	keychain: &keychain::Keychain,
	receive_amount: u64,
	kernel_offset: BlindingFactor,
	part_sig: Option<secp::Signature>,
	tx: Transaction,
) -> PartialTx {
	let (pub_excess, pub_nonce) = keychain.aggsig_get_public_keys(transaction_id);
	let mut pub_excess = pub_excess.serialize_vec(keychain.secp(), true).clone();
	let len = pub_excess.clone().len();
	let pub_excess: Vec<_> = pub_excess.drain(0..len).collect();

	let mut pub_nonce = pub_nonce.serialize_vec(keychain.secp(), true);
	let len = pub_nonce.clone().len();
	let pub_nonce: Vec<_> = pub_nonce.drain(0..len).collect();

	PartialTx {
		phase: PartialTxPhase::SenderInitiation,
		id: transaction_id.clone(),
		amount: receive_amount,
		public_blind_excess: util::to_hex(pub_excess),
		public_nonce: util::to_hex(pub_nonce),
		kernel_offset: kernel_offset.to_hex(),
		part_sig: match part_sig {
			None => String::from("00"),
			Some(p) => util::to_hex(p.serialize_der(&keychain.secp())),
		},
		tx: util::to_hex(ser::ser_vec(&tx).unwrap()),
	}
}

/// Reads a partial transaction into the amount, sum of blinding
/// factors and the transaction itself.
pub fn read_partial_tx(
	keychain: &keychain::Keychain,
	partial_tx: &PartialTx,
) -> Result<
	(
		u64,
		PublicKey,
		PublicKey,
		BlindingFactor,
		Option<Signature>,
		Transaction,
	),
	Error,
> {
	let blind_bin = util::from_hex(partial_tx.public_blind_excess.clone())
		.context(ErrorKind::GenericError("Could not decode HEX"))?;
	let blinding = PublicKey::from_slice(keychain.secp(), &blind_bin[..])
		.context(ErrorKind::GenericError("Could not construct public key"))?;

	let nonce_bin = util::from_hex(partial_tx.public_nonce.clone())
		.context(ErrorKind::GenericError("Could not decode HEX"))?;
	let nonce = PublicKey::from_slice(keychain.secp(), &nonce_bin[..])
		.context(ErrorKind::GenericError("Could not construct public key"))?;

	let kernel_offset = BlindingFactor::from_hex(&partial_tx.kernel_offset.clone())
		.context(ErrorKind::GenericError("Could not decode HEX"))?;

	let sig_bin = util::from_hex(partial_tx.part_sig.clone())
		.context(ErrorKind::GenericError("Could not decode HEX"))?;
	let sig = match sig_bin.len() {
		1 => None,
		_ => Some(Signature::from_der(keychain.secp(), &sig_bin[..])
			.context(ErrorKind::GenericError("Could not create signature"))?),
	};
	let tx_bin = util::from_hex(partial_tx.tx.clone())
		.context(ErrorKind::GenericError("Could not decode HEX"))?;
	let tx = ser::deserialize(&mut &tx_bin[..]).context(ErrorKind::GenericError(
		"Could not deserialize transaction, invalid format.",
	))?;
	Ok((partial_tx.amount, blinding, nonce, kernel_offset, sig, tx))
}

/// Amount in request to build a coinbase output.
#[derive(Serialize, Deserialize, Debug, Clone)]
pub enum WalletReceiveRequest {
	Coinbase(BlockFees),
	PartialTransaction(String),
	Finalize(String),
}

/// Fees in block to use for coinbase amount calculation
#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct BlockFees {
	pub fees: u64,
	pub height: u64,
	pub key_id: Option<keychain::Identifier>,
}

impl BlockFees {
	pub fn key_id(&self) -> Option<keychain::Identifier> {
		self.key_id.clone()
	}
}

/// Response to build a coinbase output.
#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct CbData {
	pub output: String,
	pub kernel: String,
	pub key_id: String,
}

/// a contained wallet info struct, so automated tests can parse wallet info
/// can add more fields here over time as needed
#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct WalletInfo {
	// height from which info was taken
	pub current_height: u64,
	// total amount in the wallet
	pub total: u64,
	// amount awaiting confirmation
	pub amount_awaiting_confirmation: u64,
	// confirmed but locked
	pub amount_confirmed_but_locked: u64,
	// amount currently spendable
	pub amount_currently_spendable: u64,
	// amount locked by previous transactions
	pub amount_locked: u64,
	// whether the data was confirmed against a live node
	pub data_confirmed: bool,
	// node confirming the data
	pub data_confirmed_from: String,
}