WIP: Offer struct for BOLT 12

Author: jkczyz

lightning/src/offers/mod.rs

@@ -12,17 +12,141 @@
 
 use bitcoin::bech32;
 use bitcoin::bech32::FromBase32;
+use bitcoin::blockdata::constants::genesis_block;
 use bitcoin::hash_types::BlockHash;
+use bitcoin::network::constants::Network;
 use bitcoin::secp256k1::{PublicKey, XOnlyPublicKey};
 use bitcoin::secp256k1::schnorr::Signature;
 use core::str::FromStr;
+use core::time::Duration;
 use ln::PaymentHash;
 use ln::features::OfferFeatures;
 use ln::msgs::DecodeError;
 use util::ser::{HighZeroBytesDroppedVarInt, Readable, WithLength, WithoutLength};
 
 use prelude::*;
 
+#[cfg(feature = "std")]
+use std::time::SystemTime;
+
+///
+#[derive(Debug)]
+pub struct Offer {
+	chains: Option<Vec<BlockHash>>,
+	amount: Option<Amount>,
+	description: String,
+	features: Option<OfferFeatures>,
+	absolute_expiry: Option<Duration>,
+	issuer: Option<String>,
+	destination: Destination,
+	quantity_min: Option<u64>,
+	quantity_max: Option<u64>,
+	recurrence: Option<Recurrence>,
+	send_invoice: Option<SendInvoice>,
+	signature: Option<Signature>,
+}
+
+impl Offer {
+	///
+	pub fn chain(&self) -> BlockHash {
+		self.chains
+			.as_ref()
+			.and_then(|chains| chains.first().copied())
+			.unwrap_or_else(|| genesis_block(Network::Bitcoin).block_hash())
+	}
+
+	///
+	pub fn amount(&self) -> Option<&Amount> {
+		self.amount.as_ref()
+	}
+
+	///
+	pub fn description(&self) -> &String {
+		&self.description
+	}
+
+	///
+	pub fn features(&self) -> Option<&OfferFeatures> {
+		self.features.as_ref()
+	}
+
+	///
+	pub fn absolute_expiry(&self) -> Option<Duration> {
+		self.absolute_expiry
+	}
+
+	///
+	#[cfg(feature = "std")]
+	pub fn is_expired(&self) -> bool {
+		match self.absolute_expiry() {
+			Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
+				Ok(elapsed) => elapsed > seconds_from_epoch,
+				Err(_) => false,
+			},
+			None => false,
+		}
+	}
+
+	///
+	pub fn issuer(&self) -> Option<&String> {
+		self.issuer.as_ref()
+	}
+
+	///
+	pub fn destination(&self) -> &Destination {
+		&self.destination
+	}
+
+	///
+	pub fn quantity_min(&self) -> u64 {
+		self.quantity_min.unwrap_or(1)
+	}
+
+	///
+	pub fn quantity_max(&self) -> u64 {
+		self.quantity_max.unwrap_or_else(||
+			self.quantity_min.map_or(1, |_| u64::max_value()))
+	}
+
+	///
+	pub fn signature(&self) -> Option<&Signature> {
+		self.signature.as_ref()
+	}
+}
+
+/// The amount required for an item in an [`Offer`] denominated in either bitcoin or another
+/// currency.
+#[derive(Debug)]
+pub enum Amount {
+	/// An amount of bitcoin.
+	Bitcoin {
+		/// The amount in millisatoshi.
+		amount_msats: u64,
+	},
+	/// An amount of currency specified using ISO 4712.
+	Currency {
+		/// An ISO 4712 three-letter currency code (e.g., USD).
+		iso4217_code: String,
+		/// The amount in the currency unit adjusted by the ISO 4712 exponent (e.g., USD cents).
+		amount: u64,
+	},
+}
+
+///
+#[derive(Debug)]
+pub enum Destination {
+	///
+	NodeId(XOnlyPublicKey),
+	///
+	Paths(Vec<BlindedPath>),
+}
+
+///
+#[derive(Debug)]
+pub struct SendInvoice {
+	refund_for: Option<PaymentHash>,
+}
+
 /// An `offer` TLV stream without any semantic checks, apart from any checks performed when parsing
 /// the underlying types.
 #[derive(Debug)]
@@ -63,7 +187,8 @@ impl_writeable_tlv_stream!(OfferTlvStream, {
 });
 
 #[derive(Debug)]
-struct BlindedPath {
+///
+pub struct BlindedPath {
 	blinding: PublicKey,
 	path: WithLength<Vec<OnionMessagePath>, u8>,
 }