Add Payjoin Receiver Support

Cargo.toml

@@ -78,6 +78,8 @@ log = { version = "0.4.22", default-features = false, features = ["std"]}
 vss-client = { package = "vss-client-ng", version = "0.4" }
 prost = { version = "0.11.6", default-features = false}
 
+payjoin = { version = "0.24.0", default-features = false, features = ["v2", "io"] }
+
 [target.'cfg(windows)'.dependencies]
 winapi = { version = "0.3", features = ["winbase"] }
 

src/io/mod.rs

@@ -78,3 +78,7 @@ pub(crate) const BDK_WALLET_INDEXER_KEY: &str = "indexer";
 ///
 /// [`StaticInvoice`]: lightning::offers::static_invoice::StaticInvoice
 pub(crate) const STATIC_INVOICE_STORE_PRIMARY_NAMESPACE: &str = "static_invoices";
+
+/// The payjoin sessions will be persisted under this key.
+pub(crate) const PAYJOIN_SESSION_STORE_PRIMARY_NAMESPACE: &str = "payjoin_sessions";
+pub(crate) const PAYJOIN_SESSION_STORE_SECONDARY_NAMESPACE: &str = "";

src/payment/mod.rs

@@ -14,6 +14,7 @@ mod onchain;
 mod spontaneous;
 pub(crate) mod store;
 mod unified_qr;
+pub(crate) mod payjoin_payment;
 
 pub use bolt11::Bolt11Payment;
 pub use bolt12::Bolt12Payment;

src/payment/payjoin_payment/mod.rs

@@ -0,0 +1,10 @@
+// This file is Copyright its original authors, visible in version control history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
+// http://opensource.org/licenses/MIT>, at your option. You may not use this file except in
+// accordance with one or both of these licenses.
+
+
+pub(crate) mod payjoin_session;
+pub(crate) mod persist;

src/payment/payjoin_payment/payjoin_session.rs

@@ -0,0 +1,249 @@
+// This file is Copyright its original authors, visible in version control history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
+// http://opensource.org/licenses/MIT>, at your option. You may not use this file except in
+// accordance with one or both of these licenses.
+
+use std::time::{Duration, SystemTime, UNIX_EPOCH};
+
+use lightning::ln::channelmanager::PaymentId;
+use lightning::ln::msgs::DecodeError;
+use lightning::util::ser::{Readable, Writeable};
+use lightning::{
+	_init_and_read_len_prefixed_tlv_fields, impl_writeable_tlv_based,
+	impl_writeable_tlv_based_enum, write_tlv_fields,
+};
+
+use crate::data_store::{StorableObject, StorableObjectUpdate};
+
+/// Represents a payjoin session with persisted events
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct PayjoinSession {
+	/// Session identifier (uses PaymentId from PaymentDetails)
+	pub session_id: PaymentId,
+
+	/// Direction of the payjoin (Send or Receive)
+	pub direction: PayjoinDirection,
+
+	/// HPKE public key of receiver (only for sender sessions)
+	pub receiver_pubkey: Option<Vec<u8>>,
+
+	/// Serialized session events as JSON strings
+	pub events: Vec<SerializedSessionEvent>,
+
+	/// Current status of the session
+	pub status: PayjoinStatus,
+
+	/// Unix timestamp of session completion (if completed)
+	pub completed_at: Option<u64>,
+
+	/// The timestamp, in seconds since start of the UNIX epoch, when this entry was last updated.
+	pub latest_update_timestamp: u64,
+}
+
+impl PayjoinSession {
+	pub fn new(
+		session_id: PaymentId, direction: PayjoinDirection, receiver_pubkey: Option<Vec<u8>>,
+	) -> Self {
+		let latest_update_timestamp = SystemTime::now()
+			.duration_since(UNIX_EPOCH)
+			.unwrap_or(Duration::from_secs(0))
+			.as_secs();
+		Self {
+			session_id,
+			direction,
+			receiver_pubkey,
+			events: Vec::new(),
+			status: PayjoinStatus::Active,
+			completed_at: None,
+			latest_update_timestamp,
+		}
+	}
+}
+
+impl Writeable for PayjoinSession {
+	fn write<W: lightning::util::ser::Writer>(
+		&self, writer: &mut W,
+	) -> Result<(), lightning::io::Error> {
+		write_tlv_fields!(writer, {
+			(0, self.session_id, required),
+			(2, self.direction, required),
+			(4, self.receiver_pubkey, option),
+			(6, self.events, required_vec),
+			(8, self.status, required),
+			(10, self.completed_at, required),
+			(12, self.latest_update_timestamp, required),
+		});
+		Ok(())
+	}
+}
+
+impl Readable for PayjoinSession {
+	fn read<R: lightning::io::Read>(reader: &mut R) -> Result<PayjoinSession, DecodeError> {
+		let unix_time_secs = SystemTime::now()
+			.duration_since(UNIX_EPOCH)
+			.unwrap_or(Duration::from_secs(0))
+			.as_secs();
+		_init_and_read_len_prefixed_tlv_fields!(reader, {
+			(0, session_id, required),
+			(2, direction, required),
+			(4, receiver_pubkey, option),
+			(6, events, required_vec),
+			(8, status, required),
+			(10, completed_at, option),
+			(12, latest_update_timestamp, (default_value, unix_time_secs))
+		});
+
+		let session_id: PaymentId = session_id.0.ok_or(DecodeError::InvalidValue)?;
+		let direction: PayjoinDirection = direction.0.ok_or(DecodeError::InvalidValue)?;
+		let status: PayjoinStatus = status.0.ok_or(DecodeError::InvalidValue)?;
+		let latest_update_timestamp: u64 =
+			latest_update_timestamp.0.ok_or(DecodeError::InvalidValue)?;
+
+		Ok(PayjoinSession {
+			session_id,
+			direction,
+			receiver_pubkey,
+			events,
+			status,
+			completed_at,
+			latest_update_timestamp,
+		})
+	}
+}
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+pub enum PayjoinDirection {
+	/// The session is for sending a payment
+	Send,
+	/// The session is for receiving a payment
+	Receive,
+}
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+pub enum PayjoinStatus {
+	/// The session is active
+	Active,
+	/// The session has completed successfully
+	Completed,
+	/// The session has failed
+	Failed,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct SerializedSessionEvent {
+	/// JSON representation of the event
+	pub event_json: String,
+	/// Unix timestamp of when the event occurred
+	pub created_at: u64,
+}
+
+impl_writeable_tlv_based!(SerializedSessionEvent, {
+	(0, event_json, required),
+	(2, created_at, required),
+});
+
+impl_writeable_tlv_based_enum!(PayjoinDirection,
+	(0, Send) => {},
+	(2, Receive) => {}
+);
+
+impl_writeable_tlv_based_enum!(PayjoinStatus,
+	(0, Active) => {},
+	(2, Completed) => {},
+	(4, Failed) => {}
+);
+
+/// Represents a payjoin session with persisted events
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub(crate) struct PayjoinSessionUpdate {
+	pub session_id: PaymentId,
+	pub receiver_pubkey: Option<Option<Vec<u8>>>,
+	pub events: Option<Vec<SerializedSessionEvent>>,
+	pub status: Option<PayjoinStatus>,
+	pub completed_at: Option<Option<u64>>,
+}
+
+impl PayjoinSessionUpdate {
+	pub fn new(id: PaymentId) -> Self {
+		Self {
+			session_id: id,
+			receiver_pubkey: None,
+			events: None,
+			status: None,
+			completed_at: None,
+		}
+	}
+}
+
+impl From<&PayjoinSession> for PayjoinSessionUpdate {
+	fn from(value: &PayjoinSession) -> Self {
+		Self {
+			session_id: value.session_id,
+			receiver_pubkey: Some(value.receiver_pubkey.clone()),
+			events: Some(value.events.clone()),
+			status: Some(value.status),
+			completed_at: Some(value.completed_at),
+		}
+	}
+}
+
+impl StorableObject for PayjoinSession {
+	type Id = PaymentId;
+	type Update = PayjoinSessionUpdate;
+
+	fn id(&self) -> Self::Id {
+		self.session_id
+	}
+
+	fn update(&mut self, update: &Self::Update) -> bool {
+		debug_assert_eq!(
+			self.session_id, update.session_id,
+			"We should only ever override data for the same id"
+		);
+
+		let mut updated = false;
+
+		macro_rules! update_if_necessary {
+			($val:expr, $update:expr) => {
+				if $val != $update {
+					$val = $update;
+					updated = true;
+				}
+			};
+		}
+
+		if let Some(receiver_pubkey_opt) = &update.receiver_pubkey {
+			update_if_necessary!(self.receiver_pubkey, receiver_pubkey_opt.clone());
+		}
+		if let Some(events_opt) = &update.events {
+			update_if_necessary!(self.events, events_opt.clone());
+		}
+		if let Some(status_opt) = update.status {
+			update_if_necessary!(self.status, status_opt);
+		}
+		if let Some(completed_at_opt) = update.completed_at {
+			update_if_necessary!(self.completed_at, completed_at_opt);
+		}
+
+		if updated {
+			self.latest_update_timestamp = SystemTime::now()
+				.duration_since(UNIX_EPOCH)
+				.unwrap_or(Duration::from_secs(0))
+				.as_secs();
+		}
+
+		updated
+	}
+
+	fn to_update(&self) -> Self::Update {
+		self.into()
+	}
+}
+
+impl StorableObjectUpdate<PayjoinSession> for PayjoinSessionUpdate {
+	fn id(&self) -> <PayjoinSession as StorableObject>::Id {
+		self.session_id
+	}
+}