/// # }
/// ```
///
+/// # Payments
+///
+/// [`ChannelManager`] is responsible for sending, forwarding, and receiving payments through its
+/// channels. A payment is typically initiated from a [BOLT 11] invoice or a [BOLT 12] offer, though
+/// spontaneous (i.e., keysend) payments are also possible. Incoming payments don't require
+/// maintaining any additional state as [`ChannelManager`] can reconstruct the [`PaymentPreimage`]
+/// from the [`PaymentSecret`]. Sending payments, however, require tracking in order to retry failed
+/// HTLCs.
+///
+/// After a payment is initiated, it will appear in [`list_recent_payments`] until a short time
+/// after either an [`Event::PaymentSent`] or [`Event::PaymentFailed`] is handled. Failed HTLCs
+/// for a payment will be retried according to the payment's [`Retry`] strategy or until
+/// [`abandon_payment`] is called.
+///
+/// ## BOLT 11 Invoices
+///
+/// The [`lightning-invoice`] crate is useful for creating BOLT 11 invoices. Specifically, use the
+/// functions in its `utils` module for constructing invoices that are compatible with
+/// [`ChannelManager`]. These functions serve as a convenience for building invoices with the
+/// [`PaymentHash`] and [`PaymentSecret`] returned from [`create_inbound_payment`]. To provide your
+/// own [`PaymentHash`], use [`create_inbound_payment_for_hash`] or the corresponding functions in
+/// the [`lightning-invoice`] `utils` module.
+///
+/// [`ChannelManager`] generates an [`Event::PaymentClaimable`] once the full payment has been
+/// received. Call [`claim_funds`] to release the [`PaymentPreimage`], which in turn will result in
+/// an [`Event::PaymentClaimed`].
+///
+/// ```
+/// # use lightning::events::{Event, EventsProvider, PaymentPurpose};
+/// # use lightning::ln::channelmanager::AChannelManager;
+/// #
+/// # fn example<T: AChannelManager>(channel_manager: T) {
+/// # let channel_manager = channel_manager.get_cm();
+/// // Or use utils::create_invoice_from_channelmanager
+/// let known_payment_hash = match channel_manager.create_inbound_payment(
+/// Some(10_000_000), 3600, None
+/// ) {
+/// Ok((payment_hash, _payment_secret)) => {
+/// println!("Creating inbound payment {}", payment_hash);
+/// payment_hash
+/// },
+/// Err(()) => panic!("Error creating inbound payment"),
+/// };
+///
+/// // On the event processing thread
+/// channel_manager.process_pending_events(&|event| match event {
+/// Event::PaymentClaimable { payment_hash, purpose, .. } => match purpose {
+/// PaymentPurpose::InvoicePayment { payment_preimage: Some(payment_preimage), .. } => {
+/// assert_eq!(payment_hash, known_payment_hash);
+/// println!("Claiming payment {}", payment_hash);
+/// channel_manager.claim_funds(payment_preimage);
+/// },
+/// PaymentPurpose::InvoicePayment { payment_preimage: None, .. } => {
+/// println!("Unknown payment hash: {}", payment_hash);
+/// },
+/// PaymentPurpose::SpontaneousPayment(payment_preimage) => {
+/// assert_ne!(payment_hash, known_payment_hash);
+/// println!("Claiming spontaneous payment {}", payment_hash);
+/// channel_manager.claim_funds(payment_preimage);
+/// },
+/// },
+/// Event::PaymentClaimed { payment_hash, amount_msat, .. } => {
+/// assert_eq!(payment_hash, known_payment_hash);
+/// println!("Claimed {} msats", amount_msat);
+/// },
+/// // ...
+/// # _ => {},
+/// });
+/// # }
+/// ```
+///
+/// For paying an invoice, [`lightning-invoice`] provides a `payment` module with convenience
+/// functions for use with [`send_payment`].
+///
+/// ```
+/// # use lightning::events::{Event, EventsProvider};
+/// # use lightning::ln::PaymentHash;
+/// # use lightning::ln::channelmanager::{AChannelManager, PaymentId, RecentPaymentDetails, RecipientOnionFields, Retry};
+/// # use lightning::routing::router::RouteParameters;
+/// #
+/// # fn example<T: AChannelManager>(
+/// # channel_manager: T, payment_hash: PaymentHash, recipient_onion: RecipientOnionFields,
+/// # route_params: RouteParameters, retry: Retry
+/// # ) {
+/// # let channel_manager = channel_manager.get_cm();
+/// // let (payment_hash, recipient_onion, route_params) =
+/// // payment::payment_parameters_from_invoice(&invoice);
+/// let payment_id = PaymentId([42; 32]);
+/// match channel_manager.send_payment(
+/// payment_hash, recipient_onion, payment_id, route_params, retry
+/// ) {
+/// Ok(()) => println!("Sending payment with hash {}", payment_hash),
+/// Err(e) => println!("Failed sending payment with hash {}: {:?}", payment_hash, e),
+/// }
+///
+/// let expected_payment_id = payment_id;
+/// let expected_payment_hash = payment_hash;
+/// assert!(
+/// channel_manager.list_recent_payments().iter().find(|details| matches!(
+/// details,
+/// RecentPaymentDetails::Pending {
+/// payment_id: expected_payment_id,
+/// payment_hash: expected_payment_hash,
+/// ..
+/// }
+/// )).is_some()
+/// );
+///
+/// // On the event processing thread
+/// channel_manager.process_pending_events(&|event| match event {
+/// Event::PaymentSent { payment_hash, .. } => println!("Paid {}", payment_hash),
+/// Event::PaymentFailed { payment_hash, .. } => println!("Failed paying {}", payment_hash),
+/// // ...
+/// # _ => {},
+/// });
+/// # }
+/// ```
+///
+/// ## BOLT 12 Offers
+///
+/// The [`offers`] module is useful for creating BOLT 12 offers. An [`Offer`] is a precursor to a
+/// [`Bolt12Invoice`], which must first be requested by the payer. The interchange of these messages
+/// as defined in the specification is handled by [`ChannelManager`] and its implementation of
+/// [`OffersMessageHandler`]. However, this only works with an [`Offer`] created using a builder
+/// returned by [`create_offer_builder`]. With this approach, BOLT 12 offers and invoices are
+/// stateless just as BOLT 11 invoices are.
+///
+/// ```
+/// # use lightning::events::{Event, EventsProvider, PaymentPurpose};
+/// # use lightning::ln::channelmanager::AChannelManager;
+/// # use lightning::offers::parse::Bolt12SemanticError;
+/// #
+/// # fn example<T: AChannelManager>(channel_manager: T) -> Result<(), Bolt12SemanticError> {
+/// # let channel_manager = channel_manager.get_cm();
+/// let offer = channel_manager
+/// .create_offer_builder("coffee".to_string())?
+/// # ;
+/// # // Needed for compiling for c_bindings
+/// # let builder: lightning::offers::offer::OfferBuilder<_, _> = offer.into();
+/// # let offer = builder
+/// .amount_msats(10_000_000)
+/// .build()?;
+/// let bech32_offer = offer.to_string();
+///
+/// // On the event processing thread
+/// channel_manager.process_pending_events(&|event| match event {
+/// Event::PaymentClaimable { payment_hash, purpose, .. } => match purpose {
+/// PaymentPurpose::InvoicePayment { payment_preimage: Some(payment_preimage), .. } => {
+/// println!("Claiming payment {}", payment_hash);
+/// channel_manager.claim_funds(payment_preimage);
+/// },
+/// PaymentPurpose::InvoicePayment { payment_preimage: None, .. } => {
+/// println!("Unknown payment hash: {}", payment_hash);
+/// },
+/// // ...
+/// # _ => {},
+/// },
+/// Event::PaymentClaimed { payment_hash, amount_msat, .. } => {
+/// println!("Claimed {} msats", amount_msat);
+/// },
+/// // ...
+/// # _ => {},
+/// });
+/// # Ok(())
+/// # }
+/// ```
+///
+/// Use [`pay_for_offer`] to initiated payment, which sends an [`InvoiceRequest`] for an [`Offer`]
+/// and pays the [`Bolt12Invoice`] response. In addition to success and failure events,
+/// [`ChannelManager`] may also generate an [`Event::InvoiceRequestFailed`].
+///
+/// ```
+/// # use lightning::events::{Event, EventsProvider};
+/// # use lightning::ln::channelmanager::{AChannelManager, PaymentId, RecentPaymentDetails, Retry};
+/// # use lightning::offers::offer::Offer;
+/// #
+/// # fn example<T: AChannelManager>(
+/// # channel_manager: T, offer: &Offer, quantity: Option<u64>, amount_msats: Option<u64>,
+/// # payer_note: Option<String>, retry: Retry, max_total_routing_fee_msat: Option<u64>
+/// # ) {
+/// # let channel_manager = channel_manager.get_cm();
+/// let payment_id = PaymentId([42; 32]);
+/// match channel_manager.pay_for_offer(
+/// offer, quantity, amount_msats, payer_note, payment_id, retry, max_total_routing_fee_msat
+/// ) {
+/// Ok(()) => println!("Requesting invoice for offer"),
+/// Err(e) => println!("Unable to request invoice for offer: {:?}", e),
+/// }
+///
+/// // First the payment will be waiting on an invoice
+/// let expected_payment_id = payment_id;
+/// assert!(
+/// channel_manager.list_recent_payments().iter().find(|details| matches!(
+/// details,
+/// RecentPaymentDetails::AwaitingInvoice { payment_id: expected_payment_id }
+/// )).is_some()
+/// );
+///
+/// // Once the invoice is received, a payment will be sent
+/// assert!(
+/// channel_manager.list_recent_payments().iter().find(|details| matches!(
+/// details,
+/// RecentPaymentDetails::Pending { payment_id: expected_payment_id, .. }
+/// )).is_some()
+/// );
+///
+/// // On the event processing thread
+/// channel_manager.process_pending_events(&|event| match event {
+/// Event::PaymentSent { payment_id: Some(payment_id), .. } => println!("Paid {}", payment_id),
+/// Event::PaymentFailed { payment_id, .. } => println!("Failed paying {}", payment_id),
+/// Event::InvoiceRequestFailed { payment_id, .. } => println!("Failed paying {}", payment_id),
+/// // ...
+/// # _ => {},
+/// });
+/// # }
+/// ```
+///
+/// ## BOLT 12 Refunds
+///
+/// A [`Refund`] is a request for an invoice to be paid. Like *paying* for an [`Offer`], *creating*
+/// a [`Refund`] involves maintaining state since it represents a future outbound payment.
+/// Therefore, use [`create_refund_builder`] when creating one, otherwise [`ChannelManager`] will
+/// refuse to pay any corresponding [`Bolt12Invoice`] that it receives.
+///
+/// ```
+/// # use core::time::Duration;
+/// # use lightning::events::{Event, EventsProvider};
+/// # use lightning::ln::channelmanager::{AChannelManager, PaymentId, RecentPaymentDetails, Retry};
+/// # use lightning::offers::parse::Bolt12SemanticError;
+/// #
+/// # fn example<T: AChannelManager>(
+/// # channel_manager: T, amount_msats: u64, absolute_expiry: Duration, retry: Retry,
+/// # max_total_routing_fee_msat: Option<u64>
+/// # ) -> Result<(), Bolt12SemanticError> {
+/// # let channel_manager = channel_manager.get_cm();
+/// let payment_id = PaymentId([42; 32]);
+/// let refund = channel_manager
+/// .create_refund_builder(
+/// "coffee".to_string(), amount_msats, absolute_expiry, payment_id, retry,
+/// max_total_routing_fee_msat
+/// )?
+/// # ;
+/// # // Needed for compiling for c_bindings
+/// # let builder: lightning::offers::refund::RefundBuilder<_> = refund.into();
+/// # let refund = builder
+/// .payer_note("refund for order 1234".to_string())
+/// .build()?;
+/// let bech32_refund = refund.to_string();
+///
+/// // First the payment will be waiting on an invoice
+/// let expected_payment_id = payment_id;
+/// assert!(
+/// channel_manager.list_recent_payments().iter().find(|details| matches!(
+/// details,
+/// RecentPaymentDetails::AwaitingInvoice { payment_id: expected_payment_id }
+/// )).is_some()
+/// );
+///
+/// // Once the invoice is received, a payment will be sent
+/// assert!(
+/// channel_manager.list_recent_payments().iter().find(|details| matches!(
+/// details,
+/// RecentPaymentDetails::Pending { payment_id: expected_payment_id, .. }
+/// )).is_some()
+/// );
+///
+/// // On the event processing thread
+/// channel_manager.process_pending_events(&|event| match event {
+/// Event::PaymentSent { payment_id: Some(payment_id), .. } => println!("Paid {}", payment_id),
+/// Event::PaymentFailed { payment_id, .. } => println!("Failed paying {}", payment_id),
+/// // ...
+/// # _ => {},
+/// });
+/// # Ok(())
+/// # }
+/// ```
+///
+/// Use [`request_refund_payment`] to send a [`Bolt12Invoice`] for receiving the refund. Similar to
+/// *creating* an [`Offer`], this is stateless as it represents an inbound payment.
+///
+/// ```
+/// # use lightning::events::{Event, EventsProvider, PaymentPurpose};
+/// # use lightning::ln::channelmanager::AChannelManager;
+/// # use lightning::offers::refund::Refund;
+/// #
+/// # fn example<T: AChannelManager>(channel_manager: T, refund: &Refund) {
+/// # let channel_manager = channel_manager.get_cm();
+/// match channel_manager.request_refund_payment(refund) {
+/// Ok(()) => println!("Requesting payment for refund"),
+/// Err(e) => println!("Unable to request payment for refund: {:?}", e),
+/// }
+///
+/// // On the event processing thread
+/// channel_manager.process_pending_events(&|event| match event {
+/// Event::PaymentClaimable { payment_hash, purpose, .. } => match purpose {
+/// PaymentPurpose::InvoicePayment { payment_preimage: Some(payment_preimage), .. } => {
+/// println!("Claiming payment {}", payment_hash);
+/// channel_manager.claim_funds(payment_preimage);
+/// },
+/// PaymentPurpose::InvoicePayment { payment_preimage: None, .. } => {
+/// println!("Unknown payment hash: {}", payment_hash);
+/// },
+/// // ...
+/// # _ => {},
+/// },
+/// Event::PaymentClaimed { payment_hash, amount_msat, .. } => {
+/// println!("Claimed {} msats", amount_msat);
+/// },
+/// // ...
+/// # _ => {},
+/// });
+/// # }
+/// ```
+///
/// # Persistence
///
/// Implements [`Writeable`] to write out all channel state to disk. Implies [`peer_disconnected`] for
/// [`create_channel`]: Self::create_channel
/// [`close_channel`]: Self::force_close_broadcasting_latest_txn
/// [`force_close_broadcasting_latest_txn`]: Self::force_close_broadcasting_latest_txn
+/// [BOLT 11]: https://github.com/lightning/bolts/blob/master/11-payment-encoding.md
+/// [BOLT 12]: https://github.com/rustyrussell/lightning-rfc/blob/guilt/offers/12-offer-encoding.md
+/// [`list_recent_payments`]: Self::list_recent_payments
+/// [`abandon_payment`]: Self::abandon_payment
+/// [`lightning-invoice`]: https://docs.rs/lightning_invoice/latest/lightning_invoice
+/// [`create_inbound_payment`]: Self::create_inbound_payment
+/// [`create_inbound_payment_for_hash`]: Self::create_inbound_payment_for_hash
+/// [`claim_funds`]: Self::claim_funds
+/// [`send_payment`]: Self::send_payment
+/// [`offers`]: crate::offers
+/// [`create_offer_builder`]: Self::create_offer_builder
+/// [`pay_for_offer`]: Self::pay_for_offer
+/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
+/// [`create_refund_builder`]: Self::create_refund_builder
+/// [`request_refund_payment`]: Self::request_refund_payment
/// [`peer_disconnected`]: msgs::ChannelMessageHandler::peer_disconnected
/// [`funding_created`]: msgs::FundingCreated
/// [`funding_transaction_generated`]: Self::funding_transaction_generated
projects / rust-lightning / blobdiff