feat: lnd ln backend

crates/cdk-lnd/src/lib.rs

@@ -0,0 +1,272 @@
+//! CDK lightning backend for LND
+
+// Copyright (c) 2023 Steffen (MIT)
+
+#![warn(missing_docs)]
+#![warn(rustdoc::bare_urls)]
+
+use std::path::PathBuf;
+use std::pin::Pin;
+use std::str::FromStr;
+use std::sync::Arc;
+
+use anyhow::anyhow;
+use async_trait::async_trait;
+use cdk::amount::Amount;
+use cdk::cdk_lightning::{
+    self, to_unit, CreateInvoiceResponse, MintLightning, MintMeltSettings, PayInvoiceResponse,
+    PaymentQuoteResponse, Settings, MSAT_IN_SAT,
+};
+use cdk::mint::FeeReserve;
+use cdk::nuts::{CurrencyUnit, MeltQuoteBolt11Request, MeltQuoteState, MintQuoteState};
+use cdk::util::{hex, unix_time};
+use cdk::{mint, Bolt11Invoice};
+use error::Error;
+use fedimint_tonic_lnd::lnrpc::fee_limit::Limit;
+use fedimint_tonic_lnd::lnrpc::FeeLimit;
+use fedimint_tonic_lnd::Client;
+use futures::{Stream, StreamExt};
+use tokio::sync::Mutex;
+
+pub mod error;
+
+/// Lnd mint backend
+#[derive(Clone)]
+pub struct Lnd {
+    address: String,
+    cert_file: PathBuf,
+    macaroon_file: PathBuf,
+    client: Arc<Mutex<Client>>,
+    fee_reserve: FeeReserve,
+    mint_settings: MintMeltSettings,
+    melt_settings: MintMeltSettings,
+}
+
+impl Lnd {
+    /// Create new [`Lnd`]
+    pub async fn new(
+        address: String,
+        cert_file: PathBuf,
+        macaroon_file: PathBuf,
+        fee_reserve: FeeReserve,
+        mint_settings: MintMeltSettings,
+        melt_settings: MintMeltSettings,
+    ) -> Result<Self, Error> {
+        let client = fedimint_tonic_lnd::connect(address.to_string(), &cert_file, &macaroon_file)
+            .await
+            .map_err(|err| {
+                tracing::error!("Connection error: {}", err.to_string());
+                Error::Connection
+            })?;
+
+        Ok(Self {
+            address,
+            cert_file,
+            macaroon_file,
+            client: Arc::new(Mutex::new(client)),
+            fee_reserve,
+            mint_settings,
+            melt_settings,
+        })
+    }
+}
+
+#[async_trait]
+impl MintLightning for Lnd {
+    type Err = cdk_lightning::Error;
+
+    fn get_settings(&self) -> Settings {
+        Settings {
+            mpp: true,
+            unit: CurrencyUnit::Msat,
+            mint_settings: self.mint_settings,
+            melt_settings: self.melt_settings,
+        }
+    }
+
+    async fn wait_any_invoice(
+        &self,
+    ) -> Result<Pin<Box<dyn Stream<Item = String> + Send>>, Self::Err> {
+        let mut client =
+            fedimint_tonic_lnd::connect(self.address.clone(), &self.cert_file, &self.macaroon_file)
+                .await
+                .map_err(|_| Error::Connection)?;
+
+        let stream_req = fedimint_tonic_lnd::lnrpc::InvoiceSubscription {
+            add_index: 0,
+            settle_index: 0,
+        };
+
+        let stream = client
+            .lightning()
+            .subscribe_invoices(stream_req)
+            .await
+            .unwrap()
+            .into_inner();
+
+        Ok(futures::stream::unfold(stream, |mut stream| async move {
+            match stream.message().await {
+                Ok(Some(msg)) => {
+                    if msg.state == 1 {
+                        Some((hex::encode(msg.r_hash), stream))
+                    } else {
+                        None
+                    }
+                }
+                Ok(None) => None, // End of stream
+                Err(_) => None,   // Handle errors gracefully, ends the stream on error
+            }
+        })
+        .boxed())
+    }
+
+    async fn get_payment_quote(
+        &self,
+        melt_quote_request: &MeltQuoteBolt11Request,
+    ) -> Result<PaymentQuoteResponse, Self::Err> {
+        let invoice_amount_msat = melt_quote_request
+            .request
+            .amount_milli_satoshis()
+            .ok_or(Error::UnknownInvoiceAmount)?;
+
+        let amount = to_unit(
+            invoice_amount_msat,
+            &CurrencyUnit::Msat,
+            &melt_quote_request.unit,
+        )?;
+
+        let relative_fee_reserve =
+            (self.fee_reserve.percent_fee_reserve * u64::from(amount) as f32) as u64;
+
+        let absolute_fee_reserve: u64 = self.fee_reserve.min_fee_reserve.into();
+
+        let fee = match relative_fee_reserve > absolute_fee_reserve {
+            true => relative_fee_reserve,
+            false => absolute_fee_reserve,
+        };
+
+        Ok(PaymentQuoteResponse {
+            request_lookup_id: melt_quote_request.request.payment_hash().to_string(),
+            amount,
+            fee: fee.into(),
+            state: MeltQuoteState::Unpaid,
+        })
+    }
+
+    async fn pay_invoice(
+        &self,
+        melt_quote: mint::MeltQuote,
+        partial_amount: Option<Amount>,
+        max_fee: Option<Amount>,
+    ) -> Result<PayInvoiceResponse, Self::Err> {
+        let payment_request = melt_quote.request;
+
+        let pay_req = fedimint_tonic_lnd::lnrpc::SendRequest {
+            payment_request,
+            fee_limit: max_fee.map(|f| {
+                let limit = Limit::Fixed(u64::from(f) as i64);
+
+                FeeLimit { limit: Some(limit) }
+            }),
+            amt_msat: partial_amount
+                .map(|a| {
+                    let msat = to_unit(a, &melt_quote.unit, &CurrencyUnit::Msat).unwrap();
+
+                    u64::from(msat) as i64
+                })
+                .unwrap_or_default(),
+            ..Default::default()
+        };
+
+        let payment_response = self
+            .client
+            .lock()
+            .await
+            .lightning()
+            .send_payment_sync(fedimint_tonic_lnd::tonic::Request::new(pay_req))
+            .await
+            .unwrap()
+            .into_inner();
+
+        let total_spent = payment_response
+            .payment_route
+            .map_or(0, |route| route.total_fees_msat / MSAT_IN_SAT as i64)
+            as u64;
+
+        Ok(PayInvoiceResponse {
+            payment_hash: hex::encode(payment_response.payment_hash),
+            payment_preimage: Some(hex::encode(payment_response.payment_preimage)),
+            status: MeltQuoteState::Pending,
+            total_spent: total_spent.into(),
+        })
+    }
+
+    async fn create_invoice(
+        &self,
+        amount: Amount,
+        unit: &CurrencyUnit,
+        description: String,
+        unix_expiry: u64,
+    ) -> Result<CreateInvoiceResponse, Self::Err> {
+        let time_now = unix_time();
+        assert!(unix_expiry > time_now);
+
+        let amount = to_unit(amount, unit, &CurrencyUnit::Msat)?;
+
+        let invoice_request = fedimint_tonic_lnd::lnrpc::Invoice {
+            value_msat: u64::from(amount) as i64,
+            memo: description,
+            ..Default::default()
+        };
+
+        let invoice = self
+            .client
+            .lock()
+            .await
+            .lightning()
+            .add_invoice(fedimint_tonic_lnd::tonic::Request::new(invoice_request))
+            .await
+            .unwrap()
+            .into_inner();
+
+        let bolt11 = Bolt11Invoice::from_str(&invoice.payment_request)?;
+
+        Ok(CreateInvoiceResponse {
+            request_lookup_id: bolt11.payment_hash().to_string(),
+            request: bolt11,
+            expiry: Some(unix_expiry),
+        })
+    }
+
+    async fn check_invoice_status(
+        &self,
+        request_lookup_id: &str,
+    ) -> Result<MintQuoteState, Self::Err> {
+        let invoice_request = fedimint_tonic_lnd::lnrpc::PaymentHash {
+            r_hash: hex::decode(request_lookup_id).unwrap(),
+            ..Default::default()
+        };
+
+        let invoice = self
+            .client
+            .lock()
+            .await
+            .lightning()
+            .lookup_invoice(fedimint_tonic_lnd::tonic::Request::new(invoice_request))
+            .await
+            .unwrap()
+            .into_inner();
+
+        match invoice.state {
+            // Open
+            0 => Ok(MintQuoteState::Unpaid),
+            // Settled
+            1 => Ok(MintQuoteState::Paid),
+            // Canceled
+            2 => Ok(MintQuoteState::Unpaid),
+            // Accepted
+            3 => Ok(MintQuoteState::Unpaid),
+            _ => Err(Self::Err::Anyhow(anyhow!("Invalid status"))),
+        }
+    }
+}