feat: lnbits ln backend

fix: check webhook url is valid

crates/cdk-lnbits/src/lib.rs

@@ -0,0 +1,274 @@
+//! CDK lightning backend for lnbits
+
+#![warn(missing_docs)]
+#![warn(rustdoc::bare_urls)]
+
+use std::pin::Pin;
+use std::sync::Arc;
+
+use anyhow::anyhow;
+use async_trait::async_trait;
+use axum::Router;
+use cdk::amount::Amount;
+use cdk::cdk_lightning::{
+    self, to_unit, CreateInvoiceResponse, MintLightning, MintMeltSettings, PayInvoiceResponse,
+    PaymentQuoteResponse, Settings,
+};
+use cdk::mint::FeeReserve;
+use cdk::nuts::{CurrencyUnit, MeltQuoteBolt11Request, MeltQuoteState, MintQuoteState};
+use cdk::util::unix_time;
+use cdk::{mint, Bolt11Invoice};
+use error::Error;
+use futures::stream::StreamExt;
+use futures::Stream;
+use lnbits_rs::api::invoice::CreateInvoiceRequest;
+use lnbits_rs::LNBitsClient;
+use tokio::sync::Mutex;
+
+pub mod error;
+
+/// LNBits
+#[derive(Clone)]
+pub struct LNBits {
+    lnbits_api: LNBitsClient,
+    mint_settings: MintMeltSettings,
+    melt_settings: MintMeltSettings,
+    fee_reserve: FeeReserve,
+    receiver: Arc<Mutex<Option<tokio::sync::mpsc::Receiver<String>>>>,
+    webhook_url: String,
+}
+
+impl LNBits {
+    /// Create new [`LNBits`] wallet
+    #[allow(clippy::too_many_arguments)]
+    pub async fn new(
+        admin_api_key: String,
+        invoice_api_key: String,
+        api_url: String,
+        mint_settings: MintMeltSettings,
+        melt_settings: MintMeltSettings,
+        fee_reserve: FeeReserve,
+        receiver: Arc<Mutex<Option<tokio::sync::mpsc::Receiver<String>>>>,
+        webhook_url: String,
+    ) -> Result<Self, Error> {
+        let lnbits_api = LNBitsClient::new("", &admin_api_key, &invoice_api_key, &api_url, None)?;
+
+        Ok(Self {
+            lnbits_api,
+            mint_settings,
+            melt_settings,
+            receiver,
+            fee_reserve,
+            webhook_url,
+        })
+    }
+}
+
+#[async_trait]
+impl MintLightning for LNBits {
+    type Err = cdk_lightning::Error;
+
+    fn get_settings(&self) -> Settings {
+        Settings {
+            mpp: false,
+            unit: CurrencyUnit::Sat,
+            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 receiver = self
+            .receiver
+            .lock()
+            .await
+            .take()
+            .ok_or(anyhow!("No receiver"))?;
+
+        let lnbits_api = self.lnbits_api.clone();
+
+        Ok(futures::stream::unfold(
+            (receiver, lnbits_api),
+            |(mut receiver, lnbits_api)| async move {
+                match receiver.recv().await {
+                    Some(msg) => {
+                        let check = lnbits_api.is_invoice_paid(&msg).await;
+
+                        match check {
+                            Ok(state) => {
+                                if state {
+                                    Some((msg, (receiver, lnbits_api)))
+                                } else {
+                                    None
+                                }
+                            }
+                            _ => None,
+                        }
+                    }
+                    None => None,
+                }
+            },
+        )
+        .boxed())
+    }
+
+    async fn get_payment_quote(
+        &self,
+        melt_quote_request: &MeltQuoteBolt11Request,
+    ) -> Result<PaymentQuoteResponse, Self::Err> {
+        if melt_quote_request.unit != CurrencyUnit::Sat {
+            return Err(Self::Err::Anyhow(anyhow!("Unsupported unit")));
+        }
+
+        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,
+        })
+    }
+
+    async fn pay_invoice(
+        &self,
+        melt_quote: mint::MeltQuote,
+        _partial_msats: Option<Amount>,
+        _max_fee_msats: Option<Amount>,
+    ) -> Result<PayInvoiceResponse, Self::Err> {
+        let pay_response = self
+            .lnbits_api
+            .pay_invoice(&melt_quote.request)
+            .await
+            .map_err(|err| {
+                tracing::error!("Could not pay invoice");
+                tracing::error!("{}", err.to_string());
+                Self::Err::Anyhow(anyhow!("Could not pay invoice"))
+            })?;
+
+        let invoice_info = self
+            .lnbits_api
+            .find_invoice(&pay_response.payment_hash)
+            .await
+            .map_err(|err| {
+                tracing::error!("Could not find invoice");
+                tracing::error!("{}", err.to_string());
+                Self::Err::Anyhow(anyhow!("Could not find invoice"))
+            })?;
+
+        let status = match invoice_info.pending {
+            true => MeltQuoteState::Unpaid,
+            false => MeltQuoteState::Paid,
+        };
+
+        let total_spent = Amount::from((invoice_info.amount + invoice_info.fee).unsigned_abs());
+
+        Ok(PayInvoiceResponse {
+            payment_hash: pay_response.payment_hash,
+            payment_preimage: Some(invoice_info.payment_hash),
+            status,
+            total_spent,
+        })
+    }
+
+    async fn create_invoice(
+        &self,
+        amount: Amount,
+        unit: &CurrencyUnit,
+        description: String,
+        unix_expiry: u64,
+    ) -> Result<CreateInvoiceResponse, Self::Err> {
+        if unit != &CurrencyUnit::Sat {
+            return Err(Self::Err::Anyhow(anyhow!("Unsupported unit")));
+        }
+
+        let time_now = unix_time();
+        assert!(unix_expiry > time_now);
+
+        let expiry = unix_expiry - time_now;
+
+        let invoice_request = CreateInvoiceRequest {
+            amount: to_unit(amount, unit, &CurrencyUnit::Sat)?.into(),
+            memo: Some(description),
+            unit: unit.to_string(),
+            expiry: Some(expiry),
+            webhook: Some(self.webhook_url.clone()),
+            internal: None,
+            out: false,
+        };
+
+        let create_invoice_response = self
+            .lnbits_api
+            .create_invoice(&invoice_request)
+            .await
+            .map_err(|err| {
+                tracing::error!("Could not create invoice");
+                tracing::error!("{}", err.to_string());
+                Self::Err::Anyhow(anyhow!("Could not create invoice"))
+            })?;
+
+        let request: Bolt11Invoice = create_invoice_response.payment_request.parse()?;
+        let expiry = request.expires_at().map(|t| t.as_secs());
+
+        Ok(CreateInvoiceResponse {
+            request_lookup_id: create_invoice_response.payment_hash,
+            request,
+            expiry,
+        })
+    }
+
+    async fn check_invoice_status(
+        &self,
+        request_lookup_id: &str,
+    ) -> Result<MintQuoteState, Self::Err> {
+        let paid = self
+            .lnbits_api
+            .is_invoice_paid(request_lookup_id)
+            .await
+            .map_err(|err| {
+                tracing::error!("Could not check invoice status");
+                tracing::error!("{}", err.to_string());
+                Self::Err::Anyhow(anyhow!("Could not check invoice status"))
+            })?;
+
+        let state = match paid {
+            true => MintQuoteState::Paid,
+            false => MintQuoteState::Unpaid,
+        };
+
+        Ok(state)
+    }
+}
+
+impl LNBits {
+    /// Create invoice webhook
+    pub async fn create_invoice_webhook_router(
+        &self,
+        webhook_endpoint: &str,
+        sender: tokio::sync::mpsc::Sender<String>,
+    ) -> anyhow::Result<Router> {
+        self.lnbits_api
+            .create_invoice_webhook_router(webhook_endpoint, sender)
+            .await
+    }
+}