cli: Add cli command to pay offer

src/cli.rs

@@ -1,6 +1,11 @@
 use clap::{Parser, Subcommand};
+use lndk::lnd::{get_lnd_client, string_to_network, LndCfg};
 use lndk::lndk_offers::decode;
+use lndk::{Cfg, LifecycleSignals, LndkOnionMessenger, OfferHandler, PayOfferParams};
 use std::ffi::OsString;
+use tokio::select;
+use tokio::sync::mpsc;
+use tokio::sync::mpsc::{Receiver, Sender};
 
 fn get_cert_path_default() -> OsString {
     home::home_dir()
@@ -60,23 +65,101 @@ enum Commands {
         /// The offer string to decode.
         offer_string: String,
     },
+    /// PayOffer pays a BOLT 12 offer, provided as a 'lno'-prefaced offer string.
+    PayOffer {
+        /// The offer string.
+        offer_string: String,
+
+        /// Amount the user would like to pay. If this isn't set, we'll assume the user is paying
+        /// whatever the offer amount is.
+        #[arg(required = false)]
+        amount: Option<u64>,
+    },
 }
 
-fn main() {
+#[tokio::main]
+async fn main() -> Result<(), ()> {
     let args = Cli::parse();
     match args.command {
         Commands::Decode { offer_string } => {
             println!("Decoding offer: {offer_string}.");
             match decode(offer_string) {
-                Ok(offer) => println!("Decoded offer: {:?}.", offer),
+                Ok(offer) => {
+                    println!("Decoded offer: {:?}.", offer);
+                    Ok(())
+                }
                 Err(e) => {
                     println!(
                         "ERROR please provide offer starting with lno. Provided offer is \
                         invalid, failed to decode with error: {:?}.",
                         e
-                    )
+                    );
+                    Err(())
                 }
             }
         }
+        Commands::PayOffer {
+            offer_string,
+            amount,
+        } => {
+            let offer = match decode(offer_string) {
+                Ok(offer) => offer,
+                Err(e) => {
+                    println!(
+                        "ERROR: please provide offer starting with lno. Provided offer is \
+                        invalid, failed to decode with error: {:?}.",
+                        e
+                    );
+                    return Err(());
+                }
+            };
+
+            let network = string_to_network(&args.network).map_err(|e| {
+                println!("ERROR: invalid network string: {}", e);
+            })?;
+            let lnd_cfg = LndCfg::new(args.address, args.tls_cert.into(), args.macaroon.into());
+            let client = get_lnd_client(lnd_cfg.clone()).map_err(|e| {
+                println!("ERROR: failed to connect to lnd: {}", e);
+            })?;
+
+            let (shutdown, listener) = triggered::trigger();
+            let (tx, rx): (Sender<u32>, Receiver<u32>) = mpsc::channel(1);
+            let signals = LifecycleSignals {
+                shutdown: shutdown.clone(),
+                listener,
+                started: tx,
+            };
+            let lndk_cfg = Cfg {
+                lnd: lnd_cfg,
+                log_dir: None,
+                signals,
+            };
+
+            let handler = OfferHandler::new();
+            let messenger = LndkOnionMessenger::new(handler);
+            let pay_cfg = PayOfferParams {
+                offer: offer.clone(),
+                amount,
+                network,
+                client,
+                blinded_path: offer.paths()[0].clone(),
+                reply_path: None,
+            };
+            select! {
+                _ = messenger.run(lndk_cfg) => {
+                    println!("ERROR: lndk stopped running before pay offer finished.");
+                },
+                res = messenger.offer_handler.pay_offer(pay_cfg, rx) => {
+                    match res {
+                    Ok(_) => println!("Successfully paid for offer!"),
+                                Err(_) => println!("Error paying for offer."),
+                    }
+
+                    shutdown.trigger();
+                }
+            }
+
+            Ok(())
+        }
     }
 }