Add suport for Bolt12 notifications for HTTP subscription

This commit adds support for Mint Bolt12 Notifications for HTTP when Mint does
not support WebSocket or the wallet decides not to use it, and falls back to
HTTP.

This PR fixes #992

TODO: Add a test compiling the wallet without HTTP support to test it

crates/cdk/src/wallet/subscription/http.rs

@@ -2,6 +2,7 @@ use std::collections::HashMap;
 use std::sync::Arc;
 use std::time::Duration;
 
+use cdk_common::MintQuoteBolt12Response;
 use tokio::sync::{mpsc, RwLock};
 use tokio::time;
 
@@ -15,6 +16,7 @@ use crate::Wallet;
 #[derive(Debug, Hash, PartialEq, Eq)]
 enum UrlType {
     Mint(String),
+    MintBolt12(String),
     Melt(String),
     PublicKey(nut01::PublicKey),
 }
@@ -22,6 +24,7 @@ enum UrlType {
 #[derive(Debug, Eq, PartialEq)]
 enum AnyState {
     MintQuoteState(nut23::QuoteState),
+    MintBolt12QuoteState(MintQuoteBolt12Response<String>),
     MeltQuoteState(nut05::QuoteState),
     PublicKey(nut07::State),
     Empty,
@@ -67,7 +70,12 @@ async fn convert_subscription(
             }
         }
         Kind::Bolt12MintQuote => {
-            for id in sub.1.filters.iter().map(|id| UrlType::Mint(id.clone())) {
+            for id in sub
+                .1
+                .filters
+                .iter()
+                .map(|id| UrlType::MintBolt12(id.clone()))
+            {
                 subscribed_to.insert(id, (sub.0.clone(), sub.1.id.clone(), AnyState::Empty));
             }
         }
@@ -98,6 +106,18 @@ pub async fn http_main<S: IntoIterator<Item = SubId>>(
                 for (url, (sender, _, last_state)) in subscribed_to.iter_mut() {
                     tracing::debug!("Polling: {:?}", url);
                     match url {
+                        UrlType::MintBolt12(id) => {
+                            let response = http_client.get_mint_quote_bolt12_status(id).await;
+                            if let Ok(response) = response {
+                                if *last_state == AnyState::MintBolt12QuoteState(response.clone()) {
+                                    continue;
+                                }
+                                *last_state = AnyState::MintBolt12QuoteState(response.clone());
+                                if let Err(err) = sender.try_send(NotificationPayload::MintQuoteBolt12Response(response)) {
+                                    tracing::error!("Error sending mint quote response: {:?}", err);
+                                }
+                            }
+                        },
                         UrlType::Mint(id) => {
 
                             let response = http_client.get_mint_quote_status(id).await;