feat: NIP-87 federation discovery

src/nostr.rs

@@ -1,10 +1,13 @@
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, BTreeSet};
 use std::fmt::Debug;
+use std::str::FromStr;
 use std::time::Duration;
 
+use fedimint_core::config::FederationId;
+use fedimint_core::invite_code::InviteCode;
 use iced::Subscription;
 use nostr_relay_pool::RelayStatus;
-use nostr_sdk::Url;
+use nostr_sdk::{Alphabet, EventSource, Filter, Kind, PublicKey, SingleLetterTag, TagKind, Url};
 
 #[derive(Default, Debug, Clone, PartialEq, Eq)]
 pub struct NostrState {
@@ -46,7 +49,7 @@ impl NostrModule {
     pub fn subscription(&self) -> Subscription<NostrState> {
         const POLL_DURATION: Duration = Duration::from_millis(200);
 
-        let client = self.client.clone();
+        let this = self.clone();
 
         Subscription::run_with_id(
             std::any::TypeId::of::<NostrState>(),
@@ -56,8 +59,9 @@ impl NostrModule {
             // ID is new.
             async_stream::stream! {
                 let mut last_state = NostrState::default();
+
                 loop {
-                    let new_state = Self::get_state(&client).await;
+                    let new_state = this.get_state().await;
                     if new_state != last_state {
                         yield new_state.clone();
                         last_state = new_state;
@@ -69,13 +73,67 @@ impl NostrModule {
         )
     }
 
+    pub async fn find_federations(
+        &self,
+    ) -> Result<
+        BTreeMap<FederationId, (BTreeSet<PublicKey>, BTreeSet<InviteCode>)>,
+        nostr_sdk::client::Error,
+    > {
+        let fedimint_recommendation_events = self
+            .client
+            .get_events_of(
+                vec![Filter::new()
+                    .kind(Kind::Custom(38_000))
+                    .custom_tag(SingleLetterTag::lowercase(Alphabet::K), vec!["38173"])
+                    .custom_tag(SingleLetterTag::lowercase(Alphabet::N), vec!["mainnet"])],
+                EventSource::both(None),
+            )
+            .await?;
+
+        let mut federations = BTreeMap::new();
+
+        for recommendation_event in &fedimint_recommendation_events {
+            for d_tag in recommendation_event.get_tags_content(TagKind::SingleLetter(
+                SingleLetterTag::lowercase(Alphabet::D),
+            )) {
+                if let Ok(federation_id) = FederationId::from_str(d_tag) {
+                    let (recommenders, invite_codes) = federations
+                        .entry(federation_id)
+                        .or_insert_with(|| (BTreeSet::new(), BTreeSet::new()));
+
+                    recommenders.insert(recommendation_event.pubkey);
+                    for u_tag in recommendation_event.get_tags_content(TagKind::SingleLetter(
+                        SingleLetterTag::lowercase(Alphabet::U),
+                    )) {
+                        if let Ok(invite_code) = InviteCode::from_str(u_tag) {
+                            if invite_code.federation_id() == federation_id {
+                                invite_codes.insert(invite_code);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        println!("{federations:#?}");
+        println!(
+            "Found {} recommendations for {} federations",
+            fedimint_recommendation_events.len(),
+            federations.len()
+        );
+
+        federations.retain(|_, (_, invite_codes)| !invite_codes.is_empty());
+
+        Ok(federations)
+    }
+
     /// Fetches the current state of the Nostr SDK client.
     /// Note: This is async because it's grabbing read locks
     /// on the relay `RwLock`s. No network requests are made.
-    async fn get_state(client: &nostr_sdk::Client) -> NostrState {
+    async fn get_state(&self) -> NostrState {
         let mut relay_connections = BTreeMap::new();
 
-        for (url, relay) in client.relays().await {
+        for (url, relay) in self.client.relays().await {
             relay_connections.insert(url.clone(), relay.status().await);
         }