chore: rewrite the backend (not tested) (#203)

* wip: refactor

* refactor

* clean up

* .

* rename

* add relay auth

* .

* .

* optimize

* .

* clean up

* add encryption crate

* .

* .

* .

* .

* .

* add encryption crate

* .

* refactor nip4e

* .

* fix endless loop

* fix metadata fetching

crates/state/src/storage.rs

@@ -0,0 +1,87 @@
+use std::collections::{HashMap, HashSet};
+
+use gpui::SharedString;
+use nostr_sdk::prelude::*;
+
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct Announcement {
+    id: EventId,
+    client: String,
+    public_key: PublicKey,
+}
+
+impl Announcement {
+    pub fn new(id: EventId, client_name: String, public_key: PublicKey) -> Self {
+        Self {
+            id,
+            client: client_name,
+            public_key,
+        }
+    }
+
+    pub fn id(&self) -> EventId {
+        self.id
+    }
+
+    pub fn public_key(&self) -> PublicKey {
+        self.public_key
+    }
+
+    pub fn client(&self) -> SharedString {
+        SharedString::from(self.client.clone())
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
+pub struct Response {
+    payload: String,
+    public_key: PublicKey,
+}
+
+impl Response {
+    pub fn new(payload: String, public_key: PublicKey) -> Self {
+        Self {
+            payload,
+            public_key,
+        }
+    }
+
+    pub fn public_key(&self) -> PublicKey {
+        self.public_key
+    }
+
+    pub fn payload(&self) -> &str {
+        self.payload.as_str()
+    }
+}
+
+#[derive(Debug, Clone, Default)]
+pub struct CacheManager {
+    /// Cache of messaging relays for each public key
+    relay: HashMap<PublicKey, HashSet<RelayUrl>>,
+
+    /// Cache of device announcement for each public key
+    announcement: HashMap<PublicKey, Option<Announcement>>,
+}
+
+impl CacheManager {
+    pub fn relay(&self, public_key: &PublicKey) -> Option<&HashSet<RelayUrl>> {
+        self.relay.get(public_key)
+    }
+
+    pub fn insert_relay(&mut self, public_key: PublicKey, urls: Vec<RelayUrl>) {
+        self.relay.entry(public_key).or_default().extend(urls);
+    }
+
+    pub fn announcement(&self, public_key: &PublicKey) -> Option<&Option<Announcement>> {
+        self.announcement.get(public_key)
+    }
+
+    pub fn insert_announcement(
+        &mut self,
+        public_key: PublicKey,
+        announcement: Option<Announcement>,
+    ) {
+        self.announcement.insert(public_key, announcement);
+    }
+}