nip4e: fix message encryption and sync (#57)

Reviewed-on: #57

crates/state/src/nip4e.rs

@@ -1,4 +1,3 @@
-use gpui::SharedString;
 use nostr_sdk::prelude::*;
 
 /// Announcement
@@ -6,50 +5,29 @@ use nostr_sdk::prelude::*;
 pub struct Announcement {
     /// The public key of the device that created this announcement.
     public_key: PublicKey,
-
-    /// The name of the device that created this announcement.
-    client_name: Option<String>,
 }
 
-impl From<&Event> for Announcement {
-    fn from(val: &Event) -> Self {
-        let public_key = val
+impl Announcement {
+    /// Parse an announcement from an event, returning `None` when the `n`
+    /// tag is missing or malformed so callers never mistake the author's
+    /// identity key for an encryption key.
+    pub fn from_event(event: &Event) -> Option<Self> {
+        let public_key = event
             .tags
             .iter()
             .find(|tag| tag.kind() == "n")
             .and_then(|tag| tag.content())
-            .and_then(|c| PublicKey::parse(c).ok())
-            .unwrap_or(val.pubkey);
+            .and_then(|c| PublicKey::parse(c).ok())?;
 
-        let client_name = val
-            .tags
-            .iter()
-            .find(|tag| tag.kind() == "client")
-            .and_then(|tag| tag.content())
-            .map(|c| c.to_string());
-
-        Self::new(public_key, client_name)
+        Some(Self { public_key })
     }
-}
 
-impl Announcement {
-    pub fn new(public_key: PublicKey, client_name: Option<String>) -> Self {
-        Self {
-            public_key,
-            client_name,
-        }
+    pub fn new(public_key: PublicKey) -> Self {
+        Self { public_key }
     }
 
     /// Returns the public key of the device that created this announcement.
     pub fn public_key(&self) -> PublicKey {
         self.public_key
     }
-
-    /// Returns the client name of the device that created this announcement.
-    pub fn client_name(&self) -> SharedString {
-        self.client_name
-            .as_ref()
-            .map(SharedString::from)
-            .unwrap_or(SharedString::from("Unknown"))
-    }
 }