Initial NIP-51 Mute List Implementation

damus/Util/Keys.swift

@@ -12,12 +12,25 @@ import Vault
 let PUBKEY_HRP = "npub"
 let PRIVKEY_HRP = "nsec"
 
+struct FullKeypair {
+    let pubkey: String
+    let privkey: String
+}
+
 struct Keypair {
     let pubkey: String
     let privkey: String?
     let pubkey_bech32: String
     let privkey_bech32: String?
     
+    func to_full() -> FullKeypair? {
+        guard let privkey = self.privkey else {
+            return nil
+        }
+        
+        return FullKeypair(pubkey: pubkey, privkey: privkey)
+    }
+    
     init(pubkey: String, privkey: String?) {
         self.pubkey = pubkey
         self.privkey = privkey

damus/Util/Lists.swift

@@ -0,0 +1,91 @@
+//
+//  Mute.swift
+//  damus
+//
+//  Created by William Casarin on 2023-01-25.
+//
+
+import Foundation
+
+func create_or_update_mutelist(keypair: FullKeypair, mprev: NostrEvent?, to_add: String) -> NostrEvent? {
+    return create_or_update_list_event(keypair: keypair, mprev: mprev, to_add: to_add, list_name: "mute", list_type: "p")
+}
+
+func remove_from_mutelist(keypair: FullKeypair, prev: NostrEvent, to_remove: String) -> NostrEvent? {
+    return remove_from_list_event(keypair: keypair, prev: prev, to_remove: to_remove, tag_type: "p")
+}
+
+func create_or_update_list_event(keypair: FullKeypair, mprev: NostrEvent?, to_add: String, list_name: String, list_type: String) -> NostrEvent? {
+    let pubkey = keypair.pubkey
+    
+    if let prev = mprev {
+        if let okprev = ensure_list_name(list: prev, name: list_name), prev.pubkey == keypair.pubkey {
+            return add_to_list_event(keypair: keypair, prev: okprev, to_add: to_add, tag_type: list_type)
+        }
+    }
+    
+    var tags = [["d", list_name], [list_type, to_add]]
+    let ev = NostrEvent(content: "", pubkey: pubkey, kind: 30000, tags: tags)
+    
+    ev.tags = tags
+    ev.id = calculate_event_id(ev: ev)
+    ev.sig = sign_event(privkey: keypair.privkey, ev: ev)
+    
+    return ev
+}
+
+func remove_from_list_event(keypair: FullKeypair, prev: NostrEvent, to_remove: String, tag_type: String) -> NostrEvent? {
+    var exists = false
+    for tag in prev.tags {
+        if tag.count >= 2 && tag[0] == tag_type && tag[1] == to_remove {
+            exists = true
+        }
+    }
+    
+    // make sure we actually have the pubkey to remove
+    guard exists else {
+        return nil
+    }
+    
+    let new_tags = prev.tags.filter { tag in
+        !(tag.count >= 2 && tag[0] == tag_type && tag[1] == to_remove)
+    }
+        
+    let ev = NostrEvent(content: prev.content, pubkey: keypair.pubkey, kind: 30000, tags: new_tags)
+    ev.id = calculate_event_id(ev: ev)
+    ev.sig = sign_event(privkey: keypair.privkey, ev: ev)
+    
+    return ev
+}
+
+func add_to_list_event(keypair: FullKeypair, prev: NostrEvent, to_add: String, tag_type: String) -> NostrEvent? {
+    for tag in prev.tags {
+        // we are already muting this user
+        if tag.count >= 2 && tag[0] == tag_type && tag[1] == to_add {
+            return nil
+        }
+    }
+    
+    let new = NostrEvent(content: prev.content, pubkey: keypair.pubkey, kind: 30000, tags: prev.tags)
+    new.tags.append([tag_type, to_add])
+    new.id = calculate_event_id(ev: new)
+    new.sig = sign_event(privkey: keypair.privkey, ev: new)
+    
+    return new
+}
+
+func ensure_list_name(list: NostrEvent, name: String) -> NostrEvent? {
+    for tag in list.tags {
+        if tag.count >= 2 && tag[0] == "d" {
+            if tag[1] != name {
+                return nil
+            } else {
+                return list
+            }
+        }
+    }
+    
+    list.tags.insert(["d", name], at: 0)
+    
+    return list
+}