Add trie-based user search cache to replace non-performant linear scans

Changelog-Added: Speed up user search
Tested-by: William Casarin <jb55@jb55.com>
Fixes: #1219
Closes: #1342

damus/Views/Posting/UserSearch.swift

@@ -8,7 +8,6 @@
 import SwiftUI
 
 struct SearchedUser: Identifiable {
-    let petname: String?
     let profile: Profile?
     let pubkey: String
     
@@ -28,11 +27,7 @@ struct UserSearch: View {
     @EnvironmentObject var tagModel: TagModel
     
     var users: [SearchedUser] {
-        guard let contacts = damus_state.contacts.event else {
-            return search_profiles(profiles: damus_state.profiles, search: search)
-        }
-        
-        return search_users_for_autocomplete(profiles: damus_state.profiles, tags: contacts.tags, search: search)
+        return search_profiles(profiles: damus_state.profiles, search: search)
     }
     
     func on_user_tapped(user: SearchedUser) {
@@ -99,56 +94,6 @@ struct UserSearch_Previews: PreviewProvider {
     }
 }
 
-
-func search_users_for_autocomplete(profiles: Profiles, tags: [[String]], search _search: String) -> [SearchedUser] {
-    var seen_user = Set<String>()
-    let search = _search.lowercased()
-    
-    var matches = tags.reduce(into: Array<SearchedUser>()) { arr, tag in
-        guard tag.count >= 2 && tag[0] == "p" else {
-            return
-        }
-        
-        let pubkey = tag[1]
-        guard !seen_user.contains(pubkey) else {
-            return
-        }
-        seen_user.insert(pubkey)
-        
-        var petname: String? = nil
-        if tag.count >= 4 {
-            petname = tag[3]
-        }
-        
-        let profile = profiles.lookup(id: pubkey)
-        
-        guard ((petname?.lowercased().hasPrefix(search) ?? false) ||
-            (profile?.name?.lowercased().hasPrefix(search) ?? false) ||
-            (profile?.display_name?.lowercased().hasPrefix(search) ?? false)) else {
-            return
-        }
-        
-        let searched_user = SearchedUser(petname: petname, profile: profile, pubkey: pubkey)
-        arr.append(searched_user)
-    }
-    
-    // search profile cache as well
-    for tup in profiles.enumerated() {
-        let pk = tup.element.key
-        let prof = tup.element.value.profile
-        
-        guard !seen_user.contains(pk) else {
-            continue
-        }
-        
-        if let match = profile_search_matches(profiles: profiles, profile: prof, pubkey: pk, search: search) {
-            matches.append(match)
-        }
-    }
-    
-    return matches
-}
-
 func user_tag_attr_string(profile: Profile?, pubkey: String) -> NSMutableAttributedString {
     let display_name = Profile.displayName(profile: profile, pubkey: pubkey)
     let name = display_name.username.truncate(maxLength: 50)

damus/Views/Profile/ProfilePicView.swift

@@ -162,7 +162,8 @@ func get_profile_url(picture: String?, pubkey: String, profiles: Profiles) -> UR
 }
 
 func make_preview_profiles(_ pubkey: String) -> Profiles {
-    let profiles = Profiles()
+    let user_search_cache = UserSearchCache()
+    let profiles = Profiles(user_search_cache: user_search_cache)
     let picture = "http://cdn.jb55.com/img/red-me.jpg"
     let profile = Profile(name: "jb55", display_name: "William Casarin", about: "It's me", picture: picture, banner: "", website: "https://jb55.com", lud06: nil, lud16: nil, nip05: "jb55.com", damus_donation: nil)
     let ts_profile = TimestampedProfile(profile: profile, timestamp: 0, event: test_event)

damus/Views/SearchResultsView.swift

@@ -180,33 +180,21 @@ func make_hashtagable(_ str: String) -> String {
 }
 
 func search_profiles(profiles: Profiles, search: String) -> [SearchedUser] {
+    // Search by hex pubkey.
+    if search.count == 64 && hex_decode(search) != nil, let profile = profiles.lookup(id: search) {
+        return [SearchedUser(profile: profile, pubkey: search)]
+    }
+
+    // Search by npub pubkey.
+    if search.starts(with: "npub"), let bech32_key = decode_bech32_key(search), case Bech32Key.pub(let hex) = bech32_key, let profile = profiles.lookup(id: hex) {
+        return [SearchedUser(profile: profile, pubkey: hex)]
+    }
+
     let new = search.lowercased()
-    return profiles.enumerated().reduce(into: []) { acc, els in
-        let pk = els.element.key
-        let prof = els.element.value.profile
-        
-        if let searched = profile_search_matches(profiles: profiles, profile: prof, pubkey: pk, search: new) {
-            acc.append(searched)
-        }
-    }
-}
+    let matched_pubkeys = profiles.user_search_cache.search(key: new)
 
-
-func profile_search_matches(profiles: Profiles, profile prof: Profile, pubkey pk: String, search new: String) -> SearchedUser? {
-    let lowname = prof.name.map { $0.lowercased() }
-    let lownip05 = profiles.is_validated(pk).map { $0.host.lowercased() }
-    let lowdisp = prof.display_name.map { $0.lowercased() }
-    let ok = new.count == 1 ?
-    ((lowname?.starts(with: new) ?? false) ||
-     (lownip05?.starts(with: new) ?? false) ||
-     (lowdisp?.starts(with: new) ?? false)) : (pk.starts(with: new) || String(new.dropFirst()) == pk
-        || lowname?.contains(new) ?? false
-        || lownip05?.contains(new) ?? false
-        || lowdisp?.contains(new) ?? false)
-    
-    if ok {
-        return SearchedUser(petname: nil, profile: prof, pubkey: pk)
-    }
-    
-    return nil
+    return matched_pubkeys
+        .map { ($0, profiles.lookup(id: $0)) }
+        .filter { $1 != nil }
+        .map { SearchedUser(profile: $1, pubkey: $0) }
 }