Add thread muting

Changelog-Added: Add thread muting
Closes: #893

damus/Models/MutedThreadsManager.swift

@@ -0,0 +1,76 @@
+//
+//  MutedThreadsManager.swift
+//  damus
+//
+//  Created by Terry Yiu on 4/6/23.
+//
+
+import Foundation
+
+fileprivate func getMutedThreadsKey(pubkey: String) -> String {
+    pk_setting_key(pubkey, key: "muted_threads")
+}
+
+func loadMutedThreads(pubkey: String) -> [String] {
+    let key = getMutedThreadsKey(pubkey: pubkey)
+    return UserDefaults.standard.stringArray(forKey: key) ?? []
+}
+
+func saveMutedThreads(pubkey: String, currentValue: [String], value: [String]) -> Bool {
+    let uniqueMutedThreads = Array(Set(value))
+
+    if uniqueMutedThreads != currentValue {
+        UserDefaults.standard.set(uniqueMutedThreads, forKey: getMutedThreadsKey(pubkey: pubkey))
+        return true
+    }
+
+    return false
+}
+
+class MutedThreadsManager: ObservableObject {
+
+    private let userDefaults = UserDefaults.standard
+    private let pubkey: String
+
+    private var _mutedThreadsSet: Set<String>
+    private var _mutedThreads: [String]
+    var mutedThreads: [String] {
+        get {
+            return _mutedThreads
+        }
+        set {
+            if saveMutedThreads(pubkey: pubkey, currentValue: _mutedThreads, value: newValue) {
+                self._mutedThreads = newValue
+                self.objectWillChange.send()
+            }
+        }
+    }
+
+    init(pubkey: String) {
+        self._mutedThreads = loadMutedThreads(pubkey: pubkey)
+        self._mutedThreadsSet = Set(_mutedThreads)
+        self.pubkey = pubkey
+    }
+
+    func isMutedThread(_ ev: NostrEvent) -> Bool {
+        return _mutedThreadsSet.contains(ev.thread_id(privkey: nil))
+    }
+
+    func updateMutedThread(_ ev: NostrEvent) {
+        let threadId = ev.thread_id(privkey: nil)
+        if isMutedThread(ev) {
+            mutedThreads = mutedThreads.filter { $0 != threadId }
+            _mutedThreadsSet.remove(threadId)
+            notify(.unmute_thread, ev)
+        } else {
+            mutedThreads.append(threadId)
+            _mutedThreadsSet.insert(threadId)
+            notify(.mute_thread, ev)
+        }
+    }
+
+    func clearAll() {
+        mutedThreads = []
+        _mutedThreadsSet.removeAll()
+    }
+}