Relay Filters

wip

damus/Util/RelayFilters.swift

@@ -0,0 +1,80 @@
+//
+//  RelayFilters.swift
+//  damus
+//
+//  Created by William Casarin on 2023-02-08.
+//
+
+import Foundation
+
+struct RelayFilter: Hashable {
+    let timeline: Timeline
+    let relay_id: String
+}
+
+class RelayFilters {
+    private let our_pubkey: String
+    private var disabled: Set<RelayFilter>
+    
+    func is_filtered(timeline: Timeline, relay_id: String) -> Bool {
+        let filter = RelayFilter(timeline: timeline, relay_id: relay_id)
+        let contains = disabled.contains(filter)
+        return contains
+    }
+    
+    func remove(timeline: Timeline, relay_id: String) {
+        let filter = RelayFilter(timeline: timeline, relay_id: relay_id)
+        if !disabled.contains(filter) {
+            return
+        }
+        
+        disabled.remove(filter)
+        save_relay_filters(our_pubkey, filters: disabled)
+    }
+    
+    func insert(timeline: Timeline, relay_id: String) {
+        let filter = RelayFilter(timeline: timeline, relay_id: relay_id)
+        if disabled.contains(filter) {
+            return
+        }
+        
+        disabled.insert(filter)
+        save_relay_filters(our_pubkey, filters: disabled)
+    }
+    
+    init(our_pubkey: String) {
+        self.our_pubkey = our_pubkey
+        disabled = load_relay_filters(our_pubkey)
+    }
+}
+
+func save_relay_filters(_ pubkey: String, filters: Set<RelayFilter>) {
+    let key = pk_setting_key(pubkey, key: "relay_filters")
+    let arr = Array(filters.map { filter in "\(filter.timeline)\t\(filter.relay_id)" })
+    UserDefaults.standard.set(arr, forKey: key)
+}
+
+func load_relay_filters(_ pubkey: String) -> Set<RelayFilter> {
+    let key = pk_setting_key(pubkey, key: "relay_filters")
+    guard let filters = UserDefaults.standard.stringArray(forKey: key) else {
+        return Set()
+    }
+    
+    return filters.reduce(into: Set()) { s, str in
+        let parts = str.components(separatedBy: "\t")
+        guard parts.count == 2 else {
+            return
+        }
+        guard let timeline = Timeline.init(rawValue: parts[0]) else {
+            return
+        }
+        let filter = RelayFilter(timeline: timeline, relay_id: parts[1])
+        s.insert(filter)
+    }
+}
+
+func determine_to_relays(pool: RelayPool, filters: RelayFilters) -> [String] {
+    return pool.descriptors
+        .map { $0.url.absoluteString }
+        .filter { !filters.is_filtered(timeline: .search, relay_id: $0) }
+}