Files
bitchat/bitchat/Nostr/GeoRelayDirectory.swift
T
2025-10-19 17:24:17 +01:00

346 lines
12 KiB
Swift

import BitLogger
import Foundation
import Tor
#if os(iOS)
import UIKit
#elseif os(macOS)
import AppKit
#endif
/// Directory of online Nostr relays with approximate GPS locations, used for geohash routing.
@MainActor
final class GeoRelayDirectory {
struct Entry: Hashable {
let host: String
let lat: Double
let lon: Double
}
static let shared = GeoRelayDirectory()
private(set) var entries: [Entry] = []
private let cacheFileName = "georelays_cache.csv"
private let lastFetchKey = "georelay.lastFetchAt"
private let remoteURL = URL(string: "https://raw.githubusercontent.com/permissionlesstech/georelays/refs/heads/main/nostr_relays.csv")!
private let fetchInterval: TimeInterval = TransportConfig.geoRelayFetchIntervalSeconds
private var refreshTimer: Timer?
private var retryTask: Task<Void, Never>?
private var retryAttempt: Int = 0
private var isFetching: Bool = false
private var observers: [NSObjectProtocol] = []
private init() {
entries = loadLocalEntries()
registerObservers()
startRefreshTimer()
prefetchIfNeeded()
}
deinit {
observers.forEach { NotificationCenter.default.removeObserver($0) }
refreshTimer?.invalidate()
retryTask?.cancel()
}
/// Returns up to `count` relay URLs (wss://) closest to the geohash center.
func closestRelays(toGeohash geohash: String, count: Int = 5) -> [String] {
let center = Geohash.decodeCenter(geohash)
return closestRelays(toLat: center.lat, lon: center.lon, count: count)
}
/// Returns up to `count` relay URLs (wss://) closest to the given coordinate.
func closestRelays(toLat lat: Double, lon: Double, count: Int = 5) -> [String] {
guard !entries.isEmpty, count > 0 else { return [] }
if entries.count <= count {
return entries
.sorted { a, b in
haversineKm(lat, lon, a.lat, a.lon) < haversineKm(lat, lon, b.lat, b.lon)
}
.map { "wss://\($0.host)" }
}
var best: [(entry: Entry, distance: Double)] = []
best.reserveCapacity(count)
for entry in entries {
let distance = haversineKm(lat, lon, entry.lat, entry.lon)
if best.count < count {
let idx = best.firstIndex { $0.distance > distance } ?? best.count
best.insert((entry, distance), at: idx)
} else if let worstDistance = best.last?.distance, distance < worstDistance {
let idx = best.firstIndex { $0.distance > distance } ?? best.count
best.insert((entry, distance), at: idx)
best.removeLast()
}
}
return best.map { "wss://\($0.entry.host)" }
}
// MARK: - Remote Fetch
func prefetchIfNeeded(force: Bool = false) {
guard !isFetching else { return }
let now = Date()
let last = UserDefaults.standard.object(forKey: lastFetchKey) as? Date ?? .distantPast
if !force {
guard now.timeIntervalSince(last) >= fetchInterval else { return }
} else if last != .distantPast,
now.timeIntervalSince(last) < TransportConfig.geoRelayRetryInitialSeconds {
// Skip forced fetches if we just refreshed moments ago.
return
}
cancelRetry()
fetchRemote()
}
private func fetchRemote() {
guard !isFetching else { return }
isFetching = true
let request = URLRequest(
url: remoteURL,
cachePolicy: .reloadIgnoringLocalCacheData,
timeoutInterval: 15
)
Task.detached { [weak self] in
guard let self else { return }
let ready = await TorManager.shared.awaitReady()
if !ready {
await self.handleFetchFailure(.torNotReady)
return
}
do {
let (data, _) = try await TorURLSession.shared.session.data(for: request)
guard let text = String(data: data, encoding: .utf8) else {
await self.handleFetchFailure(.invalidData)
return
}
let parsed = GeoRelayDirectory.parseCSV(text)
guard !parsed.isEmpty else {
await self.handleFetchFailure(.invalidData)
return
}
await self.handleFetchSuccess(entries: parsed, csv: text)
} catch {
await self.handleFetchFailure(.network(error))
}
}
}
private enum FetchFailure {
case torNotReady
case invalidData
case network(Error)
}
@MainActor
private func handleFetchSuccess(entries parsed: [Entry], csv: String) {
entries = parsed
persistCache(csv)
UserDefaults.standard.set(Date(), forKey: lastFetchKey)
SecureLogger.info("GeoRelayDirectory: refreshed \(parsed.count) relays from remote", category: .session)
isFetching = false
retryAttempt = 0
cancelRetry()
}
@MainActor
private func handleFetchFailure(_ reason: FetchFailure) {
switch reason {
case .torNotReady:
SecureLogger.warning("GeoRelayDirectory: Tor not ready; scheduling retry", category: .session)
case .invalidData:
SecureLogger.warning("GeoRelayDirectory: remote fetch returned invalid data; scheduling retry", category: .session)
case .network(let error):
SecureLogger.warning("GeoRelayDirectory: remote fetch failed with error: \(error.localizedDescription)", category: .session)
}
isFetching = false
scheduleRetry()
}
@MainActor
private func scheduleRetry() {
retryAttempt = min(retryAttempt + 1, 10)
let base = TransportConfig.geoRelayRetryInitialSeconds
let maxDelay = TransportConfig.geoRelayRetryMaxSeconds
let multiplier = pow(2.0, Double(max(retryAttempt - 1, 0)))
let calculated = base * multiplier
let delay = min(maxDelay, max(base, calculated))
cancelRetry()
retryTask = Task { [weak self] in
let nanoseconds = UInt64(delay * 1_000_000_000)
try? await Task.sleep(nanoseconds: nanoseconds)
await MainActor.run {
self?.prefetchIfNeeded(force: true)
}
}
}
@MainActor
private func cancelRetry() {
retryTask?.cancel()
retryTask = nil
}
private func persistCache(_ text: String) {
guard let url = cacheURL() else { return }
do {
try text.data(using: .utf8)?.write(to: url, options: .atomic)
} catch {
SecureLogger.warning("GeoRelayDirectory: failed to write cache: \(error)", category: .session)
}
}
// MARK: - Loading
private func loadLocalEntries() -> [Entry] {
// Prefer cached file if present
if let cache = cacheURL(),
let data = try? Data(contentsOf: cache),
let text = String(data: data, encoding: .utf8) {
let arr = Self.parseCSV(text)
if !arr.isEmpty { return arr }
}
// Try bundled resource(s)
let bundleCandidates = [
Bundle.main.url(forResource: "nostr_relays", withExtension: "csv"),
Bundle.main.url(forResource: "online_relays_gps", withExtension: "csv"),
Bundle.main.url(forResource: "online_relays_gps", withExtension: "csv", subdirectory: "relays")
].compactMap { $0 }
for url in bundleCandidates {
if let data = try? Data(contentsOf: url),
let text = String(data: data, encoding: .utf8) {
let arr = Self.parseCSV(text)
if !arr.isEmpty { return arr }
}
}
// Try filesystem path (development/test)
if let cwd = FileManager.default.currentDirectoryPath as String?,
let data = try? Data(contentsOf: URL(fileURLWithPath: cwd).appendingPathComponent("relays/online_relays_gps.csv")),
let text = String(data: data, encoding: .utf8) {
return Self.parseCSV(text)
}
SecureLogger.warning("GeoRelayDirectory: no local CSV found; entries empty", category: .session)
return []
}
nonisolated static func parseCSV(_ text: String) -> [Entry] {
var result: Set<Entry> = []
let lines = text.split(whereSeparator: { $0.isNewline })
for (idx, raw) in lines.enumerated() {
let line = raw.trimmingCharacters(in: .whitespacesAndNewlines)
if line.isEmpty { continue }
if idx == 0 && line.lowercased().contains("relay url") { continue }
let parts = line.split(separator: ",").map { String($0).trimmingCharacters(in: .whitespaces) }
guard parts.count >= 3 else { continue }
var host = parts[0]
host = host.replacingOccurrences(of: "https://", with: "")
host = host.replacingOccurrences(of: "http://", with: "")
host = host.replacingOccurrences(of: "wss://", with: "")
host = host.replacingOccurrences(of: "ws://", with: "")
host = host.trimmingCharacters(in: CharacterSet(charactersIn: "/"))
guard let lat = Double(parts[1]), let lon = Double(parts[2]) else { continue }
result.insert(Entry(host: host, lat: lat, lon: lon))
}
return Array(result)
}
private func cacheURL() -> URL? {
do {
let base = try FileManager.default.url(
for: .applicationSupportDirectory,
in: .userDomainMask,
appropriateFor: nil,
create: true
)
let dir = base.appendingPathComponent("bitchat", isDirectory: true)
try? FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
return dir.appendingPathComponent(cacheFileName)
} catch {
return nil
}
}
// MARK: - Observers & Timers
private func registerObservers() {
let center = NotificationCenter.default
let torReady = center.addObserver(
forName: .TorDidBecomeReady,
object: nil,
queue: .main
) { [weak self] _ in
guard let self else { return }
Task { @MainActor in
self.prefetchIfNeeded(force: true)
}
}
observers.append(torReady)
#if os(iOS)
let didBecomeActive = center.addObserver(
forName: UIApplication.didBecomeActiveNotification,
object: nil,
queue: .main
) { [weak self] _ in
guard let self else { return }
Task { @MainActor in
self.prefetchIfNeeded()
}
}
observers.append(didBecomeActive)
#elseif os(macOS)
let didBecomeActive = center.addObserver(
forName: NSApplication.didBecomeActiveNotification,
object: nil,
queue: .main
) { [weak self] _ in
guard let self else { return }
Task { @MainActor in
self.prefetchIfNeeded()
}
}
observers.append(didBecomeActive)
#endif
}
private func startRefreshTimer() {
refreshTimer?.invalidate()
let interval = TransportConfig.geoRelayRefreshCheckIntervalSeconds
guard interval > 0 else { return }
let timer = Timer.scheduledTimer(withTimeInterval: interval, repeats: true) { [weak self] _ in
guard let self else { return }
Task { @MainActor in
self.prefetchIfNeeded()
}
}
refreshTimer = timer
RunLoop.main.add(timer, forMode: .common)
}
}
// MARK: - Distance
private func haversineKm(_ lat1: Double, _ lon1: Double, _ lat2: Double, _ lon2: Double) -> Double {
let r = 6371.0 // Earth radius in km
let dLat = (lat2 - lat1) * .pi / 180
let dLon = (lon2 - lon1) * .pi / 180
let a = sin(dLat/2) * sin(dLat/2) + cos(lat1 * .pi/180) * cos(lat2 * .pi/180) * sin(dLon/2) * sin(dLon/2)
let c = 2 * atan2(sqrt(a), sqrt(1 - a))
return r * c
}