Move device token sending logic to its own component

This commit moves the device token logic to a new
PushNotificationClient, to move complexity from this specific feature
away from damusApp.swift

This commit also slightly improves the handling of device tokens, by
caching it on the client struct even if the user is using local
notifications, so that the device token can be sent to the server immediately after
switching to push notifications mode.

Signed-off-by: Daniel D’Aquino <daniel@daquino.me>
Reviewed-by: William Casarin <jb55@jb55.com>

damus/Models/DamusState.swift

@@ -36,6 +36,7 @@ class DamusState: HeadlessDamusState {
     let video: VideoController
     let ndb: Ndb
     var purple: DamusPurple
+    var push_notification_client: PushNotificationClient
 
     init(pool: RelayPool, keypair: Keypair, likes: EventCounter, boosts: EventCounter, contacts: Contacts, mutelist_manager: MutelistManager, profiles: Profiles, dms: DirectMessagesModel, previews: PreviewCache, zaps: Zaps, lnurls: LNUrls, settings: UserSettingsStore, relay_filters: RelayFilters, relay_model_cache: RelayModelCache, drafts: Drafts, events: EventCache, bookmarks: BookmarksManager, postbox: PostBox, bootstrap_relays: [RelayURL], replies: ReplyCounter, wallet: WalletModel, nav: NavigationCoordinator, music: MusicController?, video: VideoController, ndb: Ndb, purple: DamusPurple? = nil, quote_reposts: EventCounter) {
         self.pool = pool
@@ -68,6 +69,7 @@ class DamusState: HeadlessDamusState {
             keypair: keypair
         )
         self.quote_reposts = quote_reposts
+        self.push_notification_client = PushNotificationClient(keypair: keypair, settings: settings)
     }
 
     @discardableResult

damus/Models/PushNotificationClient.swift

@@ -0,0 +1,62 @@
+//
+//  PushNotificationClient.swift
+//  damus
+//
+//  Created by Daniel D’Aquino on 2024-05-17.
+//
+
+import Foundation
+
+struct PushNotificationClient {
+    let keypair: Keypair
+    let settings: UserSettingsStore
+    private(set) var device_token: Data? = nil
+    
+    mutating func set_device_token(new_device_token: Data) async throws {
+        self.device_token = new_device_token
+        if settings.enable_experimental_push_notifications && settings.notifications_mode == .push {
+            try await self.send_token()
+        }
+    }
+    
+    func send_token() async throws {
+        guard let device_token else { return }
+        // Send the device token and pubkey to the server
+        let token = device_token.map { String(format: "%02.2hhx", $0) }.joined()
+        
+        Log.info("Sending device token to server: %s", for: .push_notifications, token)
+
+        let pubkey = self.keypair.pubkey
+
+        // Send those as JSON to the server
+        let json: [String: Any] = ["deviceToken": token, "pubkey": pubkey.hex()]
+
+        // create post request
+        let url = self.settings.send_device_token_to_localhost ? Constants.DEVICE_TOKEN_RECEIVER_TEST_URL : Constants.DEVICE_TOKEN_RECEIVER_PRODUCTION_URL
+        var request = URLRequest(url: url)
+        request.httpMethod = "POST"
+
+        // insert json data to the request
+        request.httpBody = try? JSONSerialization.data(withJSONObject: json, options: [])
+        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
+
+        let task = URLSession.shared.dataTask(with: request) { data, response, error in
+            guard let data = data, error == nil else {
+                print(error?.localizedDescription ?? "No data")
+                return
+            }
+
+            if let response = response as? HTTPURLResponse, !(200...299).contains(response.statusCode) {
+                print("Unexpected status code: \(response.statusCode)")
+                return
+            }
+
+            let responseJSON = try? JSONSerialization.jsonObject(with: data, options: [])
+            if let responseJSON = responseJSON as? [String: Any] {
+                print(responseJSON)
+            }
+        }
+
+        task.resume()
+    }
+}