Reduce platform requirements

Package.swift

@@ -1,12 +1,12 @@
-// swift-tools-version: 5.6
+// swift-tools-version: 5.5
 
 import PackageDescription
 
 let package = Package(
     name: "Push-iOS",
     platforms: [
-        .macOS(.v12),
-        .iOS(.v15),
+        .macOS(.v10_15),
+        .iOS(.v13),
     ],
     products: [
         .library(
@@ -14,14 +14,15 @@ let package = Package(
             targets: ["Push"]),
     ],
     dependencies: [
-        .package(url: "https://christophhagen.de/git/ch/Push-API.git", from: "0.5.0"),
+        .package(url: "https://christophhagen.de/git/ch/Push-Definitions.git", from: "1.0.0"),
+        .package(url: "https://github.com/swift-server-community/APNSwift.git", from: "4.0.0"),
         .package(url: "https://github.com/apple/swift-crypto.git", "1.0.0" ..< "3.0.0")
     ],
     targets: [
         .target(
             name: "Push",
             dependencies: [
-                .product(name: "PushAPI", package: "Push-API"),
+                .product(name: "PushMessageDefinitions", package: "Push-Definitions"),
                 .product(name: "Crypto", package: "swift-crypto")
             ]),
     ]

Sources/Push/PushClient.swift

@@ -1,13 +1,18 @@
 import Foundation
-import PushAPI
-import SwiftUI
+import PushMessageDefinitions
 
+// Use crypto replacement on Linux
 #if canImport(CryptoKit)
 import CryptoKit
 #else
 import Crypto
 #endif
 
+// Import network types on Linux
+#if canImport(FoundationNetworking)
+import FoundationNetworking
+#endif
+
 /**
  A client to interact with a push server.
  */
@@ -76,7 +81,8 @@ public final class PushClient {
      */
     public func getUnapprovedDevices(masterKey: String) async -> [DeviceRegistration]? {
         let hash = hash(masterKey)
-        guard let data = await post(.listUnapprovedDevices, bodyData: hash) else {
+        let request = AdminRequest(keyHash: hash, application: application)
+        guard let data = await post(.listUnapprovedDevices, body: request) else {
             return nil
         }
         do {
@@ -139,6 +145,39 @@ public final class PushClient {
         var request = URLRequest(url: server.appendingPathComponent(route.rawValue))
         request.httpBody = bodyData
         request.httpMethod = "POST"
+
+        if #available(iOS 15.0, *) {
+            return await post(request)
+        } else {
+            return await withCheckedContinuation { continuation in
+                postRequest(request) { data in
+                    continuation.resume(returning: data)
+                }
+            }
+        }
+    }
+
+    private func postRequest(_ request: URLRequest, completion: @escaping (Data?) -> Void) {
+        URLSession.shared.dataTask(with: request) { data, response, error in
+            if let error = error {
+                print("Failed with error: \(error)")
+                completion(nil)
+            }
+            guard let httpResponse = response as? HTTPURLResponse else {
+                completion(nil)
+                return
+            }
+            guard httpResponse.statusCode == 200 else {
+                print("Failed with code: \(httpResponse.statusCode)")
+                completion(nil)
+                return
+            }
+            completion(data)
+        }.resume()
+    }
+
+    @available(iOS 15.0, *)
+    private func post(_ request: URLRequest) async -> Data? {
         do {
             let (data, response) = try await URLSession.shared.data(for: request)
             guard let httpResponse = response as? HTTPURLResponse else {

Tests/Push-iOSTests/Push_iOSTests.swift

@@ -1,11 +0,0 @@
-import XCTest
-@testable import Push_iOS
-
-final class Push_iOSTests: XCTestCase {
-    func testExample() throws {
-        // This is an example of a functional test case.
-        // Use XCTAssert and related functions to verify your tests produce the correct
-        // results.
-        XCTAssertEqual(Push_iOS().text, "Hello, World!")
-    }
-}