fix(ad-hoc): send device timezone offset under correct key and sign

Sources/ProcessOut/Sources/Core/DeviceMetadata/DefaultDeviceMetadataProvider.swift

@@ -9,11 +9,18 @@ import UIKit
 
 actor DefaultDeviceMetadataProvider: DeviceMetadataProvider {
 
-    init(screen: UIScreen, device: UIDevice, bundle: Bundle, keychain: Keychain) {
+    init(
+        screen: UIScreen,
+        device: UIDevice,
+        bundle: Bundle,
+        keychain: Keychain,
+        timeZone: TimeZone = .autoupdatingCurrent
+    ) {
         self.screen = screen
         self.device = device
         self.bundle = bundle
         self.keychain = keychain
+        self.timeZone = timeZone
     }
 
     // MARK: - DeviceMetadataProvider
@@ -28,7 +35,7 @@ actor DefaultDeviceMetadataProvider: DeviceMetadataProvider {
                 appLanguage: bundle.preferredLocalizations.first!, // swiftlint:disable:this force_unwrapping
                 appScreenWidth: Int(screen.nativeBounds.width), // Specified in pixels
                 appScreenHeight: Int(screen.nativeBounds.height),
-                appTimeZoneOffset: TimeZone.current.secondsFromGMT() / 60,
+                appTimezoneOffset: -timeZone.secondsFromGMT() / 60, // UTC - local, e.g. -60 for UTC+1
                 channel: "ios",
                 threedsSdk: "ios",
                 platform: "ios"
@@ -48,6 +55,7 @@ actor DefaultDeviceMetadataProvider: DeviceMetadataProvider {
     private let screen: UIScreen
     private let device: UIDevice
     private let bundle: Bundle
+    private let timeZone: TimeZone
     private let keychain: Keychain
 
     private lazy var machineName: String? = {

Sources/ProcessOut/Sources/Core/DeviceMetadata/DeviceMetadata.swift

@@ -33,8 +33,9 @@ struct DeviceMetadata: Encodable, Sendable {
     /// Height of the screen in pixels.
     let appScreenHeight: Int
 
-    /// Time zone offset in minutes.
-    let appTimeZoneOffset: Int
+    /// Difference in minutes between UTC and device local time (UTC - local), e.g. -60 for UTC+1.
+    /// Follows JavaScript `Date.getTimezoneOffset()` and EMVCo browser time zone semantics.
+    let appTimezoneOffset: Int
 
     /// Device channel. Holds device system name. Legacy field, backend uses it for 3DS SDK
     /// selection when `threedsSdk` is not set. Kept for backward compatibility.

Sources/ProcessOut/Sources/Services/Telemetry/DefaultTelemetryService.swift

@@ -97,7 +97,7 @@ final class DefaultTelemetryService: TelemetryService, @unchecked Sendable {
         )
         let device: Telemetry.DeviceMetadata = await {
             let metadata = await deviceMetadataProvider.deviceMetadata
-            return .init(language: metadata.appLanguage, model: metadata.model, timeZone: metadata.appTimeZoneOffset)
+            return .init(language: metadata.appLanguage, model: metadata.model, timeZone: metadata.appTimezoneOffset)
         }()
         return Telemetry.Metadata(application: application, device: device)
     }

Tests/ProcessOutTests/Sources/Mocks/DeviceMetadataProvider/StubDeviceMetadataProvider.swift

@@ -18,7 +18,7 @@ struct StubDeviceMetadataProvider: DeviceMetadataProvider {
             appLanguage: "en",
             appScreenWidth: 1,
             appScreenHeight: 2,
-            appTimeZoneOffset: 3,
+            appTimezoneOffset: 3,
             channel: "test",
             threedsSdk: "test",
             platform: "test"

Tests/ProcessOutTests/Sources/Unit/Connectors/Http/DefaultHttpConnectorRequestMapperTests.swift

@@ -64,7 +64,7 @@ struct DefaultHttpConnectorRequestMapperTests {
 
         // Then
         // swiftlint:disable:next line_length
-        let expectedBody = #"{"device":{"appLanguage":"en","appScreenHeight":2,"appScreenWidth":1,"appTimeZoneOffset":3,"channel":"test","id":"id","platform":"test","threedsSdk":"test"}}"#
+        let expectedBody = #"{"device":{"appLanguage":"en","appScreenHeight":2,"appScreenWidth":1,"appTimezoneOffset":3,"channel":"test","id":"id","platform":"test","threedsSdk":"test"}}"#
         #expect(urlRequest.httpBody == Data(expectedBody.utf8))
     }
 
@@ -81,7 +81,7 @@ struct DefaultHttpConnectorRequestMapperTests {
 
         // Then
         // swiftlint:disable:next line_length
-        let expectedBody = #"{"device":{"appLanguage":"en","appScreenHeight":2,"appScreenWidth":1,"appTimeZoneOffset":3,"channel":"test","id":"id","platform":"test","threedsSdk":"test"},"key":"value"}"#
+        let expectedBody = #"{"device":{"appLanguage":"en","appScreenHeight":2,"appScreenWidth":1,"appTimezoneOffset":3,"channel":"test","id":"id","platform":"test","threedsSdk":"test"},"key":"value"}"#
         #expect(urlRequest.httpBody == Data(expectedBody.utf8))
     }
 

Tests/ProcessOutTests/Sources/Unit/Core/DeviceMetadata/DefaultDeviceMetadataProviderTests.swift

@@ -0,0 +1,56 @@
+//
+//  DefaultDeviceMetadataProviderTests.swift
+//  ProcessOutTests
+//
+//  Created by Andrii Vysotskyi on 06.11.2026.
+//
+
+import UIKit
+import Testing
+@testable @_spi(PO) import ProcessOut
+
+@MainActor
+struct DefaultDeviceMetadataProviderTests {
+
+    @Test(arguments: [(3600, -60), (-18000, 300), (19800, -330), (0, 0)])
+    func deviceMetadata_returnsUtcMinusLocalTimezoneOffset(secondsFromGmt: Int, expectedOffset: Int) async throws {
+        // Given
+        let timeZone = try #require(TimeZone(secondsFromGMT: secondsFromGmt))
+        let sut = createProvider(timeZone: timeZone)
+
+        // When
+        let metadata = await sut.deviceMetadata
+
+        // Then
+        #expect(metadata.appTimezoneOffset == expectedOffset)
+    }
+
+    @Test
+    func deviceMetadata_whenEncodedWithSnakeCase_usesAppTimezoneOffsetKey() async throws {
+        // Given
+        let timeZone = try #require(TimeZone(secondsFromGMT: 3600))
+        let sut = createProvider(timeZone: timeZone)
+        let encoder = JSONEncoder()
+        encoder.keyEncodingStrategy = .convertToSnakeCase
+
+        // When
+        let data = try encoder.encode(await sut.deviceMetadata)
+
+        // Then
+        let json = try #require(try JSONSerialization.jsonObject(with: data) as? [String: Any])
+        #expect(json["app_timezone_offset"] as? Int == -60)
+        #expect(json["app_time_zone_offset"] == nil)
+    }
+
+    // MARK: - Private Methods
+
+    private func createProvider(timeZone: TimeZone) -> DefaultDeviceMetadataProvider {
+        DefaultDeviceMetadataProvider(
+            screen: .main,
+            device: .current,
+            bundle: .main,
+            keychain: Keychain(service: "com.processout.tests"),
+            timeZone: timeZone
+        )
+    }
+}