Handling invalid signature, use default one.

MailCore/API/MailApiError.swift

@@ -19,13 +19,30 @@
 import Foundation
 import MailResources
 
+/// Static definitions of Mail API error codes
+enum MailApiErrorCode {
+    /// The email is not found
+    static let mailMessageNotFound = "mail__message_not_found"
+
+    /// Invalid credentials
+    static let invalidCredentials = "invalid_credentials"
+
+    /// The server does not know about the identity used in the request
+    static let identityNotFound = "identity__not_found"
+}
+
 public class MailApiError: MailError {
-    public static let apiMessageNotFound = MailApiError(code: "mail__message_not_found",
+    /// The email is not found
+    public static let apiMessageNotFound = MailApiError(code: MailApiErrorCode.mailMessageNotFound,
                                                         localizedDescription: MailResourcesStrings.Localizable
                                                             .errorMessageNotFound,
                                                         shouldDisplay: true)
 
-    public static let apiInvalidCredential = MailApiError(code: "invalid_credentials")
+    /// Invalid credentials
+    public static let apiInvalidCredential = MailApiError(code: MailApiErrorCode.invalidCredentials)
+
+    /// The server does not know bout the identity used in the request
+    public static let apiIdentityNotFound = MailApiError(code: MailApiErrorCode.identityNotFound, shouldDisplay: false)
 
     static let allErrors: [MailApiError] = [
         // General
@@ -112,7 +129,10 @@ public class MailApiError: MailError {
         MailApiError(code: "attachment__store_to_drive_fail"),
 
         // Message
-        MailApiError(code: "message__uid_is_not_valid")
+        MailApiError(code: "message__uid_is_not_valid"),
+
+        // Signatures / Identity
+        apiIdentityNotFound
     ]
 
     static func mailApiErrorFromCode(_ code: String) -> MailApiError? {

MailCore/Cache/DraftManager.swift

@@ -78,7 +78,7 @@ public final class DraftManager {
     }
 
     /// Save a draft server side
-    private func saveDraftRemotely(draft: Draft, mailboxManager: MailboxManager) async {
+    private func saveDraftRemotely(draft: Draft, mailboxManager: MailboxManager, retry: Bool = true) async {
         guard draft.identityId != nil else {
             SentrySDK.capture(message: "We are trying to send a draft without an identityId, this will fail.")
             return
@@ -92,13 +92,47 @@ public final class DraftManager {
         do {
             try await mailboxManager.save(draft: draft)
         } catch {
-            guard error.shouldDisplay else { return }
-            alertDisplayable.show(message: error.localizedDescription)
+            // Retry with default signature on missing identity
+            if retry,
+               let mailError = error as? MailApiError,
+               mailError == MailApiError.apiIdentityNotFound {
+                guard let updatedDraft = await setDefaultSignature(draft: draft, mailboxManager: mailboxManager) else {
+                    return
+                }
+                await saveDraftRemotely(draft: updatedDraft, mailboxManager: mailboxManager, retry: false)
+            }
+            // show error if needed
+            else {
+                guard error.shouldDisplay else { return }
+                alertDisplayable.show(message: error.localizedDescription)
+            }
         }
         await draftQueue.endBackgroundTask(uuid: draft.localUUID)
     }
 
-    public func send(draft: Draft, mailboxManager: MailboxManager) async -> Date? {
+    private func setDefaultSignature(draft: Draft, mailboxManager: MailboxManager) async -> Draft? {
+        try? await mailboxManager.refreshAllSignatures()
+        let storedSignatures = mailboxManager.getStoredSignatures()
+        guard let defaultSignature = storedSignatures.defaultSignature else {
+            return nil
+        }
+
+        var updatedDraft: Draft?
+        let realm = mailboxManager.getRealm()
+        try? realm.write {
+            guard let liveDraft = realm.object(ofType: Draft.self, forPrimaryKey: draft.localUUID) else {
+                return
+            }
+            liveDraft.identityId = "\(defaultSignature.id)"
+
+            realm.add(liveDraft, update: .modified)
+
+            updatedDraft = liveDraft.detached()
+        }
+        return updatedDraft
+    }
+
+    public func send(draft: Draft, mailboxManager: MailboxManager, retry: Bool = true) async -> Date? {
         alertDisplayable.show(message: MailResourcesStrings.Localizable.snackbarEmailSending)
 
         var sendDate: Date?
@@ -110,6 +144,16 @@ public final class DraftManager {
             alertDisplayable.show(message: MailResourcesStrings.Localizable.snackbarEmailSent)
             sendDate = cancelableResponse.scheduledDate
         } catch {
+            // Retry with default signature on missing identity
+            if retry,
+               let mailError = error as? MailApiError,
+               mailError == MailApiError.apiIdentityNotFound {
+                guard let updatedDraft = await setDefaultSignature(draft: draft, mailboxManager: mailboxManager) else {
+                    return nil
+                }
+                return await send(draft: updatedDraft, mailboxManager: mailboxManager, retry: false)
+            }
+
             alertDisplayable.show(message: error.localizedDescription)
         }
         await draftQueue.endBackgroundTask(uuid: draft.localUUID)

MailCore/Cache/MailboxManager/MailboxManager+Draft.swift

@@ -53,6 +53,11 @@ public extension MailboxManager {
             try await deleteLocally(draft: draft)
             throw error
         } catch let error as MailApiError {
+            // Do not delete draft on invalid identity
+            guard error != MailApiError.apiIdentityNotFound else {
+                throw error
+            }
+
             // The api returned an error
             try await deleteLocally(draft: draft)
             throw error
@@ -72,6 +77,11 @@ public extension MailboxManager {
                 }
             }
         } catch let error as MailApiError {
+            // Do not delete draft on invalid identity
+            guard error != MailApiError.apiIdentityNotFound else {
+                throw error
+            }
+
             // The api returned an error for now we can do nothing about it so we delete the draft
             try await deleteLocally(draft: draft)
             throw error