Refactor encryption trust level

Riot/Modules/Encryption/EncryptionTrustLevel.swift

@@ -0,0 +1,68 @@
+// 
+// Copyright 2023 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Foundation
+
+/// Object responsible for calculating user and room trust level
+///
+/// For legacy reasons, the trust of multiple items is represented as `Progress` object,
+/// where `completedUnitCount` represents the number of trusted users / devices.
+@objc class EncryptionTrustLevel: NSObject {
+    struct TrustSummary {
+        let totalCount: Int64
+        let trustedCount: Int64
+        let areAllTrusted: Bool
+        
+        init(progress: Progress) {
+            totalCount = max(progress.totalUnitCount, progress.completedUnitCount)
+            trustedCount = progress.completedUnitCount
+            areAllTrusted = trustedCount == totalCount
+        }
+    }
+    
+    
+    /// Calculate trust level for a single user given their cross-signing info
+    @objc func userTrustLevel(
+        crossSigning: MXCrossSigningInfo?,
+        trustedDevicesProgress: Progress
+    ) -> UserEncryptionTrustLevel {
+        let devices = TrustSummary(progress: trustedDevicesProgress)
+        
+        // If we could cross-sign but we haven't, the user is simply not verified
+        if let crossSigning, !crossSigning.trustLevel.isVerified {
+            return .notVerified
+        
+        // If we cannot cross-sign the user (legacy behaviour) and have not signed
+        // any devices manually, the user is not verified
+        } else if crossSigning == nil && devices.trustedCount == 0 {
+            return .notVerified
+        }
+        
+        // In all other cases we check devices for trust level
+        return devices.areAllTrusted ? .trusted : .warning
+    }
+    
+    /// Calculate trust level for a room given trust level of users and their devices
+    @objc func roomTrustLevel(summary: MXUsersTrustLevelSummary) -> RoomEncryptionTrustLevel {
+        let users = TrustSummary(progress: summary.trustedUsersProgress)
+        let devices = TrustSummary(progress: summary.trustedDevicesProgress)
+        
+        guard users.totalCount > 0 && users.areAllTrusted else {
+            return .normal
+        }
+        return devices.areAllTrusted ? .trusted : .warning
+    }
+}

Riot/Modules/Encryption/EncryptionTrustLevelBadgeImageHelper.swift

@@ -0,0 +1,59 @@
+/*
+ Copyright 2020 New Vector Ltd
+ 
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+ 
+ http://www.apache.org/licenses/LICENSE-2.0
+ 
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+ */
+
+import UIKit
+
+@objcMembers
+final class EncryptionTrustLevelBadgeImageHelper: NSObject {
+    
+    static func roomBadgeImage(for trustLevel: RoomEncryptionTrustLevel) -> UIImage {
+        
+        let badgeImage: UIImage
+        
+        switch trustLevel {
+        case .warning:
+            badgeImage = Asset.Images.encryptionWarning.image
+        case .normal:
+            badgeImage = Asset.Images.encryptionNormal.image
+        case .trusted:
+            badgeImage = Asset.Images.encryptionTrusted.image
+        case .unknown:
+            badgeImage = Asset.Images.encryptionNormal.image
+        @unknown default:
+            badgeImage = Asset.Images.encryptionNormal.image
+        }
+        
+        return badgeImage
+    }
+    
+    static func userBadgeImage(for trustLevel: UserEncryptionTrustLevel) -> UIImage? {
+        
+        let badgeImage: UIImage?
+        
+        switch trustLevel {
+        case .warning:
+            badgeImage = Asset.Images.encryptionWarning.image
+        case .notVerified, .noCrossSigning:
+            badgeImage = Asset.Images.encryptionNormal.image
+        case .trusted:
+            badgeImage = Asset.Images.encryptionTrusted.image
+        default:
+            badgeImage = nil
+        }
+        
+        return badgeImage
+    }
+}

Riot/Modules/Encryption/RoomEncryptionTrustLevel.h

@@ -0,0 +1,25 @@
+// 
+// Copyright 2023 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+/**
+ RoomEncryptionTrustLevel represents the trust level in an encrypted room.
+ */
+typedef NS_ENUM(NSUInteger, RoomEncryptionTrustLevel) {
+    RoomEncryptionTrustLevelTrusted,
+    RoomEncryptionTrustLevelWarning,
+    RoomEncryptionTrustLevelNormal,
+    RoomEncryptionTrustLevelUnknown
+};