[Electric-Coin-Company#1363] Binary address book serialization

- Local storage for address book is now primary source of data
- Remote storage for address book is used as a backup, syncing is prepared and merge strategy is WIP
- The data serialization/deserialization is prepared, no encryption in place
- The data are versioned and checked
- lastUpdated data are stored as well
- Keychain stores a struct for encryption, in case there is more than just 1 key

[Electric-Coin-Company#1363] Binary address book serialization

- Subject cleanup

modules/Package.swift

@@ -408,7 +408,8 @@ let package = Package(
             dependencies: [
                 "Utils",
                 "UIComponents",
-                .product(name: "MnemonicSwift", package: "MnemonicSwift")
+                .product(name: "MnemonicSwift", package: "MnemonicSwift"),
+                .product(name: "ComposableArchitecture", package: "swift-composable-architecture")
             ],
             path: "Sources/Models"
         ),

modules/Sources/Dependencies/AddressBookClient/AddressBookInterface.swift

@@ -17,7 +17,8 @@ extension DependencyValues {
 
 @DependencyClient
 public struct AddressBookClient {
-    public let allContacts: () async throws -> IdentifiedArrayOf<ABRecord>
-    public let storeContact: (ABRecord) async throws -> IdentifiedArrayOf<ABRecord>
-    public let deleteContact: (ABRecord) async throws -> IdentifiedArrayOf<ABRecord>
+    public let allLocalContacts: () throws -> AddressBookContacts
+    public let syncContacts: (AddressBookContacts?) async throws -> AddressBookContacts
+    public let storeContact: (Contact) throws -> AddressBookContacts
+    public let deleteContact: (Contact) throws -> AddressBookContacts
 }

modules/Sources/Dependencies/AddressBookClient/AddressBookLiveKey.swift

@@ -16,108 +16,322 @@ import Combine
 import WalletStorage
 
 extension AddressBookClient: DependencyKey {
+    private enum Constants {
+        static let component = "AddressBookData"
+    }
+
     public enum AddressBookClientError: Error {
         case missingEncryptionKey
+        case documentsFolder
     }
 
     public static let liveValue: AddressBookClient = Self.live()
 
     public static func live() -> Self {
-        let latestKnownContacts = CurrentValueSubject<IdentifiedArrayOf<ABRecord>?, Never>(nil)
+        var latestKnownContacts: AddressBookContacts?
 
         @Dependency(\.remoteStorage) var remoteStorage
 
         return Self(
-            allContacts: {
+            allLocalContacts: {
                 // return latest known contacts
-                guard latestKnownContacts.value == nil else {
-                    if let contacts = latestKnownContacts.value {
+                guard latestKnownContacts == nil else {
+                    if let contacts = latestKnownContacts {
                         return contacts
                     } else {
-                        return []
+                        return .empty
+                    }
+                }
+
+                // contacts haven't been loaded from the locale storage yet, do it
+                do {
+                    guard let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else {
+                        throw AddressBookClientError.documentsFolder
                     }
+                    let fileURL = documentsDirectory.appendingPathComponent(Constants.component)
+                    let encryptedContacts = try Data(contentsOf: fileURL)
+
+                    let decryptedContacts = try AddressBookClient.decryptData(encryptedContacts)
+                    latestKnownContacts = decryptedContacts
+
+                    return decryptedContacts
+                } catch {
+                    throw error
                 }
+            },
+            syncContacts: { contacts in
+                // Ensure local contacts are prepared
+                var localContacts: AddressBookContacts
 
-                // contacts haven't been loaded from the remote storage yet, do it
-//                do {
-//                    let data = try await remoteStorage.loadAddressBookContacts()
-//
-//                    let storedContacts = try AddressBookClient.decryptData(data)
-//                    latestKnownContacts.value = storedContacts
-//
-//                    return storedContacts
-//                } catch RemoteStorageClient.RemoteStorageError.fileDoesntExist {
-//                    return []
-//                } catch {
-//                    throw error
-//                }
-                return []
+                if let contacts {
+                    localContacts = contacts
+                } else {
+                    do {
+                        guard let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else {
+                            throw AddressBookClientError.documentsFolder
+                        }
+                        let fileURL = documentsDirectory.appendingPathComponent(Constants.component)
+                        let encryptedContacts = try Data(contentsOf: fileURL)
+
+                        let decryptedContacts = try AddressBookClient.decryptData(encryptedContacts)
+                        localContacts = decryptedContacts
+
+                        return decryptedContacts
+                    } catch {
+                        throw error
+                    }
+                }
+
+                let data = try remoteStorage.loadAddressBookContacts()
+                let remoteContacts = try AddressBookClient.decryptData(data)
+
+                // Ensure remote contacts are prepared
+
+                // Merge strategy
+                print("__LD SYNCING CONTACTS...")
+                print("__LD localContacts \(localContacts)")
+                print("__LD remoteContacts \(remoteContacts)")
+
+                var syncedContacts = localContacts
+
+                // TBD
+
+                return syncedContacts
             },
             storeContact: {
-                var contacts = latestKnownContacts.value ?? []
-
+                var abContacts = latestKnownContacts ?? AddressBookContacts.empty
+                
                 // if already exists, remove it
-                if contacts.contains($0) {
-                    contacts.remove($0)
+                if abContacts.contacts.contains($0) {
+                    abContacts.contacts.remove($0)
                 }
 
-                contacts.append($0)
+                abContacts.contacts.append($0)
+
+                // encrypt data
+                let encryptedContacts = try AddressBookClient.encryptContacts(abContacts)
+                //let decryptedContacts = try AddressBookClient.decryptData(encryptedContacts)
 
-                // push encrypted data to the remote storage
-                //try await remoteStorage.storeAddressBookContacts(AddressBookClient.encryptContacts(contacts))
-                // TODO: FIXME
+                // store encrypted data to the local storage
+                guard let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else {
+                    throw AddressBookClientError.documentsFolder
+                }
+                let fileURL = documentsDirectory.appendingPathComponent(Constants.component)
+                try encryptedContacts.write(to: fileURL)
 
+                // store encrypted data to the remote storage
+                try remoteStorage.storeAddressBookContacts(encryptedContacts)
+
                 // update the latest known contacts
-                latestKnownContacts.value = contacts
+                latestKnownContacts = abContacts
 
-                return contacts
+                return abContacts
             },
             deleteContact: {
-                var contacts = latestKnownContacts.value ?? []
+                var abContacts = latestKnownContacts ?? AddressBookContacts.empty
 
                 // if it doesn't exist, do nothing
-                guard contacts.contains($0) else {
-                    return contacts
+                guard abContacts.contacts.contains($0) else {
+                    return abContacts
                 }
 
-                contacts.remove($0)
+                abContacts.contacts.remove($0)
 
-                // push encrypted data to the remote storage
-                //try await remoteStorage.storeAddressBookContacts(AddressBookClient.encryptContacts(contacts))
+                // encrypt data
+                let encryptedContacts = try AddressBookClient.encryptContacts(abContacts)
+
+                // store encrypted data to the local storage
+                guard let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else {
+                    throw AddressBookClientError.documentsFolder
+                }
+                let fileURL = documentsDirectory.appendingPathComponent(Constants.component)
+                try encryptedContacts.write(to: fileURL)
+
+                // store encrypted data to the remote storage
+                try remoteStorage.storeAddressBookContacts(encryptedContacts)
 
                 // update the latest known contacts
-                latestKnownContacts.value = contacts
+                latestKnownContacts = abContacts
 
-                return contacts
+                return abContacts
             }
         )
     }
 
-    private static func encryptContacts(_ contacts: IdentifiedArrayOf<ABRecord>) throws -> Data {
+    private static func encryptContacts(_ abContacts: AddressBookContacts) throws -> Data {
         @Dependency(\.walletStorage) var walletStorage
 
-        guard let encryptionKey = try? walletStorage.exportAddressBookKey() else {
-            throw AddressBookClient.AddressBookClientError.missingEncryptionKey
-        }
-
         // TODO: str4d
+//        guard let encryptionKeys = try? walletStorage.exportAddressBookEncryptionKeys() else {
+//            throw AddressBookClient.AddressBookClientError.missingEncryptionKey
+//        }
+
         // here you have an array of all contacts
         // you also have a key from the keychain
+        var data = Data()
+
+        // Serialize `version`
+        data.append(contentsOf: intToBytes(abContacts.version))
+
+        // Serialize `lastUpdated`
+        data.append(contentsOf: AddressBookClient.serializeDate(Date()))
 
-        return Data()
+        // Serialize `contacts.count`
+        data.append(contentsOf: intToBytes(abContacts.contacts.count))
+
+        // Serialize `contacts`
+        abContacts.contacts.forEach { contact in
+            let serializedContact = serializeContact(contact)
+            data.append(serializedContact)
+        }
+
+        return data
     }
 
-    private static func decryptData(_ data: Data) throws -> IdentifiedArrayOf<ABRecord> {
+    private static func decryptData(_ data: Data) throws -> AddressBookContacts {
         @Dependency(\.walletStorage) var walletStorage
 
-        guard let encryptionKey = try? walletStorage.exportAddressBookKey() else {
-            throw AddressBookClient.AddressBookClientError.missingEncryptionKey
-        }
-
         // TODO: str4d
+//        guard let encryptionKeys = try? walletStorage.exportAddressBookEncryptionKeys() else {
+//            throw AddressBookClient.AddressBookClientError.missingEncryptionKey
+//        }
+
         // here you have the encrypted data from the cloud, the blob
         // you also have a key from the keychain
+
+        var offset = 0
 
-        return []
+        // Deserialize `version`
+        let versionBytes = data.subdata(in: offset..<(offset + MemoryLayout<Int>.size))
+        offset += MemoryLayout<Int>.size
+
+        guard let version = AddressBookClient.bytesToInt(Array(versionBytes)) else {
+            return .empty
+        }
+
+        guard version == AddressBookContacts.Constants.version else {
+            return .empty
+        }
+
+        // Deserialize `lastUpdated`
+        guard let lastUpdated = AddressBookClient.deserializeDate(from: data, at: &offset) else {
+            return .empty
+        }
+
+        // Deserialize `contactsCount`
+        let contactsCountBytes = data.subdata(in: offset..<(offset + MemoryLayout<Int>.size))
+        offset += MemoryLayout<Int>.size
+
+        guard let contactsCount = AddressBookClient.bytesToInt(Array(contactsCountBytes)) else {
+            return .empty
+        }
+
+        var contacts: [Contact] = []
+        for _ in 0..<contactsCount {
+            if let contact = AddressBookClient.deserializeContact(from: data, at: &offset) {
+                contacts.append(contact)
+            }
+        }
+
+        let abContacts = AddressBookContacts(
+            lastUpdated: lastUpdated,
+            version: AddressBookContacts.Constants.version,
+            contacts: IdentifiedArrayOf(uniqueElements: contacts)
+        )
+
+        return abContacts
+    }
+
+    private static func serializeContact(_ contact: Contact) -> Data {
+        var data = Data()
+
+        // Serialize `lastUpdated`
+        data.append(contentsOf: AddressBookClient.serializeDate(contact.lastUpdated))
+
+        // Serialize `address` (length + UTF-8 bytes)
+        let addressBytes = stringToBytes(contact.id)
+        data.append(contentsOf: intToBytes(addressBytes.count))
+        data.append(contentsOf: addressBytes)
+
+        // Serialize `name` (length + UTF-8 bytes)
+        let nameBytes = stringToBytes(contact.name)
+        data.append(contentsOf: intToBytes(nameBytes.count))
+        data.append(contentsOf: nameBytes)
+
+        return data
+    }
+
+    private static func deserializeContact(from data: Data, at offset: inout Int) -> Contact? {
+        // Deserialize `lastUpdated`
+        guard let lastUpdated = AddressBookClient.deserializeDate(from: data, at: &offset) else {
+            return nil
+        }
+
+        // Deserialize `address`
+        guard let address = readString(from: data, at: &offset) else {
+            return nil
+        }
+
+        // Deserialize `name`
+        guard let name = readString(from: data, at: &offset) else {
+            return nil
+        }
+
+        return Contact(address: address, name: name, lastUpdated: lastUpdated)
+    }
+
+    private static func stringToBytes(_ string: String) -> [UInt8] {
+        return Array(string.utf8)
+    }
+
+    private static func bytesToString(_ bytes: [UInt8]) -> String? {
+        return String(bytes: bytes, encoding: .utf8)
+    }
+
+    private static func intToBytes(_ value: Int) -> [UInt8] {
+        withUnsafeBytes(of: value.bigEndian, Array.init)
+    }
+
+    private static func bytesToInt(_ bytes: [UInt8]) -> Int? {
+        guard bytes.count == MemoryLayout<Int>.size else {
+            return nil
+        }
+
+        return bytes.withUnsafeBytes {
+            $0.load(as: Int.self).bigEndian
+        }
+    }
+
+    private static func serializeDate(_ date: Date) -> [UInt8] {
+        // Convert Date to Unix time (number of seconds since 1970)
+        let timestamp = Int(date.timeIntervalSince1970)
+
+        // Convert the timestamp to bytes
+        return AddressBookClient.intToBytes(timestamp)
+    }
+
+    private static func deserializeDate(from data: Data, at offset: inout Int) -> Date? {
+        // Extract the bytes for the timestamp (assume it's stored as an Int)
+        let timestampBytes = data.subdata(in: offset..<(offset + MemoryLayout<Int>.size))
+        offset += MemoryLayout<Int>.size
+
+        // Convert the bytes back to an Int
+        guard let timestamp = AddressBookClient.bytesToInt(Array(timestampBytes)) else { return nil }
+
+        // Convert the timestamp back to a Date
+        return Date(timeIntervalSince1970: TimeInterval(timestamp))
+    }
+
+    // Helper function to read a string from the data using a length prefix
+    private static func readString(from data: Data, at offset: inout Int) -> String? {
+        // Read the length first (assumes the length is stored as an Int)
+        let lengthBytes = data.subdata(in: offset..<(offset + MemoryLayout<Int>.size))
+        offset += MemoryLayout<Int>.size
+        guard let length = AddressBookClient.bytesToInt(Array(lengthBytes)), length > 0 else { return nil }
+
+        // Read the string bytes
+        let stringBytes = data.subdata(in: offset..<(offset + length))
+        offset += length
+        return AddressBookClient.bytesToString(Array(stringBytes))
     }
 }