COVIDSafe code from version 1.1

CovidSafe/EncounterMessageManager.swift

@@ -0,0 +1,139 @@
+import Foundation
+
+class EncounterMessageManager {
+    let userDefaultsTempIdKey = "BROADCAST_MSG"
+    let userDefaultsAdvtKey = "ADVT_DATA"
+    let userDefaultsAdvtExpiryKey = "ADVT_EXPIRY"
+    
+    static let shared = EncounterMessageManager()
+    
+    var tempId: String? {
+        return UserDefaults.standard.string(forKey: userDefaultsTempIdKey)
+    }
+    
+    var advertisedPayload: Data? {
+        return UserDefaults.standard.data(forKey: userDefaultsAdvtKey)
+    }
+    
+    // This variable stores the expiry date of the broadcast message. At the same time, we will use this expiry date as the expiry date for the encryted advertisement payload
+    var advertisementPayloadExpiry: Date? {
+        return UserDefaults.standard.object(forKey: userDefaultsAdvtExpiryKey) as? Date
+    }
+    
+    func setup() {
+        // Check payload validity
+        if advertisementPayloadExpiry == nil ||  Date() > advertisementPayloadExpiry! {
+            // Call API to get new tempId and expiry date
+            fetchTempIdFromApi { [unowned self] (error: Error?, resp:(tempId: String, expiry: Date)?) in
+                guard let response = resp else {
+                    DLog("No response, Error: \(String(describing: error))")
+                    return
+                }
+                _ = self.setAdvertisementPayloadIntoUserDefaults(response)
+                UserDefaults.standard.set(response.tempId, forKey: self.userDefaultsTempIdKey)
+            }
+        }
+    }
+    
+    func getTempId(onComplete: @escaping (String?) -> Void) {
+        // check refreshDate
+        if advertisementPayloadExpiry == nil ||  Date() > advertisementPayloadExpiry! {
+            fetchTempIdFromApi { [unowned self] (error: Error?, resp:(tempId: String, expiry: Date)?) in
+                guard let response = resp else {
+                    DLog("No response, Error: \(String(describing: error))")
+                    onComplete(nil)
+                    return
+                }
+                UserDefaults.standard.set(response.tempId, forKey: self.userDefaultsTempIdKey)
+                UserDefaults.standard.set(response.expiry, forKey: self.userDefaultsAdvtExpiryKey)
+                
+                onComplete(response.tempId)
+                return
+            }
+        }
+        
+        // we know that tempId has not expired
+        if let msg = tempId {
+            onComplete(msg)
+        } else {
+           // this is not part of usual expected flow, just run setup and be done with it
+           setup()
+           onComplete(nil)
+        }
+    }
+    
+    // gets the anon tempid for broadcasting
+    func getAdvertisementPayload(onComplete: @escaping (Data?) -> Void) {
+         // check expiry date of payload
+         if advertisementPayloadExpiry == nil ||  Date() > advertisementPayloadExpiry! {
+            fetchTempIdFromApi { [unowned self] (error: Error?, resp:(tempId: String, expiry: Date)?) in
+                guard let response = resp else {
+                    DLog("No response, Error: \(String(describing: error))")
+                    onComplete(nil)
+                    return
+                }
+                
+                if let newPayload = self.setAdvertisementPayloadIntoUserDefaults(response) {
+                    onComplete(newPayload)
+                }
+                onComplete(nil)
+            }
+         }
+         
+         // we know that payload has not expired
+         if let payload = advertisedPayload {
+             onComplete(payload)
+         } else {
+            // this is not part of usual expected flow, just run setup and be done with it
+            setup()
+            onComplete(nil)
+         }
+     }
+    
+    private func fetchTempIdFromApi(onComplete: ((Error?, (String, Date)?) -> Void)?) {
+        DLog("Fetching tempId from API")
+        GetTempIdAPI.getTempId { (tempId: String?, expiry: Int?, error: Error?) in
+            guard error == nil else {
+                if let error = error as NSError? {
+                    let code = error.code
+                    let message = error.localizedDescription
+                    let details = error.userInfo
+                    DLog("API error. Code: \(String(describing: code)), Message: \(message), Details: \(String(describing: details))")
+                } else {
+                    DLog("Cloud function error, unable to convert error to NSError.\(error!)")
+                }
+                // if we have an existing tempid and expiry, use that
+                if let msg = self.tempId, let exp = self.advertisementPayloadExpiry {
+                    onComplete?(nil, (msg, exp))
+                } else {
+                    onComplete?(error, nil)
+                }
+                return
+            }
+
+            guard let tempId = tempId,
+                let expiry = expiry else {
+                    DLog("Unable to get tempId or expiry from API.")
+                    onComplete?(NSError(domain: "BM", code: 9999, userInfo: nil), nil)
+                    return
+            }
+
+            let date = Date(timeIntervalSince1970: TimeInterval(expiry))
+            onComplete?(nil, (tempId, date))
+        }
+    }
+    
+    private func setAdvertisementPayloadIntoUserDefaults(_ response: (tempId: String, expiry: Date)) -> Data? {
+        let peripheralCharStruct = PeripheralCharacteristicsData(modelP: DeviceIdentifier.getModel(), msg: response.tempId, org: BluetraceConfig.OrgID, v: BluetraceConfig.ProtocolVersion)
+        do {
+            let encodedPeriCharStruct = try JSONEncoder().encode(peripheralCharStruct)
+            UserDefaults.standard.set(encodedPeriCharStruct, forKey: self.userDefaultsAdvtKey)
+            UserDefaults.standard.set(response.expiry, forKey: self.userDefaultsAdvtExpiryKey)
+            return encodedPeriCharStruct
+        } catch {
+            DLog("Error: \(error)")
+        }
+        
+        return nil
+    }
+}