From 26485ba698b48c986a46e5e1ceac5f3182ec4fdd Mon Sep 17 00:00:00 2001
From: Stefan Mitterrutzner <stefan.mitterrutzner@gmail.com>
Date: Tue, 20 Apr 2021 10:29:26 +0200
Subject: [PATCH] expose oldest keydate when calling iWasExposed

---
 Sources/DP3TSDK/DP3TSDK.swift                 |  9 +++++++--
 Sources/DP3TSDK/DP3TTracing.swift             |  7 ++++++-
 Sources/DP3TSDK/Models/ExposeeListModel.swift |  6 ++++++
 Tests/DP3TSDKTests/DP3TSDKTests.swift         | 16 +++++++++++++---
 4 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/Sources/DP3TSDK/DP3TSDK.swift b/Sources/DP3TSDK/DP3TSDK.swift
index e31a6b8e..ce033fa2 100644
--- a/Sources/DP3TSDK/DP3TSDK.swift
+++ b/Sources/DP3TSDK/DP3TSDK.swift
@@ -246,7 +246,7 @@ class DP3TSDK {
     func iWasExposed(onset: Date,
                      authentication: ExposeeAuthMethod,
                      isFakeRequest: Bool = false,
-                     callback: @escaping (Result<Void, DP3TTracingError>) -> Void) {
+                     callback: @escaping (Result<DP3TTracing.IWasExposedResult, DP3TTracingError>) -> Void) {
         log.trace()
         if !isFakeRequest,
             case .infected = state.infectionStatus {
@@ -299,6 +299,11 @@ class DP3TSDK {
                     withFederationGateway = nil
                 }
 
+                let oldestNonFakeKeyDate = mutableKeys
+                    .filter { $0.fake == 0 }
+                    .map(\.date)
+                    .min()
+
                 let model = ExposeeListModel(gaenKeys: mutableKeys,
                                              withFederationGateway: withFederationGateway,
                                              fake: isFakeRequest)
@@ -313,7 +318,7 @@ class DP3TSDK {
                                 self.tracer.setEnabled(false, completionHandler: nil)
                             }
 
-                            callback(.success(()))
+                            callback(.success((.init(oldestKeyDate: oldestNonFakeKeyDate))))
                         case let .failure(error):
                             callback(.failure(.networkingError(error: error)))
                         }
diff --git a/Sources/DP3TSDK/DP3TTracing.swift b/Sources/DP3TSDK/DP3TTracing.swift
index c8f0c5bf..56591f41 100644
--- a/Sources/DP3TSDK/DP3TTracing.swift
+++ b/Sources/DP3TSDK/DP3TTracing.swift
@@ -135,6 +135,11 @@ public enum DP3TTracing {
         return instance.status
     }
 
+
+    public struct IWasExposedResult {
+        public let oldestKeyDate: Date?
+    }
+    
     /// tell the SDK that the user was exposed
     /// - Parameters:
     ///   - onset: Start date of the exposure
@@ -145,7 +150,7 @@ public enum DP3TTracing {
     public static func iWasExposed(onset: Date,
                                    authentication: ExposeeAuthMethod,
                                    isFakeRequest: Bool = false,
-                                   callback: @escaping (Result<Void, DP3TTracingError>) -> Void) {
+                                   callback: @escaping (Result<IWasExposedResult, DP3TTracingError>) -> Void) {
         instancePrecondition()
         instance.iWasExposed(onset: onset,
                              authentication: authentication,
diff --git a/Sources/DP3TSDK/Models/ExposeeListModel.swift b/Sources/DP3TSDK/Models/ExposeeListModel.swift
index 221b1bc3..509c483f 100644
--- a/Sources/DP3TSDK/Models/ExposeeListModel.swift
+++ b/Sources/DP3TSDK/Models/ExposeeListModel.swift
@@ -18,6 +18,12 @@ struct CodableDiagnosisKey: Codable, Equatable {
     let fake: UInt8
 }
 
+extension CodableDiagnosisKey {
+    var date: Date {
+        Date(timeIntervalSince1970: TimeInterval(rollingStartNumber) * TimeInterval.minute * 10)
+    }
+}
+
 /// Model of the exposed person
 struct ExposeeListModel: Encodable {
     /// Diagnosis keys
diff --git a/Tests/DP3TSDKTests/DP3TSDKTests.swift b/Tests/DP3TSDKTests/DP3TSDKTests.swift
index d1db2804..b91292b0 100644
--- a/Tests/DP3TSDKTests/DP3TSDKTests.swift
+++ b/Tests/DP3TSDKTests/DP3TSDKTests.swift
@@ -96,8 +96,18 @@ class DP3TSDKTests: XCTestCase {
         XCTAssertEqual(sdk.status.infectionStatus, .healthy)
 
         let exp = expectation(description: "infected")
-        keyProvider.keys = [ .init(keyData: Data(count: 16), rollingPeriod: 144, rollingStartNumber: DayDate().period, transmissionRiskLevel: 0, fake: 0) ]
+        let oldestDate = Date(timeIntervalSinceNow: -.day * 5)
+        keyProvider.keys = [
+            .init(keyData: Data(count: 16), rollingPeriod: 144, rollingStartNumber: DayDate(date: oldestDate.addingTimeInterval(.day)).period, transmissionRiskLevel: 0, fake: 0),
+            .init(keyData: Data(count: 16), rollingPeriod: 144, rollingStartNumber: DayDate(date: oldestDate).period, transmissionRiskLevel: 0, fake: 0),
+            .init(keyData: Data(count: 16), rollingPeriod: 144, rollingStartNumber: DayDate(date: oldestDate.addingTimeInterval(.day * 2)).period, transmissionRiskLevel: 0, fake: 0),
+        ]
         sdk.iWasExposed(onset: .init(timeIntervalSinceNow: -.day), authentication: .none) { (result) in
+            if case let Result.success(wrapper) = result {
+                XCTAssertEqual(wrapper.oldestKeyDate, DayDate(date: oldestDate).dayMin)
+            } else {
+                XCTFail()
+            }
             exp.fulfill()
         }
         wait(for: [exp], timeout: 0.1)
@@ -108,8 +118,8 @@ class DP3TSDKTests: XCTestCase {
         let rollingStartNumbers = Set(model!.gaenKeys.map(\.rollingStartNumber))
         XCTAssertEqual(rollingStartNumbers.count, model!.gaenKeys.count)
         var runningDate: Date?
-        for key in model!.gaenKeys {
-            let date = Date(timeIntervalSince1970: Double(key.rollingStartNumber) * 10 * .minute)
+        for key in model!.gaenKeys.sorted(by: { $0.date > $1.date }) {
+            let date = key.date
             guard runningDate != nil else {
                 runningDate = date
                 continue