COVIDSafe code from version 2.0 (#37)

CovidSafe/Herald/Sensor/Data/StatisticsLog.swift

@@ -0,0 +1,95 @@
+//
+//  StatisticsLog.swift
+//
+//  Copyright 2020 VMware, Inc.
+//  SPDX-License-Identifier: MIT
+//
+
+import Foundation
+
+/// CSV contact log for post event analysis and visualisation
+class StatisticsLog: NSObject, SensorDelegate {
+    private let textFile: TextFile
+    private let payloadData: PayloadData
+    private var identifierToPayload: [TargetIdentifier:String] = [:]
+    private var payloadToTime: [String:Date] = [:]
+    private var payloadToSample: [String:Sample] = [:]
+    
+    init(filename: String, payloadData: PayloadData) {
+        textFile = TextFile(filename: filename)
+        self.payloadData = payloadData
+    }
+    
+    private func csv(_ value: String) -> String {
+        return TextFile.csv(value)
+    }
+    
+    private func add(identifier: TargetIdentifier) {
+        guard let payload = identifierToPayload[identifier] else {
+            return
+        }
+        add(payload: payload)
+    }
+
+    private func add(payload: String) {
+        guard let time = payloadToTime[payload], let sample = payloadToSample[payload] else {
+            payloadToTime[payload] = Date()
+            payloadToSample[payload] = Sample()
+            return
+        }
+        let now = Date()
+        payloadToTime[payload] = now
+        sample.add(Double(now.timeIntervalSince(time)))
+        write()
+    }
+    
+    private func write() {
+        var content = "payload,count,mean,sd,min,max\n"
+        var payloadList: [String] = []
+        payloadToSample.keys.forEach() { payload in
+            guard payload != payloadData.shortName else {
+                return
+            }
+            payloadList.append(payload)
+        }
+        payloadList.sort()
+        payloadList.forEach() { payload in
+            guard let sample = payloadToSample[payload] else {
+                return
+            }
+            guard let mean = sample.mean, let sd = sample.standardDeviation, let min = sample.min, let max = sample.max else {
+                return
+            }
+            content.append("\(csv(payload)),\(sample.count),\(mean),\(sd),\(min),\(max)\n")
+        }
+        textFile.overwrite(content)
+    }
+
+
+    // MARK:- SensorDelegate
+    
+    func sensor(_ sensor: SensorType, didDetect: TargetIdentifier) {
+    }
+    
+    func sensor(_ sensor: SensorType, didRead: PayloadData, fromTarget: TargetIdentifier) {
+        identifierToPayload[fromTarget] = didRead.shortName
+        add(identifier: fromTarget)
+    }
+    
+    func sensor(_ sensor: SensorType, didRead: PayloadData, fromTarget: TargetIdentifier, atProximity: Proximity, withTxPower: Int?) {
+        identifierToPayload[fromTarget] = didRead.shortName
+        add(identifier: fromTarget)
+    }
+    
+    func sensor(_ sensor: SensorType, didMeasure: Proximity, fromTarget: TargetIdentifier) {
+        add(identifier: fromTarget)
+    }
+    
+    func sensor(_ sensor: SensorType, didShare: [PayloadData], fromTarget: TargetIdentifier, atProximity: Proximity) {
+        didShare.forEach() { payloadData in
+            add(payload: payloadData.shortName)
+        }
+    }
+       
+
+}