COVIDSafe code from version 2.0 (#37)

CovidSafe/Herald/Sensor/Data/ContactLog.swift

@@ -0,0 +1,57 @@
+//
+//  ContactLog.swift
+//
+//  Copyright 2020 VMware, Inc.
+//  SPDX-License-Identifier: MIT
+//
+
+import Foundation
+
+/// CSV contact log for post event analysis and visualisation
+class ContactLog: NSObject, SensorDelegate {
+    private let textFile: TextFile
+    private let dateFormatter = DateFormatter()
+    
+    init(filename: String) {
+        textFile = TextFile(filename: filename)
+        if textFile.empty() {
+            textFile.write("time,sensor,id,detect,read,measure,share,visit,data")
+        }
+        dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
+    }
+    
+    private func timestamp() -> String {
+        let timestamp = dateFormatter.string(from: Date())
+        return timestamp
+    }
+    
+    private func csv(_ value: String) -> String {
+        return TextFile.csv(value)
+    }
+    
+    // MARK:- SensorDelegate
+    
+    func sensor(_ sensor: SensorType, didDetect: TargetIdentifier) {
+        textFile.write(timestamp() + "," + sensor.rawValue + "," + csv(didDetect) + ",1,,,,,")
+    }
+    
+    func sensor(_ sensor: SensorType, didRead: PayloadData, fromTarget: TargetIdentifier) {
+        textFile.write(timestamp() + "," + sensor.rawValue + "," + csv(fromTarget) + ",,2,,,," + csv(didRead.shortName))
+    }
+    
+    func sensor(_ sensor: SensorType, didRead: PayloadData, fromTarget: TargetIdentifier, atProximity: Proximity, withTxPower: Int?) {
+        textFile.write(timestamp() + "," + sensor.rawValue + "," + csv(fromTarget) + ",,2,,,," + csv(didRead.shortName))
+    }
+    
+    func sensor(_ sensor: SensorType, didMeasure: Proximity, fromTarget: TargetIdentifier) {
+        textFile.write(timestamp() + "," + sensor.rawValue + "," + csv(fromTarget) + ",,,3,,," + csv(didMeasure.description))
+    }
+    
+    func sensor(_ sensor: SensorType, didShare: [PayloadData], fromTarget: TargetIdentifier, atProximity: Proximity) {
+        let prefix = timestamp() + "," + sensor.rawValue + "," + csv(fromTarget)
+        didShare.forEach() { payloadData in
+            textFile.write(prefix + ",,,,4,," + csv(payloadData.shortName))
+        }
+    }    
+
+}