Adjusted Alert Extended Info date parsing algorithm.

1Weather/Network/Notifications/NWSAlertInfoParser.swift

@@ -57,7 +57,7 @@ class NWSAlertInfoParser {
         return dateFormatter
     }()
     
-    private func parse(dateString: String, shouldBeInThePast: Bool) -> Date? {
+    private func parse(dateString: String, shouldBeBefore beforeDate: Date?, after afterDate: Date?) -> Date? {
         // There's no year here, so we've got to guess.
         let currentDate = Date()
         let calendar = Calendar(identifier: .gregorian)
@@ -65,20 +65,26 @@ class NWSAlertInfoParser {
             return nil
         }
         let dateStringWithCurrentYear = "\(currentYear) \(dateString)"
-        if shouldBeInThePast {
-            guard let dateWithCurrentYear = NWSAlertInfoParser.dateFormatter.date(from: dateStringWithCurrentYear) else {
-                return nil
-            }
-            if dateWithCurrentYear > currentDate {
-                let dateStringWithPreviousYear = "\(currentYear - 1) \(dateString)"
-                return NWSAlertInfoParser.dateFormatter.date(from: dateStringWithPreviousYear)
+        var yearAdjustment: Int? = nil
+        guard let dateWithCurrentYear = NWSAlertInfoParser.dateFormatter.date(from: dateStringWithCurrentYear) else {
+            return nil
+        }
+        if let beforeDate = beforeDate {
+            if beforeDate < dateWithCurrentYear {
+                yearAdjustment = -1
             }
-            else {
-                return dateWithCurrentYear
+        }
+        if let afterDate = afterDate {
+            if afterDate > dateWithCurrentYear {
+                yearAdjustment = 1
             }
         }
+        if let yearAdjustment = yearAdjustment {
+            let adjustedDateString = "\(currentYear + yearAdjustment) \(dateString)"
+            return NWSAlertInfoParser.dateFormatter.date(from: adjustedDateString)
+        }
         else {
-            return NWSAlertInfoParser.dateFormatter.date(from: dateStringWithCurrentYear)
+            return dateWithCurrentYear
         }
     }
     
@@ -106,11 +112,11 @@ class NWSAlertInfoParser {
         }
         result.title = (firstLine as NSString).substring(with: firstMatch.range(withName: "title"))
         let issuedDateString = (firstLine as NSString).substring(with: firstMatch.range(withName: "issuedDate"))
-        result.issueDate = parse(dateString: issuedDateString, shouldBeInThePast: true)
+        result.issueDate = parse(dateString: issuedDateString, shouldBeBefore: Date(), after: nil)
         let expiryDateRange = firstMatch.range(withName: "expiryDate")
         if expiryDateRange.location != NSNotFound {
             let expiryDateString = (firstLine as NSString).substring(with: expiryDateRange)
-            result.expiryDate = parse(dateString: expiryDateString, shouldBeInThePast: false)
+            result.expiryDate = parse(dateString: expiryDateString, shouldBeBefore: nil, after: result.issueDate)
         }
         result.issuer = (firstLine as NSString).substring(with: firstMatch.range(withName: "issuer"))
         return result