Improve Robustness of RaidChangesUtil and RaidTimeUtil (!45)

While continuing mod development with SPT 3.7.4 (namely for Questing Bots and SAIN), I found that the API I added to SPT 3.7.4 is unintuitive and clunky to use after the raid is done loading but before the countdown timer expires. With the current SPT code, calling `GetRemainingRaidSeconds()` or `GetRaidTimeRemainingFraction()` will result in an exception during this time unless you check `HasRaidStarted()` first.

These changes will prevent those methods from throwing an exception unless you try calling them before a raid has finished loading (which should rarely happen). This allows mods to more easily do things using `GetRemainingRaidSeconds()` or `GetRaidTimeRemainingFraction()` before the countdown timer expires (i.e. cache bots).

These changes only improve the robustness of the existing code and will not break any mods that use the existing API.

Co-authored-by: dwesterwick <dwesterwick@yahoo.com>
Co-authored-by: chomp <chomp@noreply.dev.sp-tarkov.com>
Reviewed-on: SPT-AKI/Modules#45
Co-authored-by: DanW <danw@noreply.dev.sp-tarkov.com>
Co-committed-by: DanW <danw@noreply.dev.sp-tarkov.com>

project/Aki.SinglePlayer/Utils/InRaid/RaidChangesUtil.cs

@@ -59,10 +59,25 @@ namespace Aki.SinglePlayer.Utils.InRaid
         /// </summary>
         public static int RaidTimeReductionSeconds => RaidTimeReductionMinutes * 60;
 
+        /// <summary>
+        /// The fraction of raid time that will be remaining when you spawn into the map
+        /// </summary>
+        public static float RaidTimeRemainingFraction => (float)NewEscapeTimeMinutes / OriginalEscapeTimeMinutes;
+
+        /// <summary>
+        /// The original minimum time (in seconds) you must stay in the raid to get a "Survived" status (unless your XP is high enough) for the current (or most recent) raid
+        /// </summary>
+        public static int OriginalSurvivalTimeSeconds { get; private set; } = int.MaxValue;
+
+        /// <summary>
+        /// The updated minimum time (in seconds) you must stay in the raid to get a "Survived" status (unless your XP is high enough) for the current (or most recent) raid
+        /// </summary>
+        public static int NewSurvivalTimeSeconds { get; private set; } = int.MaxValue;
+
         /// <summary>
         /// The reduction in the minimum time you must stay in the raid to get a "Survived" status (unless your XP is high enough) for the current (or most recent) raid 
         /// </summary>
-        public static int SurvivalTimeReductionSeconds { get; private set; } = 0;
+        public static int SurvivalTimeReductionSeconds => OriginalSurvivalTimeSeconds - NewSurvivalTimeSeconds;
 
         /// <summary>
         /// Update the changes that will be made for the raid. This should be called just before applying changes. 
@@ -81,11 +96,8 @@ namespace Aki.SinglePlayer.Utils.InRaid
             OriginalEscapeTimeMinutes = raidSettings.SelectedLocation.EscapeTimeLimit;
             NewEscapeTimeMinutes = raidChanges.RaidTimeMinutes;
 
-            SurvivalTimeReductionSeconds = 0;
+            OriginalSurvivalTimeSeconds = raidChanges.OriginalSurvivalTimeSeconds;
-            if (raidChanges.NewSurviveTimeSeconds.HasValue)
+            NewSurvivalTimeSeconds = raidChanges.NewSurviveTimeSeconds ?? OriginalSurvivalTimeSeconds;
-            {
-                SurvivalTimeReductionSeconds += raidChanges.OriginalSurvivalTimeSeconds - raidChanges.NewSurviveTimeSeconds.Value;
-            }
         }
 
         /// <summary>

project/Aki.SinglePlayer/Utils/InRaid/RaidTimeUtil.cs

@@ -9,6 +9,14 @@ namespace Aki.SinglePlayer.Utils.InRaid
     /// </summary>
     public static class RaidTimeUtil
     {
+        /// <summary>
+        /// Determines if a raid has loaded by checking if a GameTimer instance has been created for one
+        /// </summary>
+        public static bool HasRaidLoaded()
+        {
+            return Singleton<AbstractGame>.Instance?.GameTimer != null;
+        }
+
         /// <summary>
         /// Determines if a raid is in-progress by checking if the GameTimer has started
         /// </summary>
@@ -19,17 +27,22 @@ namespace Aki.SinglePlayer.Utils.InRaid
 
         /// <summary>
         /// <para>Calculates the seconds remaining in the current raid.</para>
-        /// <para>Please ensure <see cref="HasRaidStarted"/> is <c>true</c>, or this will throw an exception.</para>
+        /// <para>Please ensure <see cref="HasRaidLoaded"/> is <c>true</c>, or this will throw an exception.</para>
         /// </summary>
         /// <returns>Seconds remaining in the raid</returns>
         /// <exception cref="InvalidOperationException">Thrown if there is no raid in progress</exception>
         public static float GetRemainingRaidSeconds()
         {
-            if (!HasRaidStarted())
+            if (!HasRaidLoaded())
             {
                 throw new InvalidOperationException("The raid-time remaining can only be calculated when a raid is in-progress");
             }
 
+            if (!HasRaidStarted())
+            {
+                return RaidChangesUtil.NewEscapeTimeSeconds;
+            }
+
             float remainingTimeSeconds = Singleton<AbstractGame>.Instance.GameTimer.EscapeTimeSeconds();
 
             // Until the raid starts, remainingTimeSeconds is TimeSpan.MaxValue, so it needs to be reduced to the actual starting raid time
@@ -39,7 +52,7 @@ namespace Aki.SinglePlayer.Utils.InRaid
         /// <summary>
         /// <para>Calculates the fraction of raid-time remaining relative to the original escape time for the map. 
         /// 1.0 = the raid just started, and 0.0 = the raid is over (and you're MIA).</para>
-        /// <para>Please ensure <see cref="HasRaidStarted"/> is <c>true</c>, or this will throw an exception.</para>
+        /// <para>Please ensure <see cref="HasRaidLoaded"/> is <c>true</c>, or this will throw an exception.</para>
         /// </summary>
         /// <returns>The fraction of raid-time remaining (0.0 - 1.0) relative to the original escape time for the map</returns>
         /// <exception cref="InvalidOperationException">Thrown if there is no raid in progress</exception>