From 44ee0f11d536bcbc1bdf87f179baac8dd039dfc6 Mon Sep 17 00:00:00 2001
From: Chomp <dev@dev.sp-tarkov.com>
Date: Sun, 12 Jan 2025 16:37:28 +0000
Subject: [PATCH] Expanded `WeightedRandom()` and
 `GetWeightedWeatherTimePeriodMs()` implementation

---
 Core/Helpers/WeightedRandomHelper.cs          | 51 +++++++++++++++++--
 Core/Models/Spt/Config/WeatherConfig.cs       |  6 +--
 .../Models/Spt/Helper/WeightedRandomResult.cs |  7 +++
 Core/Services/RaidWeatherService.cs           | 10 ++--
 4 files changed, 61 insertions(+), 13 deletions(-)
 create mode 100644 Core/Models/Spt/Helper/WeightedRandomResult.cs

diff --git a/Core/Helpers/WeightedRandomHelper.cs b/Core/Helpers/WeightedRandomHelper.cs
index 090186fe..4bbf62b1 100644
--- a/Core/Helpers/WeightedRandomHelper.cs
+++ b/Core/Helpers/WeightedRandomHelper.cs
@@ -1,12 +1,17 @@
 using Core.Annotations;
+using Core.Models.Spt.Helper;
 
 namespace Core.Helpers;
 
 [Injectable]
 public class WeightedRandomHelper
 {
-    public WeightedRandomHelper()
+    private readonly ILogger _logger;
+
+    public WeightedRandomHelper(
+        ILogger logger)
     {
+        _logger = logger;
     }
 
     /// <summary>
@@ -33,10 +38,48 @@ public class WeightedRandomHelper
     /// <param name="items">List of items</param>
     /// <param name="weights">List of weights</param>
     /// <returns>Dictionary with item and index</returns>
-    public object WeightedRandom<T>(List<T> items, List<double> weights)
+    public WeightedRandomResult<T> WeightedRandom<T>(List<T> items, List<int> weights)
     {
-        // TODO - create return type  { item: any; index: number }
-        throw new NotImplementedException();
+        if (items.Count == 0)
+        {
+            _logger.LogError("Items must not be empty");
+        }
+
+        if (weights.Count == 0)
+        {
+            _logger.LogError("Item weights must not be empty");
+        }
+
+        if (items.Count != weights.Count)
+        {
+            _logger.LogError("Items and weight inputs must be of the same length");
+        }
+
+        // Preparing the cumulative weights list.
+        List<int> cumulativeWeights = [];
+        for (var i = 0; i < weights.Count; i++)
+        {
+            cumulativeWeights.Add(weights[i] + (i > 0 ? cumulativeWeights[i - 1] : 0));
+        }
+
+        // Getting the random number in a range of [0...sum(weights)]
+        int maxCumulativeWeight = cumulativeWeights[cumulativeWeights.Count - 1];
+        double randomNumber = maxCumulativeWeight * new Random().NextDouble();
+
+        // Picking the random item based on its weight.
+        for (int itemIndex = 0; itemIndex < items.Count; itemIndex++)
+        {
+            if (cumulativeWeights[itemIndex] >= randomNumber)
+            {
+                return new WeightedRandomResult<T>()
+                {
+                    Item = items[itemIndex],
+                    Index = itemIndex,
+                };
+            }
+        }
+
+        throw new InvalidOperationException("No item was picked.");
     }
 
     /// <summary>
diff --git a/Core/Models/Spt/Config/WeatherConfig.cs b/Core/Models/Spt/Config/WeatherConfig.cs
index 3f8f1478..aa553dd7 100644
--- a/Core/Models/Spt/Config/WeatherConfig.cs
+++ b/Core/Models/Spt/Config/WeatherConfig.cs
@@ -1,4 +1,4 @@
-using System.Text.Json.Serialization;
+using System.Text.Json.Serialization;
 using Core.Models.Common;
 using Core.Models.Enums;
 using Core.Utils.Json.Converters;
@@ -107,5 +107,5 @@ public class WeatherSettings<T>
     public List<T> Values { get; set; }
 
     [JsonPropertyName("weights")]
-    public List<double> Weights { get; set; }
-}
\ No newline at end of file
+    public List<int> Weights { get; set; }
+}
diff --git a/Core/Models/Spt/Helper/WeightedRandomResult.cs b/Core/Models/Spt/Helper/WeightedRandomResult.cs
new file mode 100644
index 00000000..a9532f59
--- /dev/null
+++ b/Core/Models/Spt/Helper/WeightedRandomResult.cs
@@ -0,0 +1,7 @@
+namespace Core.Models.Spt.Helper;
+
+public class WeightedRandomResult<T>
+{
+    public T Item { get; set; }
+    public int Index { get; set; }
+}
diff --git a/Core/Services/RaidWeatherService.cs b/Core/Services/RaidWeatherService.cs
index ce07588b..992bd6ae 100644
--- a/Core/Services/RaidWeatherService.cs
+++ b/Core/Services/RaidWeatherService.cs
@@ -75,13 +75,11 @@ public class RaidWeatherService
     /// <returns>milliseconds</returns>
     protected long GetWeightedWeatherTimePeriodMs()
     {
-        //var chosenTimePeriodMinutes = _weightedRandomHelper.WeightedRandom(
-        //    _weatherConfig.Weather.TimePeriod.Values,
-        //    _weatherConfig.Weather.TimePeriod.Weights).Item;
+        var chosenTimePeriodMinutes = _weightedRandomHelper.WeightedRandom(
+            _weatherConfig.Weather.TimePeriod.Values,
+            _weatherConfig.Weather.TimePeriod.Weights).Item;
 
-        //return chosenTimePeriodMinutes * 60 * 1000; // Convert to milliseconds
-
-        throw new NotImplementedException();
+        return chosenTimePeriodMinutes * 60 * 1000; // Convert to milliseconds
     }
 
     /// <summary>