Add Spaceshrooms (#17092)

Co-authored-by: metalgearsloth <comedian_vs_clown@hotmail.com>

Content.Shared/Random/Helpers/SharedRandomExtensions.cs

@@ -1,5 +1,6 @@
 using System.Linq;
 using Content.Shared.Dataset;
+using Content.Shared.FixedPoint;
 using Robust.Shared.Random;
 
 namespace Content.Shared.Random.Helpers
@@ -75,5 +76,61 @@ namespace Content.Shared.Random.Helpers
 
             throw new InvalidOperationException($"Invalid weighted pick");
         }
+
+        public static (string reagent, FixedPoint2 quantity) Pick(this WeightedRandomFillSolutionPrototype prototype, IRobustRandom? random = null)
+        {
+            var randomFill = prototype.PickRandomFill(random);
+
+            IoCManager.Resolve(ref random);
+
+            var sum = randomFill.Reagents.Count;
+            var accumulated = 0f;
+
+            var rand = random.NextFloat() * sum;
+
+            foreach (var reagent in randomFill.Reagents)
+            {
+                accumulated += 1f;
+
+                if (accumulated >= rand)
+                {
+                    return (reagent, randomFill.Quantity);
+                }
+            }
+
+            // Shouldn't happen
+            throw new InvalidOperationException($"Invalid weighted pick for {prototype.ID}!");
+        }
+
+        public static RandomFillSolution PickRandomFill(this WeightedRandomFillSolutionPrototype prototype, IRobustRandom? random = null)
+        {
+            IoCManager.Resolve(ref random);
+
+            var fills = prototype.Fills;
+            Dictionary<RandomFillSolution, float> picks = new();
+
+            foreach (var fill in fills)
+            {
+                picks[fill] = fill.Weight;
+            }
+
+            var sum = picks.Values.Sum();
+            var accumulated = 0f;
+
+            var rand = random.NextFloat() * sum;
+
+            foreach (var (randSolution, weight) in picks)
+            {
+                accumulated += weight;
+
+                if (accumulated >= rand)
+                {
+                    return randSolution;
+                }
+            }
+
+            // Shouldn't happen
+            throw new InvalidOperationException($"Invalid weighted pick for {prototype.ID}!");
+        }
     }
 }