Allow solutions to store extra reagent data (#19323)

Content.Shared/Chemistry/Reagent/ReagentQuantity.cs

@@ -0,0 +1,77 @@
+using Content.Shared.FixedPoint;
+using Robust.Shared.Serialization;
+
+namespace Content.Shared.Chemistry.Reagent;
+
+/// <summary>
+/// Simple struct for storing a <see cref="ReagentId"/> & quantity tuple.
+/// </summary>
+[Serializable, NetSerializable]
+[DataDefinition]
+public partial struct ReagentQuantity : IEquatable<ReagentQuantity>
+{
+    [DataField("Quantity", required:true)]
+    public FixedPoint2 Quantity { get; private set; }
+
+    [IncludeDataField]
+    [ViewVariables]
+    public ReagentId Reagent { get; private set; }
+
+    public ReagentQuantity(string reagentId, FixedPoint2 quantity, ReagentData? data)
+        : this(new ReagentId(reagentId, data), quantity)
+    {
+    }
+
+    public ReagentQuantity(ReagentId reagent, FixedPoint2 quantity)
+    {
+        Reagent = reagent;
+        Quantity = quantity;
+    }
+
+    public ReagentQuantity() : this(default, default)
+    {
+    }
+
+    public override string ToString()
+    {
+        return Reagent.ToString(Quantity);
+    }
+
+    public void Deconstruct(out string prototype, out FixedPoint2 quantity, out ReagentData? data)
+    {
+        prototype = Reagent.Prototype;
+        quantity = Quantity;
+        data = Reagent.Data;
+    }
+
+    public void Deconstruct(out ReagentId id, out FixedPoint2 quantity)
+    {
+        id = Reagent;
+        quantity = Quantity;
+    }
+
+    public bool Equals(ReagentQuantity other)
+    {
+        return Quantity != other.Quantity && Reagent.Equals(other.Reagent);
+    }
+
+    public override bool Equals(object? obj)
+    {
+        return obj is ReagentQuantity other && Equals(other);
+    }
+
+    public override int GetHashCode()
+    {
+        return HashCode.Combine(Reagent.GetHashCode(), Quantity);
+    }
+
+    public static bool operator ==(ReagentQuantity left, ReagentQuantity right)
+    {
+        return left.Equals(right);
+    }
+
+    public static bool operator !=(ReagentQuantity left, ReagentQuantity right)
+    {
+        return !(left == right);
+    }
+}