Move entity effects definitions to shared (#35614)

* Move entity effects to shared

* relocate spawning to server

* Generic version of EntityEffect for just raising event.

* genericise everything

* oops forgot to push you

* some condensation

* finish rebas

* unwhite the space

* oops forgot nuke

* bad rebase fix

* useless annotations begone

---------

Co-authored-by: EmoGarbage404 <retron404@gmail.com>

Content.Shared/EntityEffects/EffectConditions/ReagentThreshold.cs

@@ -0,0 +1,56 @@
+using Content.Shared.Chemistry.Reagent;
+using Content.Shared.FixedPoint;
+using Robust.Shared.Prototypes;
+
+namespace Content.Shared.EntityEffects.EffectConditions;
+
+/// <summary>
+///     Used for implementing reagent effects that require a certain amount of reagent before it should be applied.
+///     For instance, overdoses.
+///
+///     This can also trigger on -other- reagents, not just the one metabolizing. By default, it uses the
+///     one being metabolized.
+/// </summary>
+public sealed partial class ReagentThreshold : EntityEffectCondition
+{
+    [DataField]
+    public FixedPoint2 Min = FixedPoint2.Zero;
+
+    [DataField]
+    public FixedPoint2 Max = FixedPoint2.MaxValue;
+
+    // TODO use ReagentId
+    [DataField]
+    public string? Reagent;
+
+    public override bool Condition(EntityEffectBaseArgs args)
+    {
+        if (args is EntityEffectReagentArgs reagentArgs)
+        {
+            var reagent = Reagent ?? reagentArgs.Reagent?.ID;
+            if (reagent == null)
+                return true; // No condition to apply.
+
+            var quant = FixedPoint2.Zero;
+            if (reagentArgs.Source != null)
+                quant = reagentArgs.Source.GetTotalPrototypeQuantity(reagent);
+
+            return quant >= Min && quant <= Max;
+        }
+
+        // TODO: Someone needs to figure out how to do this for non-reagent effects.
+        throw new NotImplementedException();
+    }
+
+    public override string GuidebookExplanation(IPrototypeManager prototype)
+    {
+        ReagentPrototype? reagentProto = null;
+        if (Reagent is not null)
+            prototype.TryIndex(Reagent, out reagentProto);
+
+        return Loc.GetString("reagent-effect-condition-guidebook-reagent-threshold",
+            ("reagent", reagentProto?.LocalizedName ?? Loc.GetString("reagent-effect-condition-guidebook-this-reagent")),
+            ("max", Max == FixedPoint2.MaxValue ? (float) int.MaxValue : Max.Float()),
+            ("min", Min.Float()));
+    }
+}