Add FlatStatModifier and PercentStatModifier classes; introduce Stat enum for character attributes

Assets/Scripts/Modifiers/PercentStatModifier.cs

@@ -0,0 +1,57 @@
+using Data;
+using Interfaces;
+
+namespace Modifiers
+{
+    public class PercentStatModifier : IStatModifier
+    {
+        private float lastAppliedAmount;
+
+        public Stat Stat { get; set; }
+        public float Percent { get; set; }
+        public string Description => $"{Stat} +{Percent * 100}%";
+
+        public void Apply(CharacterAttributes attributes)
+        {
+            var baseValue = GetBaseValue<float>(attributes);
+            lastAppliedAmount = baseValue * Percent;
+            
+            var flatModifier = new FlatStatModifier
+            {
+                value = lastAppliedAmount,
+                stat = Stat
+            };
+            
+            flatModifier.Apply(attributes);
+        }
+
+        public void Remove(CharacterAttributes attributes)
+        {
+            var flatModifier = new FlatStatModifier
+            {
+                value = -lastAppliedAmount,
+                stat = Stat
+            };
+            
+            flatModifier.Apply(attributes);
+        }
+
+        private T GetBaseValue<T>(CharacterAttributes attributes)
+        {
+            return Stat switch
+            {
+                Stat.Health => (T)(object)attributes.Health,
+                Stat.MaxHealth => (T)(object)attributes.MaxHealth,
+                Stat.MoveSpeed => (T)(object)attributes.MoveSpeed,
+                Stat.Luck => (T)(object)attributes.Luck,
+                Stat.Armor => (T)(object)attributes.Armor,
+                Stat.Damage => (T)(object)attributes.Damage,
+                Stat.RangedDamage => (T)(object)attributes.RangedDamage,
+                Stat.MeleeDamage => (T)(object)attributes.MeleeDamage,
+                Stat.AttackRange => (T)(object)attributes.AttackRange,
+                Stat.AttackSpeed => (T)(object)attributes.AttackSpeed,
+                _ => throw new System.ArgumentOutOfRangeException()
+            };
+        }
+    }
+}