Add preliminary StatsManager

Assets/Prefabs/GlobalScripts.prefab

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Assets/Scripts/StatsManager.cs

+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+
+public enum UpgradeTypes
+{
+    ENEMY_HEALTH,
+    ENEMY_DAMAGE,
+    ENEMY_ARMOR,
+    MANA_COST,
+}
+
+class UpgradeData
+{
+    public Upgrade upgrade;
+    public int count;
+
+    public int GetUnadjustedNextUpgradeCost()
+    {
+        return (int)(upgrade.baseCost * (1 + count * upgrade.costMultiplier));
+    }
+
+    public float GetTotalEffectMultiplier()
+    {
+        return 1 + count * upgrade.effectMultiplier;
+    }
+}
+
+public class StatsManager : MonoBehaviour
+{
+
+    public static StatsManager instance { get; private set; }
+
+    EnemyStats currentEnemyStats;
+    PlayerStats currentPlayerStats;
+    [SerializeField] int currentMana;
+
+    [SerializeField] List<Upgrade> availableUpgrades;
+    Dictionary<UpgradeTypes, UpgradeData> upgrades = new Dictionary<UpgradeTypes, UpgradeData>();
+
+    public EnemyStats GetEnemyStats()
+    {
+        return currentEnemyStats;
+    }
+
+    public PlayerStats GetPlayerStats(int stage)
+    {
+        // TODO use `stage`
+        return currentPlayerStats;
+    }
+
+    public int GetMana()
+    {
+        return currentMana;
+    }
+
+    // Adjusts the given Mana cost based on the amount of Mana cost upgrades currently bought.
+    public int GetAdjustedManaCost(int cost)
+    {
+        return (int)(cost * upgrades[UpgradeTypes.MANA_COST].GetTotalEffectMultiplier());
+    }
+
+    public int GetNextUpgradeCost(UpgradeTypes type)
+    {
+        return GetAdjustedManaCost(upgrades[type].GetUnadjustedNextUpgradeCost());
+    }
+
+    // Buys an upgrade, spending the required amount of Mana in the process. Returns false if not enough Mana is available.
+    public bool BuyUpgrade(UpgradeTypes type)
+    {
+        if (!ModifyMana(GetNextUpgradeCost(type)))
+        {
+            return false;
+        }
+        upgrades[type].count++;
+        RecalculateStatMultipliers();
+        return true;
+    }
+
+    // Add (positive value) or spend (negative value) Mana.
+    public bool ModifyMana(int delta)
+    {
+        if (currentMana + delta < 0)
+        {
+            return false;
+        }
+        currentMana += delta;
+        return true;
+    }
+
+    void RecalculateStatMultipliers()
+    {
+        currentEnemyStats.healthMultiplier = upgrades[UpgradeTypes.ENEMY_HEALTH].GetTotalEffectMultiplier();
+        currentEnemyStats.damageMultiplier = upgrades[UpgradeTypes.ENEMY_DAMAGE].GetTotalEffectMultiplier();
+        currentEnemyStats.armorMultiplier = upgrades[UpgradeTypes.ENEMY_ARMOR].GetTotalEffectMultiplier();
+    }
+
+    void Awake()
+    {
+        if (instance == null)
+        {
+            instance = this;
+        }
+        else if (instance != this)
+        {
+            Destroy(gameObject);
+        }
+        DontDestroyOnLoad(gameObject);
+
+        foreach (Upgrade upgrade in availableUpgrades)
+        {
+            UpgradeData upgradeData = new UpgradeData();
+            upgrades.Add(upgrade.type, upgradeData);
+        }
+
+        currentEnemyStats.healthMultiplier = 1f;
+        currentEnemyStats.damageMultiplier = 1f;
+        currentEnemyStats.armorMultiplier = 1f;
+        currentPlayerStats.healthMultiplier = 1f;
+        currentPlayerStats.damageMultiplier = 1f;
+        currentPlayerStats.armorMultiplier = 1f;
+    }
+}
+
+public struct EnemyStats
+{
+    public float healthMultiplier;
+    public float damageMultiplier;
+    public float armorMultiplier;
+}
+
+public struct PlayerStats
+{
+    public float healthMultiplier;
+    public float damageMultiplier;
+    public float armorMultiplier;
+}

Assets/Scripts/StatsManager.cs.meta

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Assets/Scripts/Upgrades.meta

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Assets/Scripts/Upgrades/Upgrade.cs

+using UnityEngine;
+
+[CreateAssetMenu(menuName = "Upgrade")]
+public class Upgrade : ScriptableObject
+{
+
+    public UpgradeTypes type;
+    public string upgradeName;
+    public int baseCost;
+    public float costMultiplier;
+    public Sprite shopSprite;
+    [Tooltip("Multiplier of the stat that this Upgrade controls")] public float effectMultiplier;
+
+}

Assets/Scripts/Upgrades/Upgrade.cs.meta

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