aether-shards/.agent/rules/logic/EffectProcessor/RULE.md

---
description: Effect Processor architecture - the central system for executing all game state changes
globs: src/systems/EffectProcessor.js, src/systems/EffectProcessor.ts, src/types/Effects.ts
alwaysApply: false
---

# **Effect Processor Rule**

The EffectProcessor is the central system responsible for executing all changes to the game state (Damage, Healing, Movement, Spawning). It is a stateless logic engine that takes a **Definition** (What to do) and a **Context** (Who is doing it to whom), and applies the necessary mutations to the UnitManager or VoxelGrid.

## **1. System Overview**

### **Architectural Role**

- **Input:** EffectDefinition (JSON), Source (Unit), Target (Unit/Tile)
- **Output:** State Mutation (HP changed, Unit moved) + EffectResult (Log data)
- **Pattern:** Strategy Pattern. Each effect_type maps to a specific Handler Function

## **2. Integration Points**

### **A. Calling the Processor**

The Processor is never called directly by the UI. It is invoked by:

1. **SkillManager:** When an Active Skill is executed
2. **EventSystem:** When a Passive Item triggers (e.g., "On Hit -> Apply Burn")
3. **Environmental Hazard:** When a unit starts their turn on Fire/Acid

### **B. Dependencies**

The Processor requires injection of:

- VoxelGrid: To check collision, modify terrain, or move units
- UnitManager: To find neighbors (Chain Lightning) or spawn tokens (Turrets)
- RNG: A seeded random number generator for damage variance and status chances

## **3. Data Structure (JSON Schema)**

Every effect in the game must adhere to this structure. See `src/types/Effects.ts` for full TypeScript definitions.

### **Effect Types**

```typescript
export type EffectType =
  // Combat
  | "DAMAGE"
  | "HEAL"
  | "CHAIN_DAMAGE"
  | "REDIRECT_DAMAGE"
  | "PREVENT_DEATH"
  // Status & Stats
  | "APPLY_STATUS"
  | "REMOVE_STATUS"
  | "REMOVE_ALL_DEBUFFS"
  | "APPLY_BUFF"
  | "GIVE_AP"
  | "ADD_CHARGE"
  | "ADD_SHIELD"
  | "CONVERT_DAMAGE_TO_HEAL"
  | "DYNAMIC_BUFF"
  // Movement & Physics
  | "TELEPORT"
  | "MOVE_TO_TARGET"
  | "SWAP_POSITIONS"
  | "PHYSICS_PULL"
  | "PUSH"
  // World & Spawning
  | "SPAWN_OBJECT"
  | "SPAWN_HAZARD"
  | "SPAWN_LOOT"
  | "MODIFY_TERRAIN"
  | "DESTROY_VOXEL"
  | "DESTROY_OBJECTS"
  | "REVEAL_OBJECTS"
  | "COLLECT_LOOT"
  // Meta / Logic
  | "REPEAT_SKILL"
  | "CANCEL_EVENT"
  | "REDUCE_COST"
  | "BUFF_SPAWN"
  | "MODIFY_AOE";
```

### **Effect Parameters**

```typescript
export interface EffectParams {
  // Combat Magnitude
  power?: number; // Base amount (Damage/Heal)
  attribute?: string; // Stat to scale off (e.g., "strength", "magic")
  scaling?: number; // Multiplier for attribute (Default: 1.0)
  element?: "PHYSICAL" | "FIRE" | "ICE" | "SHOCK" | "VOID" | "TECH";
  
  // Chaining
  bounces?: number;
  decay?: number;
  synergy_trigger?: string; // Status ID that triggers bonus effect
  
  // Status/Buffs
  status_id?: string;
  duration?: number;
  stat?: string; // For Buffs
  value?: number; // For Buffs/Mods
  chance?: number; // 0.0 to 1.0 (Proc chance)
  
  // Physics
  force?: number; // Distance
  destination?: "TARGET" | "BEHIND_TARGET" | "ADJACENT_TO_TARGET";
  
  // World
  object_id?: string; // Unit ID to spawn
  hazard_id?: string;
  tag?: string; // Filter for objects (e.g. "COVER")
  range?: number; // AoE radius
  
  // Logic
  percentage?: number; // 0.0 - 1.0
  amount?: number; // Flat amount (AP/Charge)
  amount_range?: [number, number]; // [min, max]
  set_hp?: number; // Hard set HP value
  shape?: "CIRCLE" | "LINE" | "CONE" | "SINGLE";
  size?: number;
  multiplier?: number;
}
```

## **4. Handler Specifications**

### **Handler: DAMAGE**

- **Logic:** `FinalDamage = (BasePower + (Source[Attribute] * Scaling)) - Target.Defense`
- **Element Check:** If Target has Resistance/Weakness to `element`, modify FinalDamage
- **Result:** `Target.currentHP -= FinalDamage`

### **Handler: CHAIN_DAMAGE**

- **Logic:** Apply `DAMAGE` to primary target. Then, scan for N nearest enemies within Range R. Apply `DAMAGE * Decay` to them
- **Synergy:** If `condition.target_status` is present on a target, the chain may branch or deal double damage

### **Handler: TELEPORT**

- **Logic:** Validate destination tile (must be Air and Unoccupied). Update `Unit.position` and `VoxelGrid.unitMap`
- **Visuals:** Trigger "Vanish" VFX at old pos, "Appear" VFX at new pos

### **Handler: MODIFY_TERRAIN**

- **Logic:** Update `VoxelGrid` ID at Target coordinates
- **Use Case:** Sapper's "Breach Charge" turns `ID_WALL` into `ID_AIR`
- **Safety:** Check `VoxelGrid.isDestructible()`. Do not destroy bedrock

## **5. Conditions of Acceptance (CoA)**

**CoA 1: Attribute Scaling**

- Given a Damage Effect with `power: 10` and `attribute: "magic"`, if Source has `magic: 5`, the output damage must be 15

**CoA 2: Conditional Logic**

- Given an Effect with `condition: { target_status: "WET" }`, if the target does _not_ have the "WET" status, the effect must **not** execute (return early)

**CoA 3: State Mutation**

- When `APPLY_STATUS` is executed, the Target unit's `statusEffects` array must contain the new ID with the correct duration

**CoA 4: Physics Safety**

- When `PUSH` is executed, the system must check `VoxelGrid.isSolid()` behind the target. If a wall exists, the unit must **not** move into the wall (optionally take "Smash" damage instead)

## **6. Implementation Requirements**

- **Statelessness:** The processor should not hold state. It acts on the Unit and Grid passed to it
- **Schema:** Effects must adhere to the EffectDefinition interface (Type + Params)
- **All game state mutations** (Damage, Move, Spawn) **MUST** go through `EffectProcessor.process()`