# 49 — BP_WeaponBase

## Blueprint Spec — UE 5.5–5.7

---

### Parent Class
`Actor` (attached to character via `AttachToComponent`)

### Dependencies
- [`BPC_InventoryComponent`](../04-inventory/25_BPC_InventoryComponent.md)
- [`BPC_EquipmentSystem`](../04-inventory/28_BPC_EquipmentSystem.md)
- [`BPC_PlayerCameraManager`](../02-player/14_BPC_PlayerCameraManager.md)
- [`BPC_DamageHandler`](53_BPC_DamageHandlerComponent.md)
- [`DA_WeaponData`](../12-content/60_DA_WeaponDataAsset.md)
- [`I_Damageable`](../01-core/03_I_Damageable.md)
- [`BPC_CombatFeedbackComponent`](54_BPC_CombatFeedbackComponent.md)

### Purpose
Base class for all weapon actors (ranged and melee). Provides common weapon lifecycle: equip, unequip, fire input, ammo tracking integration, aim-down-sights, and weapon state machine. Designed to be extended by [`BP_RangedWeapon`](50_BP_RangedWeapon.md) and [`BP_MeleeWeapon`](51_BP_MeleeWeapon.md).

### Responsibilities
- Attach/detach from character socket on equip/unequip
- Manage weapon state (holstered / equipping / ready / firing / reloading)
- Handle fire input (start / stop) — base delegates to subclass
- Track aim-down-sights state and apply camera FOV transition
- Fire event dispatchers for UI state changes
- Communicate with [`BPC_EquipmentSystem`](../04-inventory/28_BPC_EquipmentSystem.md) for weapon selection
- Communicate with inventory for ammo consumption

### Does NOT Handle
- Specific fire logic (raycast / projectile / melee hitbox) — that is subclass
- Ammo math (that is [`BPC_AmmoComponent`](52_BPC_AmmoComponent.md))
- Damage calculation (that is [`BPC_DamageHandler`](53_BPC_DamageHandlerComponent.md))
- Visual / audio feedback (that is [`BPC_CombatFeedbackComponent`](54_BPC_CombatFeedbackComponent.md))
- UI display (that is HUD widget)

### Variables

| Name | Type | Description |
|------|------|-------------|
| `WeaponData` | DA_WeaponData | Weapon definition asset |
| `WeaponState` | EWeaponState | Current state machine |
| `SkeletalMesh` | USkeletalMeshComponent | Weapon visual |
| `WeaponRoot` | USceneComponent | Attachment root |
| `HolsterSocket` | FName | Socket name for holstered |
| `EquipSocket` | FName | Socket name for ready |
| `AimDownSightsFOV` | Float | FOV when ADS (e.g. 60.0) |
| `DefaultFOV` | Float | Normal FOV |
| `ADSInterpSpeed` | Float | Camera blend speed |
| `bIsAiming` | Bool | Currently ADS |
| `FireRateTimer` | FTimerHandle | Fire rate control |
| `bCanFire` | Bool | Not on cooldown |
| `EquipDuration` | Float | Seconds for equip animation |
| `HolsterDuration` | Float | Seconds for holster animation |
| `RecoilPitch` | Float | Camera pitch per shot |
| `RecoilYaw` | Float | Camera yaw per shot |

### Enums

| Enum | Values | Description |
|------|--------|-------------|
| `EWeaponState` | Holstered, Equipping, Ready, Firing, Reloading, Holstering, Broken | Weapon lifecycle |
| `EWeaponFireMode` | SemiAutomatic, FullAutomatic, BurstFire, ChargeAndRelease, MeleeSwing | Fire type |

### Functions / Events

| Name | Inputs | Outputs | Description |
|------|--------|---------|-------------|
| `Equip` | — | — | Play equip anim, attach to EquipSocket, set state to Ready |
| `Holster` | — | — | Play holster anim, attach to HolsterSocket, set state to Holstered |
| `StartFire` | — | — | Begin fire loop (if auto) or single fire (semi) |
| `StopFire` | — | — | End fire loop |
| `CanFire` | — | Bool | Check state, ammo, cooldown |
| `OnFire` | — | — | Virtual: subclass implements actual fire logic |
| `StartReload` | — | — | Begin reload sequence |
| `FinishReload` | — | — | Called after reload anim |
| `StartAim` | — | — | Blend camera to ADS FOV |
| `StopAim` | — | — | Blend camera back to DefaultFOV |
| `SetWeaponState` | NewState: EWeaponState | — | Change state and broadcast |
| `GetWeaponTag` | — | GameplayTag | Return weapon identifier |
| `OnWeaponBroken` | — | — | Weapon disabled (durability zero) |

### Event Dispatchers

| Name | Parameters | Fired When |
|------|-----------|-----------|
| `OnWeaponStateChanged` | NewState: EWeaponState, OldState: EWeaponState | State machine change |
| `OnWeaponEquipped` | WeaponRef: BP_WeaponBase | Ready to use |
| `OnWeaponHolstered` | WeaponRef: BP_WeaponBase | Stored away |
| `OnFireStarted` | — | Fire input received and valid |
| `OnFireStopped` | — | Fire input released |
| `OnAimStarted` | — | ADS enter |
| `OnAimStopped` | — | ADS exit |
| `OnReloadStarted` | — | Reload begin |
| `OnReloadCompleted` | — | Reload finish |
| `OnWeaponBroken` | — | Durability depleted |

### Blueprint Flow

```
[StartFire]
  └─► If !CanFire → return
  └─► Set WeaponState = Firing
  └─► Broadcast OnFireStarted
  └─► Call OnFire (subclass override)
  └─► If FireMode == FullAutomatic → start FireRateTimer loop
  └─► If FireMode == SemiAutomatic → block until timer clears

[StopFire]
  └─► Clear FireRateTimer
  └─► If FireMode == BurstFire → let burst complete, then stop
  └─► Set WeaponState = Ready
  └─► Broadcast OnFireStopped

[StartReload]
  └─► If WeaponState != Ready → return
  └─► Set WeaponState = Reloading
  └─► Broadcast OnReloadStarted
  └─► Start animation or timer for reload duration
  └─► On completion → FinishReload

[FinishReload]
  └─► BPC_AmmoComponent.RefillAmmo(WeaponData.MagazineSize)
  └─► Set WeaponState = Ready
  └─► Broadcast OnReloadCompleted

[StartAim / StopAim]
  └─► Set bIsAiming
  └─► Get BPC_PlayerCameraManager from owner
  └─► Set FOV with interp speed
  └─► Broadcast OnAimStarted / OnAimStopped
```

### Communications With

| Target System | Method | Why |
|---------------|--------|-----|
| [`BPC_EquipmentSystem`](../04-inventory/28_BPC_EquipmentSystem.md) | Direct | Get/return weapon socket assignment |
| [`BPC_AmmoComponent`](52_BPC_AmmoComponent.md) | Get Component | Check / consume / refill ammo |
| [`BPC_DamageHandler`](53_BPC_DamageHandlerComponent.md) | Get Component | Delegate damage processing |
| [`BPC_CombatFeedbackComponent`](54_BPC_CombatFeedbackComponent.md) | Get Component | Play muzzle flash, hit FX, sounds |
| [`BPC_PlayerCameraManager`](../02-player/14_BPC_PlayerCameraManager.md) | Get from Owner | ADS FOV blend |
| [`BPC_InventoryComponent`](../04-inventory/25_BPC_InventoryComponent.md) | Get from Owner | Check ammo inventory |
| HUD Widget | Dispatcher (via GM) | Update crosshair, ammo display |
| Owner (Player Character) | Direct | Animation blueprint queries weapon state |

### Reuse Notes
Subclass for ranged or melee specific fire implementations. The state machine prevents firing during reload, equip, or holster sequences. Weapons are data-driven via `DA_WeaponData` — design changes never require blueprint edits.