# OpenSpec Change: enterprise-gaming-weapons

- **Change ID**: enterprise-gaming-weapons
- **Package**: `@suaveplan/weapons`
- **Category**: gaming/combat
- **Target path**: `gaming/combat/weapons`
- **Status**: PROPOSED
- **Date**: 2026-04-24
- **Reference spec**: `/mnt/s/web/suaveplan/enterprise/weapons.md`

---

## Summary

Deliver `@suaveplan/weapons` on the genesis branch from scratch at enterprise quality. The package provides a weapon system with projectile ballistics, melee attacks, recoil patterns, ammo management, and attachment slots. A `WeaponRegistry` holds typed `WeaponDefinition` descriptors; `WeaponInstance` tracks runtime state (current ammo, reload timer, heat); `ProjectileSimulator` advances projectile positions each tick applying drag and gravity. All outputs are damage events consumable by `@suaveplan/combat`. Genesis adds Zod schemas for weapon definitions, structured errors, OTel shot counters, and 100% coverage.

---

## Current-state audit (genesis)

Package does not exist on genesis yet — fresh build.

---

## Available workspace deps on genesis

| Package | Role |
|---|---|
| `@suaveplan/error` (`workspace:^`) | `WeaponError`; `WEAPON.*` codes |
| `@suaveplan/types` (`workspace:^`) | `Clock`, `IdGenerator` |
| `@suaveplan/events` (`workspace:^`) | `weapon:fire`, `weapon:reload`, `weapon:empty` events |
| `@suaveplan/combat` (`workspace:^`) | `DamageEvent` type consumed by fire logic |
| `zod` (`catalog:forms`) | `WeaponDefinition`, `AmmoConfig` schemas |
| `@opentelemetry/api` (`catalog:observability`) | Shots-fired counter, reload timer histogram |

---

## Public API surface

```ts
type WeaponClass = 'pistol' | 'rifle' | 'shotgun' | 'sniper' | 'smg' | 'melee' | 'explosive'

interface WeaponDefinition {
  id: string
  name: string
  class: WeaponClass
  damage: number
  damageType: DamageType
  fireRate: number          // rounds per second
  magazineSize: number
  reloadTime: number        // seconds
  projectileSpeed?: number  // m/s; undefined = instant hitscan
  spread: number            // degrees
  recoilPattern?: Vec2[]    // sequence of screen-space offsets
  attachmentSlots?: string[]
  isMelee?: boolean
  meleeRange?: number       // meters
}

function createWeaponRegistry(): WeaponRegistry
interface WeaponRegistry {
  register(def: WeaponDefinition): void
  get(id: string): WeaponDefinition | undefined
  list(): WeaponDefinition[]
}

function createWeaponInstance(def: WeaponDefinition, options?: WeaponInstanceOptions): WeaponInstance

interface WeaponInstance {
  readonly definition: WeaponDefinition
  readonly ammo: number
  readonly isReloading: boolean
  readonly nextFireTime: number
  fire(origin: Vec3, direction: Vec3, shooterId: string): FireResult | null
  reload(): void
  tick(dt: number): void
  addAttachment(slot: string, attachment: Attachment): void
  removeAttachment(slot: string): void
}

interface FireResult {
  projectileId?: string       // present for ballistic projectiles
  damageEvent?: DamageEvent   // present for hitscan
  muzzlePosition: Vec3
  direction: Vec3
}

// Projectile simulator (ballistic weapons)
function createProjectileSimulator(options?: ProjectileSimulatorOptions): ProjectileSimulator

interface ProjectileSimulator {
  spawn(id: string, origin: Vec3, velocity: Vec3, def: WeaponDefinition): void
  tick(dt: number): ProjectileUpdate[]
  destroy(id: string): void
}

interface ProjectileUpdate {
  id: string
  position: Vec3
  velocity: Vec3
  traveledMeters: number
  expired: boolean
}

interface Attachment {
  id: string
  slot: string
  damageMultiplier?: number
  fireRateMultiplier?: number
  spreadModifier?: number
  displayName: string
}
```

### Error codes

```ts
type WeaponErrorCode =
  | 'WEAPON_NOT_FOUND'
  | 'WEAPON_EMPTY'
  | 'WEAPON_RELOADING'
  | 'WEAPON_FIRE_RATE_EXCEEDED'
  | 'WEAPON_INVALID_ATTACHMENT'
```

---

## New additions for genesis

1. **Ballistic drop** — projectile velocity decreases by `gravity * dt`; configurable drag coefficient.
2. **Recoil pattern playback** — `recoilPattern` cycles through offsets each shot, resetting after trigger release.
3. **Attachment modifiers** — multiplicative stacking for damage, fire rate, spread; additive for reload time.
4. **OTel** — `weapon.shots_fired_total` counter (by weapon class); `weapon.reload_duration_ms` histogram.

---

## File layout

```text
gaming/combat/weapons/
  package.json
  tsconfig.json
  vitest.config.ts
  src/
    index.ts
    error-codes.ts
    constants/index.ts
    types/common.ts
    types/common.md
    core/
      weapon-registry/
        weapon-registry.ts
        weapon-registry.md
        weapon-registry.types.ts
        weapon-registry.test.ts
        index.ts
      weapon-instance/
        weapon-instance.ts
        weapon-instance.md
        weapon-instance.types.ts
        weapon-instance.test.ts
        index.ts
      projectile-simulator/
        projectile-simulator.ts
        projectile-simulator.md
        projectile-simulator.types.ts
        projectile-simulator.test.ts
        index.ts
  tests/
    integration.test.ts
```

---

## Impact

**Downstream**: `@suaveplan/r3f-combat` renders muzzle flash and projectile trails from fire events. Prerequisites: `@suaveplan/error`, `@suaveplan/types`, `@suaveplan/events`, `@suaveplan/combat`.