# Transference Channel — Design Spec

> Describes the Transference Channel system: an active combat mechanic for the
> Enchanter attunement that lets the player hold a button to drain Transference
> mana and boost the cast speed of all equipment spells and melee attacks.

---

## 1. Objective

The Enchanter attunement currently lacks an active combat mechanic. The Invocation
system (Invoker attunement) provides automatic combat acceleration through
guardian channeling. The Transference Channel gives the Enchanter a **manual,
hold-to-channel button** that spends Transference mana to temporarily accelerate
all equipment-based combat actions.

**Design goals:**
- Give the Enchanter an **active, holdable** combat button
- Spend **Transference mana** — the only utility mana type — as the fuel
- Boost **equipment spells and melee attacks only** — not the player's active spell
- Create a **resource management decision**: channel now for burst speed, or
  conserve Transference for enchanting and disciplines
- Scale through a new Enchanter discipline that trades mana cost for potency
- Complement (not compete with) Invocation — different resource, different
  trigger, different target

---

## 2. The Channel Button

### 2.1 UI Placement

A **"Channel Transference"** button on the `SpireCombatPage`, visible only when:
- The Enchanter attunement is active (`attunements.enchanter.active === true`)
- The player is in `climb` action (combat)
- The player has at least 1 Transference mana

### 2.2 Interaction Model

| Property | Value |
|---|---|
| **Interaction** | Press and hold (mousedown / touchstart) to channel, release to stop |
| **Keyboard** | Optional hotkey (e.g., `C`) for accessibility |
| **Visual** | Button glows while active; shows Transference drain rate |
| **Cooldown** | None — player controls start/stop |

The hold-to-channel interaction is intentional: it creates a "power moment"
where the player chooses to actively engage. The game is fully playable without
it — this is an optional acceleration for players who want active involvement.

### 2.3 Hold Behavior

While the button is held:
1. Transference mana drains at `drainRate` per tick (see §3)
2. All equipment spells and melee attacks gain `speedMultiplier` cast speed
3. If Transference reaches 0: channel stops automatically (no penalty)
4. If player leaves `climb` action: channel stops automatically
5. If player releases button: channel stops immediately

---

## 3. Drain Rate and Speed Multiplier

### 3.1 Mana Economy Context

Transference mana is generated slowly through the Enchanter's automatic
conversion (0.2/hour at level 1, scaling with `1.5^(level-1)`). At level 10,
this is ~7.69/hour. Transference is also the fuel for all Enchanter disciplines
and the enchanting pipeline.

The Channel system is designed as a **burst expenditure** — the player
accumulates Transference over time and then spends it in combat for temporary
acceleration. The drain rate must be high enough to create meaningful decisions
("can I afford to channel right now?") but not so high that it's trivially
exhausted.

### 3.2 Base Values

| Parameter | Base Value | Description |
|---|---|---|
| `baseDrainRate` | 0.08 Transference/tick | 0.4 Transference/second at 200ms/tick |
| `baseSpeedMultiplier` | 1.5× | Equipment spells and melee attack 50% faster |

### 3.3 Duration Estimate

At base values with various Transference pool sizes:

| Transference Pool | Drain Rate | Approximate Duration |
|---|---|---|
| 20 | 0.08/tick | 250 ticks = 50 seconds |
| 50 | 0.08/tick | 625 ticks = 125 seconds |
| 100 | 0.08/tick | 1250 ticks = 250 seconds |

With discipline scaling (e.g., 1.8× speed at ~1.8× drain):

| Transference Pool | Drain Rate | Approximate Duration |
|---|---|---|
| 50 | 0.144/tick | 347 ticks = 69 seconds |
| 100 | 0.144/tick | 694 ticks = 139 seconds |

The discipline makes each "pool of Transference" worth less raw seconds but
more effective combat time because actions complete faster.

### 3.4 Scaling with Discipline

A new discipline (`transference-channeling`) controls the tradeoff between
mana cost and speed:

```
effectiveDrainRate = baseDrainRate × (1 + intensityBonus) × (1 - channelEfficiency)
effectiveSpeedMultiplier = baseSpeedMultiplier + speedBonus
```

Where `intensityBonus` and `speedBonus` come from the discipline's stat bonus
and perks (see §5).

**Design philosophy:** The discipline lets the player invest XP to get more
speed, but at proportionally higher mana cost. Perks can shift the ratio
in the player's favor (more speed per mana).

---

## 4. What Gets Boosted

### 4.1 Affected

| Action | Boosted? | Notes |
|---|---|---|
| **Equipment spell casts** | ✅ Yes | All `equipmentSpellStates` cast progress |
| **Melee sword attacks** | ✅ Yes | All `meleeSwordProgress` accumulators |

### 4.2 Not Affected

| Action | Boosted? | Notes |
|---|---|---|
| **Player's active spell** | ❌ No | The manually-selected spell is not equipment |
| **Invocation spells** | ❌ No | Invocation is pact-based, not equipment-based |
| **Golem attacks** | ❌ No | Golems are independent entities |
| **DoT ticks** | ❌ No | DoTs are time-based, not cast-based |

### 4.3 Implementation — Speed Multiplier Application

The channel state is tracked in the combat store. When active, the multiplier
is applied to `progressPerTick` calculations for equipment spells and melee:

```
// Equipment spells (in combat-actions.ts equipment spell block)
const channelMult = state.isChanneling ? state.channelSpeedMultiplier : 1.0;
const eProgressPerTick = HOURS_PER_TICK * eSpellCastSpeed * totalAttackSpeed * channelMult;

// Melee (in combat-melee.ts)
const channelMult = state.isChanneling ? state.channelSpeedMultiplier : 1.0;
const meleeProgressPerTick = HOURS_PER_TICK * swordAttackSpeed * attackSpeedMult * channelMult;
```

**Important:** The speed multiplier only affects cast *progress accumulation*.
It does NOT affect mana costs per cast. Equipment spells still cost the same
mana per cast — they just complete faster. This prevents the feedback loop
where faster casting drains mana exponentially faster.

---

## 5. New Discipline: Transference Channeling

### 5.1 Definition

| Field | Value |
|---|---|
| **ID** | `transference-channeling` |
| **Name** | Transference Channeling |
| **Attunement** | `enchanter` |
| **Mana Type** | `transference` |
| **Base Cost** | 15 |
| **Stat Bonus** | `channelIntensity` +0.10 (base) |
| **Scaling Factor** | 100 |
| **Difficulty Factor** | 180 |
| **Drain Base** | 4 |

**Main stat: `channelIntensity`**

This stat controls both the speed boost and the drain rate:

```
speedBonus = channelIntensity × 0.5        // added to baseSpeedMultiplier
intensityBonus = channelIntensity × 1.0    // multiplier on drain rate
```

At 0 XP: `channelIntensity = 0.10` → speed = 1.5 + 0.05 = 1.55×, drain = 0.08 × 1.10 = 0.088/tick.

The stat scales with XP via the standard discipline math:

```
StatBonus = baseValue × (XP / scalingFactor)^0.65
          = 0.10 × (XP / 100)^0.65
```

### 5.2 Perks

| Perk ID | Type | Threshold | Bonus | Description |
|---|---|---|---|---|
| `channel-efficiency` | `once` | 100 | `channelEfficiency` +0.15 | 15% less drain for same speed — shifts the ratio in the player's favor |
| `channel-power` | `infinite` | 200 | Every 150 XP: `channelIntensity` +0.05 | Core scaling — more speed (and proportionally more drain) |
| `channel-mastery` | `capped` | 400 | Every 200 XP: `channelEfficiency` +0.10, max 3 tiers | Late-game efficiency — up to 45% less drain |

### 5.3 Effective Formulas with Perks

```
channelEfficiency = 0 + sum of efficiency perks (0.15 from once, up to 0.30 from capped)
                   hard-capped at 0.60 — prevents drain rate from reaching 0
effectiveSpeedMultiplier = 1.5 + (channelIntensity × 0.5)
effectiveDrainRate = 0.08 × (1 + channelIntensity × 1.0) × (1 - channelEfficiency)
```

> **The `channelEfficiency` cap of 0.60** is enforced in the formula itself. Even if
> perk bonuses would exceed 0.60, the effective drain rate can never go below
> `0.08 × (1 + intensity) × 0.40`. This ensures channeling always costs meaningful
> Transference mana.

**Example at 500 XP with all perks:**
- `channelIntensity` = 0.10 × (500/100)^0.65 + 0.05 × 2 (two infinite intervals) ≈ 0.24 + 0.10 = 0.34
- `channelEfficiency` = 0.15 + 0.20 (two capped tiers) = 0.35
- Speed = 1.5 + 0.34 × 0.5 = 1.67×
- Drain = 0.08 × (1 + 0.34) × (1 - 0.35) = 0.08 × 1.34 × 0.65 = 0.070/tick

### 5.4 Discipline Identity

*"I channel transference mana through my equipment, making my enchanted gear
strike and cast faster. The more I master this, the faster I go — but it
costs more mana to sustain."*

---

## 6. Store Changes

### 6.1 Combat Store (`combatStore.ts`)

New state fields:

```typescript
// Transference Channel state
isChanneling: boolean;           // true while button is held
channelSpeedMultiplier: number;  // current speed multiplier (1.5+)
channelDrainRate: number;        // current drain rate per tick
```

New actions:

```typescript
startChanneling: () => void;
stopChanneling: () => void;
```

### 6.2 Combat State Types (`combat-state.types.ts`)

Add to `CombatState`:

```typescript
isChanneling: boolean;
channelSpeedMultiplier: number;
channelDrainRate: number;
```

Add to `CombatActions`:

```typescript
startChanneling: () => void;
stopChanneling: () => void;
```

### 6.3 No Changes To

- `manaStore.ts` — Transference mana is drained via existing element deduction
- `craftingStore.ts` — enchanting is unaffected
- `prestigeStore.ts` — no prestige interaction
- `invocation-utils.ts` — Invocation is completely separate

---

## 7. Combat Tick Integration

### 7.1 Modified Flow in `combat-actions.ts`

The channel state is read from the combat store at the start of each tick.
The speed multiplier is applied to equipment spell and melee progress:

```
1. Read isChanneling from combat store
2. If isChanneling:
   a. Drain Transference: transferencePool -= channelDrainRate
   b. If transference <= 0: stop channeling (set isChanneling = false)
3. Compute channelMult = isChanneling ? channelSpeedMultiplier : 1.0
4. Equipment spell progress: eProgressPerTick *= channelMult
5. Melee progress: meleeProgressPerTick *= channelMult
```

> **File size note:** `combat-actions.ts` is currently 377 lines. Adding channel drain
> logic and speed multiplier application may push it toward the 400-line limit. If so,
> extract the channel logic into a new file (e.g., `combat-channel.ts`) and call it
> from `processCombatTick`.

### 7.2 Transference Drain

Transference is drained from the mana store. The drain uses the existing
element deduction pattern:

```typescript
// Per tick while channeling:
const transferencePool = useManaStore.getState().elements.transference;
if (transferencePool.current >= channelDrainRate) {
  useManaStore.getState().deductElement('transference', channelDrainRate);
} else {
  // Insufficient mana — stop channeling
  useCombatStore.getState().stopChanneling();
}
```

### 7.3 Auto-Stop Conditions

Channeling stops when any of the following is true:
1. Player releases the button
2. Transference mana reaches 0
3. Player leaves `climb` action
4. Enchanter attunement is deactivated mid-combat

> **Room transitions:** Channeling **persists** across room transitions within the same
> climb. If the player is channeling and kills an enemy (triggering
> `advanceRoomOrFloor`), channeling continues into the next room. The `isChanneling`
> state is stored on the combat store and is not reset by room transitions — only by
> the auto-stop conditions above or by spire exit.

---

## 8. UI Changes

### 8.1 SpireCombatPage

Add a **"Channel Transference"** button between the SpireHeader and RoomDisplay:

- **Visible when:** Enchanter active + in `climb` action
- **Button style:** Teal-colored (#1ABC9C, matching Enchanter), with Transference icon (🔗)
- **While channeling:** Button glows, shows drain rate per second
- **Transference bar:** Small bar below button showing remaining Transference mana
- **Tooltip:** "Hold to channel transference mana through your equipment, boosting attack speed"

### 8.2 SpireCombatControls

Add a compact channel status indicator:
- Shows "⚡ Channeling" with speed multiplier when active
- Hidden when not channeling

### 8.3 No New Tabs

All channel information is visible in the existing SpireCombatPage layout.

---

## 9. Data Flow Summary

```
Player holds button
  → startChanneling() [combatStore]
  → isChanneling = true, channelSpeedMultiplier = 1.5+, channelDrainRate = 0.08+

gameStore.tick()
  → buildTickContext() [snapshots all stores]
  → processCombatTick() [combat-actions.ts]
    → If isChanneling:
        - Deduct transference mana from manaStore
        - If transference <= 0: stopChanneling()
    → channelMult = isChanneling ? channelSpeedMultiplier : 1.0
    → Equipment spell progress: eProgressPerTick *= channelMult
    → Melee progress: meleeProgressPerTick *= channelMult
  → applyTickWrites() [writes combat store changes back]

Player releases button
  → stopChanneling() [combatStore]
  → isChanneling = false
```

---

## 10. Acceptance Criteria

| # | Criterion |
|---|---|
| AC-1 | "Channel Transference" button is visible on SpireCombatPage when Enchanter is active and player is in `climb` action. |
| AC-2 | Button is hidden when Enchanter is inactive, player is not in `climb`, or Transference pool is 0. |
| AC-3 | Holding the button (mousedown) activates channeling; releasing deactivates it. |
| AC-4 | While channeling, Transference mana drains at `channelDrainRate` per tick. |
| AC-5 | When Transference reaches 0, channeling stops automatically with no penalty. |
| AC-6 | While channeling, all equipment spell cast progress is multiplied by `channelSpeedMultiplier`. |
| AC-7 | While channeling, all melee sword attack progress is multiplied by `channelSpeedMultiplier`. |
| AC-8 | The player's active spell is NOT affected by channeling. |
| AC-9 | Invocation spells are NOT affected by channeling. |
| AC-10 | Golem attacks are NOT affected by channeling. |
| AC-11 | DoT ticks are NOT affected by channeling. |
| AC-12 | Base drain rate is 0.08 Transference/tick; base speed multiplier is 1.5×. |
| AC-13 | `transference-channeling` discipline scales `channelIntensity` stat with XP. |
| AC-14 | `channel-efficiency` once perk (100 XP) grants 15% drain reduction. |
| AC-15 | `channel-power` infinite perk (200 XP, every 150 XP) grants +0.05 `channelIntensity`. |
| AC-16 | `channel-mastery` capped perk (400 XP, every 200 XP, max 3 tiers) grants +0.10 `channelEfficiency` per tier. |
| AC-17 | `channelEfficiency` is capped at 0.60 (prevents drain from reaching 0). |
| AC-18 | Channel state resets on spire exit (`isChanneling = false`). |
| AC-19 | Existing saves without channel fields get default values (`isChanneling = false`, `channelSpeedMultiplier = 1.5`, `channelDrainRate = 0.08`). |
| AC-20 | Channel stops automatically when player leaves `climb` action. |
| AC-21 | Speed multiplier affects cast progress accumulation only — mana costs per cast are unchanged. |

---

## 11. Files Reference

| File | Role |
|---|---|
| `src/lib/game/stores/combatStore.ts` | New channel state fields + `startChanneling`/`stopChanneling` actions |
| `src/lib/game/stores/combat-state.types.ts` | Type definitions for new state |
| `src/lib/game/stores/combat-actions.ts` | Channel drain + speed multiplier application for equipment spells (or extracted to `combat-channel.ts` if file size exceeds 400 lines) |
| `src/lib/game/stores/combat-melee.ts` | Speed multiplier application for melee attacks |
| `src/lib/game/data/disciplines/enchanter.ts` | Add `transference-channeling` discipline definition |

> **Implementation note:** `enchanter.ts` currently has 4 disciplines (146 lines). If
> adding `transference-channeling` would push it toward the 400-line limit (e.g. when
> combined with the `room-enchanting` discipline from the room enchantments spec),
> create a new file `enchanter-combat.ts` (following the existing pattern of
> `enchanter-utility.ts`, `enchanter-spells.ts`, etc.) and re-export from
> `data/disciplines/index.ts`.
| `src/lib/game/effects/discipline-effects.ts` | Add `channelIntensity` and `channelEfficiency` to known bonus stats |
| `src/components/game/tabs/SpireCombatPage/SpireCombatPage.tsx` | Channel button UI |
| `src/components/game/tabs/SpireCombatPage/SpireCombatControls.tsx` | Compact channel status indicator |
| `docs/specs/attunements/enchanter/systems/transference-channel-spec.md` | **THIS FILE** |

---

## 12. Out of Scope

- Channel affecting the player's active spell
- Channel affecting Invocation spells
- Channel affecting golem attacks
- Channel affecting DoT ticks
- Auto-channel toggle (manual hold only in v1)
- Channel working outside of combat (`climb` action only)
- Prestige upgrades that affect channeling
- Channel interacting with the enchanting pipeline (Design/Prepare/Apply)
