# Header Text Player Meter — Implementation Plan

> **For Claude:** REQUIRED SUB-SKILL: Use superpowers:executing-plans to implement this plan task-by-task.

**Goal:** Add a gradient fill meter to the "ROOM CODE:" header that visually indicates lobby fill (playerCount / maxPlayers), animating left-to-right from the header color (pink) to white, with a pulse effect at 100%.

**Architecture:** The existing `RoomCodeDisplay` component gains meter state tracking and a `requestAnimationFrame` interpolation loop. CSS `background-clip: text` with a dynamic `linear-gradient` replaces the flat `header.style.color`. The `OverlayManager` already broadcasts `playerCount` and `maxPlayers` in context — no state management changes needed.

**Tech Stack:** Vanilla JS (ES modules), CSS `background-clip: text`, `requestAnimationFrame`.

---

### Task 1: Revert Player List Default to Unchecked

**Files:**
- Modify: `optimized-controls.html:669` (the `player-list-enabled` checkbox)

**Step 1: Remove the `checked` attribute**

In `optimized-controls.html`, change:

```html
<input type="checkbox" id="player-list-enabled" checked>
```

to:

```html
<input type="checkbox" id="player-list-enabled">
```

**Step 2: Verify in browser**

Open `http://localhost:8080/optimized-controls.html`, expand Player List Settings, confirm the checkbox is unchecked by default.

**Step 3: Commit**

```bash
git add optimized-controls.html
git commit -m "fix: disable player list by default"
```

---

### Task 2: Update `#header` CSS for Gradient Text Support

**Files:**
- Modify: `optimized-controls.html` — `<style>` block, `#header` rule (lines ~30-42)

**Step 1: Replace `#header` CSS**

Find the existing `#header` rule:

```css
#header {
    position: absolute;
    width: 100%;
    text-align: center;
    transform: translateY(-220px);
    color: #f35dcb;
    font-size: 80px;
    font-weight: bold;
    text-shadow: 3px 3px 8px rgba(0, 0, 0, 0.8);
    letter-spacing: 2px;
    opacity: 0;
    transition: opacity 0.5s ease;
}
```

Replace with:

```css
#header {
    position: absolute;
    width: 100%;
    text-align: center;
    transform: translateY(-220px);
    color: #f35dcb;
    font-size: 80px;
    font-weight: bold;
    letter-spacing: 2px;
    opacity: 0;
    transition: opacity 0.5s ease;
    /* Meter gradient support */
    background: linear-gradient(to right, #ffffff 0%, #ffffff 0%, #f35dcb 0%, #f35dcb 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    filter: drop-shadow(3px 3px 8px rgba(0, 0, 0, 0.8));
}
```

Key changes: removed `text-shadow` (incompatible with transparent text), added `background` gradient, `background-clip: text`, `-webkit-text-fill-color: transparent`, and `filter: drop-shadow()` to replace the shadow.

**Step 2: Add pulse keyframes and class**

After the `#header` rule, add:

```css
@keyframes meter-full-pulse {
    0%   { filter: drop-shadow(3px 3px 8px rgba(0,0,0,0.8)); }
    50%  { filter: drop-shadow(0 0 20px rgba(255,255,255,0.6)) drop-shadow(3px 3px 8px rgba(0,0,0,0.8)); }
    100% { filter: drop-shadow(3px 3px 8px rgba(0,0,0,0.8)); }
}

#header.meter-full-pulse {
    animation: meter-full-pulse 0.6s ease-out;
}
```

**Step 3: Verify in browser**

Load the page. The header text should still appear pink during the animation cycle but now rendered via gradient clip instead of flat color. The shadow should look the same (via `drop-shadow`).

**Step 4: Commit**

```bash
git add optimized-controls.html
git commit -m "feat: add CSS gradient-clip and pulse keyframes for header meter"
```

---

### Task 3: Add Meter State and Gradient Logic to `RoomCodeDisplay`

**Files:**
- Modify: `js/room-code-display.js`

**Step 1: Add private meter fields**

After the existing private fields (`#elements`, `#inputs`, `#animationTimers`, `#active`), add:

```javascript
/** @type {number} Current fill 0-1 */
#meterFill = 0;

/** @type {number} Target fill 0-1 */
#meterTarget = 0;

/** @type {number | null} */
#meterRafId = null;

/** @type {boolean} Whether the pulse has fired for the current 100% state */
#meterPulseFired = false;
```

**Step 2: Add `#applyMeterGradient()` method**

This reads the current `#meterFill` and the configured header color, then sets the gradient on the header element.

```javascript
#applyMeterGradient() {
    const header = this.#elements?.header;
    const inputs = this.#inputs;
    if (!header || !inputs) return;

    const pct = Math.round(this.#meterFill * 100);
    const baseColor = inputs.headerColor.value || '#f35dcb';

    header.style.background =
        `linear-gradient(to right, #ffffff 0%, #ffffff ${pct}%, ${baseColor} ${pct}%, ${baseColor} 100%)`;
    header.style.webkitBackgroundClip = 'text';
    header.style.backgroundClip = 'text';
    header.style.webkitTextFillColor = 'transparent';
}
```

**Step 3: Add `#animateMeterTo(target)` method**

Smooth `requestAnimationFrame` interpolation from current fill to target over ~400ms.

```javascript
#animateMeterTo(target) {
    const clamped = Math.max(0, Math.min(1, target));
    this.#meterTarget = clamped;

    if (this.#meterRafId != null) {
        cancelAnimationFrame(this.#meterRafId);
        this.#meterRafId = null;
    }

    const start = this.#meterFill;
    const delta = clamped - start;
    if (Math.abs(delta) < 0.001) {
        this.#meterFill = clamped;
        this.#applyMeterGradient();
        this.#checkFullPulse();
        return;
    }

    const duration = 400;
    const startTime = performance.now();

    const step = (now) => {
        const elapsed = now - startTime;
        const t = Math.min(elapsed / duration, 1);
        const eased = 1 - Math.pow(1 - t, 3); // ease-out cubic
        this.#meterFill = start + delta * eased;
        this.#applyMeterGradient();

        if (t < 1) {
            this.#meterRafId = requestAnimationFrame(step);
        } else {
            this.#meterRafId = null;
            this.#meterFill = clamped;
            this.#applyMeterGradient();
            this.#checkFullPulse();
        }
    };

    this.#meterRafId = requestAnimationFrame(step);
}
```

**Step 4: Add `#checkFullPulse()` method**

```javascript
#checkFullPulse() {
    const header = this.#elements?.header;
    if (!header) return;

    if (this.#meterFill >= 1 && !this.#meterPulseFired) {
        this.#meterPulseFired = true;
        header.classList.add('meter-full-pulse');
        header.addEventListener('animationend', () => {
            header.classList.remove('meter-full-pulse');
        }, { once: true });
    }

    if (this.#meterFill < 1) {
        this.#meterPulseFired = false;
    }
}
```

**Step 5: Modify `#applySettings()` — replace color line with gradient**

In the existing `#applySettings()` method, find:

```javascript
header.style.color = inputs.headerColor.value;
```

Replace with:

```javascript
this.#applyMeterGradient();
```

This ensures that whenever settings are applied, the gradient is re-rendered with the correct header color and current fill level.

**Step 6: Modify `update(ctx)` — add meter update logic**

The existing `update()` only checks roomCode changes. After the existing roomCode check, add meter logic:

```javascript
// After the existing roomCode change check:
const count = Number(ctx?.playerCount ?? 0);
const max = Number(ctx?.maxPlayers ?? 0);
const newTarget = max > 0 ? count / max : 0;

if (Math.abs(newTarget - this.#meterTarget) > 0.001) {
    this.#animateMeterTo(newTarget);
}
```

**Step 7: Modify `deactivate()` — cancel RAF and reset meter**

Add before the existing opacity fade-out code:

```javascript
if (this.#meterRafId != null) {
    cancelAnimationFrame(this.#meterRafId);
    this.#meterRafId = null;
}
this.#meterFill = 0;
this.#meterTarget = 0;
this.#meterPulseFired = false;
```

**Step 8: Modify `activate(ctx)` — seed initial meter from context**

After the existing `this.#applySettings()` call, add:

```javascript
const count = Number(ctx?.playerCount ?? 0);
const max = Number(ctx?.maxPlayers ?? 0);
const initialFill = max > 0 ? count / max : 0;
this.#meterFill = Math.max(0, Math.min(1, initialFill));
this.#meterTarget = this.#meterFill;
this.#meterPulseFired = false;
this.#applyMeterGradient();
```

**Step 9: Update `getStatus()` — include meter info**

Add `meterFill` to the returned object:

```javascript
getStatus() {
    // ... existing code ...
    return {
        active: this.#active,
        roomCode,
        timersRunning: this.#animationTimers.length > 0,
        meterFill: Math.round(this.#meterFill * 100),
    };
}
```

**Step 10: Verify in browser**

1. Open the overlay, connect to API.
2. Trigger a game (or use Update/Preview button).
3. The header should appear 100% pink (0 players).
4. As players join, the gradient should animate left-to-right toward white.
5. At full capacity, a brief pulse/glow should fire.

**Step 11: Commit**

```bash
git add js/room-code-display.js
git commit -m "feat: add animated gradient meter to header text based on player count"
```

---

### Task 4: Update Dashboard Status for Meter

**Files:**
- Modify: `js/controls.js` — `formatStatusRow` function

**Step 1: Include meter fill in roomCode status display**

In `formatStatusRow`, find the `roomCode` case:

```javascript
if (name === 'roomCode') {
    const rc = /** @type {{ active?: boolean, roomCode?: string }} */ (s);
    return rc.active ? `Active (${rc.roomCode ?? ''})` : 'Inactive';
}
```

Change to:

```javascript
if (name === 'roomCode') {
    const rc = /** @type {{ active?: boolean, roomCode?: string, meterFill?: number }} */ (s);
    if (!rc.active) return 'Inactive';
    const meter = rc.meterFill != null ? ` | Meter: ${rc.meterFill}%` : '';
    return `Active (${rc.roomCode ?? ''})${meter}`;
}
```

**Step 2: Commit**

```bash
git add js/controls.js
git commit -m "feat: show meter fill percentage in dashboard status"
```

---

### Task 5: End-to-End Verification

**Step 1: Full flow test**

1. Load `http://localhost:8080/optimized-controls.html`.
2. Confirm player list checkbox is unchecked by default.
3. Connect to the API WebSocket.
4. Trigger a game via the Game Picker (or use Preview/Update button with a room code).
5. Observe: header appears 100% pink.
6. As players join, gradient fills left-to-right, animating smoothly.
7. When lobby is full, text is 100% white and pulse fires.
8. When game starts/ends, header deactivates, meter resets.
9. New lobby → header starts fresh at 0% fill.

**Step 2: Edge case test**

- Use Update/Preview with `max_players: 2`. Join 1 player (50%), then 2nd (100% + pulse).
- Disconnect/reconnect mid-lobby — meter should reset and re-seed from context.

**Step 3: Final commit (if any polish needed)**

```bash
git add -A
git commit -m "polish: header meter edge cases and cleanup"
```