# Shell & Logs Windows Feature Specification

## Overview
Shell and Logs windows are specialized detail windows that stream real-time data from Kubernetes pods. Shell provides an interactive terminal, while Logs shows container output.

---

## Shell Window

### Purpose
Interactive pseudo-terminal session inside the application, connected to a pod via `kubectl exec`.

### Implementation

#### Client-Side (xterm.js)
```typescript
// Initialization
import { Terminal } from 'xterm';
import { FitAddon } from 'xterm-addon-fit';

const term = new Terminal({
  rows: 24,
  cols: 80,
  fontFamily: 'IBM Plex Mono',
  fontSize: 12,
  theme: {
    background: '#0b0e13',
    foreground: '#e6edf6',
    cursor: '#4dd6e8'
  }
});

const fitAddon = new FitAddon();
term.loadAddon(fitAddon);
fitAddon.fit();
```

#### WebSocket Connection
```typescript
// On krate creation with shell tab
const ws = new WebSocket(`/ws/shell?pod=${pod}&ns=${ns}`);

ws.onopen = () => {
  term.focus();
};

ws.onmessage = (event) => {
  term.write(event.data);  // stdout/stderr
};

term.onData((data) => {
  ws.send(data);  // stdin (keypresses, etc.)
});

term.onResize(({ rows, cols }) => {
  ws.send(JSON.stringify({ type: 'resize', rows, cols }));
});
```

### Keyboard Routing

#### Mouse-Over Focus
- Track `mouseenter`/`mouseleave` per window
- Set `hoveredWindowId` on shell windows
- Global `keydown` handler routes to shell when focused

#### Critical: Space Key
- **Must NOT open spotlight** when shell has focus
- Shell window handles space as input (terminal command)
- Implementation:
  ```typescript
  document.addEventListener('keydown', (e) => {
    if (hoveredWindowId && isShellWindow(hoveredWindowId)) {
      // Space goes to shell
      return;  // Don't trigger canvas shortcuts
    }
    // Handle canvas shortcuts (space pan, etc.)
  }, { capture: true });
  ```

### Scroll Wheel Behavior
- On shell content: Scroll terminal (not canvas)
- On empty canvas: Pan
- **Ctrl/⌘ + scroll over shell**: Zoom canvas (not terminal zoom)
  - Use `{ capture: true }` on canvas wheel handler
  - Check `e.ctrlKey || e.metaKey`
  - If true: zoom canvas; otherwise: let event propagate

### Terminal Features
- **Full PTY emulation**: Support all ANSI escapes
- **Resize**: Send new size on container resize
- **Paste**: Support Ctrl+Shift+V or Shift+Insert
- **Copy**: Ctrl+Shift+C or Ctrl+C (custom)
- **Search**: `/` to search, `n`/`N` for next/prev
- **Font scaling**: Ctrl+wheel for terminal font size

### Backend Implementation (Go)
```go
// WebSocket connection
func (s *Server) handleShell(w http.ResponseWriter, r *http.Request) {
    ws, err := upgrader.Upgrade(w, r, nil)
    if err != nil {
        return
    }
    defer ws.Close()

    pod := r.URL.Query().Get("pod")
    ns := r.URL.Query().Get("ns")

    // Create k8s exec request
    req := s.client.CoreV1().RESTClient().Post().
        Name(pod).Namespace(ns).Resource("pods").SubResource("exec")
    req.VersionedParams(&v1.ExecOptions{
        Stdin:     true,
        Stdout:    true,
        Stderr:    true,
        Terminal:  true,
    }, scheme.ParameterCodec)

    exec, err := remotecommand.NewSPDYExecutor(s.config, "POST", req.URL())
    if err != nil {
        ws.Close()
        return
    }

    // Stream between WebSocket and exec
    exec.Stream(remotecommand.StreamOptions{
        Stdin: ws,
        Stdout: ws,
        Stderr: ws,
        TermSize: &remotecommand.TerminalSize{
            Width:  80,
            Height: 24,
        },
    })
}
```

---

## Logs Window

### Purpose
Live-tailing container logs, showing output in real-time.

### Streaming
```typescript
// WebSocket connection
const ws = new WebSocket(`/ws/logs?pod=${pod}&ns=${ns}`);

ws.onmessage = (event) => {
  const line = event.data;
  addLogLine(line);
};

function addLogLine(line: string) {
  const entry = parseLogLine(line);
  logBuffer.push(entry);
  
  // Auto-scroll if at bottom
  if (atBottom()) {
    scrollToBottom();
  }
}
```

### Auto-Scroll Behavior
- **New lines arrive**: Auto-scroll to bottom
- **User scrolls up**: Stop auto-scrolling
- **Detection**:
  ```typescript
  function atBottom(): boolean {
    const threshold = 50;  // px
    return (scrollTop + clientHeight + threshold) >= scrollHeight;
  }
  ```

### Color Coding
Parse lines and color-code by pattern:

```typescript
function parseLogLine(line: string): LogEntry {
  // Pattern matching for common log levels
  if (line.includes('ERROR') || line.includes('ERR')) {
    return { text: line, color: '#ef6f6f' };  // Red
  } else if (line.includes('WARN') || line.includes('WARNING')) {
    return { text: line, color: '#e8b54a' };  // Amber
  } else if (line.includes('INFO') || line.includes('I ')) {
    return { text: line, color: '#b9c6d8' };  // Default
  } else {
    return { text: line, color: '#c7d2e0' };  // Muted
  }
}
```

### Timestamps
- **Default**: Include timestamps
- **Toggle**: Optional button to show/hide
- **Format**: ISO 8601 or container format

### Scrollbar Styling
- Width: 8px
- Track: rgba(140,165,200,.1)
- Thumb: rgba(140,165,200,.3)
- Hover thumb: rgba(140,165,200,.5)

### Content Rendering
```typescript
<pre style={{ overflow: 'auto', height: '286px', fontFamily: 'IBM Plex Mono' }}>
  {logs.map((line, i) => (
    <div key={i} style={{ color: line.color }}>
      {line.timestamp && <span className="timestamp">{line.timestamp} </span>}
      {line.text}
    </div>
  ))}
</pre>
```

---

## View-Specific Behavior

### Shell Tab
- **Enabled for**: Pods, and workloads that support exec
- **Disabled for**: Deployments, Services, etc.
- **Visual**: `opacity: 0.45` for disabled
- **Label**: Show "shell" but don't route to it

### Logs Tab
- **Enabled for**: Pods and workloads ( Deployments, StatefulSets, DaemonSets)
- **Disabled for**: ConfigMaps, Secrets, PVCs, etc.
- **Visual**: Same as shell

---

## Keyboard Shortcuts

| Key | Context | Action |
|---|---|---|
| ↑ / ↓ | Logs shell focused | Navigate scroll (logs) / line history (shell) |
| PageUp / PageDown | Logs focused | Page scroll |
| Ctrl+L | Logs focused | Clear screen (only in shell) |
| Ctrl+C | Shell focused | Send interrupt to shell |
| Ctrl+Z | Shell focused | Send suspend (if supported) |
| Ctrl+Shift+F | Logs focused | Find (future enhancement) |
| Ctrl+Shift+V | Shell focused | Paste |
| Ctrl+Shift+C | Shell focused | Copy selection |

---

## Error Handling

### Connection Errors
- **Shell**: Show error border, keep terminal buffer, retry button
- **Logs**: Show error indicator, auto-reconnect with backoff

### Reconnection Strategy
```typescript
let retries = 0;
const maxRetries = 5;

function reconnect() {
  if (retries >= maxRetries) {
    showFatalError('Connection failed');
    return;
  }
  
  setTimeout(() => {
    retries++;
    connect();
  }, Math.min(1000 * 2^retries, 10000));  // Exponential backoff
}
```

### Buffer Management
- **Shell**: Keep last 1000 lines in buffer
- **Logs**: Keep last 2000 lines
- **Overflow**: Drop oldest lines, mark with "..." indicator

---

## State Management

### Shell State
```typescript
interface ShellState {
  connected: boolean;
  rows: number;
  cols: number;
  buffer: string[];  // Last N lines
  cursor: { x, y };
}
```

### Logs State
```typescript
interface LogsState {
  lines: LogEntry[];
  scrollTop: number;
  autoScroll: boolean;
  timestamp: boolean;
}
```

---

## Gotchas

### Critical Issues
1. **Space key routing**: Must distinguish between shell space (input) and canvas space-pan
2. **Ctrl/⌘+scroll**: Intercept on canvas with `{ capture: true }`, check modifier
3. **Terminal resize**: Send `TermSize` on window resize events
4. **Paste security**: Sanitize pasted content, avoid escape sequences
5. **Cursor position**: xterm.js tracks cursor; keep in sync with server
6. **Buffer overflow**: Implement LRU buffer, don't memory leak

### Performance
1. **Throttle updates**: Don't render on every log line, batch
2. **Virtual scrolling**: For logs with many lines
3. **Web Worker**: Offload parsing to worker for large logs

### Animation
1. **Blinking cursor**: CSS animation or xterm.js built-in
2. **Auto-scroll indicator**: Small arrow when scrolled up
3. **Connection status**: Green/amber/red dot

## Testing Checklist
- [ ] Shell key press → terminal receives it
- [ ] Terminal output → WebSocket → UI
- [ ] Resize → terminal resizes correctly
- [ ] Space in shell ≠ spotlight open
- [ ] Ctrl+scroll over shell ≠ zoom canvas
- [ ] Logs auto-scroll works (and stops on manual scroll)
- [ ] Connection loss → retry with backoff
- [ ] Buffer overflow → old lines dropped
- [ ] Shell interrupt (Ctrl+C) handled
- [ ] Paste works (Ctrl+Shift+V)