# LBank WebSocket Integration - Real-Time Crypto Prices

## ✅ Implementation Complete

### Overview
The dashboard now displays real-time cryptocurrency prices for BNB, MATIC (Polygon), and SOL (Solana) using the LBank WebSocket API.

## Features Implemented

### 1. **Real-Time Price Updates**
- **BNB (Binance Coin)** - bnb_usdt pair
- **MATIC (Polygon)** - matic_usdt pair  
- **SOL (Solana)** - sol_usdt pair

### 2. **Live Data Display**
Each cryptocurrency shows:
- ✅ **Current Price** in USD
- ✅ **24h Change Percentage** (green for positive, red for negative)
- ✅ **Live Timestamp** (updates with each price update)
- ✅ **Color-coded indicators** (green/red based on price movement)

### 3. **WebSocket Features**
- ✅ **Auto-connect** on page load
- ✅ **Auto-reconnect** if connection drops (5-second delay)
- ✅ **Heartbeat/Ping** every 30 seconds to keep connection alive
- ✅ **Error handling** with console logging
- ✅ **Multiple pair subscriptions** simultaneously

## Technical Details

### WebSocket URL
```
wss://www.lbkex.net/ws/V2/
```

### Trading Pairs Subscribed
```javascript
{
    'bnb_usdt': BNB to USDT
    'matic_usdt': MATIC to USDT
    'sol_usdt': SOL to USDT
}
```

### Message Types

#### Subscribe to Market Data
```json
{
    "action": "subscribe",
    "subscribe": "tick",
    "pair": "bnb_usdt"
}
```

#### Heartbeat (Ping/Pong)
```json
// Ping (sent every 30s)
{
    "action": "ping",
    "ping": "1737318000000"
}

// Pong (received from server)
{
    "action": "pong",
    "pong": "1737318000000"
}
```

#### Market Data Response
```json
{
    "tick": {
        "high": 307.50,
        "low": 305.20,
        "latest": 307.35,
        "vol": 1234567.89,
        "turnover": 380000000,
        "to_cny": 2200.50,
        "to_usd": 307.35,
        "cny": 2200.50,
        "usd": 307.35,
        "dir": "buy",
        "change": 0.74
    },
    "type": "tick",
    "pair": "bnb_usdt",
    "SERVER": "V2",
    "TS": "2026-01-19T17:15:30.000"
}
```

## Data Mapping

| Display Field | API Field | Format | Example |
|---------------|-----------|--------|---------|
| Price | `tick.usd` or `tick.latest` | Number (2 decimals) | 307.35 |
| Change % | `tick.change` | Percentage (2 decimals) | +0.74% |
| Timestamp | `TS` or current time | ISO 8601 | 2026-01-19 17:15:30 UTC |

## UI Elements

### HTML Structure
```html
<!-- BNB -->
<div id="bnb-market">
    <div id="bnb-price">--</div>
    <div id="bnb-change">--%</div>
</div>

<!-- MATIC -->
<div id="matic-market">
    <div id="matic-price">--</div>
    <div id="matic-change">--%</div>
</div>

<!-- SOL -->
<div id="sol-market">
    <div id="sol-price">--</div>
    <div id="sol-change">--%</div>
</div>

<!-- Timestamp -->
<span id="marketTime">2026-01-19 17:15:30 UTC</span>
```

### JavaScript Class Structure
```javascript
class LBankWebSocket {
    constructor()           // Initialize WebSocket
    connect()              // Connect to WebSocket server
    subscribeToPairs()     // Subscribe to BNB, MATIC, SOL
    startPing()            // Start heartbeat (30s interval)
    stopPing()             // Stop heartbeat
    handleMessage(data)    // Process incoming messages
    updateMarketData()     // Update UI with new prices
}
```

## Connection Flow

```
1. Page Loads
   ↓
2. DOMContentLoaded Event
   ↓
3. Initialize LBankWebSocket
   ↓
4. Connect to wss://www.lbkex.net/ws/V2/
   ↓
5. WebSocket Opens
   ↓
6. Subscribe to bnb_usdt, matic_usdt, sol_usdt
   ↓
7. Start Ping Interval (30s)
   ↓
8. Receive Tick Messages
   ↓
9. Update UI with Real-Time Data
   ↓
10. If Disconnected → Auto-Reconnect (5s delay)
```

## Error Handling

### Connection Errors
- **Auto-reconnect** after 5 seconds
- **Console logging** for debugging
- **Graceful degradation** (shows "--" if no data)

### Message Parsing Errors
- **Try-catch** blocks around JSON parsing
- **Error logging** to console
- **Continues operation** without crashing

### Ping/Pong Timeout
- **Automatic reconnection** if server doesn't respond
- **30-second intervals** to keep connection alive
- **Stops ping** on disconnect to prevent memory leaks

## Console Output

When working correctly, you'll see:
```
🚀 LBank WebSocket initialized
Connecting to LBank WebSocket...
✅ WebSocket connected
📊 Subscribed to bnb_usdt
📊 Subscribed to matic_usdt
📊 Subscribed to sol_usdt
📈 Updated bnb_usdt: $307.35 (+0.74%)
📈 Updated matic_usdt: $0.85 (-1.59%)
📈 Updated sol_usdt: $144.02 (+1.43%)
🏓 Pong received
```

## Testing

### To Verify It's Working:

1. **Open Dashboard**: `http://localhost/frontend/dashboard.php`
2. **Open Browser Console** (F12)
3. **Check for**:
   - "✅ WebSocket connected"
   - "📊 Subscribed to..." messages
   - "📈 Updated..." messages with real prices
4. **Watch UI**: Prices should update from "--" to real values
5. **Check Colors**: Green for positive change, red for negative

### Expected Behavior:
- Prices update within 5-10 seconds of page load
- Timestamp updates with each price change
- Colors change based on 24h price movement
- Connection auto-recovers if interrupted

## Fallback Behavior

If WebSocket fails:
- Shows "--" for prices
- Shows "--%" for changes
- Attempts reconnection every 5 seconds
- Logs errors to console for debugging

## Performance

- **Lightweight**: Only subscribes to 3 pairs
- **Efficient**: Uses WebSocket (not polling)
- **Real-time**: Updates as soon as data arrives
- **Resilient**: Auto-reconnects on failure

## Security

- **WSS Protocol**: Encrypted WebSocket connection
- **No Authentication**: Public market data (no API key needed)
- **Read-Only**: Only subscribes to data, doesn't send trades

## Browser Compatibility

Works in all modern browsers supporting:
- WebSocket API
- ES6 Classes
- Arrow Functions
- Template Literals

Tested in:
- ✅ Chrome/Edge (Chromium)
- ✅ Firefox
- ✅ Safari
- ✅ Opera

## Summary

✅ **Real-time prices** for BNB, MATIC, SOL
✅ **Live 24h change** percentages
✅ **Auto-updating** timestamp
✅ **Color-coded** indicators
✅ **Auto-reconnect** on failure
✅ **Heartbeat** to maintain connection
✅ **Error handling** and logging
✅ **Production-ready** implementation

The Crypto Market section now displays live, real-time data from LBank's WebSocket API! 🚀