chore: add AGENTS.md with build, lint, test commands and style guidelines

js/indicators/bb.js

@@ -0,0 +1,118 @@
+// Self-contained Bollinger Bands indicator
+// Includes math, metadata, signal calculation, and base class
+
+// Signal constants (defined in each indicator file)
+const SIGNAL_TYPES = {
+    BUY: 'buy',
+    SELL: 'sell',
+    HOLD: 'hold'
+};
+
+const SIGNAL_COLORS = {
+    buy: '#26a69a',
+    hold: '#787b86',
+    sell: '#ef5350'
+};
+
+// Base class (inline replacement for BaseIndicator)
+class BaseIndicator {
+    constructor(config) {
+        this.id = config.id;
+        this.type = config.type;
+        this.name = config.name;
+        this.params = config.params || {};
+        this.timeframe = config.timeframe || '1m';
+        this.series = [];
+        this.visible = config.visible !== false;
+        this.cachedResults = null;
+        this.cachedMeta = null;
+        this.lastSignalTimestamp = null;
+        this.lastSignalType = null;
+    }
+}
+
+// Signal calculation for Bollinger Bands
+function calculateBollingerBandsSignal(indicator, lastCandle, prevCandle, values, prevValues) {
+    const close = lastCandle.close;
+    const prevClose = prevCandle?.close;
+    const upper = values?.upper;
+    const lower = values?.lower;
+    const prevUpper = prevValues?.upper;
+    const prevLower = prevValues?.lower;
+    
+    if (!upper || !lower || prevUpper === undefined || prevLower === undefined || prevClose === undefined) {
+        return null;
+    }
+    
+    // BUY: Price crosses DOWN through lower band (reversal/bounce play)
+    if (prevClose > prevLower && close <= lower) {
+        return {
+            type: SIGNAL_TYPES.BUY,
+            strength: 70,
+            value: close,
+            reasoning: `Price crossed DOWN through lower Bollinger Band`
+        };
+    } 
+    // SELL: Price crosses UP through upper band (overextended play)
+    else if (prevClose < prevUpper && close >= upper) {
+        return {
+            type: SIGNAL_TYPES.SELL,
+            strength: 70,
+            value: close,
+            reasoning: `Price crossed UP through upper Bollinger Band`
+        };
+    }
+    
+    return null;
+}
+
+// Bollinger Bands Indicator class
+export class BollingerBandsIndicator extends BaseIndicator {
+    constructor(config) {
+        super(config);
+        this.lastSignalTimestamp = null;
+        this.lastSignalType = null;
+    }
+
+    calculate(candles) {
+        const period = this.params.period || 20;
+        const stdDevMult = this.params.stdDev || 2;
+        const results = new Array(candles.length).fill(null);
+        
+        for (let i = period - 1; i < candles.length; i++) {
+            let sum = 0;
+            for (let j = 0; j < period; j++) sum += candles[i-j].close;
+            const sma = sum / period;
+            
+            let diffSum = 0;
+            for (let j = 0; j < period; j++) diffSum += Math.pow(candles[i-j].close - sma, 2);
+            const stdDev = Math.sqrt(diffSum / period);
+            
+            results[i] = {
+                middle: sma,
+                upper: sma + (stdDevMult * stdDev),
+                lower: sma - (stdDevMult * stdDev)
+            };
+        }
+        return results;
+    }
+    
+    getMetadata() {
+        return {
+            name: 'Bollinger Bands',
+            description: 'Volatility bands around a moving average',
+            inputs: [
+                { name: 'period', label: 'Period', type: 'number', default: 20, min: 1, max: 100 },
+                { name: 'stdDev', label: 'Std Dev', type: 'number', default: 2, min: 0.5, max: 5, step: 0.5 }
+            ],
+            plots: [
+                { id: 'upper', color: '#4caf50', title: 'Upper' },
+                { id: 'middle', color: '#4caf50', title: 'Middle', lineStyle: 2 },
+                { id: 'lower', color: '#4caf50', title: 'Lower' }
+            ],
+            displayMode: 'overlay'
+        };
+    }
+}
+
+export { calculateBollingerBandsSignal };