import { BaseIndicator } from './base.js';

export class RSIIndicator extends BaseIndicator {
    calculate(candles) {
        const period = this.params.period || 14;
        
        // 1. Calculate RSI using RMA (Wilder's Smoothing)
        let rsiValues = new Array(candles.length).fill(null);
        let upSum = 0;
        let downSum = 0;
        const rmaAlpha = 1 / period;
        
        for (let i = 1; i < candles.length; i++) {
            const diff = candles[i].close - candles[i-1].close;
            const up = diff > 0 ? diff : 0;
            const down = diff < 0 ? -diff : 0;
            
            if (i < period) {
                upSum += up;
                downSum += down;
            } else if (i === period) {
                upSum += up;
                downSum += down;
                const avgUp = upSum / period;
                const avgDown = downSum / period;
                rsiValues[i] = avgDown === 0 ? 100 : (avgUp === 0 ? 0 : 100 - (100 / (1 + avgUp / avgDown)));
                upSum = avgUp; // Store for next RMA step
                downSum = avgDown;
            } else {
                upSum = (up - upSum) * rmaAlpha + upSum;
                downSum = (down - downSum) * rmaAlpha + downSum;
                rsiValues[i] = downSum === 0 ? 100 : (upSum === 0 ? 0 : 100 - (100 / (1 + upSum / downSum)));
            }
        }
        
        // Combine results
        return rsiValues.map((rsi, i) => {
            return {
                paneBg: 100, // Background lightening trick
                rsi: rsi,
                upperBand: 70,
                lowerBand: 30
            };
        });
    }
    
    getMetadata() {
        const plots = [
            // Background lightness trick (spans from 0 to 100 constantly)
            // Making it darker by reducing opacity since the main background is dark.
            { id: 'paneBg', type: 'baseline', baseValue: 0, color: 'transparent',
              topLineColor: 'transparent', bottomLineColor: 'transparent',
              topFillColor1: 'rgba(255, 255, 255, 0.015)', topFillColor2: 'rgba(255, 255, 255, 0.015)',
              bottomFillColor1: 'transparent', bottomFillColor2: 'transparent',
              title: '', lastValueVisible: false, width: 0 },

            // Overbought Gradient Fill (> 70)
            { id: 'rsi', type: 'baseline', baseValue: 70, color: 'transparent',
              topLineColor: 'transparent', bottomLineColor: 'transparent',
              topFillColor1: 'rgba(244, 67, 54, 0.8)', topFillColor2: 'rgba(244, 67, 54, 0.2)',
              bottomFillColor1: 'transparent', bottomFillColor2: 'transparent',
              title: '', lastValueVisible: false, width: 0 },
              
            // Oversold Gradient Fill (< 30)
            { id: 'rsi', type: 'baseline', baseValue: 30, color: 'transparent',
              topLineColor: 'transparent', bottomLineColor: 'transparent',
              topFillColor1: 'transparent', topFillColor2: 'transparent',
              bottomFillColor1: 'rgba(76, 175, 80, 0.2)', bottomFillColor2: 'rgba(76, 175, 80, 0.8)',
              title: '', lastValueVisible: false, width: 0 },
              
            // RSI Line
            { id: 'rsi', color: '#7E57C2', title: '', width: 1, lastValueVisible: true },
            
            // Bands
            { id: 'upperBand', color: '#787B86', title: '', style: 'dashed', width: 1, lastValueVisible: false },
            { id: 'lowerBand', color: '#787B86', title: '', style: 'dashed', width: 1, lastValueVisible: false }
        ];
        
        return {
            name: 'RSI',
            description: 'Relative Strength Index',
            inputs: [
                { name: 'period', label: 'RSI Length', type: 'number', default: 14, min: 1, max: 100 }
            ],
            plots: plots,
            displayMode: 'pane',
            paneMin: 0,
            paneMax: 100
        };
    }
}