package com.xcong.excoin.modules.okxNewPrice.indicator;

import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.ArrayList;
import java.util.List;

/**
 * Technical indicators base class, provides common calculation methods
 * 
 * Indicator combination strategy:
 * 1. Trend judgment (MA/AdvancedMA/MACD): Determine the overall trend direction of prices
 * 2. Momentum confirmation (RSI/KDJ): Confirm the strength and sustainability of the current trend
 * 3. Volatility reference (BOLL): Determine reasonable price volatility range and breakthrough timing
 * 
 * Long/Short direction selection logic:
 * - Long signal: MA bullish arrangement + MACD golden cross + RSI(30-70) + BOLL price between upper and middle band
 * - Short signal: MA bearish arrangement + MACD death cross + RSI(30-70) + BOLL price between lower and middle band
 * - Consolidation signal: AdvancedMA three-line convergence + RSI(40-60) + BOLL bandwidth narrowing
 * 
 * Open and close position strategies:
 * - Open long: MA golden cross + MACD golden cross + KDJ golden cross + RSI(30-70) + price breaks through BOLL middle band
 * - Open short: MA death cross + MACD death cross + KDJ death cross + RSI(30-70) + price breaks below BOLL middle band
 * - Close long: MA death cross + MACD death cross + RSI overbought(>70) + price breaks below BOLL middle band
 * - Close short: MA golden cross + MACD golden cross + RSI oversold(<30) + price breaks through BOLL middle band
 */
public abstract class IndicatorBase {

    /**
     * Calculate moving average
     * @param prices Price list
     * @param period Period
     * @return Moving average value
     */
    protected BigDecimal calculateMA(List<BigDecimal> prices, int period) {
        if (prices == null || prices.size() < period) {
            return BigDecimal.ZERO;
        }
        BigDecimal sum = BigDecimal.ZERO;
        for (int i = prices.size() - period; i < prices.size(); i++) {
            sum = sum.add(prices.get(i));
        }
        return sum.divide(new BigDecimal(period), 8, RoundingMode.HALF_UP);
    }

    /**
     * Calculate exponential moving average
     * @param prices Price list
     * @param period Period
     * @param prevEMA Previous EMA value
     * @return Exponential moving average value
     */
    protected BigDecimal calculateEMA(List<BigDecimal> prices, int period, BigDecimal prevEMA) {
        if (prices == null || prices.size() == 0) {
            return BigDecimal.ZERO;
        }
        if (prevEMA == null || prevEMA.compareTo(BigDecimal.ZERO) == 0) {
            return calculateMA(prices, Math.min(period, prices.size()));
        }
        BigDecimal k = new BigDecimal(2).divide(new BigDecimal(period + 1), 8, RoundingMode.HALF_UP);
        BigDecimal currentPrice = prices.get(prices.size() - 1);
        return currentPrice.multiply(k).add(prevEMA.multiply(BigDecimal.ONE.subtract(k)));
    }

    /**
     * Calculate standard deviation
     * @param prices Price list
     * @param period Period
     * @return Standard deviation
     */
    protected BigDecimal calculateStdDev(List<BigDecimal> prices, int period) {
        if (prices == null || prices.size() < period) {
            return BigDecimal.ZERO;
        }
        BigDecimal ma = calculateMA(prices, period);
        BigDecimal sumSquares = BigDecimal.ZERO;
        for (int i = prices.size() - period; i < prices.size(); i++) {
            BigDecimal diff = prices.get(i).subtract(ma);
            sumSquares = sumSquares.add(diff.multiply(diff));
        }
        BigDecimal variance = sumSquares.divide(new BigDecimal(period), 8, RoundingMode.HALF_UP);
        return sqrt(variance);
    }

    /**
     * Calculate square root (simplified implementation)
     * @param value Input value
     * @return Square root
     */
    protected BigDecimal sqrt(BigDecimal value) {
        if (value.compareTo(BigDecimal.ZERO) < 0) {
            return BigDecimal.ZERO;
        }
        return new BigDecimal(Math.sqrt(value.doubleValue())).setScale(8, RoundingMode.HALF_UP);
    }

    /**
     * Get recent price data
     * @param prices All price data
     * @param period Period
     * @return Recent period price data
     */
    protected List<BigDecimal> getRecentPrices(List<BigDecimal> prices, int period) {
        if (prices == null || prices.size() == 0) {
            return new ArrayList<>();
        }
        int startIndex = Math.max(0, prices.size() - period);
        return prices.subList(startIndex, prices.size());
    }

    /**
     * Calculate ATR (Average True Range)
     * @param high High price list
     * @param low Low price list
     * @param close Close price list
     * @param period Period
     * @return ATR value
     */
    protected BigDecimal calculateATR(List<BigDecimal> high, List<BigDecimal> low, List<BigDecimal> close, int period) {
        if (high == null || low == null || close == null || 
            high.size() < period || low.size() < period || close.size() < period) {
            return BigDecimal.ZERO;
        }

        List<BigDecimal> trList = new ArrayList<>();
        for (int i = 1; i < high.size(); i++) {
            BigDecimal trueRange = calculateTrueRange(high.get(i), low.get(i), close.get(i - 1));
            trList.add(trueRange);
        }

        // Use simple moving average to calculate ATR
        return calculateMA(trList, Math.min(period, trList.size()));
    }

    /**
     * Calculate True Range
     * @param high Current high price
     * @param low Current low price
     * @param prevClose Previous close price
     * @return True range
     */
    protected BigDecimal calculateTrueRange(BigDecimal high, BigDecimal low, BigDecimal prevClose) {
        BigDecimal h1 = high.subtract(low);
        BigDecimal h2 = high.subtract(prevClose).abs();
        BigDecimal h3 = low.subtract(prevClose).abs();
        return h1.max(h2).max(h3);
    }

    /**
     * Calculate normalized volatility (based on ATR)
     * @param close Close price list
     * @param atr ATR value
     * @return Normalized volatility (percentage)
     */
    protected BigDecimal normalizeVolatility(List<BigDecimal> close, BigDecimal atr) {
        if (close == null || close.size() == 0 || atr.compareTo(BigDecimal.ZERO) == 0) {
            return BigDecimal.ZERO;
        }
        return atr.divide(close.get(close.size() - 1), 4, RoundingMode.HALF_UP).multiply(new BigDecimal(100));
    }
}