// comboStrategy.js
const RSI_PERIOD = 14;
const MACD_FAST = 12;
const MACD_SLOW = 26;
const MACD_SIGNAL = 9;

function calculateRSI(prices, period = RSI_PERIOD) {
  let gains = [], losses = [];
  for (let i = 1; i < prices.length; i++) {
    const change = prices[i] - prices[i - 1];
    gains.push(change > 0 ? change : 0);
    losses.push(change < 0 ? Math.abs(change) : 0);
  }

  let avgGain = gains.slice(-period).reduce((a, b) => a + b) / period;
  let avgLoss = losses.slice(-period).reduce((a, b) => a + b) / period;

  if (avgLoss === 0) return 100;
  const rs = avgGain / avgLoss;
  return 100 - (100 / (1 + rs));
}

function calculateMACD(prices, fast = MACD_FAST, slow = MACD_SLOW) {
  const ema = (arr, period) => {
    const k = 2 / (period + 1);
    let emaArr = [arr[0]];
    for (let i = 1; i < arr.length; i++) {
      emaArr.push(arr[i] * k + emaArr[i - 1] * (1 - k));
    }
    return emaArr;
  };

  const emaFast = ema(prices, fast);
  const emaSlow = ema(prices, slow);
  const macdLine = emaFast.map((v, i) => v - emaSlow[i]);

  const signalLine = ema(macdLine, MACD_SIGNAL);
  const histogram = macdLine.map((v, i) => v - signalLine[i]);

  return { macdLine, signalLine, histogram };
}

function generateSignal(prices, volumes) {
  const rsi = calculateRSI(prices);
  const { macdLine, signalLine, histogram } = calculateMACD(prices);

  const currentRSI = rsi[rsi.length - 1];
  const prevRSI = rsi[rsi.length - 2];

  const currentMacd = macdLine[macdLine.length - 1];
  const prevMacd = macdLine[macdLine.length - 2];
  const currentSignal = signalLine[signalLine.length - 1];
  const prevSignal = signalLine[signalLine.length - 2];

  // Condition 1: RSI reversal
  const rsiBullish = prevRSI < 30 && currentRSI >= 30;
  const rsiBearish = prevRSI > 70 && currentRSI <= 70;

  // Condition 2: MACD crossover
  const macdBullish = prevMacd < prevSignal && currentMacd >= currentSignal;
  const macdBearish = prevMacd > prevSignal && currentMacd <= currentSignal;

  // Condition 3: Volume spike
  const volChange = ((volumes[volumes.length - 1] - volumes[volumes.length - 2]) / volumes[volumes.length - 2]) * 100;
  const volumeValid = volChange > 20;

  if (rsiBullish && macdBullish && volumeValid) return 'BUY';
  if (rsiBearish && macdBearish && volumeValid) return 'SELL';
  return 'HOLD';
}

// Usage Example
const samplePrices = [42000, 42150, 42300, 42500, 42800, 43200, 43500, 43300, 43100, 42900];
const sampleVolumes = [1000, 1100, 1200, 1350, 1600, 2100, 1950, 1800, 1750, 1700];

console.log('Signal:', generateSignal(samplePrices, sampleVolumes));