/**
* Hull Moving Average (HMA) Indicator
* Moving average designed to reduce lag while maintaining smoothness
*/
import { calculateWMA } from './wma'
export function calculateHMA(closes: number[], period: number = 16): number[] {
if (closes.length < 3 || period < 2) return []
// Use adaptive period if data is insufficient
const effectivePeriod = Math.min(period, Math.max(2, closes.length - 1))
const halfPeriod = Math.max(1, Math.floor(effectivePeriod / 2))
const sqrtPeriod = Math.max(1, Math.floor(Math.sqrt(effectivePeriod)))
const hma: number[] = []
// If we have very limited data, use simplified calculation
if (closes.length < effectivePeriod + sqrtPeriod) {
// Simplified HMA: use weighted average of recent prices
const recentPrices = closes.slice(-Math.min(closes.length, effectivePeriod))
const wma = calculateWMA(recentPrices, Math.min(recentPrices.length, effectivePeriod))
if (wma.length > 0) {
return [wma[wma.length - 1]]
}
// Ultimate fallback: return last close
return [closes[closes.length - 1]]
}
// Standard HMA calculation
const requiredLength = effectivePeriod + sqrtPeriod - 1
const startIdx = Math.max(0, requiredLength - 1)
for (let i = startIdx; i < closes.length; i++) {
// Step 1: Calculate WMA for half period, multiplied by 2
const halfStart = Math.max(0, i - halfPeriod - sqrtPeriod + 1)
const halfEnd = Math.max(halfStart + 1, i - sqrtPeriod + 1)
const wmaHalf = calculateWMA(closes.slice(halfStart, halfEnd), Math.min(halfPeriod, halfEnd - halfStart))
const wmaHalfValue = wmaHalf.length > 0 ? wmaHalf[wmaHalf.length - 1] * 2 : closes[i] * 2
// Step 2: Calculate WMA for full period
const fullStart = Math.max(0, i - effectivePeriod - sqrtPeriod + 1)
const fullEnd = Math.max(fullStart + 1, i - sqrtPeriod + 1)
const wmaFull = calculateWMA(closes.slice(fullStart, fullEnd), Math.min(effectivePeriod, fullEnd - fullStart))
const wmaFullValue = wmaFull.length > 0 ? wmaFull[wmaFull.length - 1] : closes[i]
// Step 3: Calculate Raw HMA
const rawHMA = wmaHalfValue - wmaFullValue
// Step 4: Calculate final HMA using WMA of Raw HMA
const rawHMAData = [rawHMA]
// Build historical Raw HMA data for sqrtPeriod WMA calculation
for (let j = 1; j < sqrtPeriod; j++) {
const idx = i - j
if (idx >= 0) {
const prevHalfStart = Math.max(0, idx - halfPeriod - sqrtPeriod + 1)
const prevHalfEnd = Math.max(prevHalfStart + 1, idx - sqrtPeriod + 1)
const prevWmaHalf = calculateWMA(closes.slice(prevHalfStart, prevHalfEnd), Math.min(halfPeriod, prevHalfEnd - prevHalfStart))
const prevWmaHalfValue = prevWmaHalf.length > 0 ? prevWmaHalf[prevWmaHalf.length - 1] * 2 : closes[idx] * 2
const prevFullStart = Math.max(0, idx - effectivePeriod - sqrtPeriod + 1)
const prevFullEnd = Math.max(prevFullStart + 1, idx - sqrtPeriod + 1)
const prevWmaFull = calculateWMA(closes.slice(prevFullStart, prevFullEnd), Math.min(effectivePeriod, prevFullEnd - prevFullStart))
const prevWmaFullValue = prevWmaFull.length > 0 ? prevWmaFull[prevWmaFull.length - 1] : closes[idx]
rawHMAData.unshift(prevWmaHalfValue - prevWmaFullValue)
}
}
// Calculate final HMA as WMA of Raw HMA data
const finalHMA = calculateWMA(rawHMAData, Math.min(sqrtPeriod, rawHMAData.length))
if (finalHMA.length > 0) {
hma.push(finalHMA[finalHMA.length - 1])
} else {
hma.push(rawHMA)
}
}
return hma.length > 0 ? hma : [closes[closes.length - 1]]
}
