/**
* Trailing Stop Exit Condition Checker
* Track highest/lowest price since entry and update trailing stop dynamically
*/
import { PositionState, ExitCondition, ExitReason } from '../types'
export interface TrailingStopConfig {
enabled: boolean
distancePct: number // Distance percentage (e.g., 1%)
activateAfterGainPct?: number // Only activate trailing stop after X% gain (default: 1%)
}
export function checkTrailingStop(
position: PositionState,
currentPrice: number,
config: TrailingStopConfig
): ExitCondition | null {
if (!config.enabled) {
return null
}
const activateAfterGain = config.activateAfterGainPct != null ? config.activateAfterGainPct : 1
const entryPrice = position.entryPrice
// Check if position is in profit enough to activate trailing stop
const gainPct = position.side === 'LONG'
? ((currentPrice - entryPrice) / entryPrice) * 100
: ((entryPrice - currentPrice) / entryPrice) * 100
if (gainPct < activateAfterGain) {
// Not enough gain yet, don't activate trailing stop
return null
}
// Update highest/lowest price
const highestPrice = position.highestPrice != null
? Math.max(position.highestPrice, currentPrice)
: currentPrice
const lowestPrice = position.lowestPrice != null
? Math.min(position.lowestPrice, currentPrice)
: currentPrice
// Calculate trailing stop level
const trailingStopLevel = position.side === 'LONG'
? highestPrice * (1 - config.distancePct / 100)
: lowestPrice * (1 + config.distancePct / 100)
// Check if current price hit trailing stop
const shouldExit = position.side === 'LONG'
? currentPrice <= trailingStopLevel
: currentPrice >= trailingStopLevel
if (!shouldExit) {
return null
}
return {
reason: 'TRAILING_STOP' as ExitReason,
priority: 4, // After take profit
shouldExit: true,
exitSize: 100, // Full exit
exitPrice: trailingStopLevel,
metadata: {
trailingStopLevel,
currentPrice,
highestPrice: position.side === 'LONG' ? highestPrice : undefined,
lowestPrice: position.side === 'SHORT' ? lowestPrice : undefined,
distancePct: config.distancePct,
gainPct,
side: position.side
},
timestamp: Date.now(),
description: `Trailing stop hit at ${trailingStopLevel.toFixed(4)} (current: ${currentPrice.toFixed(4)}, ${config.distancePct}% from ${position.side === 'LONG' ? 'high' : 'low'})`
}
}
export function updateTrailingStop(
position: PositionState,
currentPrice: number,
config: TrailingStopConfig
): PositionState {
const activateAfterGain = config.activateAfterGainPct != null ? config.activateAfterGainPct : 1
const entryPrice = position.entryPrice
// Check if position is in profit enough to activate trailing stop
const gainPct = position.side === 'LONG'
? ((currentPrice - entryPrice) / entryPrice) * 100
: ((entryPrice - currentPrice) / entryPrice) * 100
if (gainPct < activateAfterGain) {
// Not enough gain yet
return position
}
// Update highest/lowest price
const highestPrice = position.highestPrice != null
? Math.max(position.highestPrice, currentPrice)
: currentPrice
const lowestPrice = position.lowestPrice != null
? Math.min(position.lowestPrice, currentPrice)
: currentPrice
// Calculate trailing stop level
const trailingStopLevel = position.side === 'LONG'
? highestPrice * (1 - config.distancePct / 100)
: lowestPrice * (1 + config.distancePct / 100)
return {
...position,
highestPrice,
lowestPrice,
trailingStop: trailingStopLevel,
trailingStopActive: true
}
}
