/**
* Utilities for parsing and working with Elasticsearch date math expressions
*/
/**
* Resolve a date string (ISO or relative math) to a Javascript Date object
* Supports:
* - "now"
* - Relative math: "now-1d", "now+2w", "now-1M"
* - Rounding: "now/d", "now/M", "now/y"
* - Combined: "now-1d/d"
*
* @param dateStr - Date string
* @returns Date object
* @throws Error if date format is invalid
*/
export function resolveDate(dateStr: string): Date {
if (dateStr === 'now') {
return new Date();
}
// Handle standard Elasticsearch date math: now[+|-][num][unit][/rounding]
if (dateStr.startsWith('now')) {
const now = new Date();
let workingStr = dateStr.substring(3); // Remove 'now'
// 1. Parse Offset (e.g. -1d, +2w)
// Match optional +/- followed by digits and unit
const offsetMatch = workingStr.match(/^([+-])(\d+)([dMwYy])/);
if (offsetMatch) {
const operator = offsetMatch[1];
const value = parseInt(offsetMatch[2], 10);
const unit = offsetMatch[3];
const multiplier = operator === '-' ? -1 : 1;
const amount = value * multiplier;
switch (unit) {
case 'd':
case 'D':
now.setDate(now.getDate() + amount);
break;
case 'w':
case 'W':
now.setDate(now.getDate() + (amount * 7));
break;
case 'M':
now.setMonth(now.getMonth() + amount);
break;
case 'y':
case 'Y':
now.setFullYear(now.getFullYear() + amount);
break;
}
// Advance string past the offset
workingStr = workingStr.substring(offsetMatch[0].length);
}
// 2. Parse Rounding (e.g. /d, /M)
// Check if remaining string starts with /
if (workingStr.startsWith('/')) {
const roundingUnit = workingStr.substring(1, 2); // get char after /
switch (roundingUnit) {
case 'd':
case 'D':
now.setHours(0, 0, 0, 0);
break;
case 'w':
case 'W':
// Set to previous Monday (or Sunday depending on locale, standard ES is Monday iirc but let's stick to simple day rounding for now or 0 day of week)
// For simplicity/safety let's assume Sunday=0. ES uses Monday as start of week usually.
// Let's implement Monday rounding:
const day = now.getDay();
const diff = now.getDate() - day + (day === 0 ? -6 : 1); // adjust when day is sunday
now.setDate(diff);
now.setHours(0, 0, 0, 0);
break;
case 'M':
now.setDate(1);
now.setHours(0, 0, 0, 0);
break;
case 'y':
case 'Y':
now.setMonth(0, 1);
now.setHours(0, 0, 0, 0);
break;
}
workingStr = workingStr.substring(2);
}
if (workingStr.length > 0) {
// If there's still junk left, it might be invalid or unsupported syntax
// For now, if we processed something, ignoring trailing junk might be risky, but throwing is safer
throw new Error(`Invalid or unsupported date math format: ${dateStr}`);
}
return now;
}
// Handle ISO strings
const parsed = new Date(dateStr);
if (isNaN(parsed.getTime())) {
throw new Error(`Invalid date format: ${dateStr}`);
}
return parsed;
}
/**
* Legacy wrapper for backward compatibility, though discouraged.
* returns number of days relative to now.
*/
export function parseDateMath(dateStr: string): number {
if (dateStr === 'now') return 0;
try {
const date = resolveDate(dateStr);
const now = new Date();
const diffTime = Math.abs(now.getTime() - date.getTime());
return Math.ceil(diffTime / (1000 * 60 * 60 * 24));
} catch (e) {
// Fallback for very simple day parsing if resolveDate fails or strictly for "now-Nd" extraction
const match = dateStr.match(/now-(\d+)([dwMy])/);
if (match) {
const value = parseInt(match[1], 10);
const unit = match[2];
if (unit === 'd' || unit === 'D') return value;
if (unit === 'w' || unit === 'W') return value * 7;
if (unit === 'M') return value * 30;
if (unit === 'y' || unit === 'Y') return value * 365;
return 0;
}
return 30;
}
}
/**
* Cap a time period to a maximum number of days
* @param startDate - Start date string
* @param endDate - End date string
* @param maxDays - Maximum number of days allowed
* @param logger - Logger instance for warnings
* @returns Adjusted dates and whether adjustment was made
*/
export function capTimePeriod(
startDate: string,
endDate: string,
maxDays: number,
logger: { warn: (message: string, meta: any) => void }
): { startDate: string; endDate: string; wasAdjusted: boolean } {
const startDays = parseDateMath(startDate);
const endDays = parseDateMath(endDate);
const periodDays = Math.abs(startDays - endDays);
if (periodDays > maxDays) {
const adjustedStart = startDate.startsWith('now-') ? `now-${maxDays}d` : startDate;
logger.warn('Time period capped to prevent data limit errors', {
originalStartDate: startDate,
originalEndDate: endDate,
originalPeriodDays: periodDays,
adjustedStartDate: adjustedStart,
adjustedEndDate: endDate,
adjustedPeriodDays: maxDays,
});
return { startDate: adjustedStart, endDate, wasAdjusted: true };
}
return { startDate, endDate, wasAdjusted: false };
}
