// Copyright 2026 Stefan Prodan.
// SPDX-License-Identifier: AGPL-3.0
/**
* Convert a cron expression to human-readable format.
* Handles common cron patterns; falls back to raw expression for complex ones.
* @param {string} cron - Cron expression (5 fields: minute hour day month weekday)
* @returns {string} Human-readable description
*/
export function formatCronExpression(cron) {
if (!cron || typeof cron !== 'string') return cron
const parts = cron.trim().split(/\s+/)
if (parts.length !== 5) return cron
const [minute, hour, day, month, weekday] = parts
// Every minute
if (minute === '*' && hour === '*' && day === '*' && month === '*' && weekday === '*') {
return 'Every minute'
}
// Every N minutes
if (minute.startsWith('*/') && hour === '*' && day === '*' && month === '*' && weekday === '*') {
const interval = parseInt(minute.slice(2), 10)
if (interval === 1) return 'Every minute'
return `Every ${interval} minutes`
}
// Every hour at specific minute
if (!minute.includes('*') && !minute.includes('/') && hour === '*' && day === '*' && month === '*' && weekday === '*') {
const min = parseInt(minute, 10)
if (min === 0) return 'Every hour'
return `Every hour at minute ${min}`
}
// Every N hours
if (minute === '0' && hour.startsWith('*/') && day === '*' && month === '*' && weekday === '*') {
const interval = parseInt(hour.slice(2), 10)
if (interval === 1) return 'Every hour'
return `Every ${interval} hours`
}
// Daily at specific time
if (!minute.includes('*') && !hour.includes('*') && day === '*' && month === '*' && weekday === '*') {
const h = parseInt(hour, 10)
const m = parseInt(minute, 10)
const time = `${h.toString().padStart(2, '0')}:${m.toString().padStart(2, '0')}`
return `Daily at ${time}`
}
// Weekly on specific day
if (!minute.includes('*') && !hour.includes('*') && day === '*' && month === '*' && !weekday.includes('*')) {
const h = parseInt(hour, 10)
const m = parseInt(minute, 10)
const time = `${h.toString().padStart(2, '0')}:${m.toString().padStart(2, '0')}`
const dayNames = ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday']
const dayNum = parseInt(weekday, 10)
const dayName = dayNames[dayNum] || weekday
return `Weekly on ${dayName} at ${time}`
}
// Monthly on specific day
if (!minute.includes('*') && !hour.includes('*') && !day.includes('*') && month === '*' && weekday === '*') {
const h = parseInt(hour, 10)
const m = parseInt(minute, 10)
const d = parseInt(day, 10)
const time = `${h.toString().padStart(2, '0')}:${m.toString().padStart(2, '0')}`
const suffix = d === 1 ? 'st' : d === 2 ? 'nd' : d === 3 ? 'rd' : 'th'
return `Monthly on the ${d}${suffix} at ${time}`
}
// Fall back to raw expression for complex patterns
return cron
}
// Regex to validate cron field: digits, *, /, -, or comma
const cronFieldPattern = /^[\d*/,-]+$/
/**
* Check if a string looks like a cron expression.
* @param {string} str - String to check
* @returns {boolean} True if it looks like a cron expression
*/
function isCronExpression(str) {
const parts = str.trim().split(/\s+/)
if (parts.length !== 5) return false
return parts.every(part => cronFieldPattern.test(part))
}
/**
* Format a cron schedule message for display.
* Converts cron expression to human-readable format with "Schedule: " prefix.
* @param {string} message - Cron expression or status message
* @returns {string} Human-readable schedule or original message
*/
export function formatScheduleMessage(message) {
if (!message || typeof message !== 'string') return message
if (!isCronExpression(message)) return message
return `Schedule: ${formatCronExpression(message)}`
}
