dhis2/d2

import { isInteger } from '../../lib/check'
import {
    validateIfValueIsInteger,
    formatAsISODate,
    getCurrentYear,
    getMonthNamesForLocale,
} from '../helpers'

export function generateFinancialOctoberPeriodsUpToYear(
    year = getCurrentYear(),
    numberOfYears = 10,
    locale = 'en'
) {
    validateIfValueIsInteger(year)
    if (!isInteger(numberOfYears) || numberOfYears < 1) {
        throw new Error(
            'FinancialOctober generator parameter `numberOfYears` should be an integer larger than 0.'
        )
    }

    const periods = []
    const date = new Date(`30 Sep ${year + 1}`)
    const monthNames = getMonthNamesForLocale(locale)

    for (let i = 0; i < numberOfYears; i++) {
        const period = {}
        period.endDate = formatAsISODate(date)
        date.setYear(date.getFullYear() - 1)
        date.setDate(date.getDate() + 1)
        period.startDate = formatAsISODate(date)
        period.name = `${monthNames[9]} ${date.getFullYear()} - ${
            monthNames[8]
        } ${date.getFullYear() + 1}`
        period.id = `${date.getFullYear()}Oct`
        periods.push(period)
        date.setDate(date.getDate() - 1)
    }

    // FinancialOctober periods are collected backwards. If isReverse is true, then do nothing. Else reverse to correct order and return.
    return periods.reverse()
}