import { PrescribedMedicationType } from '../types'

export const convertYyyyMmDdNumberToIsoDate = (dateNumber: number): string => {
  const year = Math.floor(dateNumber / 10000)
  const month = Math.floor((dateNumber % 10000) / 100)
    .toString()
    .padStart(2, '0')
  const day = (dateNumber % 100).toString().padStart(2, '0')
  return `${year}-${month}-${day}`
}

export const getTreatmentStartDate = (prescribedMedication?: PrescribedMedicationType): string => {
  if (prescribedMedication?.medication.beginMoment) {
    return convertYyyyMmDdNumberToIsoDate(prescribedMedication?.medication.beginMoment)
  } else {
    return new Date().toISOString().split('T')[0]
  }
}

export const getExecutableUntilDate = (prescribedMedication?: PrescribedMedicationType): string => {
  if (prescribedMedication?.medication.endMoment) {
    return convertYyyyMmDdNumberToIsoDate(prescribedMedication.medication.endMoment)
  } else {
    const startDay = new Date()
    const nextYear = new Date(startDay)
    nextYear.setFullYear(startDay.getFullYear() + 1)
    return nextYear.toISOString().split('T')[0]
  }
}

// also known as formatToDayMonthYear
export const formatTimestamp = (timestamp?: number): string | undefined => {
  if (!timestamp) {
    return undefined
  } else {
    const date = new Date(timestamp)
    const day = String(date.getDate()).padStart(2, '0')
    const month = String(date.getMonth() + 1).padStart(2, '0') // Months are zero-based
    const year = date.getFullYear()

    return `${day}-${month}-${year}`
  }
}

export function dateDecode(date: number): Date {
  return date > 99990000 ? new Date(date / 10000000000, ((date / 100000000) % 100) - 1, (date / 1000000) % 100) : new Date(date / 10000, ((date / 100) % 100) - 1, date % 100)
}

export function dateEncode(date: Date): number {
  return date.getFullYear() * 10000 + (date.getMonth() + 1) * 100 + date.getDate()
}

export function offsetDate(date: number, offsetInDays: number): number {
  const result = new Date(dateDecode(date)) // Decode the date
  result.setDate(result.getDate() + offsetInDays) // Add or subtract the offset in days
  return dateEncode(result) // Encode it back to the required format
}