export const ONE_DAY = 24 * 60 * 60 * 1000

// format the date to the format we want
export const formatDate = (date: Date): string => {
  const year = date.getUTCFullYear()
  const month = (date.getUTCMonth() + 1 + '').padStart(2, '0')
  const day = (date.getUTCDate() + '').padStart(2, '0')
  return `${year}${month}${day}`
}

// get formated datestring of yesterday
export const yesterday = (date?: Date) => {
  date = date || new Date()
  date.setUTCDate(date.getUTCDate() - 1)
  return date
}

export const nextday = (date?: Date) => {
  date = date || new Date()
  date.setUTCDate(date.getUTCDate() + 1)
  return date
}

// calc days between two Date
export function daysBetween(date1: Date, date2: Date) {
  // hours*minutes*seconds*milliseconds
  const diffInMs = Math.abs(date1.getTime() - date2.getTime())
  const diffInDays = Math.round(diffInMs / ONE_DAY)
  return diffInDays
}

// get begin of one day
export const getDayBegin = (date: Date): Date => {
  let result = new Date(date.getTime())
  result.setUTCHours(0, 0, 0, 0)
  return result
}

// get begin of n day ago
export const getNDayAgo = (n: number, begin: boolean): Date => {
  const date = new Date(Date.now() - n * ONE_DAY)
  if (begin) {
    return getDayBegin(date)
  } else {
    return date
  }
}

// get begin of this month
export const getMonthBegin = (date: Date): Date => {
  const year = date.getUTCFullYear()
  const month = date.getUTCMonth()
  return new Date(year, month, 1)
}