import emailPipe from './emailPipe'

const asterisk = '*'
const dot = '.'
const emptyString = ''
const atSymbol = '@'
const caretTrap = '[]'
const space = ' '
const g = 'g'
const anyNonWhitespaceRegExp = /[^\s]/
const anyNonDotOrWhitespaceRegExp = /[^.\s]/
const allWhitespaceRegExp = /\s/g

function emailMask(rawValue, config) {
  rawValue = rawValue.replace(allWhitespaceRegExp, emptyString)

  const {placeholderChar, currentCaretPosition} = config
  const indexOfFirstAtSymbol = rawValue.indexOf(atSymbol)
  const indexOfLastDot = rawValue.lastIndexOf(dot)
  const indexOfTopLevelDomainDot = (indexOfLastDot < indexOfFirstAtSymbol) ? -1 : indexOfLastDot

  let localPartToDomainConnector = getConnector(rawValue, indexOfFirstAtSymbol + 1, atSymbol)
  let domainNameToTopLevelDomainConnector = getConnector(rawValue, indexOfTopLevelDomainDot - 1, dot)

  let localPart = getLocalPart(rawValue, indexOfFirstAtSymbol, placeholderChar)
  let domainName = getDomainName(rawValue, indexOfFirstAtSymbol, indexOfTopLevelDomainDot, placeholderChar)
  let topLevelDomain = getTopLevelDomain(rawValue, indexOfTopLevelDomainDot, placeholderChar, currentCaretPosition)

  localPart = convertToMask(localPart)
  domainName = convertToMask(domainName)
  topLevelDomain = convertToMask(topLevelDomain, true)

  const mask = localPart
    .concat(localPartToDomainConnector)
    .concat(domainName)
    .concat(domainNameToTopLevelDomainConnector)
    .concat(topLevelDomain)

  return mask
}

function getConnector(rawValue, indexOfConnection, connectionSymbol) {
  const connector = []

  if (rawValue[indexOfConnection] === connectionSymbol) {
    connector.push(connectionSymbol)
  } else {
    connector.push(caretTrap, connectionSymbol)
  }

  connector.push(caretTrap)

  return connector
}

function getLocalPart(rawValue, indexOfFirstAtSymbol) {
  if (indexOfFirstAtSymbol === -1) {
    return rawValue
  } else {
    return rawValue.slice(0, indexOfFirstAtSymbol)
  }
}

function getDomainName(rawValue, indexOfFirstAtSymbol, indexOfTopLevelDomainDot, placeholderChar) {
  let domainName = emptyString

  if (indexOfFirstAtSymbol !== -1) {
    if (indexOfTopLevelDomainDot === -1) {
      domainName = rawValue.slice(indexOfFirstAtSymbol + 1, rawValue.length)
    } else {
      domainName = rawValue.slice(indexOfFirstAtSymbol + 1, indexOfTopLevelDomainDot)
    }
  }

  domainName = domainName.replace(new RegExp(`[\\s${placeholderChar}]`, g), emptyString)

  if (domainName === atSymbol) {
    return asterisk
  } else if (domainName.length < 1) {
    return space
  } else if (domainName[domainName.length - 1] === dot) {
    return domainName.slice(0, domainName.length - 1)
  } else {
    return domainName
  }
}

function getTopLevelDomain(rawValue, indexOfTopLevelDomainDot, placeholderChar, currentCaretPosition) {
  let topLevelDomain = emptyString

  if (indexOfTopLevelDomainDot !== -1) {
    topLevelDomain = rawValue.slice(indexOfTopLevelDomainDot + 1, rawValue.length)
  }

  topLevelDomain = topLevelDomain.replace(new RegExp(`[\\s${placeholderChar}.]`, g), emptyString)

  if (topLevelDomain.length === 0) {
    return (rawValue[indexOfTopLevelDomainDot - 1] === dot && currentCaretPosition !== rawValue.length) ?
      asterisk :
      emptyString
  } else {
    return topLevelDomain
  }
}

function convertToMask(str, noDots) {
  return str
    .split(emptyString)
    .map((char) => char === space ? char : (noDots) ? anyNonDotOrWhitespaceRegExp : anyNonWhitespaceRegExp)
}

export default {mask: emailMask, pipe: emailPipe}