text: import isValidNumber from '../validate_'
  import parseDigits from '../helpers/parseDigits'
  
  import {
  	startsWith,
  	endsWith
  } from './util'
  
  /**
   * Leniency when finding potential phone numbers in text segments
   * The levels here are ordered in increasing strictness.
   */
  export default
  {
  	/**
  	 * Phone numbers accepted are "possible", but not necessarily "valid".
  	 */
  	POSSIBLE(number, candidate, metadata)
  	{
  		return true
  	},
  
  	/**
  	 * Phone numbers accepted are "possible" and "valid".
  	 * Numbers written in national format must have their national-prefix
  	 * present if it is usually written for a number of this type.
  	 */
  	VALID(number, candidate, metadata)
  	{
  		if (!isValidNumber(number, undefined, metadata) ||
  			!containsOnlyValidXChars(number, candidate.toString(), metadata))
  		{
  			return false
  		}
  
      // Skipped for simplicity.
  		// return isNationalPrefixPresentIfRequired(number, metadata)
      return true
    },
  
  	/**
  	 * Phone numbers accepted are "valid" and
  	 * are grouped in a possible way for this locale. For example, a US number written as
  	 * "65 02 53 00 00" and "650253 0000" are not accepted at this leniency level, whereas
  	 * "650 253 0000", "650 2530000" or "6502530000" are.
  	 * Numbers with more than one '/' symbol in the national significant number
  	 * are also dropped at this level.
  	 *
  	 * Warning: This level might result in lower coverage especially for regions outside of
  	 * country code "+1". If you are not sure about which level to use,
  	 * email the discussion group libphonenumber-discuss@googlegroups.com.
  	 */
  	STRICT_GROUPING(number, candidate, metadata, regExpCache)
  	{
  		const candidateString = candidate.toString()
  
  		if (!isValidNumber(number, undefined, metadata)
  			|| !containsOnlyValidXChars(number, candidateString, metadata)
  			|| containsMoreThanOneSlashInNationalNumber(number, candidateString)
  			|| !isNationalPrefixPresentIfRequired(number, metadata))
  		{
  			return false
  		}
  
  		return checkNumberGroupingIsValid
  		(
  			number,
  			candidate,
  			metadata,
  			allNumberGroupsRemainGrouped,
  			regExpCache
  		)
    },
  
  	/**
  	 * Phone numbers accepted are {@linkplain PhoneNumberUtil#isValidNumber(PhoneNumber) valid} and
  	 * are grouped in the same way that we would have formatted it, or as a single block. For
  	 * example, a US number written as "650 2530000" is not accepted at this leniency level, whereas
  	 * "650 253 0000" or "6502530000" are.
  	 * Numbers with more than one '/' symbol are also dropped at this level.
  	 * <p>
  	 * Warning: This level might result in lower coverage especially for regions outside of country
  	 * code "+1". If you are not sure about which level to use, email the discussion group
  	 * libphonenumber-discuss@googlegroups.com.
  	 */
  	EXACT_GROUPING(number, candidate, metadata, regExpCache)
  	{
  		const candidateString = candidate.toString()
  
  		if (!isValidNumber(number, undefined, metadata)
  			|| !containsOnlyValidXChars(number, candidateString, metadata)
  			|| containsMoreThanOneSlashInNationalNumber(number, candidateString)
  			|| !isNationalPrefixPresentIfRequired(number, metadata))
  		{
  			return false
  		}
  
  		return checkNumberGroupingIsValid
  		(
  			number,
  			candidate,
  			metadata,
  			allNumberGroupsAreExactlyPresent,
  			regExpCache
  		)
  	}
  }
  
  function containsOnlyValidXChars(number, candidate, metadata)
  {
    // The characters 'x' and 'X' can be (1) a carrier code, in which case they always precede the
    // national significant number or (2) an extension sign, in which case they always precede the
    // extension number. We assume a carrier code is more than 1 digit, so the first case has to
    // have more than 1 consecutive 'x' or 'X', whereas the second case can only have exactly 1 'x'
    // or 'X'. We ignore the character if it appears as the last character of the string.
    for (let index = 0; index < candidate.length - 1; index++)
    {
      const charAtIndex = candidate.charAt(index)
  
      if (charAtIndex === 'x' || charAtIndex === 'X')
      {
        const charAtNextIndex = candidate.charAt(index + 1)
  
        if (charAtNextIndex === 'x' || charAtNextIndex === 'X')
        {
          // This is the carrier code case, in which the 'X's always precede the national
          // significant number.
          index++
          if (util.isNumberMatch(number, candidate.substring(index)) != MatchType.NSN_MATCH)
          {
            return false
          }
  	      // This is the extension sign case, in which the 'x' or 'X' should always precede the
  	      // extension number.
        }
        else if (parseDigits(candidate.substring(index)) !== number.ext)
        {
          return false
        }
      }
    }
  
    return true
  }
  
  function isNationalPrefixPresentIfRequired(number, _metadata)
  {
    // First, check how we deduced the country code. If it was written in international format, then
    // the national prefix is not required.
    if (number.getCountryCodeSource() != 'FROM_DEFAULT_COUNTRY')
    {
      return true
    }
  
    const phoneNumberRegion = util.getRegionCodeForCountryCode(number.getCountryCode())
  
    const metadata = util.getMetadataForRegion(phoneNumberRegion)
    if (metadata == null)
    {
      return true
    }
  
    // Check if a national prefix should be present when formatting this number.
    const nationalNumber = util.getNationalSignificantNumber(number)
    const formatRule = util.chooseFormattingPatternForNumber(metadata.numberFormats(), nationalNumber)
  
    // To do this, we check that a national prefix formatting rule was present
    // and that it wasn't just the first-group symbol ($1) with punctuation.
    if (formatRule && formatRule.getNationalPrefixFormattingRule().length > 0)
    {
      if (formatRule.getNationalPrefixOptionalWhenFormatting())
      {
        // The national-prefix is optional in these cases, so we don't need to check if it was
        // present.
        return true
      }
  
      if (PhoneNumberUtil.formattingRuleHasFirstGroupOnly(
          formatRule.getNationalPrefixFormattingRule()))
      {
        // National Prefix not needed for this number.
        return true
      }
  
      // Normalize the remainder.
      const rawInputCopy = PhoneNumberUtil.normalizeDigitsOnly(number.getRawInput())
  
      // Check if we found a national prefix and/or carrier code at the start of the raw input, and
      // return the result.
      return util.maybeStripNationalPrefixAndCarrierCode(rawInputCopy, metadata, null)
    }
  
    return true
  }
  
  export function containsMoreThanOneSlashInNationalNumber(number, candidate)
  {
    const firstSlashInBodyIndex = candidate.indexOf('/')
    if (firstSlashInBodyIndex < 0)
    {
      // No slashes, this is okay.
      return false
    }
  
    // Now look for a second one.
    const secondSlashInBodyIndex = candidate.indexOf('/', firstSlashInBodyIndex + 1)
    if (secondSlashInBodyIndex < 0)
    {
      // Only one slash, this is okay.
      return false
    }
  
    // If the first slash is after the country calling code, this is permitted.
    const candidateHasCountryCode =
        (number.getCountryCodeSource() === CountryCodeSource.FROM_NUMBER_WITH_PLUS_SIGN
         || number.getCountryCodeSource() === CountryCodeSource.FROM_NUMBER_WITHOUT_PLUS_SIGN)
  
    if (candidateHasCountryCode
        && PhoneNumberUtil.normalizeDigitsOnly(candidate.substring(0, firstSlashInBodyIndex))
            === String(number.getCountryCode()))
    {
      // Any more slashes and this is illegal.
      return candidate.slice(secondSlashInBodyIndex + 1).indexOf('/') >= 0
    }
  
    return true
  }
  
  function checkNumberGroupingIsValid(
    number,
    candidate,
    metadata,
    checkGroups,
    regExpCache
  ) {
    const normalizedCandidate = normalizeDigits(candidate, true /* keep non-digits */)
    let formattedNumberGroups = getNationalNumberGroups(metadata, number, null)
    if (checkGroups(metadata, number, normalizedCandidate, formattedNumberGroups)) {
      return true
    }
  
    // If this didn't pass, see if there are any alternate formats that match, and try them instead.
    const alternateFormats = MetadataManager.getAlternateFormatsForCountry(number.getCountryCode())
    const nationalSignificantNumber = util.getNationalSignificantNumber(number)
  
    if (alternateFormats) {
      for (const alternateFormat of alternateFormats.numberFormats()) {
        if (alternateFormat.leadingDigitsPatterns().length > 0) {
          // There is only one leading digits pattern for alternate formats.
          const leadingDigitsRegExp = regExpCache.getPatternForRegExp('^' + alternateFormat.leadingDigitsPatterns()[0])
          if (!leadingDigitsRegExp.test(nationalSignificantNumber)) {
            // Leading digits don't match; try another one.
            continue
          }
        }
        formattedNumberGroups = getNationalNumberGroups(metadata, number, alternateFormat)
        if (checkGroups(metadata, number, normalizedCandidate, formattedNumberGroups)) {
          return true
        }
      }
    }
  
    return false
  }
  
  /**
   * Helper method to get the national-number part of a number, formatted without any national
   * prefix, and return it as a set of digit blocks that would be formatted together following
   * standard formatting rules.
   */
  function getNationalNumberGroups(
  	metadata,
  	number,
  	formattingPattern
  ) {
    if (formattingPattern) {
      // We format the NSN only, and split that according to the separator.
      const nationalSignificantNumber = util.getNationalSignificantNumber(number)
      return util.formatNsnUsingPattern(nationalSignificantNumber,
                                        formattingPattern, 'RFC3966', metadata).split('-')
  	}
  
    // This will be in the format +CC-DG1-DG2-DGX;ext=EXT where DG1..DGX represents groups of digits.
    const rfc3966Format = formatNumber(number, 'RFC3966', metadata)
  
    // We remove the extension part from the formatted string before splitting it into different
    // groups.
    let endIndex = rfc3966Format.indexOf(';')
    if (endIndex < 0) {
      endIndex = rfc3966Format.length
    }
  
    // The country-code will have a '-' following it.
    const startIndex = rfc3966Format.indexOf('-') + 1
    return rfc3966Format.slice(startIndex, endIndex).split('-')
  }
  
  function allNumberGroupsAreExactlyPresent
  (
  	metadata,
  	number,
  	normalizedCandidate,
  	formattedNumberGroups
  )
  {
    const candidateGroups = normalizedCandidate.split(NON_DIGITS_PATTERN)
  
    // Set this to the last group, skipping it if the number has an extension.
    let candidateNumberGroupIndex =
        number.hasExtension() ? candidateGroups.length - 2 : candidateGroups.length - 1
  
    // First we check if the national significant number is formatted as a block.
    // We use contains and not equals, since the national significant number may be present with
    // a prefix such as a national number prefix, or the country code itself.
    if (candidateGroups.length == 1
        || candidateGroups[candidateNumberGroupIndex].contains(
            util.getNationalSignificantNumber(number)))
    {
      return true
    }
  
    // Starting from the end, go through in reverse, excluding the first group, and check the
    // candidate and number groups are the same.
    let formattedNumberGroupIndex = (formattedNumberGroups.length - 1)
    while (formattedNumberGroupIndex > 0 && candidateNumberGroupIndex >= 0)
    {
      if (candidateGroups[candidateNumberGroupIndex] !== formattedNumberGroups[formattedNumberGroupIndex])
      {
        return false
      }
      formattedNumberGroupIndex--
      candidateNumberGroupIndex--
    }
  
    // Now check the first group. There may be a national prefix at the start, so we only check
    // that the candidate group ends with the formatted number group.
    return (candidateNumberGroupIndex >= 0
        && endsWith(candidateGroups[candidateNumberGroupIndex], formattedNumberGroups[0]))
  }
  
  
  function allNumberGroupsRemainGrouped
  (
  	metadata,
  	number,
  	normalizedCandidate,
  	formattedNumberGroups
  )
  {
    let fromIndex = 0
    if (number.getCountryCodeSource() !== CountryCodeSource.FROM_DEFAULT_COUNTRY)
    {
      // First skip the country code if the normalized candidate contained it.
      const countryCode = String(number.getCountryCode())
      fromIndex = normalizedCandidate.indexOf(countryCode) + countryCode.length()
    }
  
    // Check each group of consecutive digits are not broken into separate groupings in the
    // {@code normalizedCandidate} string.
    for (let i = 0; i < formattedNumberGroups.length; i++)
    {
      // Fails if the substring of {@code normalizedCandidate} starting from {@code fromIndex}
      // doesn't contain the consecutive digits in formattedNumberGroups[i].
      fromIndex = normalizedCandidate.indexOf(formattedNumberGroups[i], fromIndex)
      if (fromIndex < 0) {
        return false
      }
      // Moves {@code fromIndex} forward.
      fromIndex += formattedNumberGroups[i].length()
      if (i == 0 && fromIndex < normalizedCandidate.length())
      {
        // We are at the position right after the NDC. We get the region used for formatting
        // information based on the country code in the phone number, rather than the number itself,
        // as we do not need to distinguish between different countries with the same country
        // calling code and this is faster.
        const region = util.getRegionCodeForCountryCode(number.getCountryCode())
        if (util.getNddPrefixForRegion(region, true) != null
            && Character.isDigit(normalizedCandidate.charAt(fromIndex))) {
          // This means there is no formatting symbol after the NDC. In this case, we only
          // accept the number if there is no formatting symbol at all in the number, except
          // for extensions. This is only important for countries with national prefixes.
          const nationalSignificantNumber = util.getNationalSignificantNumber(number)
          return startsWith
          (
        	  normalizedCandidate.slice(fromIndex - formattedNumberGroups[i].length),
             nationalSignificantNumber
          )
        }
      }
    }
  
    // The check here makes sure that we haven't mistakenly already used the extension to
    // match the last group of the subscriber number. Note the extension cannot have
    // formatting in-between digits.
    return normalizedCandidate.slice(fromIndex).contains(number.getExtension())
  }