/**
 * This file is a copy of validator.js isEmail method - v13.7.0:
 * https://github.com/validatorjs/validator.js/blob/531dc7f1f75613bec75c6d888b46480455e78dc7/src/lib/isEmail.js
 */
/* eslint-disable camelcase */
const assertString = require('./util/assert-string');
const merge = require('./util/merge');
const isByteLength = require('./is-byte-length');
const isFQDN = require('./is-fqdn');
const isIP = require('./is-ip');

const default_email_options = {
    allow_display_name: false,
    require_display_name: false,
    allow_utf8_local_part: true,
    require_tld: true,
    blacklisted_chars: '',
    ignore_max_length: false,
    host_blacklist: [],
    host_whitelist: []
};

/* eslint-disable max-len */
/* eslint-disable no-control-regex */
const splitNameAddress = /^([^\x00-\x1F\x7F-\x9F\cX]+)</i;
const emailUserPart = /^[a-z\d!#$%&'*+\-/=?^_`{|}~]+$/i;
const gmailUserPart = /^[a-z\d]+$/;
const quotedEmailUser = /^([\s\x01-\x08\x0b\x0c\x0e-\x1f\x7f\x21\x23-\x5b\x5d-\x7e]|(\\[\x01-\x09\x0b\x0c\x0d-\x7f]))*$/i;
const emailUserUtf8Part = /^[a-z\d!#$%&'*+\-/=?^_`{|}~\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]+$/i;
const quotedEmailUserUtf8 = /^([\s\x01-\x08\x0b\x0c\x0e-\x1f\x7f\x21\x23-\x5b\x5d-\x7e\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]|(\\[\x01-\x09\x0b\x0c\x0d-\x7f\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]))*$/i;
const defaultMaxEmailLength = 254;
/* eslint-enable max-len */
/* eslint-enable no-control-regex */

/**
 * Validate display name according to the RFC2822: https://tools.ietf.org/html/rfc2822#appendix-A.1.2
 * @param {String} display_name
 */
function validateDisplayName(display_name) {
    const display_name_without_quotes = display_name.replace(/^"(.+)"$/, '$1');
    // display name with only spaces is not valid
    if (!display_name_without_quotes.trim()) {
        return false;
    }

    // check whether display name contains illegal character
    const contains_illegal = /[.";<>]/.test(display_name_without_quotes);
    if (contains_illegal) {
        // if contains illegal characters,
        // must to be enclosed in double-quotes, otherwise it's not a valid display name
        if (display_name_without_quotes === display_name) {
            return false;
        }

        // the quotes in display name must start with character symbol \
        const all_start_with_back_slash =
            display_name_without_quotes.split('"').length === display_name_without_quotes.split('\\"').length;
        if (!all_start_with_back_slash) {
            return false;
        }
    }

    return true;
}

module.exports = function isEmail(str, options) {
    assertString(str);
    options = merge(options, default_email_options);

    if (options.require_display_name || options.allow_display_name) {
        const display_email = str.match(splitNameAddress);
        if (display_email) {
            let display_name = display_email[1];

            // Remove display name and angle brackets to get email address
            // Can be done in the regex but will introduce a ReDOS (See  #1597 for more info)
            str = str.replace(display_name, '').replace(/(^<|>$)/g, '');

            // sometimes need to trim the last space to get the display name
            // because there may be a space between display name and email address
            // eg. myname <address@gmail.com>
            // the display name is `myname` instead of `myname `, so need to trim the last space
            if (display_name.endsWith(' ')) {
                display_name = display_name.slice(0, -1);
            }

            if (!validateDisplayName(display_name)) {
                return false;
            }
        } else if (options.require_display_name) {
            return false;
        }
    }
    if (!options.ignore_max_length && str.length > defaultMaxEmailLength) {
        return false;
    }

    const parts = str.split('@');
    const domain = parts.pop();
    const lower_domain = domain.toLowerCase();

    if (options.host_blacklist.includes(lower_domain)) {
        return false;
    }

    if (options.host_whitelist.length > 0 && !options.host_whitelist.includes(lower_domain)) {
        return false;
    }

    let user = parts.join('@');

    if (options.domain_specific_validation && (lower_domain === 'gmail.com' || lower_domain === 'googlemail.com')) {
        /*
          Previously we removed dots for gmail addresses before validating.
          This was removed because it allows `multiple..dots@gmail.com`
          to be reported as valid, but it is not.
          Gmail only normalizes single dots, removing them from here is pointless,
          should be done in normalizeEmail
        */
        user = user.toLowerCase();

        // Removing sub-address from username before gmail validation
        const username = user.split('+')[0];

        // Dots are not included in gmail length restriction
        if (!isByteLength(username.replace(/\./g, ''), {min: 6, max: 30})) {
            return false;
        }

        const user_parts = username.split('.');
        for (let i = 0; i < user_parts.length; i++) {
            if (!gmailUserPart.test(user_parts[i])) {
                return false;
            }
        }
    }

    if (options.ignore_max_length === false && (
        !isByteLength(user, {max: 64}) ||
        !isByteLength(domain, {max: 254}))
    ) {
        return false;
    }

    if (!isFQDN(domain, {require_tld: options.require_tld})) {
        if (!options.allow_ip_domain) {
            return false;
        }

        if (!isIP(domain)) {
            if (!domain.startsWith('[') || !domain.endsWith(']')) {
                return false;
            }

            let noBracketdomain = domain.slice(1, -1);

            if (noBracketdomain.length === 0 || !isIP(noBracketdomain)) {
                return false;
            }
        }
    }

    if (user[0] === '"') {
        user = user.slice(1, user.length - 1);
        return options.allow_utf8_local_part ?
            quotedEmailUserUtf8.test(user) :
            quotedEmailUser.test(user);
    }

    const pattern = options.allow_utf8_local_part ?
        emailUserUtf8Part : emailUserPart;

    const user_parts = user.split('.');
    for (let i = 0; i < user_parts.length; i++) {
        if (!pattern.test(user_parts[i])) {
            return false;
        }
    }
    if (options.blacklisted_chars) {
        if (user.search(new RegExp(`[${options.blacklisted_chars}]+`, 'g')) !== -1) {
            return false;
        }
    }

    return true;
};