/**
 * Support utilities for anonymising data
 *
 */
'use strict';

const _ = require('lodash');
const utils = require('../ComServe/utils.js');

module.exports = {
    anonymisePhoneNumber,
    anonymiseAccountNumber,
    anonymiseSortCode,
    anonymiseWorldpayServiceKey,
    anonymiseCardPAN,
    anonymiseMerchantID,
    anonymiseAccount,
    anonymiseDevice,
    anonymiseAddress,
    anonymiseKYC
};

/**
 * Helper function to anonymise a phone number.  This converts something like
 *    +441506592361
 * into
 *    +44 1*** ***361
 *
 * @param {string} phoneNumber  - the phone number string
 * @returns {string}            - the anonymised number
 */
function anonymisePhoneNumber(phoneNumber) {
    let tempString;

    /**
     * We display 8 digits, so make sure we aren't returning almost everything.
     */
    if (phoneNumber.length > 10) {
        tempString =
            phoneNumber.substr(0, 3) +
            ' ' +
            phoneNumber.substr(3, 1) +
            '*** ***' +
            phoneNumber.substr(-3);
    } else {
        /**
         * To short to be a good number, so just return an empty string (as if there was no number)
         */
        tempString = '';
    }

    return tempString;
}

/**
 * Anonymises an account number which is passed as a string.  It retains the last 3 characters
 * and adds 5 stars at the beginning regardless of actual length.
 *   - AccountNumber    12345678 => *****678
 *
 * @type {Function} anonymiseAccountNumber
 * @param {!string} accountNumber - Expected input is an 8 digit string.
 * @returns {!string} Anonymised account number.
 */
function anonymiseAccountNumber(accountNumber) {
    if (!accountNumber) {
        return '';
    }
    return ('*****' + accountNumber.substr(-3));
}

/**
 * Anonymises a sort code which is passed as a string.  It retains the last 2 characters
 * and adds 4 stars and dashes at the beginning regardless of actual length.
 *   - SortCode    12-34-56 => **-**-56
 *
 * @type {Function} anonymiseSortCode
 * @param {!string} sortCode - Expected input is an 8 character string.
 * @returns {!string} Anonymised sort code number.
 */
function anonymiseSortCode(sortCode) {
    if (!sortCode) {
        return '';
    }
    return ('**-**-' + sortCode.substr(-2));
}

/**
 * Anonymises a worldpay service key which is passed as a string.  It retains the first 1 and last 4 characters,
 * replaces all Hex characters with stars retaining dashes.
 *   - serviceKey T_S_713d2a60-a20b-4047-bc3a-3e863a11e414 => T_S_********-****-****-****-********e414
 * The function does not work with 8 or less characters so simply returns what it received.
 *
 * @type {Function} anonymiseWorldpayServiceKey
 * @param {!string} serviceKey - Expected input is an 40 character string.
 * @returns {!string} Anonymised card PAN.
 */
function anonymiseWorldpayServiceKey(serviceKey) {
    if (!serviceKey) {
        throw new Error('service key not set');
    }
    if ((/^(?:T_S_|T_C_|L_S_|L_C_)[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/.test(serviceKey))) {
        let anonServiceKey = serviceKey.slice(0);
        anonServiceKey = anonServiceKey.substr(0, 4) + '********-****-****-****-********' + anonServiceKey.substr(anonServiceKey.length - 4);
        return anonServiceKey;
    } else {
        throw new Error('service key not consistent with a Worldpay service key');
    }
}

/**
 * Anonymises a card PAN which is passed as a string.  It retains the first 1 and last 3 characters,
 * adds stars and spaces after every quad in the middle regardless of actual length.
 *   - CardPAN    0123 4567 8901 2345=> 0*** **** **** *345
 * The function does not work with 4 or less characters so simply returns what it received.
 *
 * @type {Function} anonymiseCardPAN
 * @param {!string} cardPAN - Expected input is an 8 character string.
 * @returns {!string} Anonymised card PAN.
 */
function anonymiseCardPAN(cardPAN) {
    if (!cardPAN) {
        throw new Error('cardPAN not set');
    }

    const tempCardPAN = cardPAN.slice(0).replace(/ /g, '');

    if (tempCardPAN.length < 5) {
        return tempCardPAN;
    }

    /**
     * CardPAN is not always 16 digits.
     */
    let anonPAN = tempCardPAN.substr(0, 1);
    for (let xx = 1; xx < tempCardPAN.length; xx++) {
        if ((xx % 4) === 0) {
            anonPAN += ' ';
        }
        if (xx > (tempCardPAN.length - 4)) {
            anonPAN += tempCardPAN.substr(xx, 1);
        } else {
            anonPAN += '*';
        }
    }

    return anonPAN;
}

/**
 * Anonymises a merchant acquirer ID which is passed as a string.  It retains the last 3 characters
 * and adds 5 stars at the beginning regardless of actual length.
 *   - AcquirerMerchantID    ABCDEFGH => *****FGH
 *
 * @type {Function} anonymiseMerchantID
 * @param {!string} merchantID - Expected input is an 8 digit string.
 * @returns {!string} Anonymised merchant ID.
 */
function anonymiseMerchantID(merchantID) {
    if (!merchantID) {
        return '';
    }
    return ('*****' + merchantID.substr(-3));
}

/**
 * Anonymises the given account by:
 * 1. Deleting any fields that are not appropriate for this type of account
 * 2. Anonymising any remaining fields.
 *
 * @param {Object} account  - the account object to anonymise
 * W074 cyclomatic complexity problem ignored on line.  Suspected software error.
 */
function anonymiseAccount(account) { // jshint ignore:line
    if (!account) {
        return;
    }

    const fields = ['AccountNumber', 'SortCode', 'CardPAN', 'AcquirerMerchantID'];
    const keep = [];

    switch (account.AccountType) {
        case utils.PaymentInstrumentType.CREDIT_DEBIT_PAYMENT_CARD:
            keep.push('CardPAN');
            break;
        case 'Bank Account':
            keep.push('AccountNumber');
            keep.push('SortCode');
            break;
        case 'Credit/Debit Receiving Account':
            keep.push('AcquirerMerchantID');
            break;
        default:
            // Not a known type, so delete everything.
            break;
    }

    _.forEach(
        fields,
        (value) => {
            if (keep.indexOf(value) === -1) {
                // Not in the keep list, so delete
                delete account[value];
            }
        });

    /**
     * Now anonymise anything that's left
     */
    if (account.AccountNumber !== undefined) {
        account.AccountNumber = anonymiseAccountNumber(account.AccountNumber);
    }
    if (account.SortCode !== undefined) {
        account.SortCode = anonymiseSortCode(account.SortCode);
    }
    if (account.AcquirerMerchantID !== undefined) {
        account.AcquirerMerchantID = anonymiseMerchantID(account.AcquirerMerchantID);
    }
}

/**
 * Anonymises the given device by:
 * 1. Anonymising fields as follows:
 * - DeviceNumber        => +44 7*** ***234
 *
 * @param {Object} device  - the device object to anonymise
 */
function anonymiseDevice(device) {
    if (!device) {
        return;
    }

    /**
     * Anonymise fields
     */
    if (device.DeviceNumber !== undefined) {
        device.DeviceNumber = anonymisePhoneNumber(device.DeviceNumber);
    }
}

/**
 * Anonymises the given address by:
 * 1. Anonymising fields as follows:
 * - PhoneNumber        => +44 1*** ***234
 *
 * @param {Object} address  - the address object to anonymise
 */
function anonymiseAddress(address) {
    if (!address) {
        return;
    }

    /**
     * Anonymise fields
     */
    if (address.PhoneNumber) {
        address.PhoneNumber = anonymisePhoneNumber(address.PhoneNumber);
    }
}

/**
 * Anonymises KYC data:
 * 1. Remove the date of birth
 *
 * @param {Object} kyc  - The object to be anonymised
 */
function anonymiseKYC(kyc) {
    if (!kyc) {
        return;
    }

    kyc.DateOfBirth = null;
}