// tslint:disable:no-bitwise
/**
 * Original work Copyright (c) 2018 PoC-Consortium
 * Modified work Copyright (c) 2019 Burst Apps Team
 */

import {initialCodeword, alphabet, cwmap, gexp, gmult, AddressPrefix} from './internal';


// TODO: should be split into separate file and get better naming
/**
 * @internal
 * Check for valid Burst address (format: BURST-XXXX-XXXX-XXXX-XXXXX)
 * @param {string} address The address
 * @return {boolean} true, if is a valid address, else false
 * @module util
 */
export const isValid = (address: string): boolean => {
    if (address.indexOf(`${AddressPrefix}-`) === 0) {
        address = address.substr(6);
    }

    const codeword = initialCodeword.slice();
    let codewordLength = 0;

    for (let i = 0; i < address.length; i++) {
        const pos = alphabet.indexOf(address.charAt(i));

        if (pos <= -1 || pos > alphabet.length) {
            continue;
        }

        if (codewordLength > 16) {
            return false;
        }

        const codeworkIndex = cwmap[codewordLength];
        codeword[codeworkIndex] = pos;
        codewordLength++;
    }

    if (codewordLength !== 17) {
        return false;
    }

    let sum = 0;

    for (let i = 1; i < 5; i++) {
        let t = 0;

        for (let j = 0; j < 31; j++) {
            if (j > 12 && j < 27) {
                continue;
            }

            let pos = j;
            if (j > 26) {
                pos -= 14;
            }

            t ^= gmult(codeword[pos], gexp[(i * j) % 31]);
        }

        sum |= t;
    }

    return (sum === 0);
};

// TODO: make this deprectated in favor of Address in core package
/**
 * Check for valid Burst address (format: BURST-XXXX-XXXX-XXXX-XXXXX)
 * @param {string} address The address
 * @return {boolean} true, if is a valid address, else false
 * @module util
 */
export const isBurstAddress = (address: string): boolean => {
    const addressRegExp = new RegExp(`${AddressPrefix}\-[A-Z0-9]{4}\-[A-Z0-9]{4}\-[A-Z0-9]{4}\-[A-Z0-9]{5}(-\w+)?`, 'i');

    if (!addressRegExp.test(address)) {
        return false;
    }

    const index = address.lastIndexOf('-');
    const extension = address.substr(index + 1);
    const hasExtension = extension.length > 5;
    address = hasExtension ? address.substr(0, index ) : address;

    // ignoring public key validation as this is involved crypto package.

    return isValid(address);
};