import { decodeProto, TYPES } from "../../lib/protobuf-decoder/protobufDecoder";
import { TOTP } from "../../lib/totp-quickjs";
import { base64decode, encode } from "../../lib/totp-quickjs/base32decoder";

const otpauthScheme = "otpauth:/";
const googleMigrationScheme = "otpauth-migration:/";

export function getTOTPByLink(link) {
    if (link.includes(otpauthScheme)) return getByOtpauthScheme(link);
    if (link.includes(googleMigrationScheme))
        return getByGoogleMigrationScheme(link);

    return null;
}

function getHashType(algorithm) {
    if (algorithm == "SHA1") return "SHA-1";
    if (algorithm == "SHA256") return "SHA-256";
    if (algorithm == "SHA512") return "SHA-512";
    else return "SHA-1";
}

function getByOtpauthScheme(link) {
    try {
        let args = link.split("/", otpauthScheme.length);
        let type = args[2]; //Returns 'hotp' or 'totp'
        let issuer = args[3].split(":")[0]?.split("?")[0]; //Returns issuer
        let client =
            args[3].split(":")[1]?.split("?")[0] ??
            args[3].split(":")[0]?.split("?")[0]; //Returns client
        let secret = args[3].split("secret=")[1]?.split("&")[0]; //Returns secret
        let period = args[3].split("period=")[1]?.split("&")[0]; //Returns period
        let digits = args[3].split("digit=")[1]?.split("&")[0]; //Returns digits
        let algorithm = args[3].split("algorithm=")[1]?.split("&")[0]; //Returns algorithm
        let offset = args[3].split("offset=")[1]?.split("&")[0] ?? 0; //Returns offset

        if (type.toLowerCase() != "totp")
            throw new Error("Type is not valid, requires 'TOTP'");

        if (secret === undefined) throw new Error("Secret not defined");

        if (issuer == client) {
            issuer = args[3].split("issuer=")[1]?.split("&")[0];
        }

        issuer = decodeURIComponent(issuer);
        client = decodeURIComponent(client);

        return new TOTP(
            secret,
            issuer,
            client,
            Number(digits),
            Number(period),
            Number(offset),
            getHashType(algorithm),
        );
    } catch (err) {
        console.log(`ERR: ${err}`);
        return null;
    }
}

function getByGoogleMigrationScheme(link) {
    let data = link.split("data=")[1]; //Returns base64 encoded data
    data = decodeURIComponent(data);
    let decode = base64decode(data);
    let proto = decodeProto(decode);

    let protoTotps = [];

    proto.parts.forEach((part) => {
        if (part.type == TYPES.LENDELIM) {
            protoTotps.push(decodeProto(part.value));
        }
    });

    let totps = [];
    protoTotps.forEach((x) => {
        let type = x.parts.filter((x) => x.index == 6)[0]; //find type of OTP
        if (type.value !== "2") {
            console.log("ERR: it's a not TOTP record");
            return;
        }
        let secret = x.parts.filter((x) => x.index == 1)[0].value;
        secret = encode(secret);

        let name = bytesToString(x.parts.filter((x) => x.index == 2)[0].value);
        let issuer = bytesToString(
            x.parts.filter((x) => x.index == 3)[0].value,
        );

        totps.push(new TOTP(secret, issuer, name, 6, 30, 0, "SHA-1"));
    });

    return totps;
}

function bytesToString(bytes) {
    let str = "";
    for (let i = 0; i < bytes.length; i++) {
        str += String.fromCharCode(bytes[i]);
    }
    return str;
}