const UserError = require('vn-loopback/util/user-error');
const OTP_CHAR = ':';
function original({id, phone}) {
    // Suma el número de teléfono y el número aleatorio
    let suma = parseInt(phone) + parseInt(id);

    // Convierte la suma a una cadena y toma solo los últimos 6 dígitos
    let resultado = suma.toString().slice(-6);

    // Devuelve los últimos 6 dígitos
    return parseInt(resultado); // Devolvemos un número entero, no una cadena
}
function reverse(params) {
    const _original = original(params);
    return parseInt(_original.toString().split('').reverse().join(''));
}

function generateOTP(params, _otpType) {
    const otpIndex = Math.floor(Math.random() * Object.keys(OTP_TYPES).length);
    const otpType = _otpType ?? Object.keys(OTP_TYPES)[otpIndex];
    const otp = OTP_TYPES[otpType](params);
    return formatOTP(otpType, otp);
}

function formatOTP(otpType, otpValue) {
    return `${otpType}${OTP_CHAR}${otpValue}`;
}

function checkOTP(params, otp) {
    const [otpType, value] = otp.split(OTP_CHAR);
    return generateOTP(params, otpType) === formatOTP(otpType, value);
}

const OTP_TYPES = {
    // 'A': original,
    'B': reverse,
};
module.exports = Self => {
    Self.remoteMethod('recoverPasswordSMS', {
        description: 'Send SMS to the user',
        accepts: [
            {
                arg: 'ctx',
                type: 'Object',
                http: {source: 'context'}
            },
            {
                arg: 'id',
                type: 'string',
                description: 'The user id',
                required: true
            },
            {
                arg: 'phone',
                type: 'string',
                description: 'The user name or email',
                required: true
            },
            {
                arg: 'otp',
                type: 'string',
                description: 'The directory for mail'
            }
        ],
        returns: {
            type: 'Object',
            root: true
        },
        http: {
            path: `/recoverPasswordSMS`,
            verb: 'POST'
        }
    });

    Self.recoverPasswordSMS = async function(ctx, id, phone, otp) {
        const usesPhone = new RegExp(/([+]\d{2})?\d{9}/, 'g').test(+phone);

        if (!usesPhone) throw new UserError('Phone not valid');

        let query = {
            fields: ['id', 'phone', 'email'],
            where: {id, phone}
        };

        const user = await Self.findOne(query);
        if (!user) throw new UserError('Credentials not valid');

        try {
            if (otp) {
                return {
                    valid: checkOTP(query.where, otp),
                    token: await user.accessTokens.create({})
                };
            }
            return {otp: generateOTP(query.where)};
        } catch (err) {
            if (err.code === 'EMAIL_NOT_FOUND')
                return;
            else
                throw err;
        }
    };
};