// Copyright 2017 Joyent, Inc.

module.exports = {

read: read,
write: write

};

var assert = require('assert-plus'); var Buffer = require('safer-buffer').Buffer; var Key = require('../key'); var PrivateKey = require('../private-key'); var utils = require('../utils'); var SSHBuffer = require('../ssh-buffer'); var Dhe = require('../dhe');

var supportedAlgos = {

'rsa-sha1' : 5,
'rsa-sha256' : 8,
'rsa-sha512' : 10,
'ecdsa-p256-sha256' : 13,
'ecdsa-p384-sha384' : 14
/*
 * ed25519 is hypothetically supported with id 15
 * but the common tools available don't appear to be
 * capable of generating/using ed25519 keys
 */

};

var supportedAlgosById = {}; Object.keys(supportedAlgos).forEach(function (k) {

supportedAlgosById[supportedAlgos[k]] = k.toUpperCase();

});

function read(buf, options) {

if (typeof (buf) !== 'string') {
        assert.buffer(buf, 'buf');
        buf = buf.toString('ascii');
}
var lines = buf.split('\n');
if (lines[0].match(/^Private-key-format\: v1/)) {
        var algElems = lines[1].split(' ');
        var algoNum = parseInt(algElems[1], 10);
        var algoName = algElems[2];
        if (!supportedAlgosById[algoNum])
                throw (new Error('Unsupported algorithm: ' + algoName));
        return (readDNSSECPrivateKey(algoNum, lines.slice(2)));
}

// skip any comment-lines
var line = 0;
/* JSSTYLED */
while (lines[line].match(/^\;/))
        line++;
// we should now have *one single* line left with our KEY on it.
if ((lines[line].match(/\. IN KEY /) ||
    lines[line].match(/\. IN DNSKEY /)) && lines[line+1].length === 0) {
        return (readRFC3110(lines[line]));
}
throw (new Error('Cannot parse dnssec key'));

}

function readRFC3110(keyString) {

var elems = keyString.split(' ');
//unused var flags = parseInt(elems[3], 10);
//unused var protocol = parseInt(elems[4], 10);
var algorithm = parseInt(elems[5], 10);
if (!supportedAlgosById[algorithm])
        throw (new Error('Unsupported algorithm: ' + algorithm));
var base64key = elems.slice(6, elems.length).join();
var keyBuffer = Buffer.from(base64key, 'base64');
if (supportedAlgosById[algorithm].match(/^RSA-/)) {
        // join the rest of the body into a single base64-blob
        var publicExponentLen = keyBuffer.readUInt8(0);
        if (publicExponentLen != 3 && publicExponentLen != 1)
                throw (new Error('Cannot parse dnssec key: ' +
                    'unsupported exponent length'));

        var publicExponent = keyBuffer.slice(1, publicExponentLen+1);
        publicExponent = utils.mpNormalize(publicExponent);
        var modulus = keyBuffer.slice(1+publicExponentLen);
        modulus = utils.mpNormalize(modulus);
        // now, make the key
        var rsaKey = {
                type: 'rsa',
                parts: []
        };
        rsaKey.parts.push({ name: 'e', data: publicExponent});
        rsaKey.parts.push({ name: 'n', data: modulus});
        return (new Key(rsaKey));
}
if (supportedAlgosById[algorithm] === 'ECDSA-P384-SHA384' ||
    supportedAlgosById[algorithm] === 'ECDSA-P256-SHA256') {
        var curve = 'nistp384';
        var size = 384;
        if (supportedAlgosById[algorithm].match(/^ECDSA-P256-SHA256/)) {
                curve = 'nistp256';
                size = 256;
        }

        var ecdsaKey = {
                type: 'ecdsa',
                curve: curve,
                size: size,
                parts: [
                        {name: 'curve', data: Buffer.from(curve) },
                        {name: 'Q', data: utils.ecNormalize(keyBuffer) }
                ]
        };
        return (new Key(ecdsaKey));
}
throw (new Error('Unsupported algorithm: ' +
    supportedAlgosById[algorithm]));

}

function elementToBuf(e) {

return (Buffer.from(e.split(' ')[1], 'base64'));

}

function readDNSSECRSAPrivateKey(elements) {

var rsaParams = {};
elements.forEach(function (element) {
        if (element.split(' ')[0] === 'Modulus:')
                rsaParams['n'] = elementToBuf(element);
        else if (element.split(' ')[0] === 'PublicExponent:')
                rsaParams['e'] = elementToBuf(element);
        else if (element.split(' ')[0] === 'PrivateExponent:')
                rsaParams['d'] = elementToBuf(element);
        else if (element.split(' ')[0] === 'Prime1:')
                rsaParams['p'] = elementToBuf(element);
        else if (element.split(' ')[0] === 'Prime2:')
                rsaParams['q'] = elementToBuf(element);
        else if (element.split(' ')[0] === 'Exponent1:')
                rsaParams['dmodp'] = elementToBuf(element);
        else if (element.split(' ')[0] === 'Exponent2:')
                rsaParams['dmodq'] = elementToBuf(element);
        else if (element.split(' ')[0] === 'Coefficient:')
                rsaParams['iqmp'] = elementToBuf(element);
});
// now, make the key
var key = {
        type: 'rsa',
        parts: [
                { name: 'e', data: utils.mpNormalize(rsaParams['e'])},
                { name: 'n', data: utils.mpNormalize(rsaParams['n'])},
                { name: 'd', data: utils.mpNormalize(rsaParams['d'])},
                { name: 'p', data: utils.mpNormalize(rsaParams['p'])},
                { name: 'q', data: utils.mpNormalize(rsaParams['q'])},
                { name: 'dmodp',
                    data: utils.mpNormalize(rsaParams['dmodp'])},
                { name: 'dmodq',
                    data: utils.mpNormalize(rsaParams['dmodq'])},
                { name: 'iqmp',
                    data: utils.mpNormalize(rsaParams['iqmp'])}
        ]
};
return (new PrivateKey(key));

}

function readDNSSECPrivateKey(alg, elements) {

if (supportedAlgosById[alg].match(/^RSA-/)) {
        return (readDNSSECRSAPrivateKey(elements));
}
if (supportedAlgosById[alg] === 'ECDSA-P384-SHA384' ||
    supportedAlgosById[alg] === 'ECDSA-P256-SHA256') {
        var d = Buffer.from(elements[0].split(' ')[1], 'base64');
        var curve = 'nistp384';
        var size = 384;
        if (supportedAlgosById[alg] === 'ECDSA-P256-SHA256') {
                curve = 'nistp256';
                size = 256;
        }
        // DNSSEC generates the public-key on the fly (go calculate it)
        var publicKey = utils.publicFromPrivateECDSA(curve, d);
        var Q = publicKey.part['Q'].data;
        var ecdsaKey = {
                type: 'ecdsa',
                curve: curve,
                size: size,
                parts: [
                        {name: 'curve', data: Buffer.from(curve) },
                        {name: 'd', data: d },
                        {name: 'Q', data: Q }
                ]
        };
        return (new PrivateKey(ecdsaKey));
}
throw (new Error('Unsupported algorithm: ' + supportedAlgosById[alg]));

}

function dnssecTimestamp(date) {

var year = date.getFullYear() + ''; //stringify
var month = (date.getMonth() + 1);
var timestampStr = year + month + date.getUTCDate();
timestampStr += '' + date.getUTCHours() + date.getUTCMinutes();
timestampStr += date.getUTCSeconds();
return (timestampStr);

}

function rsaAlgFromOptions(opts) {

if (!opts || !opts.hashAlgo || opts.hashAlgo === 'sha1')
        return ('5 (RSASHA1)');
else if (opts.hashAlgo === 'sha256')
        return ('8 (RSASHA256)');
else if (opts.hashAlgo === 'sha512')
        return ('10 (RSASHA512)');
else
        throw (new Error('Unknown or unsupported hash: ' +
            opts.hashAlgo));

}

function writeRSA(key, options) {

// if we're missing parts, add them.
if (!key.part.dmodp || !key.part.dmodq) {
        utils.addRSAMissing(key);
}

var out = '';
out += 'Private-key-format: v1.3\n';
out += 'Algorithm: ' + rsaAlgFromOptions(options) + '\n';
var n = utils.mpDenormalize(key.part['n'].data);
out += 'Modulus: ' + n.toString('base64') + '\n';
var e = utils.mpDenormalize(key.part['e'].data);
out += 'PublicExponent: ' + e.toString('base64') + '\n';
var d = utils.mpDenormalize(key.part['d'].data);
out += 'PrivateExponent: ' + d.toString('base64') + '\n';
var p = utils.mpDenormalize(key.part['p'].data);
out += 'Prime1: ' + p.toString('base64') + '\n';
var q = utils.mpDenormalize(key.part['q'].data);
out += 'Prime2: ' + q.toString('base64') + '\n';
var dmodp = utils.mpDenormalize(key.part['dmodp'].data);
out += 'Exponent1: ' + dmodp.toString('base64') + '\n';
var dmodq = utils.mpDenormalize(key.part['dmodq'].data);
out += 'Exponent2: ' + dmodq.toString('base64') + '\n';
var iqmp = utils.mpDenormalize(key.part['iqmp'].data);
out += 'Coefficient: ' + iqmp.toString('base64') + '\n';
// Assume that we're valid as-of now
var timestamp = new Date();
out += 'Created: ' + dnssecTimestamp(timestamp) + '\n';
out += 'Publish: ' + dnssecTimestamp(timestamp) + '\n';
out += 'Activate: ' + dnssecTimestamp(timestamp) + '\n';
return (Buffer.from(out, 'ascii'));

}

function writeECDSA(key, options) {

var out = '';
out += 'Private-key-format: v1.3\n';

if (key.curve === 'nistp256') {
        out += 'Algorithm: 13 (ECDSAP256SHA256)\n';
} else if (key.curve === 'nistp384') {
        out += 'Algorithm: 14 (ECDSAP384SHA384)\n';
} else {
        throw (new Error('Unsupported curve'));
}
var base64Key = key.part['d'].data.toString('base64');
out += 'PrivateKey: ' + base64Key + '\n';

// Assume that we're valid as-of now
var timestamp = new Date();
out += 'Created: ' + dnssecTimestamp(timestamp) + '\n';
out += 'Publish: ' + dnssecTimestamp(timestamp) + '\n';
out += 'Activate: ' + dnssecTimestamp(timestamp) + '\n';

return (Buffer.from(out, 'ascii'));

}

function write(key, options) {

if (PrivateKey.isPrivateKey(key)) {
        if (key.type === 'rsa') {
                return (writeRSA(key, options));
        } else if (key.type === 'ecdsa') {
                return (writeECDSA(key, options));
        } else {
                throw (new Error('Unsupported algorithm: ' + key.type));
        }
} else if (Key.isKey(key)) {
        /*
         * RFC3110 requires a keyname, and a keytype, which we
         * don't really have a mechanism for specifying such
         * additional metadata.
         */
        throw (new Error('Format "dnssec" only supports ' +
            'writing private keys'));
} else {
        throw (new Error('key is not a Key or PrivateKey'));
}

}