'use strict';

var Message = Message || require('./Message');

var RootCerts = require('./common/RootCerts');

var PayPro = require('./common/PayPro');

var asn1 = require('asn1.js');
var rfc3280 = require('asn1.js/rfc/3280');
var rfc5280 = require('asn1.js/rfc/5280');

PayPro.prototype.x509Sign = function(key) {
  var self = this;
  var crypto = require('crypto');
  var pki_type = this.get('pki_type');
  var pki_data = this.get('pki_data'); // contains one or more x509 certs
  pki_data = PayPro.X509Certificates.decode(pki_data);
  pki_data = pki_data.certificate;
  var details = this.get('serialized_payment_details');
  var type = pki_type.split('+')[1].toUpperCase();

  var trusted = pki_data.map(function(cert) {
    var der = cert.toString('hex');
    var pem = self._DERtoPEM(der, 'CERTIFICATE');
    return RootCerts.getTrusted(pem);
  });

  // XXX Figure out what to do here
  if (!trusted.length) {
    // throw new Error('Unstrusted certificate.');
  } else {
    trusted.forEach(function(name) {
      // console.log('Certificate: %s', name);
    });
  }

  var signature = crypto.createSign('RSA-' + type);
  var buf = this.serializeForSig();
  signature.update(buf);
  var sig = signature.sign(key);
  return sig;
};

PayPro.prototype.x509Verify = function() {
  var self = this;
  var crypto = require('crypto');
  var pki_type = this.get('pki_type');
  var sig = this.get('signature');
  var pki_data = this.get('pki_data');
  pki_data = PayPro.X509Certificates.decode(pki_data);
  pki_data = pki_data.certificate;
  var details = this.get('serialized_payment_details');
  var buf = this.serializeForSig();
  var type = pki_type.split('+')[1].toUpperCase();

  var verifier = crypto.createVerify('RSA-' + type);
  verifier.update(buf);

  var signedCert = pki_data[0];
  var der = signedCert.toString('hex');
  var pem = this._DERtoPEM(der, 'CERTIFICATE');
  var verified = verifier.verify(pem, sig);

  var chain = pki_data;

  var chainVerified = chain.every(function(cert, i) {
    var der = cert.toString('hex');
    var pem = self._DERtoPEM(der, 'CERTIFICATE');
    var name = RootCerts.getTrusted(pem);

    var ncert = chain[i + 1];
    // The root cert, check if it's trusted:
    if (!ncert || name) {
      if (!ncert && !name) {
        return false;
      }
      chain.length = 0;
      return true;
    }
    var nder = ncert.toString('hex');
    var npem = self._DERtoPEM(nder, 'CERTIFICATE');

    //
    // Get Public Key from next certificate:
    //
    var ndata = new Buffer(nder, 'hex');
    var nc = rfc3280.Certificate.decode(ndata, 'der');
    var npubKeyAlg = PayPro.getAlgorithm(
      nc.tbsCertificate.subjectPublicKeyInfo.algorithm.algorithm);
    var npubKey = nc.tbsCertificate.subjectPublicKeyInfo.subjectPublicKey.data;
    npubKey = self._DERtoPEM(npubKey, npubKeyAlg + ' PUBLIC KEY');

    //
    // Get Signature Value from current certificate:
    //
    var data = new Buffer(der, 'hex');
    var c = rfc3280.Certificate.decode(data, 'der');
    var sigAlg = PayPro.getAlgorithm(c.signatureAlgorithm.algorithm, 1);
    var sig = c.signature.data;

    //
    // Check Validity of Certificates
    //
    var validityVerified = true;
    var now = Date.now();
    var cBefore = c.tbsCertificate.validity.notBefore.value;
    var cAfter = c.tbsCertificate.validity.notAfter.value;
    var nBefore = nc.tbsCertificate.validity.notBefore.value;
    var nAfter = nc.tbsCertificate.validity.notAfter.value;
    if (cBefore > now || cAfter < now || nBefore > now || nAfter < now) {
      validityVerified = false;
    }

    //
    // Check the Issuer matches the Subject of the next certificate:
    //
    var issuer = c.tbsCertificate.issuer;
    var subject = nc.tbsCertificate.subject;
    var issuerVerified = issuer.type === subject.type && issuer.value.every(function(issuerArray, i) {
      var subjectArray = subject.value[i];
      return issuerArray.every(function(issuerObject, i) {
        var subjectObject = subjectArray[i];

        var issuerObjectType = issuerObject.type.join('.');
        var subjectObjectType = subjectObject.type.join('.');

        var issuerObjectValue = issuerObject.value.toString('hex');
        var subjectObjectValue = subjectObject.value.toString('hex');

        return issuerObjectType === subjectObjectType
          && issuerObjectValue === subjectObjectValue;
      });
    });

    //
    // Verify current certificate signature
    //

    // Grab the raw DER To-Be-Signed Certificate to verify:
    // First 10 bytes usually look like:
    // [ 48, 130, 5, 32, 48, 130, 4, 8, 160, 3 ]
    var start = 0;
    var starts = 0;
    for (var start = 0; start < data.length; start++) {
      if (starts === 1 && data[start] === 48) {
        break;
      }
      if (starts < 1 && data[start] === 48) {
        starts++;
      }
    }

    // The bytes *after* the TBS (including the last TBS byte) will look like
    // (note the 48 - the start of the sig, and the 122 - the end of the TBS):
    // [ 122, 48, 13, 6, 9, 42, 134, 72, 134, 247, 13, 1, 1, 11, 5, 0, 3, ... ]

    // The certificate in these examples has a `start` of 4, and an `end` of
    // 1040. The 4 bytes is the DER SEQ of the Certificate, right before the
    // SEQ of the TBSCertificate.

    var end = 0;
    var ends = 0;
    for (var end = data.length - 1; end > 0; end--) {
      if (ends === 2 && data[end] === 48) {
        break;
      }
      if (ends < 2 && data[end] === 0) {
        ends++;
      }
    }

    console.log(Array.prototype.slice.call(data.slice(end - 1)));
    console.log(Array.prototype.slice.call(data.slice(0, start + 6)));
    console.log('start=%d, end=%d', start, end);

    var tbs = data.slice(start, end);

    var verifier = crypto.createVerify('RSA-' + sigAlg);
    verifier.update(tbs);
    var sigVerified = verifier.verify(npubKey, sig);

    return validityVerified
      && issuerVerified
      && sigVerified;
  });

  console.log('verified && chainVerified:', verified && chainVerified);

  return verified && chainVerified;
};

module.exports = PayPro;