/* prettier-ignore */

/********************************************************************************
 *   Ledger Communication toolkit
 *   (c) 2016 Ledger
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 ********************************************************************************/

'use strict';

// MEW - Require u2f instead of expecting it in global scope
var u2f = require('./u2f-api');

var Ledger3 = function(scrambleKey, timeoutSeconds) {
  this.scrambleKey = new Buffer(scrambleKey, 'ascii');
  this.timeoutSeconds = timeoutSeconds;
};

Ledger3.wrapApdu = function(apdu, key) {
  var result = new Buffer(apdu.length);
  for (var i = 0; i < apdu.length; i++) {
    result[i] = apdu[i] ^ key[i % key.length];
  }
  return result;
};

// Convert from normal to web-safe, strip trailing "="s
Ledger3.webSafe64 = function(base64) {
  return base64.replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/, '');
};

// Convert from web-safe to normal, add trailing "="s
Ledger3.normal64 = function(base64) {
  return (
    base64.replace(/\-/g, '+').replace(/_/g, '/') +
    '=='.substring(0, 3 * base64.length % 4)
  );
};

Ledger3.prototype.u2fCallback = function(response, callback) {
  if (typeof response['signatureData'] != 'undefined') {
    var data = new Buffer(
      Ledger3.normal64(response['signatureData']),
      'base64'
    );
    callback(data.toString('hex', 5));
  } else {
    callback(undefined, response);
  }
};

// callback is function(response, error)
Ledger3.prototype.exchange = function(apduHex, callback) {
  var apdu = new Buffer(apduHex, 'hex');
  var keyHandle = Ledger3.wrapApdu(apdu, this.scrambleKey);
  var challenge = new Buffer(
    '0000000000000000000000000000000000000000000000000000000000000000',
    'hex'
  );
  var key = {};
  key['version'] = 'U2F_V2';
  key['keyHandle'] = Ledger3.webSafe64(keyHandle.toString('base64'));
  var self = this;
  var localCallback = function(result) {
    self.u2fCallback(result, callback);
  };
  u2f.sign(
    location.origin,
    Ledger3.webSafe64(challenge.toString('base64')),
    [key],
    localCallback,
    this.timeoutSeconds
  );
};

module.exports = Ledger3;