// adapted from https://github.com/apatil/pemstrip
var findProc = /Proc-Type: 4,ENCRYPTED\r?\nDEK-Info: AES-((?:128)|(?:192)|(?:256))-CBC,([0-9A-H]+)\r?\n\r?\n([0-9A-z\n\r\+\/\=]+)\r?\n/m;
var startRegex =/^-----BEGIN (.*) KEY-----\r?\n/m;
var fullRegex = /^-----BEGIN (.*) KEY-----\r?\n([0-9A-z\n\r\+\/\=]+)\r?\n-----END \1 KEY-----$/m;
var evp = require('./EVP_BytesToKey');
var ciphers = require('browserify-aes');
module.exports = function (okey, password) {
  var key = okey.toString();
  var match = key.match(findProc);
  var decrypted;
  if (!match) {
    var match2 = key.match(fullRegex);
    decrypted = new Buffer(match2[2].replace(/\r?\n/g, ''), 'base64');
  } else {
    var suite = 'aes' + match[1];
    var iv = new Buffer(match[2], 'hex');
    var cipherText = new Buffer(match[3].replace(/\r?\n/g, ''), 'base64');
    var cipherKey = evp(password, iv.slice(0,8), parseInt(match[1]));
    var out = [];
    var cipher = ciphers.createDecipheriv(suite, cipherKey, iv);
    out.push(cipher.update(cipherText));
    out.push(cipher.final());
    decrypted = Buffer.concat(out);
  }
  var tag = key.match(startRegex)[1] + ' KEY';
  return {
    tag: tag,
    data: decrypted
  };
};

// http://stackoverflow.com/a/7033705
function wrap (str) {
  var chunks = []

  for (var i = 0; i < str.length; i += 64) {
    chunks.push(str.slice(i, i + 64))
  }
  return chunks.join("\n")
}
