(function () {
    var C = typeof window === 'undefined' ? require('./Crypto').Crypto : window.Crypto;

    // Shortcuts
    var util = C.util;
    var charenc = C.charenc;
    var UTF8 = charenc.UTF8;
    var Binary = charenc.Binary;
    var MARC4 = (C.MARC4 = {
        /**
         * Public API
         */

        encrypt: function (message, password) {
            var // Convert to bytes
                m = UTF8.stringToBytes(message);
            var // Generate random IV
                iv = util.randomBytes(16);
            var // Generate key
                k =
                    password.constructor == String
                        ? // Derive key from passphrase
                          C.PBKDF2(password, iv, 32, {
                              asBytes: true
                          })
                        : // else, assume byte array representing cryptographic key
                          password; // Encrypt
            MARC4._marc4(m, k, 1536);

            // Return ciphertext
            return util.bytesToBase64(iv.concat(m));
        },
        decrypt: function (ciphertext, password) {
            var // Convert to bytes
                c = util.base64ToBytes(ciphertext);
            var // Separate IV and message
                iv = c.splice(0, 16);
            var // Generate key
                k =
                    password.constructor == String
                        ? // Derive key from passphrase
                          C.PBKDF2(password, iv, 32, {
                              asBytes: true
                          })
                        : // else, assume byte array representing cryptographic key
                          password; // Decrypt
            MARC4._marc4(c, k, 1536);

            // Return plaintext
            return UTF8.bytesToString(c);
        },
        /**
         * Internal methods
         */

        // The core
        _marc4: function (m, k, drop) {
            // State variables
            var i;
            var j;
            var s;
            var temp; // Key setup
            for (i = 0, s = []; i < 256; i++) {
                s[i] = i;
            }
            for (i = 0, j = 0; i < 256; i++) {
                j = (j + s[i] + k[i % k.length]) % 256;

                // Swap
                temp = s[i];
                s[i] = s[j];
                s[j] = temp;
            }

            // Clear counters
            i = j = 0;

            // Encryption
            for (var k = -drop; k < m.length; k++) {
                i = (i + 1) % 256;
                j = (j + s[i]) % 256;

                // Swap
                temp = s[i];
                s[i] = s[j];
                s[j] = temp;

                // Stop here if we're still dropping keystream
                if (k < 0) {
                    continue;
                }

                // Encrypt
                m[k] ^= s[(s[i] + s[j]) % 256];
            }
        }
    });
})();
