// GPG4Browsers - An OpenPGP implementation in javascript
// Copyright (C) 2011 Recurity Labs GmbH
// 
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// 
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
// 
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

/**
 * @fileoverview The openpgp base class should provide all of the functionality 
 * to consume the openpgp.js library. All additional classes are documented 
 * for extending and developing on top of the base library.
 */

var armor = require('./encoding/armor.js');
var packet = require('./packet');
var util = require('./util');

/**
 * GPG4Browsers Core interface. A single instance is hold
 * from the beginning. To use this library call "openpgp.init()"
 * @alias openpgp
 * @class
 * @classdesc Main Openpgp.js class. Use this to initiate and make all calls to this library.
 */
function _openpgp () {
	this.tostring = "";
	
	/**
	 * initializes the library:
	 * - reading the keyring from local storage
	 * - reading the config from local storage
	 */
	function init() {
		this.config = new openpgp_config();
		this.config.read();
		this.keyring = new openpgp_keyring();
		this.keyring.init();
	}
	
	/**
	 * reads message packets out of an OpenPGP armored text and
	 * returns an array of message objects
	 * @param {String} armoredText text to be parsed
	 * @return {openpgp_msg_message[]} on error the function
	 * returns null
	 */
	function readArmoredPackets(armoredText) {
    //TODO how do we want to handle bad text? Exception throwing
		var input = armor.decode(armoredText.replace(/\r/g,'')).openpgp;
		return readDearmoredPackets(input);
		}
		
	/**
	 * reads message packets out of an OpenPGP armored text and
	 * returns an array of message objects. Can be called externally or internally.
	 * External call will parse a de-armored messaged and return messages found.
	 * Internal will be called to read packets wrapped in other packets (i.e. compressed)
	 * @param {String} input dearmored text of OpenPGP packets, to be parsed
	 * @return {openpgp_msg_message[]} on error the function
	 * returns null
	 */
	function readDearmoredPackets(input){
    var packetList = new packet.list();
    packetList.read(input);
    return packetList;
	}

  function encryptMessage(publicKeyPacketlist, message) {

  }

  function encryptAndSignMessage(publicKeyPacketlist, privateKeyPacketlist, message) {

  }

  function decryptMessage(privateKeyPacketlist, messagePacketlist) {

  }

  function decryptAndVerifyMessage(privateKeyPacketlist, publicKeyPacketlist, messagePacketlist) {

  }

  function verifyMessage(publicKeyPacketlist, messagePacketlist) {

  }
	
	/**
	 * creates a binary string representation of an encrypted and signed message.
	 * The message will be encrypted with the public keys specified and signed
	 * with the specified private key.
	 * @param {Object} privatekey {obj: [openpgp_msg_privatekey]} Private key 
	 * to be used to sign the message
	 * @param {Object[]} publickeys An arraf of {obj: [openpgp_msg_publickey]}
	 * - public keys to be used to encrypt the message 
	 * @param {String} messagetext message text to encrypt and sign
	 * @return {String} a binary string representation of the message which 
	 * can be OpenPGP armored
	 */
	function write_signed_and_encrypted_message(privatekey, publickeys, messagetext) {
		var result = "";
    var i;
		var literal = new openpgp_packet_literaldata().write_packet(messagetext.replace(/\r\n/g,"\n").replace(/\n/g,"\r\n"));
		util.print_debug_hexstr_dump("literal_packet: |"+literal+"|\n",literal);
		for (i = 0; i < publickeys.length; i++) {
			var onepasssignature = new openpgp_packet_onepasssignature();
			var onepasssigstr = "";
			if (i === 0)
				onepasssigstr = onepasssignature.write_packet(1, openpgp.config.config.prefer_hash_algorithm,  privatekey, false);
			else
				onepasssigstr = onepasssignature.write_packet(1, openpgp.config.config.prefer_hash_algorithm,  privatekey, false);
			util.print_debug_hexstr_dump("onepasssigstr: |"+onepasssigstr+"|\n",onepasssigstr);
			var datasignature = new openpgp_packet_signature().write_message_signature(1, messagetext.replace(/\r\n/g,"\n").replace(/\n/g,"\r\n"), privatekey);
			util.print_debug_hexstr_dump("datasignature: |"+datasignature.openpgp+"|\n",datasignature.openpgp);
			if (i === 0) {
				result = onepasssigstr+literal+datasignature.openpgp;
			} else {
				result = onepasssigstr+result+datasignature.openpgp;
			}
		}
		
		util.print_debug_hexstr_dump("signed packet: |"+result+"|\n",result);
		// signatures done.. now encryption
		var sessionkey = openpgp_crypto_generateSessionKey(openpgp.config.config.encryption_cipher); 
		var result2 = "";
		
		// creating session keys for each recipient
		for (i = 0; i < publickeys.length; i++) {
			var pkey = publickeys[i].getEncryptionKey();
			if (pkey === null) {
				util.print_error("no encryption key found! Key is for signing only.");
				return null;
			}
			result2 += new openpgp_packet_encryptedsessionkey().
					write_pub_key_packet(
						pkey.getKeyId(),
						pkey.MPIs,
						pkey.publicKeyAlgorithm,
						openpgp.config.config.encryption_cipher,
						sessionkey);
		}
		if (openpgp.config.config.integrity_protect) {
			result2 += new openpgp_packet_encryptedintegrityprotecteddata().write_packet(openpgp.config.config.encryption_cipher, sessionkey, result);
		} else {
			result2 += new openpgp_packet_encrypteddata().write_packet(openpgp.config.config.encryption_cipher, sessionkey, result);
		}
		return armor.encode(3,result2,null,null);
	}
	/**
	 * creates a binary string representation of an encrypted message.
	 * The message will be encrypted with the public keys specified 
	 * @param {Object[]} publickeys An array of {obj: [openpgp_msg_publickey]}
	 * -public keys to be used to encrypt the message 
	 * @param {String} messagetext message text to encrypt
	 * @return {String} a binary string representation of the message
	 * which can be OpenPGP armored
	 */
	function write_encrypted_message(publickeys, messagetext) {
		var result = "";
		var literal = new openpgp_packet_literaldata().write_packet(messagetext.replace(/\r\n/g,"\n").replace(/\n/g,"\r\n"));
		util.print_debug_hexstr_dump("literal_packet: |"+literal+"|\n",literal);
		result = literal;
		
		// signatures done.. now encryption
		var sessionkey = openpgp_crypto_generateSessionKey(openpgp.config.config.encryption_cipher); 
		var result2 = "";
		
		// creating session keys for each recipient
		for (var i = 0; i < publickeys.length; i++) {
			var pkey = publickeys[i].getEncryptionKey();
			if (pkey === null) {
				util.print_error("no encryption key found! Key is for signing only.");
				return null;
			}
			result2 += new openpgp_packet_encryptedsessionkey().
					write_pub_key_packet(
						pkey.getKeyId(),
						pkey.MPIs,
						pkey.publicKeyAlgorithm,
						openpgp.config.config.encryption_cipher,
						sessionkey);
		}
		if (openpgp.config.config.integrity_protect) {
			result2 += new openpgp_packet_encryptedintegrityprotecteddata().write_packet(openpgp.config.config.encryption_cipher, sessionkey, result);
		} else {
			result2 += new openpgp_packet_encrypteddata().write_packet(openpgp.config.config.encryption_cipher, sessionkey, result);
		}
		return armor.encode(3,result2,null,null);
	}
	
	/**
	 * creates a binary string representation a signed message.
	 * The message will be signed with the specified private key.
	 * @param {Object} privatekey {obj: [openpgp_msg_privatekey]}
	 * - the private key to be used to sign the message 
	 * @param {String} messagetext message text to sign
	 * @return {Object} {Object: text [String]}, openpgp: {String} a binary
	 *  string representation of the message which can be OpenPGP
	 *   armored(openpgp) and a text representation of the message (text). 
	 * This can be directly used to OpenPGP armor the message
	 */
	function write_signed_message(privatekey, messagetext) {
		var sig = new openpgp_packet_signature().write_message_signature(1, messagetext.replace(/\r\n/g,"\n").replace(/\n/,"\r\n"), privatekey);
		var result = {text: messagetext.replace(/\r\n/g,"\n").replace(/\n/,"\r\n"), openpgp: sig.openpgp, hash: sig.hash};
		return armor.encode(2,result, null, null);
	}
	
	/**
	 * generates a new key pair for openpgp. Beta stage. Currently only 
	 * supports RSA keys, and no subkeys.
	 * @param {Integer} keyType to indicate what type of key to make. 
	 * RSA is 1. Follows algorithms outlined in OpenPGP.
	 * @param {Integer} numBits number of bits for the key creation. (should 
	 * be 1024+, generally)
	 * @param {String} userId assumes already in form of "User Name 
	 * <username@email.com>"
	 * @param {String} passphrase The passphrase used to encrypt the resulting private key
	 * @return {Object} {privateKey: [openpgp_msg_privatekey], 
	 * privateKeyArmored: [string], publicKeyArmored: [string]}
	 */
	function generate_key_pair(keyType, numBits, userId, passphrase){
		var userIdPacket = new openpgp_packet_userid();
		var userIdString = userIdPacket.write_packet(userId);
		
		var keyPair = openpgp_crypto_generateKeyPair(keyType,numBits, passphrase, openpgp.config.config.prefer_hash_algorithm, 3);
		var privKeyString = keyPair.privateKey;
		var privKeyPacket = new openpgp_packet_keymaterial().read_priv_key(privKeyString.string,3,privKeyString.string.length);
		if(!privKeyPacket.decryptSecretMPIs(passphrase))
      util.print_error('Issue creating key. Unable to read resulting private key');
		var privKey = new openpgp_msg_privatekey();
		privKey.privateKeyPacket = privKeyPacket;
		privKey.getPreferredSignatureHashAlgorithm = function(){return openpgp.config.config.prefer_hash_algorithm};//need to override this to solve catch 22 to generate signature. 8 is value for SHA256
		
		var publicKeyString = privKey.privateKeyPacket.publicKey.data;
		var hashData = String.fromCharCode(0x99)+ String.fromCharCode(((publicKeyString.length) >> 8) & 0xFF) 
			+ String.fromCharCode((publicKeyString.length) & 0xFF) +publicKeyString+String.fromCharCode(0xB4) +
			String.fromCharCode((userId.length) >> 24) +String.fromCharCode(((userId.length) >> 16) & 0xFF) 
			+ String.fromCharCode(((userId.length) >> 8) & 0xFF) + String.fromCharCode((userId.length) & 0xFF) + userId;
		var signature = new openpgp_packet_signature();
		signature = signature.write_message_signature(16,hashData, privKey);
		var publicArmored = armor.encode(4, keyPair.publicKey.string + userIdString + signature.openpgp );

		var privArmored = armor.encode(5,privKeyString.string+userIdString+signature.openpgp);
		
		return {privateKey : privKey, privateKeyArmored: privArmored, publicKeyArmored: publicArmored};
	}
	
	this.generate_key_pair = generate_key_pair;
	this.write_signed_message = write_signed_message; 
	this.write_signed_and_encrypted_message = write_signed_and_encrypted_message;
	this.write_encrypted_message = write_encrypted_message;
	this.readArmoredPackets = readArmoredPackets;
	this.readDearmoredPackets = readDearmoredPackets;
	this.init = init;
}

module.exports = new _openpgp();