// 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

var openpgp = require('openpgp');

/**
 * @class
 * @classdesc The class that deals with storage of the keyring. Currently the only option is to use HTML5 local storage.
 */
var keyring = function() {
  this.keys = [];

  /**
   * Initialization routine for the keyring. This method reads the 
   * keyring from HTML5 local storage and initializes this instance.
   * This method is called by openpgp.init().
   */
  function init() {
    var armoredKeys = JSON.parse(window.localStorage.getItem("armoredKeys"));
    if (armoredKeys !== null && armoredKeys.length === 0) {
      var key;
      for (var i = 0; i < armoredKeys.length; i++) {
        key = openpgp.key.readArmored(armoredKeys[i]);
        this.keys.push(key);
      }
    } else {
      this.keys = [];
    }
  }
  this.init = init;

  /**
   * Saves the current state of the keyring to HTML5 local storage.
   * The privateKeys array and publicKeys array gets Stringified using JSON
   */
  function store() {
    var armoredKeys = [];
    for (var i = 0; i < this.keys.length; i++) {
      armoredKeys.push(this.keys[i].armor());
    }
    window.localStorage.setItem("armoredKeys", JSON.stringify(armoredKeys));
  }
  this.store = store;

  function emailKeyCheck(key, email) {
    email = email.toLowerCase();
    var keyEmails = key.getUserIds();
    for (var i; i < keyEmails.length; i++) {
      //we need to get just the email from the userid key
      keyEmail = keyEmails[i].split('<')[1].split('>')[0].trim().toLowerCase();
      if (keyEmail == email) {
        return true;
      }
    }
    return false;
  }

  function idKeyCheck(key, id) {
    var keyid = key.getKeyId();
    if (keyid && keyid.write() == id) {
      return true;
    }
    return false;
  }

  function checkForIdentityAndPacketMatch(identityFunction, identityInput, keyType) {
    var results = [];
    for (var p = 0; p < this.keys.length; p++) {
      var key = this.keys[p];
      switch (keyType) {
        case openpgp.enums.packet.public_key:
          if (key.isPublic() && identityFunction(identityInput, key)) {
            results.push(key);
          }
          break;
        case openpgp.enums.packet.private_key:
          if (key.isPrivate() && identityFunction(identityInput, key)) {
            results.push(key);
          }
          break;
      }
    }
    return results;
  }
  this.checkForIdentityAndPacketMatch = checkForIdentityAndPacketMatch;

  /**
   * searches all public keys in the keyring matching the address or address part of the user ids
   * @param {String} email email address to search for
   * @return {openpgp.key.Key[]} The public keys associated with provided email address.
   */
  function getPublicKeyForAddress(email) {
    return checkForIdentityAndPacketMatch(emailPacketCheck, email, openpgp.enums.packet.public_key);
  }
  this.getPublicKeyForAddress = getPublicKeyForAddress;

  /**
   * Searches the keyring for a private key containing the specified email address
   * @param {String} email email address to search for
   * @return {openpgp.key.Key[]} private keys found
   */
  function getPrivateKeyForAddress(email) {
    return checkForIdentityAndPacketMatch(emailPacketCheck, email, openpgp.enums.packet.secret_key);
  }
  this.getPrivateKeyForAddress = getPrivateKeyForAddress;

  /**
   * Searches the keyring for public keys having the specified key id
   * @param {String} keyId provided as string of hex number (lowercase)
   * @return {openpgp.key.Key[]} public keys found
   */
  function getKeysForKeyId(keyId) {
    return this.checkForIdentityAndPacketMatch(idPacketCheck, keyId);
  }
  this.getKeysForKeyId = getKeysForKeyId;

  /**
   * Imports a key from an ascii armored message
   * @param {String} armored message to read the keys/key from
   */
  function importKey(armored) {
    this.keys.push(openpgp.key.readArmored(armored));

    return true;
  }
  this.importKey = importKey;

  /**
   * returns the armored message representation of the key at key ring index
   * @param {Integer} index the index of the key within the array
   * @return {String} armored message representing the key object
   */
  function exportKey(index) {
    return this.keys[index].armor();
  }
  this.exportKey = exportKey;

  /**
   * Removes a public key from the public key keyring at the specified index 
   * @param {Integer} index the index of the public key within the publicKeys array
   * @return {openpgp.key.Key} The public key object which has been removed
   */
  function removeKey(index) {
    var removed = this.keys.splice(index, 1);

    return removed;
  }
  this.removeKey = removeKey;

  /**
   * returns the armored message representation of the public key portion of the key at key ring index
   * @param {Integer} index the index of the key within the array
   * @return {String} armored message representing the public key object
   */
  function exportPublicKey(index) {
    return this.keys[index].toPublic().armor();
  }
  this.exportPublicKey = exportPublicKey;

};

module.exports = new keyring();