/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (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.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Weave.
 *
 * The Initial Developer of the Original Code is Mozilla.
 * Portions created by the Initial Developer are Copyright (C) 2008
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *  Dan Mills <thunder@mozilla.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

const EXPORTED_SYMBOLS = ['CryptoWrapper', 'CryptoMeta', 'CryptoMetas'];

const Cc = Components.classes;
const Ci = Components.interfaces;
const Cr = Components.results;
const Cu = Components.utils;

Cu.import("resource://weave/util.js");
Cu.import("resource://weave/base_records/wbo.js");
Cu.import("resource://weave/base_records/keys.js");

function CryptoWrapper(uri) {
  this._CryptoWrap_init(uri);
}
CryptoWrapper.prototype = {
  __proto__: WBORecord.prototype,
  _logName: "Record.CryptoWrapper",

  _CryptoWrap_init: function CryptoWrap_init(uri) {
    // FIXME: this will add a json filter, meaning our payloads will be json
    //        encoded, even though they are already a string
    this._WBORec_init(uri);
    this.data.payload = {
      encryption: "",
      ciphertext: null
    };
  },

  // FIXME: we make no attempt to ensure cleartext is in sync
  //        with the encrypted payload
  cleartext: null,

  encrypt: function CryptoWrapper_encrypt(passphrase) {
    // No need to encrypt deleted records
    if (this.deleted)
      return;

    let pubkey = PubKeys.getDefaultKey();
    let privkey = PrivKeys.get(pubkey.privateKeyUri);

    let meta = CryptoMetas.get(this.encryption);
    let symkey = meta.getKey(privkey, passphrase);

    this.ciphertext = Svc.Crypto.encrypt(JSON.stringify([this.cleartext]),
					 symkey, meta.bulkIV);
    this.cleartext = null;
  },

  decrypt: function CryptoWrapper_decrypt(passphrase) {
    // Deleted records aren't encrypted
    if (this.deleted)
      return;

    let pubkey = PubKeys.getDefaultKey();
    let privkey = PrivKeys.get(pubkey.privateKeyUri);

    let meta = CryptoMetas.get(this.encryption);
    let symkey = meta.getKey(privkey, passphrase);

    // note: payload is wrapped in an array, see _encrypt
    this.cleartext = JSON.parse(Svc.Crypto.decrypt(this.ciphertext,
							symkey, meta.bulkIV))[0];
    this.ciphertext = null;

    return this.cleartext;
  },

  toString: function CryptoWrap_toString() "{ " + [
      "id: " + this.id,
      "parent: " + this.parentid,
      "index: " + this.sortindex,
      "modified: " + this.modified,
      "payload: " + (this.deleted ? "DELETED" : JSON.stringify(this.cleartext))
    ].join("\n  ") + " }",
};

Utils.deferGetSet(CryptoWrapper, "payload", ["encryption", "ciphertext"]);

function CryptoMeta(uri) {
  this._CryptoMeta_init(uri);
}
CryptoMeta.prototype = {
  __proto__: WBORecord.prototype,
  _logName: "Record.CryptoMeta",

  _CryptoMeta_init: function CryptoMeta_init(uri) {
    this._WBORec_init(uri);
    this.data.payload = {
      bulkIV: null,
      keyring: {}
    };
  },

  generateIV: function CryptoMeta_generateIV() {
    this.bulkIV = Svc.Crypto.generateRandomIV();
  },

  getKey: function CryptoMeta_getKey(privkey, passphrase) {
    // We cache the unwrapped key, as it's expensive to generate
    if (this._unwrappedKey)
      return this._unwrappedKey;

    // get the uri to our public key
    let pubkeyUri = privkey.publicKeyUri.spec;

    // each hash key is a relative uri, resolve those and match against ours
    let wrapped_key;
    for (let relUri in this.payload.keyring) {
      if (pubkeyUri == this.baseUri.resolve(relUri))
        wrapped_key = this.payload.keyring[relUri];
    }
    if (!wrapped_key)
      throw "keyring doesn't contain a key for " + pubkeyUri;

    return this._unwrappedKey = Svc.Crypto.unwrapSymmetricKey(wrapped_key,
      privkey.keyData, passphrase.password, privkey.salt, privkey.iv);
  },

  addKey: function CryptoMeta_addKey(new_pubkey, privkey, passphrase) {
    let symkey = this.getKey(privkey, passphrase);
    this.addUnwrappedKey(new_pubkey, symkey);
  },

  addUnwrappedKey: function CryptoMeta_addUnwrappedKey(new_pubkey, symkey) {
    // get the new public key
    if (typeof new_pubkey == "string")
      new_pubkey = PubKeys.get(new_pubkey);

    // each hash key is a relative uri, resolve those and
    // if we find the one we're about to add, remove it
    for (let relUri in this.payload.keyring) {
      if (pubkeyUri == this.uri.resolve(relUri))
        delete this.payload.keyring[relUri];
    }

    this.payload.keyring[new_pubkey.uri.spec] =
      Svc.Crypto.wrapSymmetricKey(symkey, new_pubkey.keyData);
  }
};

Utils.deferGetSet(CryptoMeta, "data.payload", "bulkIV");

Utils.lazy(this, 'CryptoMetas', CryptoRecordManager);

function CryptoRecordManager() { this._init(); }
CryptoRecordManager.prototype = {
  __proto__: RecordManager.prototype,
  _recordType: CryptoMeta
};