/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

var EXPORTED_SYMBOLS = ["PasswordEngine", "LoginRec", "PasswordValidator"];

const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
const { Collection, CryptoWrapper } = ChromeUtils.import(
  "resource://services-sync/record.js"
);
const { SCORE_INCREMENT_XLARGE } = ChromeUtils.import(
  "resource://services-sync/constants.js"
);
const { CollectionValidator } = ChromeUtils.import(
  "resource://services-sync/collection_validator.js"
);
const { Store, SyncEngine, LegacyTracker } = ChromeUtils.import(
  "resource://services-sync/engines.js"
);
const { Svc, Utils } = ChromeUtils.import("resource://services-sync/util.js");
const { Async } = ChromeUtils.import("resource://services-common/async.js");

const SYNCABLE_LOGIN_FIELDS = [
  // `nsILoginInfo` fields.
  "hostname",
  "formSubmitURL",
  "httpRealm",
  "username",
  "password",
  "usernameField",
  "passwordField",

  // `nsILoginMetaInfo` fields.
  "timeCreated",
  "timePasswordChanged",
];

// Compares two logins to determine if their syncable fields changed. The login
// manager fires `modifyLogin` for changes to all fields, including ones we
// don't sync. In particular, `timeLastUsed` changes shouldn't mark the login
// for upload; otherwise, we might overwrite changed passwords before they're
// downloaded (bug 973166).
function isSyncableChange(oldLogin, newLogin) {
  oldLogin.QueryInterface(Ci.nsILoginMetaInfo).QueryInterface(Ci.nsILoginInfo);
  newLogin.QueryInterface(Ci.nsILoginMetaInfo).QueryInterface(Ci.nsILoginInfo);
  for (let property of SYNCABLE_LOGIN_FIELDS) {
    if (oldLogin[property] != newLogin[property]) {
      return true;
    }
  }
  return false;
}

function LoginRec(collection, id) {
  CryptoWrapper.call(this, collection, id);
}
LoginRec.prototype = {
  __proto__: CryptoWrapper.prototype,
  _logName: "Sync.Record.Login",

  cleartextToString() {
    let o = Object.assign({}, this.cleartext);
    if (o.password) {
      o.password = "X".repeat(o.password.length);
    }
    return JSON.stringify(o);
  },
};

Utils.deferGetSet(LoginRec, "cleartext", [
  "hostname",
  "formSubmitURL",
  "httpRealm",
  "username",
  "password",
  "usernameField",
  "passwordField",
  "timeCreated",
  "timePasswordChanged",
]);

function PasswordEngine(service) {
  SyncEngine.call(this, "Passwords", service);
}
PasswordEngine.prototype = {
  __proto__: SyncEngine.prototype,
  _storeObj: PasswordStore,
  _trackerObj: PasswordTracker,
  _recordObj: LoginRec,

  syncPriority: 2,

  // Metadata for syncing is stored in the login manager. We also migrate it
  // from preferences which can be removed eventually via bug 1651568. Note that
  // we don't support profile downgrades - once it's migrated, the login manager
  // becomes the single source of truth.
  // Note also that the syncID is stored encrypted and null is returned if it
  // can't be decrypted - this is done for that 'return null' side-effect rather
  // than due to privacy - we want failure to decrypt the store to be treated as
  // an engine reset.
  async getSyncID() {
    let legacyValue = this._syncID; // the base preference getter.
    if (legacyValue) {
      await Services.logins.setSyncID(legacyValue);
      Svc.Prefs.reset(this.name + ".syncID");
      this._log.debug(`migrated syncID of ${legacyValue} to the logins store`);
      return legacyValue;
    }
    return Services.logins.getSyncID();
  },

  async ensureCurrentSyncID(newSyncID) {
    // getSyncID above really only exists for this function - the rest of sync
    // has already moved away from it, and even our tests  barely use it.
    // When we remove the migration code (bug 1651568) we should consider
    // removing getSyncID() from both here and the login manager, and pushing
    // this ensureCurrentSyncID() function down into the login manager.
    let existingSyncID = await this.getSyncID();
    if (existingSyncID == newSyncID) {
      return existingSyncID;
    }
    this._log.debug("Engine syncIDs: " + [newSyncID, existingSyncID]);

    await Services.logins.setSyncID(newSyncID);
    await Services.logins.setLastSync(0);
    return newSyncID;
  },

  async getLastSync() {
    let legacyValue = await super.getLastSync();
    if (legacyValue) {
      await this.setLastSync(legacyValue);
      Svc.Prefs.reset(this.name + ".lastSync");
      this._log.debug(
        `migrated timestamp of ${legacyValue} to the logins store`
      );
      return legacyValue;
    }
    return Services.logins.getLastSync();
  },

  async setLastSync(timestamp) {
    await Services.logins.setLastSync(timestamp);
  },

  async _syncFinish() {
    await SyncEngine.prototype._syncFinish.call(this);

    // Delete the Weave credentials from the server once.
    if (!Svc.Prefs.get("deletePwdFxA", false)) {
      try {
        let ids = [];
        for (let host of Utils.getSyncCredentialsHosts()) {
          for (let info of Services.logins.findLogins(host, "", "")) {
            ids.push(info.QueryInterface(Ci.nsILoginMetaInfo).guid);
          }
        }
        if (ids.length) {
          let coll = new Collection(this.engineURL, null, this.service);
          coll.ids = ids;
          let ret = await coll.delete();
          this._log.debug("Delete result: " + ret);
          if (!ret.success && ret.status != 400) {
            // A non-400 failure means try again next time.
            return;
          }
        } else {
          this._log.debug("Didn't find any passwords to delete");
        }
        // If there were no ids to delete, or we succeeded, or got a 400,
        // record success.
        Svc.Prefs.set("deletePwdFxA", true);
        Svc.Prefs.reset("deletePwd"); // The old prefname we previously used.
      } catch (ex) {
        if (Async.isShutdownException(ex)) {
          throw ex;
        }
        this._log.debug("Password deletes failed", ex);
      }
    }
  },

  async _findDupe(item) {
    let login = this._store._nsLoginInfoFromRecord(item);
    if (!login) {
      return null;
    }

    let logins = Services.logins.findLogins(
      login.origin,
      login.formActionOrigin,
      login.httpRealm
    );

    await Async.promiseYield(); // Yield back to main thread after synchronous operation.

    // Look for existing logins that match the origin, but ignore the password.
    for (let local of logins) {
      if (login.matches(local, true) && local instanceof Ci.nsILoginMetaInfo) {
        return local.guid;
      }
    }

    return null;
  },

  async pullAllChanges() {
    let changes = {};
    let ids = await this._store.getAllIDs();
    for (let [id, info] of Object.entries(ids)) {
      changes[id] = info.timePasswordChanged / 1000;
    }
    return changes;
  },

  getValidator() {
    return new PasswordValidator();
  },
};

function PasswordStore(name, engine) {
  Store.call(this, name, engine);
  this._nsLoginInfo = new Components.Constructor(
    "@mozilla.org/login-manager/loginInfo;1",
    Ci.nsILoginInfo,
    "init"
  );
}
PasswordStore.prototype = {
  __proto__: Store.prototype,

  _newPropertyBag() {
    return Cc["@mozilla.org/hash-property-bag;1"].createInstance(
      Ci.nsIWritablePropertyBag2
    );
  },

  /**
   * Return an instance of nsILoginInfo (and, implicitly, nsILoginMetaInfo).
   */
  _nsLoginInfoFromRecord(record) {
    function nullUndefined(x) {
      return x == undefined ? null : x;
    }

    function stringifyNullUndefined(x) {
      return x == undefined || x == null ? "" : x;
    }

    if (record.formSubmitURL && record.httpRealm) {
      this._log.warn(
        "Record " +
          record.id +
          " has both formSubmitURL and httpRealm. Skipping."
      );
      return null;
    }

    // Passing in "undefined" results in an empty string, which later
    // counts as a value. Explicitly `|| null` these fields according to JS
    // truthiness. Records with empty strings or null will be unmolested.
    let info = new this._nsLoginInfo(
      record.hostname,
      nullUndefined(record.formSubmitURL),
      nullUndefined(record.httpRealm),
      stringifyNullUndefined(record.username),
      record.password,
      record.usernameField,
      record.passwordField
    );

    info.QueryInterface(Ci.nsILoginMetaInfo);
    info.guid = record.id;
    if (record.timeCreated && !isNaN(new Date(record.timeCreated).getTime())) {
      info.timeCreated = record.timeCreated;
    }
    if (
      record.timePasswordChanged &&
      !isNaN(new Date(record.timePasswordChanged).getTime())
    ) {
      info.timePasswordChanged = record.timePasswordChanged;
    }

    return info;
  },

  async _getLoginFromGUID(id) {
    let prop = this._newPropertyBag();
    prop.setPropertyAsAUTF8String("guid", id);

    let logins = Services.logins.searchLogins(prop);
    await Async.promiseYield(); // Yield back to main thread after synchronous operation.

    if (logins.length > 0) {
      this._log.trace(logins.length + " items matching " + id + " found.");
      return logins[0];
    }

    this._log.trace("No items matching " + id + " found. Ignoring");
    return null;
  },

  async getAllIDs() {
    let items = {};
    let logins = Services.logins.getAllLogins();

    for (let i = 0; i < logins.length; i++) {
      // Skip over Weave password/passphrase entries.
      let metaInfo = logins[i].QueryInterface(Ci.nsILoginMetaInfo);
      if (Utils.getSyncCredentialsHosts().has(metaInfo.origin)) {
        continue;
      }

      items[metaInfo.guid] = metaInfo;
    }

    return items;
  },

  async changeItemID(oldID, newID) {
    this._log.trace("Changing item ID: " + oldID + " to " + newID);

    let oldLogin = await this._getLoginFromGUID(oldID);
    if (!oldLogin) {
      this._log.trace("Can't change item ID: item doesn't exist");
      return;
    }
    if (await this._getLoginFromGUID(newID)) {
      this._log.trace("Can't change item ID: new ID already in use");
      return;
    }

    let prop = this._newPropertyBag();
    prop.setPropertyAsAUTF8String("guid", newID);

    Services.logins.modifyLogin(oldLogin, prop);
  },

  async itemExists(id) {
    return !!(await this._getLoginFromGUID(id));
  },

  async createRecord(id, collection) {
    let record = new LoginRec(collection, id);
    let login = await this._getLoginFromGUID(id);

    if (!login) {
      record.deleted = true;
      return record;
    }

    record.hostname = login.origin;
    record.formSubmitURL = login.formActionOrigin;
    record.httpRealm = login.httpRealm;
    record.username = login.username;
    record.password = login.password;
    record.usernameField = login.usernameField;
    record.passwordField = login.passwordField;

    // Optional fields.
    login.QueryInterface(Ci.nsILoginMetaInfo);
    record.timeCreated = login.timeCreated;
    record.timePasswordChanged = login.timePasswordChanged;

    return record;
  },

  async create(record) {
    let login = this._nsLoginInfoFromRecord(record);
    if (!login) {
      return;
    }

    this._log.trace("Adding login for " + record.hostname);
    this._log.trace(
      "httpRealm: " +
        JSON.stringify(login.httpRealm) +
        "; " +
        "formSubmitURL: " +
        JSON.stringify(login.formActionOrigin)
    );
    Services.logins.addLogin(login);
  },

  async remove(record) {
    this._log.trace("Removing login " + record.id);

    let loginItem = await this._getLoginFromGUID(record.id);
    if (!loginItem) {
      this._log.trace("Asked to remove record that doesn't exist, ignoring");
      return;
    }

    Services.logins.removeLogin(loginItem);
  },

  async update(record) {
    let loginItem = await this._getLoginFromGUID(record.id);
    if (!loginItem) {
      this._log.trace("Skipping update for unknown item: " + record.hostname);
      return;
    }

    this._log.trace("Updating " + record.hostname);
    let newinfo = this._nsLoginInfoFromRecord(record);
    if (!newinfo) {
      return;
    }

    Services.logins.modifyLogin(loginItem, newinfo);
  },

  async wipe() {
    Services.logins.removeAllUserFacingLogins();
  },
};

function PasswordTracker(name, engine) {
  LegacyTracker.call(this, name, engine);
}
PasswordTracker.prototype = {
  __proto__: LegacyTracker.prototype,

  onStart() {
    Svc.Obs.add("passwordmgr-storage-changed", this.asyncObserver);
  },

  onStop() {
    Svc.Obs.remove("passwordmgr-storage-changed", this.asyncObserver);
  },

  async observe(subject, topic, data) {
    if (this.ignoreAll) {
      return;
    }

    // A single add, remove or change or removing all items
    // will trigger a sync for MULTI_DEVICE.
    switch (data) {
      case "modifyLogin": {
        subject.QueryInterface(Ci.nsIArrayExtensions);
        let oldLogin = subject.GetElementAt(0);
        let newLogin = subject.GetElementAt(1);
        if (!isSyncableChange(oldLogin, newLogin)) {
          this._log.trace(`${data}: Ignoring change for ${newLogin.guid}`);
          break;
        }
        const tracked = await this._trackLogin(newLogin);
        if (tracked) {
          this._log.trace(`${data}: Tracking change for ${newLogin.guid}`);
        }
        break;
      }

      case "addLogin":
      case "removeLogin":
        subject
          .QueryInterface(Ci.nsILoginMetaInfo)
          .QueryInterface(Ci.nsILoginInfo);
        const tracked = await this._trackLogin(subject);
        if (tracked) {
          this._log.trace(data + ": " + subject.guid);
        }
        break;

      // Bug 1613620: We iterate through the removed logins and track them to ensure
      // the logins are deleted across synced devices/accounts
      case "removeAllLogins":
        subject.QueryInterface(Ci.nsIArrayExtensions);
        let count = subject.Count();
        for (let i = 0; i < count; i++) {
          let currentSubject = subject.GetElementAt(i);
          let tracked = await this._trackLogin(currentSubject);
          if (tracked) {
            this._log.trace(data + ": " + currentSubject.guid);
          }
        }
        this.score += SCORE_INCREMENT_XLARGE;
        break;
    }
  },

  async _trackLogin(login) {
    if (Utils.getSyncCredentialsHosts().has(login.origin)) {
      // Skip over Weave password/passphrase changes.
      return false;
    }
    const added = await this.addChangedID(login.guid);
    if (!added) {
      return false;
    }
    this.score += SCORE_INCREMENT_XLARGE;
    return true;
  },
};

class PasswordValidator extends CollectionValidator {
  constructor() {
    super("passwords", "id", [
      "hostname",
      "formSubmitURL",
      "httpRealm",
      "password",
      "passwordField",
      "username",
      "usernameField",
    ]);
  }

  getClientItems() {
    let logins = Services.logins.getAllLogins();
    let syncHosts = Utils.getSyncCredentialsHosts();
    let result = logins
      .map(l => l.QueryInterface(Ci.nsILoginMetaInfo))
      .filter(l => !syncHosts.has(l.origin));
    return Promise.resolve(result);
  }

  normalizeClientItem(item) {
    return {
      id: item.guid,
      guid: item.guid,
      hostname: item.hostname,
      formSubmitURL: item.formSubmitURL,
      httpRealm: item.httpRealm,
      password: item.password,
      passwordField: item.passwordField,
      username: item.username,
      usernameField: item.usernameField,
      original: item,
    };
  }

  async normalizeServerItem(item) {
    return Object.assign({ guid: item.id }, item);
  }
}