text: "use strict";
  
  var toError = require('./utils').toError,
    Define = require('./metadata'),
    shallowClone = require('./utils').shallowClone;
  
  /**
   * @fileOverview The **Admin** class is an internal class that allows convenient access to
   * the admin functionality and commands for MongoDB.
   *
   * **ADMIN Cannot directly be instantiated**
   * @example
   * var MongoClient = require('mongodb').MongoClient,
   *   test = require('assert');
   * // Connection url
   * var url = 'mongodb://localhost:27017/test';
   * // Connect using MongoClient
   * MongoClient.connect(url, function(err, db) {
   *   // Use the admin database for the operation
   *   var adminDb = db.admin();
   *
   *   // List all the available databases
   *   adminDb.listDatabases(function(err, dbs) {
   *     test.equal(null, err);
   *     test.ok(dbs.databases.length > 0);
   *     db.close();
   *   });
   * });
   */
  
  /**
   * Create a new Admin instance (INTERNAL TYPE, do not instantiate directly)
   * @class
   * @return {Admin} a collection instance.
   */
  var Admin = function(db, topology, promiseLibrary) {
    if(!(this instanceof Admin)) return new Admin(db, topology);
    var self = this;
  
    // Internal state
    this.s = {
        db: db
      , topology: topology
      , promiseLibrary: promiseLibrary
    }
  }
  
  var define = Admin.define = new Define('Admin', Admin, false);
  
  /**
   * The callback format for results
   * @callback Admin~resultCallback
   * @param {MongoError} error An error instance representing the error during the execution.
   * @param {object} result The result object if the command was executed successfully.
   */
  
  /**
   * Execute a command
   * @method
   * @param {object} command The command hash
   * @param {object} [options=null] Optional settings.
   * @param {(ReadPreference|string)} [options.readPreference=null] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
   * @param {number} [options.maxTimeMS=null] Number of milliseconds to wait before aborting the query.
   * @param {Admin~resultCallback} [callback] The command result callback
   * @return {Promise} returns Promise if no callback passed
   */
  Admin.prototype.command = function(command, options, callback) {
    var self = this;
    var args = Array.prototype.slice.call(arguments, 1);
    callback = args.pop();
    if(typeof callback != 'function') args.push(callback);
    options = args.length ? args.shift() : {};
  
    // Execute using callback
    if(typeof callback == 'function') return this.s.db.executeDbAdminCommand(command, options, function(err, doc) {
      return callback != null ? callback(err, doc) : null;
    });
  
    // Return a Promise
    return new this.s.promiseLibrary(function(resolve, reject) {
      self.s.db.executeDbAdminCommand(command, options, function(err, doc) {
        if(err) return reject(err);
        resolve(doc);
      });
    });
  }
  
  define.classMethod('command', {callback: true, promise:true});
  
  /**
   * Retrieve the server information for the current
   * instance of the db client
   *
   * @param {Admin~resultCallback} [callback] The command result callback
   * @return {Promise} returns Promise if no callback passed
   */
  Admin.prototype.buildInfo = function(callback) {
    var self = this;
    // Execute using callback
    if(typeof callback == 'function') return this.serverInfo(callback);
  
    // Return a Promise
    return new this.s.promiseLibrary(function(resolve, reject) {
      self.serverInfo(function(err, r) {
        if(err) return reject(err);
        resolve(r);
      });
    });
  }
  
  define.classMethod('buildInfo', {callback: true, promise:true});
  
  /**
   * Retrieve the server information for the current
   * instance of the db client
   *
   * @param {Admin~resultCallback} [callback] The command result callback
   * @return {Promise} returns Promise if no callback passed
   */
  Admin.prototype.serverInfo = function(callback) {
    var self = this;
    // Execute using callback
    if(typeof callback == 'function') return this.s.db.executeDbAdminCommand({buildinfo:1}, function(err, doc) {
      if(err != null) return callback(err, null);
      callback(null, doc);
    });
  
    // Return a Promise
    return new this.s.promiseLibrary(function(resolve, reject) {
      self.s.db.executeDbAdminCommand({buildinfo:1}, function(err, doc) {
        if(err) return reject(err);
        resolve(doc);
      });
    });
  }
  
  define.classMethod('serverInfo', {callback: true, promise:true});
  
  /**
   * Retrieve this db's server status.
   *
   * @param {Admin~resultCallback} [callback] The command result callback
   * @return {Promise} returns Promise if no callback passed
   */
  Admin.prototype.serverStatus = function(callback) {
    var self = this;
  
    // Execute using callback
    if(typeof callback == 'function') return serverStatus(self, callback)
  
    // Return a Promise
    return new this.s.promiseLibrary(function(resolve, reject) {
      serverStatus(self, function(err, r) {
        if(err) return reject(err);
        resolve(r);
      });
    });
  };
  
  var serverStatus = function(self, callback) {
    self.s.db.executeDbAdminCommand({serverStatus: 1}, function(err, doc) {
      if(err == null && doc.ok === 1) {
        callback(null, doc);
      } else {
        if(err) return callback(err, false);
        return callback(toError(doc), false);
      }
    });
  }
  
  define.classMethod('serverStatus', {callback: true, promise:true});
  
  /**
   * Retrieve the current profiling Level for MongoDB
   *
   * @param {Admin~resultCallback} [callback] The command result callback
   * @return {Promise} returns Promise if no callback passed
   */
  Admin.prototype.profilingLevel = function(callback) {
    var self = this;
  
    // Execute using callback
    if(typeof callback == 'function') return profilingLevel(self, callback)
  
    // Return a Promise
    return new this.s.promiseLibrary(function(resolve, reject) {
      profilingLevel(self, function(err, r) {
        if(err) return reject(err);
        resolve(r);
      });
    });
  };
  
  var profilingLevel = function(self, callback) {
    self.s.db.executeDbAdminCommand({profile:-1}, function(err, doc) {
      doc = doc;
  
      if(err == null && doc.ok === 1) {
        var was = doc.was;
        if(was == 0) return callback(null, "off");
        if(was == 1) return callback(null, "slow_only");
        if(was == 2) return callback(null, "all");
          return callback(new Error("Error: illegal profiling level value " + was), null);
      } else {
        err != null ? callback(err, null) : callback(new Error("Error with profile command"), null);
      }
    });
  }
  
  define.classMethod('profilingLevel', {callback: true, promise:true});
  
  /**
   * Ping the MongoDB server and retrieve results
   *
   * @param {Admin~resultCallback} [callback] The command result callback
   * @return {Promise} returns Promise if no callback passed
   */
  Admin.prototype.ping = function(options, callback) {
    var self = this;
    var args = Array.prototype.slice.call(arguments, 0);
    callback = args.pop();
    if(typeof callback != 'function') args.push(callback);
  
    // Execute using callback
    if(typeof callback == 'function') return this.s.db.executeDbAdminCommand({ping: 1}, callback);
  
    // Return a Promise
    return new this.s.promiseLibrary(function(resolve, reject) {
      self.s.db.executeDbAdminCommand({ping: 1}, function(err, r) {
        if(err) return reject(err);
        resolve(r);
      });
    });
  }
  
  define.classMethod('ping', {callback: true, promise:true});
  
  /**
   * Authenticate a user against the server.
   * @method
   * @param {string} username The username.
   * @param {string} [password] The password.
   * @param {Admin~resultCallback} [callback] The command result callback
   * @return {Promise} returns Promise if no callback passed
   */
  Admin.prototype.authenticate = function(username, password, options, callback) {
    var self = this;
    if(typeof options == 'function') callback = options, options = {};
    options = shallowClone(options);
    options.authdb = 'admin';
    
    // Execute using callback
    if(typeof callback == 'function') return this.s.db.authenticate(username, password, options, callback);
  
    // Return a Promise
    return new this.s.promiseLibrary(function(resolve, reject) {
      self.s.db.authenticate(username, password, options, function(err, r) {
        if(err) return reject(err);
        resolve(r);
      });
    });
  }
  
  define.classMethod('authenticate', {callback: true, promise:true});
  
  /**
   * Logout user from server, fire off on all connections and remove all auth info
   * @method
   * @param {Admin~resultCallback} [callback] The command result callback
   * @return {Promise} returns Promise if no callback passed
   */
  Admin.prototype.logout = function(callback) {
    var self = this;
    // Execute using callback
    if(typeof callback == 'function') return this.s.db.logout({authdb: 'admin'}, callback);
  
    // Return a Promise
    return new this.s.promiseLibrary(function(resolve, reject) {
      self.s.db.logout({authdb: 'admin'}, function(err, r) {
        if(err) return reject(err);
        resolve(r);
      });
    });
  }
  
  define.classMethod('logout', {callback: true, promise:true});
  
  // Get write concern
  var writeConcern = function(options, db) {
    options = shallowClone(options);
  
    // If options already contain write concerns return it
    if(options.w || options.wtimeout || options.j || options.fsync) {
      return options;
    }
  
    // Set db write concern if available
    if(db.writeConcern) {
      if(options.w) options.w = db.writeConcern.w;
      if(options.wtimeout) options.wtimeout = db.writeConcern.wtimeout;
      if(options.j) options.j = db.writeConcern.j;
      if(options.fsync) options.fsync = db.writeConcern.fsync;
    }
  
    // Return modified options
    return options;
  }
  
  /**
   * Add a user to the database.
   * @method
   * @param {string} username The username.
   * @param {string} password The password.
   * @param {object} [options=null] Optional settings.
   * @param {(number|string)} [options.w=null] The write concern.
   * @param {number} [options.wtimeout=null] The write concern timeout.
   * @param {boolean} [options.j=false] Specify a journal write concern.
   * @param {boolean} [options.fsync=false] Specify a file sync write concern.
   * @param {object} [options.customData=null] Custom data associated with the user (only Mongodb 2.6 or higher)
   * @param {object[]} [options.roles=null] Roles associated with the created user (only Mongodb 2.6 or higher)
   * @param {Admin~resultCallback} [callback] The command result callback
   * @return {Promise} returns Promise if no callback passed
   */
  Admin.prototype.addUser = function(username, password, options, callback) {
    var self = this;
    var args = Array.prototype.slice.call(arguments, 2);
    callback = args.pop();
    if(typeof callback != 'function') args.push(callback);
    options = args.length ? args.shift() : {};
    options = options || {};
    // Get the options
    options = writeConcern(options, self.s.db)
    // Set the db name to admin
    options.dbName = 'admin';
  
    // Execute using callback
    if(typeof callback == 'function')
      return self.s.db.addUser(username, password, options, callback);
  
    // Return a Promise
    return new this.s.promiseLibrary(function(resolve, reject) {
      self.s.db.addUser(username, password, options, function(err, r) {
        if(err) return reject(err);
        resolve(r);
      });
    });
  }
  
  define.classMethod('addUser', {callback: true, promise:true});
  
  /**
   * Remove a user from a database
   * @method
   * @param {string} username The username.
   * @param {object} [options=null] Optional settings.
   * @param {(number|string)} [options.w=null] The write concern.
   * @param {number} [options.wtimeout=null] The write concern timeout.
   * @param {boolean} [options.j=false] Specify a journal write concern.
   * @param {boolean} [options.fsync=false] Specify a file sync write concern.
   * @param {Admin~resultCallback} [callback] The command result callback
   * @return {Promise} returns Promise if no callback passed
   */
  Admin.prototype.removeUser = function(username, options, callback) {
    var self = this;
    var args = Array.prototype.slice.call(arguments, 1);
    callback = args.pop();
    if(typeof callback != 'function') args.push(callback);
    options = args.length ? args.shift() : {};
    options = options || {};
    // Get the options
    options = writeConcern(options, self.s.db)
    // Set the db name
    options.dbName = 'admin';
  
    // Execute using callback
    if(typeof callback == 'function')
      return self.s.db.removeUser(username, options, callback);
  
    // Return a Promise
    return new this.s.promiseLibrary(function(resolve, reject) {
      self.s.db.removeUser(username, options, function(err, r) {
        if(err) return reject(err);
        resolve(r);
      });
    });
  }
  
  define.classMethod('removeUser', {callback: true, promise:true});
  
  /**
   * Set the current profiling level of MongoDB
   *
   * @param {string} level The new profiling level (off, slow_only, all).
   * @param {Admin~resultCallback} [callback] The command result callback.
   * @return {Promise} returns Promise if no callback passed
   */
  Admin.prototype.setProfilingLevel = function(level, callback) {
    var self = this;
  
    // Execute using callback
    if(typeof callback == 'function') return setProfilingLevel(self, level, callback);
  
    // Return a Promise
    return new this.s.promiseLibrary(function(resolve, reject) {
      setProfilingLevel(self, level, function(err, r) {
        if(err) return reject(err);
        resolve(r);
      });
    });
  };
  
  var setProfilingLevel = function(self, level, callback) {
    var command = {};
    var profile = 0;
  
    if(level == "off") {
      profile = 0;
    } else if(level == "slow_only") {
      profile = 1;
    } else if(level == "all") {
      profile = 2;
    } else {
      return callback(new Error("Error: illegal profiling level value " + level));
    }
  
    // Set up the profile number
    command['profile'] = profile;
  
    self.s.db.executeDbAdminCommand(command, function(err, doc) {
      doc = doc;
  
      if(err == null && doc.ok === 1)
        return callback(null, level);
      return err != null ? callback(err, null) : callback(new Error("Error with profile command"), null);
    });
  }
  
  define.classMethod('setProfilingLevel', {callback: true, promise:true});
  
  /**
   * Retrive the current profiling information for MongoDB
   *
   * @param {Admin~resultCallback} [callback] The command result callback.
   * @return {Promise} returns Promise if no callback passed
   */
  Admin.prototype.profilingInfo = function(callback) {
    var self = this;
  
    // Execute using callback
    if(typeof callback == 'function') return profilingInfo(self, callback);
  
    // Return a Promise
    return new this.s.promiseLibrary(function(resolve, reject) {
      profilingInfo(self, function(err, r) {
        if(err) return reject(err);
        resolve(r);
      });
    });
  };
  
  var profilingInfo = function(self, callback) {
    try {
      self.s.topology.cursor("admin.system.profile", { find: 'system.profile', query: {}}, {}).toArray(callback);
    } catch (err) {
      return callback(err, null);
    }
  }
  
  define.classMethod('profilingLevel', {callback: true, promise:true});
  
  /**
   * Validate an existing collection
   *
   * @param {string} collectionName The name of the collection to validate.
   * @param {object} [options=null] Optional settings.
   * @param {Admin~resultCallback} [callback] The command result callback.
   * @return {Promise} returns Promise if no callback passed
   */
  Admin.prototype.validateCollection = function(collectionName, options, callback) {
    var self = this;
    var args = Array.prototype.slice.call(arguments, 1);
    callback = args.pop();
    if(typeof callback != 'function') args.push(callback);
    options = args.length ? args.shift() : {};
    options = options || {};
  
    // Execute using callback
    if(typeof callback == 'function')
      return validateCollection(self, collectionName, options, callback);
  
    // Return a Promise
    return new this.s.promiseLibrary(function(resolve, reject) {
      validateCollection(self, collectionName, options, function(err, r) {
        if(err) return reject(err);
        resolve(r);
      });
    });
  };
  
  var validateCollection = function(self, collectionName, options, callback) {
    var command = {validate: collectionName};
    var keys = Object.keys(options);
  
    // Decorate command with extra options
    for(var i = 0; i < keys.length; i++) {
      if(options.hasOwnProperty(keys[i])) {
        command[keys[i]] = options[keys[i]];
      }
    }
  
    self.s.db.command(command, function(err, doc) {
      if(err != null) return callback(err, null);
  
      if(doc.ok === 0)
        return callback(new Error("Error with validate command"), null);
      if(doc.result != null && doc.result.constructor != String)
        return callback(new Error("Error with validation data"), null);
      if(doc.result != null && doc.result.match(/exception|corrupt/) != null)
        return callback(new Error("Error: invalid collection " + collectionName), null);
      if(doc.valid != null && !doc.valid)
        return callback(new Error("Error: invalid collection " + collectionName), null);
  
      return callback(null, doc);
    });
  }
  
  define.classMethod('validateCollection', {callback: true, promise:true});
  
  /**
   * List the available databases
   *
   * @param {Admin~resultCallback} [callback] The command result callback.
   * @return {Promise} returns Promise if no callback passed
   */
  Admin.prototype.listDatabases = function(callback) {
    var self = this;
    // Execute using callback
    if(typeof callback == 'function') return self.s.db.executeDbAdminCommand({listDatabases:1}, {}, callback);
  
    // Return a Promise
    return new this.s.promiseLibrary(function(resolve, reject) {
      self.s.db.executeDbAdminCommand({listDatabases:1}, {}, function(err, r) {
        if(err) return reject(err);
        resolve(r);
      });
    });
  }
  
  define.classMethod('listDatabases', {callback: true, promise:true});
  
  /**
   * Get ReplicaSet status
   *
   * @param {Admin~resultCallback} [callback] The command result callback.
   * @return {Promise} returns Promise if no callback passed
   */
  Admin.prototype.replSetGetStatus = function(callback) {
    var self = this;
    // Execute using callback
    if(typeof callback == 'function') return replSetGetStatus(self, callback);
    // Return a Promise
    return new this.s.promiseLibrary(function(resolve, reject) {
      replSetGetStatus(self, function(err, r) {
        if(err) return reject(err);
        resolve(r);
      });
    });
  };
  
  var replSetGetStatus = function(self, callback) {
    self.s.db.executeDbAdminCommand({replSetGetStatus:1}, function(err, doc) {
      if(err == null && doc.ok === 1)
        return callback(null, doc);
      if(err) return callback(err, false);
      callback(toError(doc), false);
    });
  }
  
  define.classMethod('replSetGetStatus', {callback: true, promise:true});
  
  module.exports = Admin;
  