fruitstand/examples/nodejs-mongodb-angularjs-web-development/node_modules/mongoose/lib/model.js

fruit stand

/*!
 * Module dependencies.
 */

var Document = require('./document')
  , MongooseArray = require('./types/array')
  , MongooseBuffer = require('./types/buffer')
  , MongooseError = require('./error')
  , VersionError = MongooseError.VersionError
  , DivergentArrayError = MongooseError.DivergentArrayError
  , Query = require('./query')
  , Aggregate = require('./aggregate')
  , Schema = require('./schema')
  , Types = require('./schema/index')
  , utils = require('./utils')
  , hasOwnProperty = utils.object.hasOwnProperty
  , isMongooseObject = utils.isMongooseObject
  , EventEmitter = require('events').EventEmitter
  , merge = utils.merge
  , Promise = require('./promise')
  , assert = require('assert')
  , util = require('util')
  , tick = utils.tick
  , Query = require('./query.js')

var VERSION_WHERE = 1
  , VERSION_INC = 2
  , VERSION_ALL = VERSION_WHERE | VERSION_INC;

/**
 * Model constructor
 *
 * Provides the interface to MongoDB collections as well as creates document instances.
 *
 * @param {Object} doc values with which to create the document
 * @inherits Document
 * @event `error`: If listening to this event, it is emitted when a document was saved without passing a callback and an `error` occurred. If not listening, the event bubbles to the connection used to create this Model.
 * @event `index`: Emitted after `Model#ensureIndexes` completes. If an error occurred it is passed with the event.
 * @api public
 */

function Model (doc, fields, skipId) {
  Document.call(this, doc, fields, skipId);
};

/*!
 * Inherits from Document.
 *
 * All Model.prototype features are available on
 * top level (non-sub) documents.
 */

Model.prototype.__proto__ = Document.prototype;

/**
 * Connection the model uses.
 *
 * @api public
 * @property db
 */

Model.prototype.db;

/**
 * Collection the model uses.
 *
 * @api public
 * @property collection
 */

Model.prototype.collection;

/**
 * The name of the model
 *
 * @api public
 * @property modelName
 */

Model.prototype.modelName;

/*!
 * Handles doc.save() callbacks
 */

function handleSave (promise, self) {
  return tick(function handleSave (err, result) {
    if (err) {
      // If the initial insert fails provide a second chance.
      // (If we did this all the time we would break updates)
      if (self.$__.inserting) {
        self.isNew = true;
        self.emit('isNew', true);
      }
      promise.error(err);
      promise = self = null;
      return;
    }

    self.$__storeShard();

    var numAffected;
    if (result) {
      // when inserting, the array of created docs is returned
      numAffected = result.length
        ? result.length
        : result;
    } else {
      numAffected = 0;
    }

    // was this an update that required a version bump?
    if (self.$__.version && !self.$__.inserting) {
      var doIncrement = VERSION_INC === (VERSION_INC & self.$__.version);
      self.$__.version = undefined;

      // increment version if was successful
      if (numAffected > 0) {
        if (doIncrement) {
          var key = self.schema.options.versionKey;
          var version = self.getValue(key) | 0;
          self.setValue(key, version + 1);
        }
      } else {
        // the update failed. pass an error back
        promise.error(new VersionError);
        promise = self = null;
        return;
      }
    }

    self.emit('save', self, numAffected);
    promise.complete(self, numAffected);
    promise = self = null;
  });
}

/**
 * Saves this document.
 *
 * ####Example:
 *
 *     product.sold = Date.now();
 *     product.save(function (err, product, numberAffected) {
 *       if (err) ..
 *     })
 *
 * The callback will receive three parameters, `err` if an error occurred, `product` which is the saved `product`, and `numberAffected` which will be 1 when the document was found and updated in the database, otherwise 0.
 *
 * The `fn` callback is optional. If no `fn` is passed and validation fails, the validation error will be emitted on the connection used to create this model.
 *
 *     var db = mongoose.createConnection(..);
 *     var schema = new Schema(..);
 *     var Product = db.model('Product', schema);
 *
 *     db.on('error', handleError);
 *
 * However, if you desire more local error handling you can add an `error` listener to the model and handle errors there instead.
 *
 *     Product.on('error', handleError);
 *
 * @param {Function} [fn] optional callback
 * @api public
 * @see middleware http://mongoosejs.com/docs/middleware.html
 */

Model.prototype.save = function save (fn) {
  var promise = new Promise(fn)
    , complete = handleSave(promise, this)
    , options = {}

  if (this.schema.options.safe) {
    options.safe = this.schema.options.safe;
  }

  if (this.isNew) {
    // send entire doc
    var obj = this.toObject({ depopulate: 1 });

    if (!utils.object.hasOwnProperty(obj || {}, '_id')) {
      // documents must have an _id else mongoose won't know
      // what to update later if more changes are made. the user
      // wouldn't know what _id was generated by mongodb either
      // nor would the ObjectId generated my mongodb necessarily
      // match the schema definition.
      return complete(new Error('document must have an _id before saving'));
    }

    this.$__version(true, obj);
    this.collection.insert(obj, options, complete);
    this.$__reset();
    this.isNew = false;
    this.emit('isNew', false);
    // Make it possible to retry the insert
    this.$__.inserting = true;

  } else {
    // Make sure we don't treat it as a new object on error,
    // since it already exists
    this.$__.inserting = false;

    var delta = this.$__delta();

    if (delta) {
      if (delta instanceof Error) return complete(delta);
      var where = this.$__where(delta[0]);
      this.$__reset();
      this.collection.update(where, delta[1], options, complete);
    } else {
      this.$__reset();
      complete(null);
    }

    this.emit('isNew', false);
  }
};

/*!
 * Apply the operation to the delta (update) clause as
 * well as track versioning for our where clause.
 *
 * @param {Document} self
 * @param {Object} where
 * @param {Object} delta
 * @param {Object} data
 * @param {Mixed} val
 * @param {String} [operation]
 */

function operand (self, where, delta, data, val, op) {
  // delta
  op || (op = '$set');
  if (!delta[op]) delta[op] = {};
  delta[op][data.path] = val;

  // disabled versioning?
  if (false === self.schema.options.versionKey) return;

  // already marked for versioning?
  if (VERSION_ALL === (VERSION_ALL & self.$__.version)) return;

  switch (op) {
    case '$set':
    case '$unset':
    case '$pop':
    case '$pull':
    case '$pullAll':
    case '$push':
    case '$pushAll':
    case '$addToSet':
      break;
    default:
      // nothing to do
      return;
  }

  // ensure updates sent with positional notation are
  // editing the correct array element.
  // only increment the version if an array position changes.
  // modifying elements of an array is ok if position does not change.

  if ('$push' == op || '$pushAll' == op || '$addToSet' == op) {
    self.$__.version = VERSION_INC;
  }
  else if (/^\$p/.test(op)) {
    // potentially changing array positions
    self.increment();
  }
  else if (Array.isArray(val)) {
    // $set an array
    self.increment();
  }
  // now handling $set, $unset
  else if (/\.\d+\.|\.\d+$/.test(data.path)) {
    // subpath of array
    self.$__.version = VERSION_WHERE;
  }
}

/*!
 * Compiles an update and where clause for a `val` with _atomics.
 *
 * @param {Document} self
 * @param {Object} where
 * @param {Object} delta
 * @param {Object} data
 * @param {Array} value
 */

function handleAtomics (self, where, delta, data, value) {
  if (delta.$set && delta.$set[data.path]) {
    // $set has precedence over other atomics
    return;
  }

  if ('function' == typeof value.$__getAtomics) {
    value.$__getAtomics().forEach(function (atomic) {
      var op = atomic[0];
      var val = atomic[1];
      operand(self, where, delta, data, val, op);
    })
    return;
  }

  // legacy support for plugins

  var atomics = value._atomics
    , ops = Object.keys(atomics)
    , i = ops.length
    , val
    , op;

  if (0 === i) {
    // $set

    if (isMongooseObject(value)) {
      value = value.toObject({ depopulate: 1 });
    } else if (value.valueOf) {
      value = value.valueOf();
    }

    return operand(self, where, delta, data, value);
  }

  while (i--) {
    op = ops[i];
    val = atomics[op];

    if (isMongooseObject(val)) {
      val = val.toObject({ depopulate: 1 })
    } else if (Array.isArray(val)) {
      val = val.map(function (mem) {
        return isMongooseObject(mem)
          ? mem.toObject({ depopulate: 1 })
          : mem;
      })
    } else if (val.valueOf) {
      val = val.valueOf()
    }

    if ('$addToSet' === op)
      val = { $each: val };

    operand(self, where, delta, data, val, op);
  }
}

/**
 * Produces a special query document of the modified properties used in updates.
 *
 * @api private
 * @method $__delta
 * @memberOf Model
 */

Model.prototype.$__delta = function () {
  var dirty = this.$__dirty();
  if (!dirty.length && VERSION_ALL != this.$__.version) return;

  var where = {}
    , delta = {}
    , len = dirty.length
    , divergent = []
    , d = 0
    , val
    , obj

  for (; d < len; ++d) {
    var data = dirty[d]
    var value = data.value
    var schema = data.schema

    var match = checkDivergentArray(this, data.path, value);
    if (match) {
      divergent.push(match);
      continue;
    }

    if (divergent.length) continue;

    if (undefined === value) {
      operand(this, where, delta, data, 1, '$unset');

    } else if (null === value) {
      operand(this, where, delta, data, null);

    } else if (value._path && value._atomics) {
      // arrays and other custom types (support plugins etc)
      handleAtomics(this, where, delta, data, value);

    } else if (value._path && Buffer.isBuffer(value)) {
      // MongooseBuffer
      value = value.toObject();
      operand(this, where, delta, data, value);

    } else {
      value = utils.clone(value, { depopulate: 1 });
      operand(this, where, delta, data, value);
    }
  }

  if (divergent.length) {
    return new DivergentArrayError(divergent);
  }

  if (this.$__.version) {
    this.$__version(where, delta);
  }

  return [where, delta];
}

/*!
 * Determine if array was populated with some form of filter and is now
 * being updated in a manner which could overwrite data unintentionally.
 *
 * @see https://github.com/LearnBoost/mongoose/issues/1334
 * @param {Document} doc
 * @param {String} path
 * @return {String|undefined}
 */

function checkDivergentArray (doc, path, array) {
  // see if we populated this path
  var pop = doc.populated(path, true);

  if (!pop && doc.$__.selected) {
    // If any array was selected using an $elemMatch projection, we deny the update.
    // NOTE: MongoDB only supports projected $elemMatch on top level array.
    var top = path.split('.')[0];
    if (doc.$__.selected[top] && doc.$__.selected[top].$elemMatch) {
      return top;
    }
  }

  if (!(pop && array instanceof MongooseArray)) return;

  // If the array was populated using options that prevented all
  // documents from being returned (match, skip, limit) or they
  // deselected the _id field, $pop and $set of the array are
  // not safe operations. If _id was deselected, we do not know
  // how to remove elements. $pop will pop off the _id from the end
  // of the array in the db which is not guaranteed to be the
  // same as the last element we have here. $set of the entire array
  // would be similarily destructive as we never received all
  // elements of the array and potentially would overwrite data.
  var check = pop.options.match ||
              pop.options.options && hasOwnProperty(pop.options.options, 'limit') || // 0 is not permitted
              pop.options.options && pop.options.options.skip || // 0 is permitted
              pop.options.select && // deselected _id?
                (0 === pop.options.select._id ||
                /\s?-_id\s?/.test(pop.options.select))

  if (check) {
    var atomics = array._atomics;
    if (0 === Object.keys(atomics).length || atomics.$set || atomics.$pop) {
      return path;
    }
  }
}

/**
 * Appends versioning to the where and update clauses.
 *
 * @api private
 * @method $__version
 * @memberOf Model
 */

Model.prototype.$__version = function (where, delta) {
  var key = this.schema.options.versionKey;

  if (true === where) {
    // this is an insert
    if (key) this.setValue(key, delta[key] = 0);
    return;
  }

  // updates

  // only apply versioning if our versionKey was selected. else
  // there is no way to select the correct version. we could fail
  // fast here and force them to include the versionKey but
  // thats a bit intrusive. can we do this automatically?
  if (!this.isSelected(key)) {
    return;
  }

  // $push $addToSet don't need the where clause set
  if (VERSION_WHERE === (VERSION_WHERE & this.$__.version)) {
    where[key] = this.getValue(key);
  }

  if (VERSION_INC === (VERSION_INC & this.$__.version)) {
    delta.$inc || (delta.$inc = {});
    delta.$inc[key] = 1;
  }
}

/**
 * Signal that we desire an increment of this documents version.
 *
 * ####Example:
 *
 *     Model.findById(id, function (err, doc) {
 *       doc.increment();
 *       doc.save(function (err) { .. })
 *     })
 *
 * @see versionKeys http://mongoosejs.com/docs/guide.html#versionKey
 * @api public
 */

Model.prototype.increment = function increment () {
  this.$__.version = VERSION_ALL;
  return this;
}

/**
 * Returns a query object which applies shardkeys if they exist.
 *
 * @api private
 * @method $__where
 * @memberOf Model
 */

Model.prototype.$__where = function _where (where) {
  where || (where = {});

  var paths
    , len

  if (this.$__.shardval) {
    paths = Object.keys(this.$__.shardval)
    len = paths.length

    for (var i = 0; i < len; ++i) {
      where[paths[i]] = this.$__.shardval[paths[i]];
    }
  }

  where._id = this._doc._id;
  return where;
}

/**
 * Removes this document from the db.
 *
 * ####Example:
 *
 *     product.remove(function (err, product) {
 *       if (err) return handleError(err);
 *       Product.findById(product._id, function (err, product) {
 *         console.log(product) // null
 *       })
 *     })
 *
 * @param {Function} [fn] optional callback
 * @api public
 */

Model.prototype.remove = function remove (fn) {
  if (this.$__.removing) {
    this.$__.removing.addBack(fn);
    return this;
  }

  var promise = this.$__.removing = new Promise(fn)
    , where = this.$__where()
    , self = this
    , options = {}

  if (this.schema.options.safe) {
    options.safe = this.schema.options.safe;
  }

  this.collection.remove(where, options, tick(function (err) {
    if (err) {
      promise.error(err);
      promise = self = self.$__.removing = where = options = null;
      return;
    }
    self.emit('remove', self);
    promise.complete(self);
    promise = self = where = options = null;
  }));

  return this;
};

/**
 * Returns another Model instance.
 *
 * ####Example:
 *
 *     var doc = new Tank;
 *     doc.model('User').findById(id, callback);
 *
 * @param {String} name model name
 * @api public
 */

Model.prototype.model = function model (name) {
  return this.db.model(name);
};

/**
 * Adds a discriminator type.
 *
 * ####Example:
 *
 *     function BaseSchema() {
 *       Schema.apply(this, arguments);
 *
 *       this.add({
 *         name: String,
 *         createdAt: Date
 *       });
 *     }
 *     util.inherits(BaseSchema, Schema);
 *
 *     var PersonSchema = new BaseSchema();
 *     var BossSchema = new BaseSchema({ department: String });
 *
 *     var Person = mongoose.model('Person', PersonSchema);
 *     var Boss = Person.discriminator('Boss', BossSchema);
 *
 * @param {String} name   discriminator model name
 * @param {Schema} schema discriminator model schema
 * @api public
 */

Model.discriminator = function discriminator (name, schema) {
  if (!(schema instanceof Schema)) {
    throw new Error("You must pass a valid discriminator Schema");
  }

  if (this.schema.discriminatorMapping && !this.schema.discriminatorMapping.isRoot) {
    throw new Error("Discriminator \"" + name + "\" can only be a discriminator of the root model");
  }

  var key = this.schema.options.discriminatorKey;
  if (schema.path(key)) {
    throw new Error("Discriminator \"" + name + "\" cannot have field with name \"" + key + "\"");
  }

  // merges base schema into new discriminator schema and sets new type field.
  (function mergeSchemas(schema, baseSchema) {
    utils.merge(schema, baseSchema);

    var obj = {};
    obj[key] = { type: String, default: name };
    schema.add(obj);
    schema.discriminatorMapping = { key: key, value: name, isRoot: false };

    if (baseSchema.options.collection) {
      schema.options.collection = baseSchema.options.collection;
    }

      // throws error if options are invalid
    (function validateOptions(a, b) {
      a = utils.clone(a);
      b = utils.clone(b);
      delete a.toJSON;
      delete a.toObject;
      delete b.toJSON;
      delete b.toObject;

      if (!utils.deepEqual(a, b)) {
        throw new Error("Discriminator options are not customizable (except toJSON & toObject)");
      }
    })(schema.options, baseSchema.options);

    var toJSON = schema.options.toJSON
      , toObject = schema.options.toObject;

    schema.options = utils.clone(baseSchema.options);
    if (toJSON)   schema.options.toJSON = toJSON;
    if (toObject) schema.options.toObject = toObject;

    schema.callQueue = baseSchema.callQueue.concat(schema.callQueue);
    schema._requiredpaths = undefined; // reset just in case Schema#requiredPaths() was called on either schema
  })(schema, this.schema);

  if (!this.discriminators) {
    this.discriminators = {};
  }

  if (!this.schema.discriminatorMapping) {
    this.schema.discriminatorMapping = { key: key, value: null, isRoot: true };
  }

  if (this.discriminators[name]) {
    throw new Error("Discriminator with name \"" + name + "\" already exists");
  }

  this.discriminators[name] = this.db.model(name, schema, this.collection.name);
  this.discriminators[name].prototype.__proto__ = this.prototype;

  return this.discriminators[name];
};

// Model (class) features

/*!
 * Give the constructor the ability to emit events.
 */

for (var i in EventEmitter.prototype)
  Model[i] = EventEmitter.prototype[i];

/**
 * Called when the model compiles.
 *
 * @api private
 */

Model.init = function init () {
  if (this.schema.options.autoIndex) {
    this.ensureIndexes();
  }

  this.schema.emit('init', this);
};

/**
 * Sends `ensureIndex` commands to mongo for each index declared in the schema.
 *
 * ####Example:
 *
 *     Event.ensureIndexes(function (err) {
 *       if (err) return handleError(err);
 *     });
 *
 * After completion, an `index` event is emitted on this `Model` passing an error if one occurred.
 *
 * ####Example:
 *
 *     var eventSchema = new Schema({ thing: { type: 'string', unique: true }})
 *     var Event = mongoose.model('Event', eventSchema);
 *
 *     Event.on('index', function (err) {
 *       if (err) console.error(err); // error occurred during index creation
 *     })
 *
 * _NOTE: It is not recommended that you run this in production. Index creation may impact database performance depending on your load. Use with caution._
 *
 * The `ensureIndex` commands are not sent in parallel. This is to avoid the `MongoError: cannot add index with a background operation in progress` error. See [this ticket](https://github.com/LearnBoost/mongoose/issues/1365) for more information.
 *
 * @param {Function} [cb] optional callback
 * @return {Promise}
 * @api public
 */

Model.ensureIndexes = function ensureIndexes (cb) {
  var promise = new Promise(cb);

  var indexes = this.schema.indexes();
  if (!indexes.length) {
    process.nextTick(promise.fulfill.bind(promise));
    return promise;
  }

  // Indexes are created one-by-one to support how MongoDB < 2.4 deals
  // with background indexes.

  var self = this
    , safe = self.schema.options.safe

  function done (err) {
    self.emit('index', err);
    promise.resolve(err);
  }

  function create () {
    var index = indexes.shift();
    if (!index) return done();

    var options = index[1];
    options.safe = safe;
    self.collection.ensureIndex(index[0], options, tick(function (err) {
      if (err) return done(err);
      create();
    }));
  }

  create();
  return promise;
}

/**
 * Schema the model uses.
 *
 * @property schema
 * @receiver Model
 * @api public
 */

Model.schema;

/*!
 * Connection instance the model uses.
 *
 * @property db
 * @receiver Model
 * @api public
 */

Model.db;

/*!
 * Collection the model uses.
 *
 * @property collection
 * @receiver Model
 * @api public
 */

Model.collection;

/**
 * Base Mongoose instance the model uses.
 *
 * @property base
 * @receiver Model
 * @api public
 */

Model.base;

/**
 * Registered discriminators for this model.
 *
 * @property discriminators
 * @receiver Model
 * @api public
 */

Model.discriminators;

/**
 * Removes documents from the collection.
 *
 * ####Example:
 *
 *     Comment.remove({ title: 'baby born from alien father' }, function (err) {
 *
 *     });
 *
 * ####Note:
 *
 * To remove documents without waiting for a response from MongoDB, do not pass a `callback`, then call `exec` on the returned [Query](#query-js):
 *
 *     var query = Comment.remove({ _id: id });
 *     query.exec();
 *
 * ####Note:
 *
 * This method sends a remove command directly to MongoDB, no Mongoose documents are involved. Because no Mongoose documents are involved, _no middleware (hooks) are executed_.
 *
 * @param {Object} conditions
 * @param {Function} [callback]
 * @return {Query}
 * @api public
 */

Model.remove = function remove (conditions, callback) {
  if ('function' === typeof conditions) {
    callback = conditions;
    conditions = {};
  }

  // get the mongodb collection object
  var mq = new Query(conditions, {}, this, this.collection);

  return mq.remove(callback);
};

/**
 * Finds documents
 *
 * The `conditions` are cast to their respective SchemaTypes before the command is sent.
 *
 * ####Examples:
 *
 *     // named john and at least 18
 *     MyModel.find({ name: 'john', age: { $gte: 18 }});
 *
 *     // executes immediately, passing results to callback
 *     MyModel.find({ name: 'john', age: { $gte: 18 }}, function (err, docs) {});
 *
 *     // name LIKE john and only selecting the "name" and "friends" fields, executing immediately
 *     MyModel.find({ name: /john/i }, 'name friends', function (err, docs) { })
 *
 *     // passing options
 *     MyModel.find({ name: /john/i }, null, { skip: 10 })
 *
 *     // passing options and executing immediately
 *     MyModel.find({ name: /john/i }, null, { skip: 10 }, function (err, docs) {});
 *
 *     // executing a query explicitly
 *     var query = MyModel.find({ name: /john/i }, null, { skip: 10 })
 *     query.exec(function (err, docs) {});
 *
 *     // using the promise returned from executing a query
 *     var query = MyModel.find({ name: /john/i }, null, { skip: 10 });
 *     var promise = query.exec();
 *     promise.addBack(function (err, docs) {});
 *
 * @param {Object} conditions
 * @param {Object} [fields] optional fields to select
 * @param {Object} [options] optional
 * @param {Function} [callback]
 * @return {Query}
 * @see field selection #query_Query-select
 * @see promise #promise-js
 * @api public
 */

Model.find = function find (conditions, fields, options, callback) {
  if ('function' == typeof conditions) {
    callback = conditions;
    conditions = {};
    fields = null;
    options = null;
  } else if ('function' == typeof fields) {
    callback = fields;
    fields = null;
    options = null;
  } else if ('function' == typeof options) {
    callback = options;
    options = null;
  }

  // get the raw mongodb collection object
  var mq = new Query({}, options, this, this.collection);
  mq.select(fields);
  if (this.schema.discriminatorMapping && mq._selectedInclusively()) {
    mq.select(this.schema.options.discriminatorKey);
  }

  return mq.find(conditions, callback);
};

/**
 * Finds a single document by id.
 *
 * The `id` is cast based on the Schema before sending the command.
 *
 * ####Example:
 *
 *     // find adventure by id and execute immediately
 *     Adventure.findById(id, function (err, adventure) {});
 *
 *     // same as above
 *     Adventure.findById(id).exec(callback);
 *
 *     // select only the adventures name and length
 *     Adventure.findById(id, 'name length', function (err, adventure) {});
 *
 *     // same as above
 *     Adventure.findById(id, 'name length').exec(callback);
 *
 *     // include all properties except for `length`
 *     Adventure.findById(id, '-length').exec(function (err, adventure) {});
 *
 *     // passing options (in this case return the raw js objects, not mongoose documents by passing `lean`
 *     Adventure.findById(id, 'name', { lean: true }, function (err, doc) {});
 *
 *     // same as above
 *     Adventure.findById(id, 'name').lean().exec(function (err, doc) {});
 *
 * @param {ObjectId|HexId} id objectid, or a value that can be casted to one
 * @param {Object} [fields] optional fields to select
 * @param {Object} [options] optional
 * @param {Function} [callback]
 * @return {Query}
 * @see field selection #query_Query-select
 * @see lean queries #query_Query-lean
 * @api public
 */

Model.findById = function findById (id, fields, options, callback) {
  return this.findOne({ _id: id }, fields, options, callback);
};

/**
 * Finds one document.
 *
 * The `conditions` are cast to their respective SchemaTypes before the command is sent.
 *
 * ####Example:
 *
 *     // find one iphone adventures - iphone adventures??
 *     Adventure.findOne({ type: 'iphone' }, function (err, adventure) {});
 *
 *     // same as above
 *     Adventure.findOne({ type: 'iphone' }).exec(function (err, adventure) {});
 *
 *     // select only the adventures name
 *     Adventure.findOne({ type: 'iphone' }, 'name', function (err, adventure) {});
 *
 *     // same as above
 *     Adventure.findOne({ type: 'iphone' }, 'name').exec(function (err, adventure) {});
 *
 *     // specify options, in this case lean
 *     Adventure.findOne({ type: 'iphone' }, 'name', { lean: true }, callback);
 *
 *     // same as above
 *     Adventure.findOne({ type: 'iphone' }, 'name', { lean: true }).exec(callback);
 *
 *     // chaining findOne queries (same as above)
 *     Adventure.findOne({ type: 'iphone' }).select('name').lean().exec(callback);
 *
 * @param {Object} conditions
 * @param {Object} [fields] optional fields to select
 * @param {Object} [options] optional
 * @param {Function} [callback]
 * @return {Query}
 * @see field selection #query_Query-select
 * @see lean queries #query_Query-lean
 * @api public
 */

Model.findOne = function findOne (conditions, fields, options, callback) {
  if ('function' == typeof options) {
    callback = options;
    options = null;
  } else if ('function' == typeof fields) {
    callback = fields;
    fields = null;
    options = null;
  } else if ('function' == typeof conditions) {
    callback = conditions;
    conditions = {};
    fields = null;
    options = null;
  }

  // get the mongodb collection object
  var mq = new Query({}, options, this, this.collection);
  mq.select(fields);
  if (this.schema.discriminatorMapping && mq._selectedInclusively()) {
    mq.select(this.schema.options.discriminatorKey);
  }

  return mq.findOne(conditions, callback);
};

/**
 * Counts number of matching documents in a database collection.
 *
 * ####Example:
 *
 *     Adventure.count({ type: 'jungle' }, function (err, count) {
 *       if (err) ..
 *       console.log('there are %d jungle adventures', count);
 *     });
 *
 * @param {Object} conditions
 * @param {Function} [callback]
 * @return {Query}
 * @api public
 */

Model.count = function count (conditions, callback) {
  if ('function' === typeof conditions)
    callback = conditions, conditions = {};

  // get the mongodb collection object
  var mq = new Query({}, {}, this, this.collection);

  return mq.count(conditions, callback);
};

/**
 * Creates a Query for a `distinct` operation.
 *
 * Passing a `callback` immediately executes the query.
 *
 * ####Example
 *
 *     Link.distinct('url', { clicks: {$gt: 100}}, function (err, result) {
 *       if (err) return handleError(err);
 *
 *       assert(Array.isArray(result));
 *       console.log('unique urls with more than 100 clicks', result);
 *     })
 *
 *     var query = Link.distinct('url');
 *     query.exec(callback);
 *
 * @param {String} field
 * @param {Object} [conditions] optional
 * @param {Function} [callback]
 * @return {Query}
 * @api public
 */

Model.distinct = function distinct (field, conditions, callback) {
  // get the mongodb collection object
  var mq = new Query({}, {}, this, this.collection);

  if ('function' == typeof conditions) {
    callback = conditions;
    conditions = {};
  }

  return mq.distinct(conditions, field, callback);
};

/**
 * Creates a Query, applies the passed conditions, and returns the Query.
 *
 * For example, instead of writing:
 *
 *     User.find({age: {$gte: 21, $lte: 65}}, callback);
 *
 * we can instead write:
 *
 *     User.where('age').gte(21).lte(65).exec(callback);
 *
 * Since the Query class also supports `where` you can continue chaining
 *
 *     User
 *     .where('age').gte(21).lte(65)
 *     .where('name', /^b/i)
 *     ... etc
 *
 * @param {String} path
 * @param {Object} [val] optional value
 * @return {Query}
 * @api public
 */

Model.where = function where (path, val) {
  // get the mongodb collection object
  var mq = new Query({}, {}, this, this.collection).find({});
  return mq.where.apply(mq, arguments);
};

/**
 * Creates a `Query` and specifies a `$where` condition.
 *
 * Sometimes you need to query for things in mongodb using a JavaScript expression. You can do so via `find({ $where: javascript })`, or you can use the mongoose shortcut method $where via a Query chain or from your mongoose Model.
 *
 *     Blog.$where('this.comments.length > 5').exec(function (err, docs) {});
 *
 * @param {String|Function} argument is a javascript string or anonymous function
 * @method $where
 * @memberOf Model
 * @return {Query}
 * @see Query.$where #query_Query-%24where
 * @api public
 */

Model.$where = function $where () {
  var mq = new Query({}, {}, this, this.collection).find({});
  return mq.$where.apply(mq, arguments);
};

/**
 * Issues a mongodb findAndModify update command.
 *
 * Finds a matching document, updates it according to the `update` arg, passing any `options`, and returns the found document (if any) to the callback. The query executes immediately if `callback` is passed else a Query object is returned.
 *
 * ####Options:
 *
 * - `new`: bool - true to return the modified document rather than the original. defaults to true
 * - `upsert`: bool - creates the object if it doesn't exist. defaults to false.
 * - `sort`: if multiple docs are found by the conditions, sets the sort order to choose which doc to update
 * - `select`: sets the document fields to return
 *
 * ####Examples:
 *
 *     A.findOneAndUpdate(conditions, update, options, callback) // executes
 *     A.findOneAndUpdate(conditions, update, options)  // returns Query
 *     A.findOneAndUpdate(conditions, update, callback) // executes
 *     A.findOneAndUpdate(conditions, update)           // returns Query
 *     A.findOneAndUpdate()                             // returns Query
 *
 * ####Note:
 *
 * All top level update keys which are not `atomic` operation names are treated as set operations:
 *
 * ####Example:
 *
 *     var query = { name: 'borne' };
 *     Model.findOneAndUpdate(query, { name: 'jason borne' }, options, callback)
 *
 *     // is sent as
 *     Model.findOneAndUpdate(query, { $set: { name: 'jason borne' }}, options, callback)
 *
 * This helps prevent accidentally overwriting your document with `{ name: 'jason borne' }`.
 *
 * ####Note:
 *
 * Although values are cast to their appropriate types when using the findAndModify helpers, the following are *not* applied:
 *
 * - defaults
 * - setters
 * - validators
 * - middleware
 *
 * If you need those features, use the traditional approach of first retrieving the document.
 *
 *     Model.findOne({ name: 'borne' }, function (err, doc) {
 *       if (err) ..
 *       doc.name = 'jason borne';
 *       doc.save(callback);
 *     })
 *
 * @param {Object} [conditions]
 * @param {Object} [update]
 * @param {Object} [options]
 * @param {Function} [callback]
 * @return {Query}
 * @see mongodb http://www.mongodb.org/display/DOCS/findAndModify+Command
 * @api public
 */

Model.findOneAndUpdate = function (conditions, update, options, callback) {
  if ('function' == typeof options) {
    callback = options;
    options = null;
  }
  else if (1 === arguments.length) {
    if ('function' == typeof conditions) {
      var msg = 'Model.findOneAndUpdate(): First argument must not be a function.\n\n'
              + '  ' + this.modelName + '.findOneAndUpdate(conditions, update, options, callback)\n'
              + '  ' + this.modelName + '.findOneAndUpdate(conditions, update, options)\n'
              + '  ' + this.modelName + '.findOneAndUpdate(conditions, update)\n'
              + '  ' + this.modelName + '.findOneAndUpdate(update)\n'
              + '  ' + this.modelName + '.findOneAndUpdate()\n';
      throw new TypeError(msg)
    }
    update = conditions;
    conditions = undefined;
  }

  var fields;
  if (options && options.fields) {
    fields = options.fields;
    options.fields = undefined;
  }

  var mq = new Query({}, {}, this, this.collection);
  mq.select(fields);

  return mq.findOneAndUpdate(conditions, update, options, callback);
}

/**
 * Issues a mongodb findAndModify update command by a documents id.
 *
 * Finds a matching document, updates it according to the `update` arg, passing any `options`, and returns the found document (if any) to the callback. The query executes immediately if `callback` is passed else a Query object is returned.
 *
 * ####Options:
 *
 * - `new`: bool - true to return the modified document rather than the original. defaults to true
 * - `upsert`: bool - creates the object if it doesn't exist. defaults to false.
 * - `sort`: if multiple docs are found by the conditions, sets the sort order to choose which doc to update
 * - `select`: sets the document fields to return
 *
 * ####Examples:
 *
 *     A.findByIdAndUpdate(id, update, options, callback) // executes
 *     A.findByIdAndUpdate(id, update, options)  // returns Query
 *     A.findByIdAndUpdate(id, update, callback) // executes
 *     A.findByIdAndUpdate(id, update)           // returns Query
 *     A.findByIdAndUpdate()                     // returns Query
 *
 * Finds a matching document, updates it according to the `update` arg, passing any `options`, and returns the found document (if any) to the callback. The query executes      immediately if `callback` is passed else a Query object is returned.
 *
 * ####Options:
 *
 * - `new`: bool - true to return the modified document rather than the original. defaults to true
 * - `upsert`: bool - creates the object if it doesn't exist. defaults to false.
 * - `sort`: if multiple docs are found by the conditions, sets the sort order to choose which doc to update
 *
 * ####Note:
 *
 * All top level update keys which are not `atomic` operation names are treated as set operations:
 *
 * ####Example:
 *
 *     Model.findByIdAndUpdate(id, { name: 'jason borne' }, options, callback)
 *
 *     // is sent as
 *     Model.findByIdAndUpdate(id, { $set: { name: 'jason borne' }}, options, callback)
 *
 * This helps prevent accidentally overwriting your document with `{ name: 'jason borne' }`.
 *
 * ####Note:
 *
 * Although values are cast to their appropriate types when using the findAndModify helpers, the following are *not* applied:
 *
 * - defaults
 * - setters
 * - validators
 * - middleware
 *
 * If you need those features, use the traditional approach of first retrieving the document.
 *
 *     Model.findById(id, function (err, doc) {
 *       if (err) ..
 *       doc.name = 'jason borne';
 *       doc.save(callback);
 *     })
 *
 * @param {ObjectId|HexId} id an ObjectId or string that can be cast to one.
 * @param {Object} [update]
 * @param {Object} [options]
 * @param {Function} [callback]
 * @return {Query}
 * @see Model.findOneAndUpdate #model_Model.findOneAndUpdate
 * @see mongodb http://www.mongodb.org/display/DOCS/findAndModify+Command
 * @api public
 */

Model.findByIdAndUpdate = function (id, update, options, callback) {
  var args;

  if (1 === arguments.length) {
    if ('function' == typeof id) {
      var msg = 'Model.findByIdAndUpdate(): First argument must not be a function.\n\n'
                + '  ' + this.modelName + '.findByIdAndUpdate(id, callback)\n'
                + '  ' + this.modelName + '.findByIdAndUpdate(id)\n'
                + '  ' + this.modelName + '.findByIdAndUpdate()\n';
      throw new TypeError(msg)
    }
    return this.findOneAndUpdate({_id: id }, undefined);
  }

  args = utils.args(arguments, 1);

  // if a model is passed in instead of an id
  if (id && id._id) {
    id = id._id;
  }
  if (id) {
    args.unshift({ _id: id });
  }
  return this.findOneAndUpdate.apply(this, args);
}

/**
 * Issue a mongodb findAndModify remove command.
 *
 * Finds a matching document, removes it, passing the found document (if any) to the callback.
 *
 * Executes immediately if `callback` is passed else a Query object is returned.
 *
 * ####Options:
 *
 * - `sort`: if multiple docs are found by the conditions, sets the sort order to choose which doc to update
 * - `select`: sets the document fields to return
 *
 * ####Examples:
 *
 *     A.findOneAndRemove(conditions, options, callback) // executes
 *     A.findOneAndRemove(conditions, options)  // return Query
 *     A.findOneAndRemove(conditions, callback) // executes
 *     A.findOneAndRemove(conditions) // returns Query
 *     A.findOneAndRemove()           // returns Query
 *
 * Although values are cast to their appropriate types when using the findAndModify helpers, the following are *not* applied:
 *
 * - defaults
 * - setters
 * - validators
 * - middleware
 *
 * If you need those features, use the traditional approach of first retrieving the document.
 *
 *     Model.findById(id, function (err, doc) {
 *       if (err) ..
 *       doc.remove(callback);
 *     })
 *
 * @param {Object} conditions
 * @param {Object} [options]
 * @param {Function} [callback]
 * @return {Query}
 * @see mongodb http://www.mongodb.org/display/DOCS/findAndModify+Command
 * @api public
 */

Model.findOneAndRemove = function (conditions, options, callback) {
  if (1 === arguments.length && 'function' == typeof conditions) {
    var msg = 'Model.findOneAndRemove(): First argument must not be a function.\n\n'
              + '  ' + this.modelName + '.findOneAndRemove(conditions, callback)\n'
              + '  ' + this.modelName + '.findOneAndRemove(conditions)\n'
              + '  ' + this.modelName + '.findOneAndRemove()\n';
    throw new TypeError(msg)
  }

  if ('function' == typeof options) {
    callback = options;
    options = undefined;
  }

  var fields;
  if (options) {
    fields = options.select;
    options.select = undefined;
  }

  var mq = new Query({}, {}, this, this.collection);
  mq.select(fields);

  return mq.findOneAndRemove(conditions, options, callback);
}

/**
 * Issue a mongodb findAndModify remove command by a documents id.
 *
 * Finds a matching document, removes it, passing the found document (if any) to the callback.
 *
 * Executes immediately if `callback` is passed, else a `Query` object is returned.
 *
 * ####Options:
 *
 * - `sort`: if multiple docs are found by the conditions, sets the sort order to choose which doc to update
 * - `select`: sets the document fields to return
 *
 * ####Examples:
 *
 *     A.findByIdAndRemove(id, options, callback) // executes
 *     A.findByIdAndRemove(id, options)  // return Query
 *     A.findByIdAndRemove(id, callback) // executes
 *     A.findByIdAndRemove(id) // returns Query
 *     A.findByIdAndRemove()           // returns Query
 *
 * @param {ObjectId|HexString} id ObjectId or string that can be cast to one
 * @param {Object} [options]
 * @param {Function} [callback]
 * @return {Query}
 * @see Model.findOneAndRemove #model_Model.findOneAndRemove
 * @see mongodb http://www.mongodb.org/display/DOCS/findAndModify+Command
 */

Model.findByIdAndRemove = function (id, options, callback) {
  if (1 === arguments.length && 'function' == typeof id) {
    var msg = 'Model.findByIdAndRemove(): First argument must not be a function.\n\n'
              + '  ' + this.modelName + '.findByIdAndRemove(id, callback)\n'
              + '  ' + this.modelName + '.findByIdAndRemove(id)\n'
              + '  ' + this.modelName + '.findByIdAndRemove()\n';
    throw new TypeError(msg)
  }

  return this.findOneAndRemove({ _id: id }, options, callback);
}

/**
 * Shortcut for creating a new Document that is automatically saved to the db if valid.
 *
 * ####Example:
 *
 *     // pass individual docs
 *     Candy.create({ type: 'jelly bean' }, { type: 'snickers' }, function (err, jellybean, snickers) {
 *       if (err) // ...
 *     });
 *
 *     // pass an array
 *     var array = [{ type: 'jelly bean' }, { type: 'snickers' }];
 *     Candy.create(array, function (err, jellybean, snickers) {
 *       if (err) // ...
 *     });
 *
 *     // callback is optional; use the returned promise if you like:
 *     var promise = Candy.create({ type: 'jawbreaker' });
 *     promise.then(function (jawbreaker) {
 *       // ...
 *     })
 *
 * @param {Array|Object...} doc(s)
 * @param {Function} [fn] callback
 * @return {Promise}
 * @api public
 */

Model.create = function create (doc, fn) {
  var promise = new Promise
    , args

  if (Array.isArray(doc)) {
    args = doc;

    if ('function' == typeof fn) {
      promise.onResolve(fn);
    }

  } else {
    var last  = arguments[arguments.length - 1];

    if ('function' == typeof last) {
      promise.onResolve(last);
      args = utils.args(arguments, 0, arguments.length - 1);
    } else {
      args = utils.args(arguments);
    }
  }

  var count = args.length;

  if (0 === count) {
    promise.complete();
    return promise;
  }

  var self = this;
  var docs = [];

  args.forEach(function (arg, i) {
    var doc = new self(arg);
    docs[i] = doc;
    doc.save(function (err) {
      if (err) return promise.error(err);
      --count || promise.complete.apply(promise, docs);
    });
  });

  return promise;
};

/**
 * Updates documents in the database without returning them.
 *
 * ####Examples:
 *
 *     MyModel.update({ age: { $gt: 18 } }, { oldEnough: true }, fn);
 *     MyModel.update({ name: 'Tobi' }, { ferret: true }, { multi: true }, function (err, numberAffected, raw) {
 *       if (err) return handleError(err);
 *       console.log('The number of updated documents was %d', numberAffected);
 *       console.log('The raw response from Mongo was ', raw);
 *     });
 *
 * ####Valid options:
 *
 *  - `safe` (boolean) safe mode (defaults to value set in schema (true))
 *  - `upsert` (boolean) whether to create the doc if it doesn't match (false)
 *  - `multi` (boolean) whether multiple documents should be updated (false)
 *  - `strict` (boolean) overrides the `strict` option for this update
 *
 * All `update` values are cast to their appropriate SchemaTypes before being sent.
 *
 * The `callback` function receives `(err, numberAffected, rawResponse)`.
 *
 * - `err` is the error if any occurred
 * - `numberAffected` is the count of updated documents Mongo reported
 * - `rawResponse` is the full response from Mongo
 *
 * ####Note:
 *
 * All top level keys which are not `atomic` operation names are treated as set operations:
 *
 * ####Example:
 *
 *     var query = { name: 'borne' };
 *     Model.update(query, { name: 'jason borne' }, options, callback)
 *
 *     // is sent as
 *     Model.update(query, { $set: { name: 'jason borne' }}, options, callback)
 *
 * This helps prevent accidentally overwriting all documents in your collection with `{ name: 'jason borne' }`.
 *
 * ####Note:
 *
 * Be careful to not use an existing model instance for the update clause (this won't work and can cause weird behavior like infinite loops). Also, ensure that the update clause does not have an _id property, which causes Mongo to return a "Mod on _id not allowed" error.
 *
 * ####Note:
 *
 * To update documents without waiting for a response from MongoDB, do not pass a `callback`, then call `exec` on the returned [Query](#query-js):
 *
 *     Comment.update({ _id: id }, { $set: { text: 'changed' }}).exec();
 *
 * ####Note:
 *
 * Although values are casted to their appropriate types when using update, the following are *not* applied:
 *
 * - defaults
 * - setters
 * - validators
 * - middleware
 *
 * If you need those features, use the traditional approach of first retrieving the document.
 *
 *     Model.findOne({ name: 'borne' }, function (err, doc) {
 *       if (err) ..
 *       doc.name = 'jason borne';
 *       doc.save(callback);
 *     })
 *
 * @see strict http://mongoosejs.com/docs/guide.html#strict
 * @param {Object} conditions
 * @param {Object} update
 * @param {Object} [options]
 * @param {Function} [callback]
 * @return {Query}
 * @api public
 */

Model.update = function update (conditions, doc, options, callback) {
  var mq = new Query({}, {}, this, this.collection);
  return mq.update(conditions, doc, options, callback);
};

/**
 * Executes a mapReduce command.
 *
 * `o` is an object specifying all mapReduce options as well as the map and reduce functions. All options are delegated to the driver implementation.
 *
 * ####Example:
 *
 *     var o = {};
 *     o.map = function () { emit(this.name, 1) }
 *     o.reduce = function (k, vals) { return vals.length }
 *     User.mapReduce(o, function (err, results) {
 *       console.log(results)
 *     })
 *
 * ####Other options:
 *
 * - `query` {Object} query filter object.
 * - `limit` {Number} max number of documents
 * - `keeptemp` {Boolean, default:false} keep temporary data
 * - `finalize` {Function} finalize function
 * - `scope` {Object} scope variables exposed to map/reduce/finalize during execution
 * - `jsMode` {Boolean, default:false} it is possible to make the execution stay in JS. Provided in MongoDB > 2.0.X
 * - `verbose` {Boolean, default:false} provide statistics on job execution time.
 * - `out*` {Object, default: {inline:1}} sets the output target for the map reduce job.
 *
 * ####* out options:
 *
 * - `{inline:1}` the results are returned in an array
 * - `{replace: 'collectionName'}` add the results to collectionName: the results replace the collection
 * - `{reduce: 'collectionName'}` add the results to collectionName: if dups are detected, uses the reducer / finalize functions
 * - `{merge: 'collectionName'}` add the results to collectionName: if dups exist the new docs overwrite the old
 *
 * If `options.out` is set to `replace`, `merge`, or `reduce`, a Model instance is returned that can be used for further querying. Queries run against this model are all executed with the `lean` option; meaning only the js object is returned and no Mongoose magic is applied (getters, setters, etc).
 *
 * ####Example:
 *
 *     var o = {};
 *     o.map = function () { emit(this.name, 1) }
 *     o.reduce = function (k, vals) { return vals.length }
 *     o.out = { replace: 'createdCollectionNameForResults' }
 *     o.verbose = true;
 *
 *     User.mapReduce(o, function (err, model, stats) {
 *       console.log('map reduce took %d ms', stats.processtime)
 *       model.find().where('value').gt(10).exec(function (err, docs) {
 *         console.log(docs);
 *       });
 *     })
 *
 *     // a promise is returned so you may instead write
 *     var promise = User.mapReduce(o);
 *     promise.then(function (model, stats) {
 *       console.log('map reduce took %d ms', stats.processtime)
 *       return model.find().where('value').gt(10).exec();
 *     }).then(function (docs) {
 *        console.log(docs);
 *     }).then(null, handleError).end()
 *
 * @param {Object} o an object specifying map-reduce options
 * @param {Function} [callback] optional callback
 * @see http://www.mongodb.org/display/DOCS/MapReduce
 * @return {Promise}
 * @api public
 */

Model.mapReduce = function mapReduce (o, callback) {
  var promise = new Promise(callback);
  var self = this;

  if (!Model.mapReduce.schema) {
    var opts = { noId: true, noVirtualId: true, strict: false }
    Model.mapReduce.schema = new Schema({}, opts);
  }

  if (!o.out) o.out = { inline: 1 };
  if (false !== o.verbose) o.verbose = true;

  o.map = String(o.map);
  o.reduce = String(o.reduce);

  if (o.query) {
    var q = new Query(o.query);
    q.cast(this);
    o.query = q._conditions;
    q = undefined;
  }

  this.collection.mapReduce(null, null, o, function (err, ret, stats) {
    if (err) return promise.error(err);

    if (ret.findOne && ret.mapReduce) {
      // returned a collection, convert to Model
      var model = Model.compile(
          '_mapreduce_' + ret.collectionName
        , Model.mapReduce.schema
        , ret.collectionName
        , self.db
        , self.base);

      model._mapreduce = true;

      return promise.fulfill(model, stats);
    }

    promise.fulfill(ret, stats);
  });

  return promise;
}

/**
 * geoNear support for Mongoose
 *
 * ####Options:
 * - `lean` {Boolean} return the raw object
 * - All options supported by the driver ar