/*!
 * Module dependencies.
 */

var EmbeddedDocument = require('./embedded');
var Document = require('../document');
var ObjectId = require('./objectid');
var utils = require('../utils');
var isMongooseObject = utils.isMongooseObject;

/**
 * Mongoose Array constructor.
 *
 * ####NOTE:
 *
 * _Values always have to be passed to the constructor to initialize, otherwise `MongooseArray#push` will mark the array as modified._
 *
 * @param {Array} values
 * @param {String} path
 * @param {Document} doc parent document
 * @api private
 * @inherits Array
 * @see http://bit.ly/f6CnZU
 */

function MongooseArray(values, path, doc) {
  var arr = [].concat(values);

  utils.decorate( arr, MongooseArray.mixin );
  arr.isMongooseArray = true;

  var _options = { enumerable: false, configurable: true, writable: true };
  var keys = Object.keys(MongooseArray.mixin).
    concat(['isMongooseArray', 'validators', '_path']);
  for (var i = 0; i < keys.length; ++i) {
    Object.defineProperty(arr, keys[i], _options);
  }

  arr._atomics = {};
  arr.validators = [];
  arr._path = path;

  // Because doc comes from the context of another function, doc === global
  // can happen if there was a null somewhere up the chain (see #3020)
  // RB Jun 17, 2015 updated to check for presence of expected paths instead
  // to make more proof against unusual node environments
  if (doc && doc instanceof Document) {
    arr._parent = doc;
    arr._schema = doc.schema.path(path);
  }

  return arr;
}

MongooseArray.mixin = {

  /**
   * Stores a queue of atomic operations to perform
   *
   * @property _atomics
   * @api private
   */

  _atomics: undefined,

  /**
   * Parent owner document
   *
   * @property _parent
   * @api private
   * @receiver MongooseArray
   */

  _parent: undefined,

  /**
   * Casts a member based on this arrays schema.
   *
   * @param {any} value
   * @return value the casted value
   * @method _cast
   * @api private
   * @receiver MongooseArray
   */

  _cast: function(value) {
    var owner = this._owner;
    var populated = false;
    var Model;

    if (this._parent) {
      // if a populated array, we must cast to the same model
      // instance as specified in the original query.
      if (!owner) {
        owner = this._owner = this._parent.ownerDocument
          ? this._parent.ownerDocument()
          : this._parent;
      }

      populated = owner.populated(this._path, true);
    }

    if (populated && null != value) {
      // cast to the populated Models schema
      Model = populated.options.model;

      // only objects are permitted so we can safely assume that
      // non-objects are to be interpreted as _id
      if (Buffer.isBuffer(value) ||
          value instanceof ObjectId || !utils.isObject(value)) {
        value = { _id: value };
      }

      // gh-2399
      // we should cast model only when it's not a discriminator
      var isDisc = value.schema && value.schema.discriminatorMapping &&
        value.schema.discriminatorMapping.key !== undefined;
      if (!isDisc) {
        value = new Model(value);
      }
      return this._schema.caster.cast(value, this._parent, true);
    }

    return this._schema.caster.cast(value, this._parent, false);
  },

  /**
   * Marks this array as modified.
   *
   * If it bubbles up from an embedded document change, then it takes the following arguments (otherwise, takes 0 arguments)
   *
   * @param {EmbeddedDocument} embeddedDoc the embedded doc that invoked this method on the Array
   * @param {String} embeddedPath the path which changed in the embeddedDoc
   * @method _markModified
   * @api private
   * @receiver MongooseArray
   */

  _markModified: function(elem, embeddedPath) {
    var parent = this._parent,
        dirtyPath;

    if (parent) {
      dirtyPath = this._path;

      if (arguments.length) {
        if (null != embeddedPath) {
          // an embedded doc bubbled up the change
          dirtyPath = dirtyPath + '.' + this.indexOf(elem) + '.' + embeddedPath;
        } else {
          // directly set an index
          dirtyPath = dirtyPath + '.' + elem;
        }
      }

      parent.markModified(dirtyPath);
    }

    return this;
  },

  /**
   * Register an atomic operation with the parent.
   *
   * @param {Array} op operation
   * @param {any} val
   * @method _registerAtomic
   * @api private
   * @receiver MongooseArray
   */

  _registerAtomic: function(op, val) {
    if ('$set' == op) {
      // $set takes precedence over all other ops.
      // mark entire array modified.
      this._atomics = { $set: val };
      return this;
    }

    var atomics = this._atomics;

    // reset pop/shift after save
    if ('$pop' == op && !('$pop' in atomics)) {
      var self = this;
      this._parent.once('save', function() {
        self._popped = self._shifted = null;
      });
    }

    // check for impossible $atomic combos (Mongo denies more than one
    // $atomic op on a single path
    if (this._atomics.$set ||
        Object.keys(atomics).length && !(op in atomics)) {
      // a different op was previously registered.
      // save the entire thing.
      this._atomics = { $set: this };
      return this;
    }

    var selector;

    if (op === '$pullAll' || op === '$pushAll' || op === '$addToSet') {
      atomics[op] || (atomics[op] = []);
      atomics[op] = atomics[op].concat(val);
    } else if (op === '$pullDocs') {
      var pullOp = atomics['$pull'] || (atomics['$pull'] = {});
      if (val[0] instanceof EmbeddedDocument) {
        selector = pullOp['$or'] || (pullOp['$or'] = []);
        Array.prototype.push.apply(selector, val.map(function(v) {
          return v.toObject({ virtuals: false });
        }));
      } else {
        selector = pullOp['_id'] || (pullOp['_id'] = {'$in' : [] });
        selector['$in'] = selector['$in'].concat(val);
      }
    } else {
      atomics[op] = val;
    }

    return this;
  },

  /**
   * Depopulates stored atomic operation values as necessary for direct insertion to MongoDB.
   *
   * If no atomics exist, we return all array values after conversion.
   *
   * @return {Array}
   * @method $__getAtomics
   * @memberOf MongooseArray
   * @api private
   */

  $__getAtomics: function() {
    var ret = [];
    var keys = Object.keys(this._atomics);
    var i = keys.length;

    if (0 === i) {
      ret[0] = ['$set', this.toObject({ depopulate: 1, transform: false })];
      return ret;
    }

    while (i--) {
      var op = keys[i];
      var val = this._atomics[op];

      // the atomic values which are arrays are not MongooseArrays. we
      // need to convert their elements as if they were MongooseArrays
      // to handle populated arrays versus DocumentArrays properly.
      if (isMongooseObject(val)) {
        val = val.toObject({ depopulate: 1, transform: false });
      } else if (Array.isArray(val)) {
        val = this.toObject.call(val, { depopulate: 1, transform: false });
      } else if (val.valueOf) {
        val = val.valueOf();
      }

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

      ret.push([op, val]);
    }

    return ret;
  },

  /**
   * Returns the number of pending atomic operations to send to the db for this array.
   *
   * @api private
   * @return {Number}
   * @method hasAtomics
   * @receiver MongooseArray
   */

  hasAtomics: function hasAtomics() {
    if (!(this._atomics && 'Object' === this._atomics.constructor.name)) {
      return 0;
    }

    return Object.keys(this._atomics).length;
  },

  /**
   * Internal helper for .map()
   *
   * @api private
   * @return {Number}
   * @method _mapCast
   * @receiver MongooseArray
   */
  _mapCast: function(val, index) {
    return this._cast(val, this.length + index);
  },

  /**
   * Wraps [`Array#push`](https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/push) with proper change tracking.
   *
   * @param {Object} [args...]
   * @api public
   * @method push
   * @receiver MongooseArray
   */

  push: function() {
    var values = [].map.call(arguments, this._mapCast, this);
    values = this._schema.applySetters(values, this._parent);
    var ret = [].push.apply(this, values);

    // $pushAll might be fibbed (could be $push). But it makes it easier to
    // handle what could have been $push, $pushAll combos
    this._registerAtomic('$pushAll', values);
    this._markModified();
    return ret;
  },

  /**
   * Pushes items to the array non-atomically.
   *
   * ####NOTE:
   *
   * _marks the entire array as modified, which if saved, will store it as a `$set` operation, potentially overwritting any changes that happen between when you retrieved the object and when you save it._
   *
   * @param {any} [args...]
   * @api public
   * @method nonAtomicPush
   * @receiver MongooseArray
   */

  nonAtomicPush: function() {
    var values = [].map.call(arguments, this._mapCast, this);
    var ret = [].push.apply(this, values);
    this._registerAtomic('$set', this);
    this._markModified();
    return ret;
  },

  /**
   * Pops the array atomically at most one time per document `save()`.
   *
   * #### NOTE:
   *
   * _Calling this mulitple times on an array before saving sends the same command as calling it once._
   * _This update is implemented using the MongoDB [$pop](http://www.mongodb.org/display/DOCS/Updating/#Updating-%24pop) method which enforces this restriction._
   *
   *      doc.array = [1,2,3];
   *
   *      var popped = doc.array.$pop();
   *      console.log(popped); // 3
   *      console.log(doc.array); // [1,2]
   *
   *      // no affect
   *      popped = doc.array.$pop();
   *      console.log(doc.array); // [1,2]
   *
   *      doc.save(function (err) {
   *        if (err) return handleError(err);
   *
   *        // we saved, now $pop works again
   *        popped = doc.array.$pop();
   *        console.log(popped); // 2
   *        console.log(doc.array); // [1]
   *      })
   *
   * @api public
   * @method $pop
   * @memberOf MongooseArray
   * @see mongodb http://www.mongodb.org/display/DOCS/Updating/#Updating-%24pop
   * @method $pop
   * @receiver MongooseArray
   */

  $pop: function() {
    this._registerAtomic('$pop', 1);
    this._markModified();

    // only allow popping once
    if (this._popped) return;
    this._popped = true;

    return [].pop.call(this);
  },

  /**
   * Wraps [`Array#pop`](https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/pop) with proper change tracking.
   *
   * ####Note:
   *
   * _marks the entire array as modified which will pass the entire thing to $set potentially overwritting any changes that happen between when you retrieved the object and when you save it._
   *
   * @see MongooseArray#$pop #types_array_MongooseArray-%24pop
   * @api public
   * @method pop
   * @receiver MongooseArray
   */

  pop: function() {
    var ret = [].pop.call(this);
    this._registerAtomic('$set', this);
    this._markModified();
    return ret;
  },

  /**
   * Atomically shifts the array at most one time per document `save()`.
   *
   * ####NOTE:
   *
   * _Calling this mulitple times on an array before saving sends the same command as calling it once._
   * _This update is implemented using the MongoDB [$pop](http://www.mongodb.org/display/DOCS/Updating/#Updating-%24pop) method which enforces this restriction._
   *
   *      doc.array = [1,2,3];
   *
   *      var shifted = doc.array.$shift();
   *      console.log(shifted); // 1
   *      console.log(doc.array); // [2,3]
   *
   *      // no affect
   *      shifted = doc.array.$shift();
   *      console.log(doc.array); // [2,3]
   *
   *      doc.save(function (err) {
   *        if (err) return handleError(err);
   *
   *        // we saved, now $shift works again
   *        shifted = doc.array.$shift();
   *        console.log(shifted ); // 2
   *        console.log(doc.array); // [3]
   *      })
   *
   * @api public
   * @memberOf MongooseArray
   * @method $shift
   * @see mongodb http://www.mongodb.org/display/DOCS/Updating/#Updating-%24pop
   */

  $shift: function $shift() {
    this._registerAtomic('$pop', -1);
    this._markModified();

    // only allow shifting once
    if (this._shifted) return;
    this._shifted = true;

    return [].shift.call(this);
  },

  /**
   * Wraps [`Array#shift`](https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/unshift) with proper change tracking.
   *
   * ####Example:
   *
   *     doc.array = [2,3];
   *     var res = doc.array.shift();
   *     console.log(res) // 2
   *     console.log(doc.array) // [3]
   *
   * ####Note:
   *
   * _marks the entire array as modified, which if saved, will store it as a `$set` operation, potentially overwritting any changes that happen between when you retrieved the object and when you save it._
   *
   * @api public
   * @method shift
   * @receiver MongooseArray
   */

  shift: function() {
    var ret = [].shift.call(this);
    this._registerAtomic('$set', this);
    this._markModified();
    return ret;
  },

  /**
   * Pulls items from the array atomically. Equality is determined by casting
   * the provided value to an embedded document and comparing using
   * [the `Document.equals()` function.](./api.html#document_Document-equals)
   *
   * ####Examples:
   *
   *     doc.array.pull(ObjectId)
   *     doc.array.pull({ _id: 'someId' })
   *     doc.array.pull(36)
   *     doc.array.pull('tag 1', 'tag 2')
   *
   * To remove a document from a subdocument array we may pass an object with a matching `_id`.
   *
   *     doc.subdocs.push({ _id: 4815162342 })
   *     doc.subdocs.pull({ _id: 4815162342 }) // removed
   *
   * Or we may passing the _id directly and let mongoose take care of it.
   *
   *     doc.subdocs.push({ _id: 4815162342 })
   *     doc.subdocs.pull(4815162342); // works
   *
   * @param {any} [args...]
   * @see mongodb http://www.mongodb.org/display/DOCS/Updating/#Updating-%24pull
   * @api public
   * @method pull
   * @receiver MongooseArray
   */

  pull: function() {
    var values = [].map.call(arguments, this._cast, this),
        cur = this._parent.get(this._path),
        i = cur.length,
        mem;

    while (i--) {
      mem = cur[i];
      if (mem instanceof EmbeddedDocument) {
        if (values.some(function(v) { return v.equals(mem); } )) {
          [].splice.call(cur, i, 1);
        }
      } else if (~cur.indexOf.call(values, mem)) {
        [].splice.call(cur, i, 1);
      }
    }

    if (values[0] instanceof EmbeddedDocument) {
      this._registerAtomic('$pullDocs', values.map(function(v) {
        return v._id || v;
      }));
    } else {
      this._registerAtomic('$pullAll', values);
    }

    this._markModified();
    return this;
  },

  /**
   * Wraps [`Array#splice`](https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/splice) with proper change tracking and casting.
   *
   * ####Note:
   *
   * _marks the entire array as modified, which if saved, will store it as a `$set` operation, potentially overwritting any changes that happen between when you retrieved the object and when you save it._
   *
   * @api public
   * @method splice
   * @receiver MongooseArray
   */

  splice: function splice() {
    var ret, vals, i;

    if (arguments.length) {
      vals = [];
      for (i = 0; i < arguments.length; ++i) {
        vals[i] = i < 2
          ? arguments[i]
          : this._cast(arguments[i], arguments[0] + (i - 2));
      }
      ret = [].splice.apply(this, vals);
      this._registerAtomic('$set', this);
      this._markModified();
    }

    return ret;
  },

  /**
   * Wraps [`Array#unshift`](https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/unshift) with proper change tracking.
   *
   * ####Note:
   *
   * _marks the entire array as modified, which if saved, will store it as a `$set` operation, potentially overwritting any changes that happen between when you retrieved the object and when you save it._
   *
   * @api public
   * @method unshift
   * @receiver MongooseArray
   */

  unshift: function() {
    var values = [].map.call(arguments, this._cast, this);
    values = this._schema.applySetters(values, this._parent);
    [].unshift.apply(this, values);
    this._registerAtomic('$set', this);
    this._markModified();
    return this.length;
  },

  /**
   * Wraps [`Array#sort`](https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/sort) with proper change tracking.
   *
   * ####NOTE:
   *
   * _marks the entire array as modified, which if saved, will store it as a `$set` operation, potentially overwritting any changes that happen between when you retrieved the object and when you save it._
   *
   * @api public
   * @method sort
   * @receiver MongooseArray
   */

  sort: function() {
    var ret = [].sort.apply(this, arguments);
    this._registerAtomic('$set', this);
    this._markModified();
    return ret;
  },

  /**
   * Adds values to the array if not already present.
   *
   * ####Example:
   *
   *     console.log(doc.array) // [2,3,4]
   *     var added = doc.array.addToSet(4,5);
   *     console.log(doc.array) // [2,3,4,5]
   *     console.log(added)     // [5]
   *
   * @param {any} [args...]
   * @return {Array} the values that were added
   * @receiver MongooseArray
   * @api public
   * @method addToSet
   */

  addToSet: function addToSet() {
    var values = [].map.call(arguments, this._mapCast, this);
    values = this._schema.applySetters(values, this._parent);
    var added = [];
    var type = values[0] instanceof EmbeddedDocument ? 'doc' :
               values[0] instanceof Date ? 'date' :
               '';

    values.forEach(function(v) {
      var found;
      switch (type) {
        case 'doc':
          found = this.some(function(doc) { return doc.equals(v); });
          break;
        case 'date':
          var val = +v;
          found = this.some(function(d) { return +d === val; });
          break;
        default:
          found = ~this.indexOf(v);
      }

      if (!found) {
        [].push.call(this, v);
        this._registerAtomic('$addToSet', v);
        this._markModified();
        [].push.call(added, v);
      }
    }, this);

    return added;
  },

  /**
   * Sets the casted `val` at index `i` and marks the array modified.
   *
   * ####Example:
   *
   *     // given documents based on the following
   *     var Doc = mongoose.model('Doc', new Schema({ array: [Number] }));
   *
   *     var doc = new Doc({ array: [2,3,4] })
   *
   *     console.log(doc.array) // [2,3,4]
   *
   *     doc.array.set(1,"5");
   *     console.log(doc.array); // [2,5,4] // properly cast to number
   *     doc.save() // the change is saved
   *
   *     // VS not using array#set
   *     doc.array[1] = "5";
   *     console.log(doc.array); // [2,"5",4] // no casting
   *     doc.save() // change is not saved
   *
   * @return {Array} this
   * @api public
   * @method set
   * @receiver MongooseArray
   */

  set: function set(i, val) {
    var value = this._cast(val, i);
    value = this._schema.caster instanceof EmbeddedDocument ?
            value :
            this._schema.caster.applySetters(val, this._parent)
            ;
    this[i] = value;
    this._markModified(i);
    return this;
  },

  /**
   * Returns a native js Array.
   *
   * @param {Object} options
   * @return {Array}
   * @api public
   * @method toObject
   * @receiver MongooseArray
   */

  toObject: function(options) {
    if (options && options.depopulate) {
      return this.map(function(doc) {
        return doc instanceof Document
          ? doc.toObject(options)
          : doc;
      });
    }

    return this.slice();
  },

  /**
   * Helper for console.log
   *
   * @api public
   * @method inspect
   * @receiver MongooseArray
   */

  inspect: function() {
    return JSON.stringify(this);
  },

  /**
   * Return the index of `obj` or `-1` if not found.
   *
   * @param {Object} obj the item to look for
   * @return {Number}
   * @api public
   * @method indexOf
   * @receiver MongooseArray
   */

  indexOf: function indexOf(obj) {
    if (obj instanceof ObjectId) obj = obj.toString();
    for (var i = 0, len = this.length; i < len; ++i) {
      if (obj == this[i])
        return i;
    }
    return -1;
  }
};

/**
 * Alias of [pull](#types_array_MongooseArray-pull)
 *
 * @see MongooseArray#pull #types_array_MongooseArray-pull
 * @see mongodb http://www.mongodb.org/display/DOCS/Updating/#Updating-%24pull
 * @api public
 * @memberOf MongooseArray
 * @method remove
 */

MongooseArray.mixin.remove = MongooseArray.mixin.pull;

/*!
 * Module exports.
 */

module.exports = exports = MongooseArray;
