"use strict";

var common = require('./common')
	, utils = require('../utils')
  , toError = require('../utils').toError
  , f = require('util').format
	, handleCallback = require('../utils').handleCallback
  , shallowClone = utils.shallowClone
  , WriteError = common.WriteError
  , BulkWriteResult = common.BulkWriteResult
  , LegacyOp = common.LegacyOp
  , ObjectID = require('mongodb-core').BSON.ObjectID
  , Define = require('../metadata')
  , Batch = common.Batch
  , mergeBatchResults = common.mergeBatchResults;

/**
 * Create a FindOperatorsUnordered instance (INTERNAL TYPE, do not instantiate directly)
 * @class
 * @property {number} length Get the number of operations in the bulk.
 * @return {FindOperatorsUnordered} a FindOperatorsUnordered instance.
 */
var FindOperatorsUnordered = function(self) {
  this.s = self.s;
}

/**
 * Add a single update document to the bulk operation
 *
 * @method
 * @param {object} doc update operations
 * @throws {MongoError}
 * @return {UnorderedBulkOperation}
 */
FindOperatorsUnordered.prototype.update = function(updateDocument) {
  // Perform upsert
  var upsert = typeof this.s.currentOp.upsert == 'boolean' ? this.s.currentOp.upsert : false;

  // Establish the update command
  var document = {
      q: this.s.currentOp.selector
    , u: updateDocument
    , multi: true
    , upsert: upsert
  }

  // Clear out current Op
  this.s.currentOp = null;
  // Add the update document to the list
  return addToOperationsList(this, common.UPDATE, document);
}

/**
 * Add a single update one document to the bulk operation
 *
 * @method
 * @param {object} doc update operations
 * @throws {MongoError}
 * @return {UnorderedBulkOperation}
 */
FindOperatorsUnordered.prototype.updateOne = function(updateDocument) {
  // Perform upsert
  var upsert = typeof this.s.currentOp.upsert == 'boolean' ? this.s.currentOp.upsert : false;

  // Establish the update command
  var document = {
      q: this.s.currentOp.selector
    , u: updateDocument
    , multi: false
    , upsert: upsert
  }

  // Clear out current Op
  this.s.currentOp = null;
  // Add the update document to the list
  return addToOperationsList(this, common.UPDATE, document);
}

/**
 * Add a replace one operation to the bulk operation
 *
 * @method
 * @param {object} doc the new document to replace the existing one with
 * @throws {MongoError}
 * @return {UnorderedBulkOperation}
 */
FindOperatorsUnordered.prototype.replaceOne = function(updateDocument) {
  this.updateOne(updateDocument);
}

/**
 * Upsert modifier for update bulk operation
 *
 * @method
 * @throws {MongoError}
 * @return {UnorderedBulkOperation}
 */
FindOperatorsUnordered.prototype.upsert = function() {
  this.s.currentOp.upsert = true;
  return this;
}

/**
 * Add a remove one operation to the bulk operation
 *
 * @method
 * @throws {MongoError}
 * @return {UnorderedBulkOperation}
 */
FindOperatorsUnordered.prototype.removeOne = function() {
  // Establish the update command
  var document = {
      q: this.s.currentOp.selector
    , limit: 1
  }

  // Clear out current Op
  this.s.currentOp = null;
  // Add the remove document to the list
  return addToOperationsList(this, common.REMOVE, document);
}

/**
 * Add a remove operation to the bulk operation
 *
 * @method
 * @throws {MongoError}
 * @return {UnorderedBulkOperation}
 */
FindOperatorsUnordered.prototype.remove = function() {
  // Establish the update command
  var document = {
      q: this.s.currentOp.selector
    , limit: 0
  }

  // Clear out current Op
  this.s.currentOp = null;
  // Add the remove document to the list
  return addToOperationsList(this, common.REMOVE, document);
}

//
// Add to the operations list
//
var addToOperationsList = function(_self, docType, document) {
  // Get the bsonSize
  var bsonSize = _self.s.bson.calculateObjectSize(document, false);
  // Throw error if the doc is bigger than the max BSON size
  if(bsonSize >= _self.s.maxBatchSizeBytes) throw toError("document is larger than the maximum size " + _self.s.maxBatchSizeBytes);
  // Holds the current batch
  _self.s.currentBatch = null;
  // Get the right type of batch
  if(docType == common.INSERT) {
    _self.s.currentBatch = _self.s.currentInsertBatch;
  } else if(docType == common.UPDATE) {
    _self.s.currentBatch = _self.s.currentUpdateBatch;
  } else if(docType == common.REMOVE) {
    _self.s.currentBatch = _self.s.currentRemoveBatch;
  }

  // Create a new batch object if we don't have a current one
  if(_self.s.currentBatch == null) _self.s.currentBatch = new Batch(docType, _self.s.currentIndex);

  // Check if we need to create a new batch
  if(((_self.s.currentBatch.size + 1) >= _self.s.maxWriteBatchSize)
    || ((_self.s.currentBatch.sizeBytes + bsonSize) >= _self.s.maxBatchSizeBytes)
    || (_self.s.currentBatch.batchType != docType)) {
    // Save the batch to the execution stack
    _self.s.batches.push(_self.s.currentBatch);

    // Create a new batch
    _self.s.currentBatch = new Batch(docType, _self.s.currentIndex);
  }

  // We have an array of documents
  if(Array.isArray(document)) {
    throw toError("operation passed in cannot be an Array");
  } else {
    _self.s.currentBatch.operations.push(document);
    _self.s.currentBatch.originalIndexes.push(_self.s.currentIndex);
    _self.s.currentIndex = _self.s.currentIndex + 1;
  }

  // Save back the current Batch to the right type
  if(docType == common.INSERT) {
    _self.s.currentInsertBatch = _self.s.currentBatch;
    _self.s.bulkResult.insertedIds.push({index: _self.s.currentIndex, _id: document._id});
  } else if(docType == common.UPDATE) {
    _self.s.currentUpdateBatch = _self.s.currentBatch;
  } else if(docType == common.REMOVE) {
    _self.s.currentRemoveBatch = _self.s.currentBatch;
  }

  // Update current batch size
  _self.s.currentBatch.size = _self.s.currentBatch.size + 1;
  _self.s.currentBatch.sizeBytes = _self.s.currentBatch.sizeBytes + bsonSize;

  // Return self
  return _self;
}

/**
 * Create a new UnorderedBulkOperation instance (INTERNAL TYPE, do not instantiate directly)
 * @class
 * @return {UnorderedBulkOperation} a UnorderedBulkOperation instance.
 */
var UnorderedBulkOperation = function(topology, collection, options) {
	options = options == null ? {} : options;

	// Contains reference to self
	var self = this;
	// Get the namesspace for the write operations
  var namespace = collection.collectionName;
  // Used to mark operation as executed
  var executed = false;

	// Current item
  // var currentBatch = null;
	var currentOp = null;
	var currentIndex = 0;
  var batches = [];

  // The current Batches for the different operations
  var currentInsertBatch = null;
  var currentUpdateBatch = null;
  var currentRemoveBatch = null;

	// Handle to the bson serializer, used to calculate running sizes
	var bson = topology.bson;

  // Set max byte size
  var maxBatchSizeBytes = topology.isMasterDoc && topology.isMasterDoc.maxBsonObjectSize
    ? topology.isMasterDoc.maxBsonObjectSize : (1024*1025*16);
  var maxWriteBatchSize = topology.isMasterDoc && topology.isMasterDoc.maxWriteBatchSize
    ? topology.isMasterDoc.maxWriteBatchSize : 1000;

  // Get the write concern
  var writeConcern = common.writeConcern(shallowClone(options), collection, options);

  // Get the promiseLibrary
  var promiseLibrary = options.promiseLibrary;

  // No promise library selected fall back
  if(!promiseLibrary) {
    promiseLibrary = typeof global.Promise == 'function' ?
      global.Promise : require('es6-promise').Promise;
  }

  // Final results
  var bulkResult = {
  	  ok: 1
    , writeErrors: []
    , writeConcernErrors: []
    , insertedIds: []
    , nInserted: 0
    , nUpserted: 0
    , nMatched: 0
    , nModified: 0
    , nRemoved: 0
    , upserted: []
  };

  // Internal state
  this.s = {
    // Final result
      bulkResult: bulkResult
    // Current batch state
    , currentInsertBatch: null
    , currentUpdateBatch: null
    , currentRemoveBatch: null
    , currentBatch: null
    , currentIndex: 0
    , batches: []
    // Write concern
    , writeConcern: writeConcern
    // Max batch size options
    , maxBatchSizeBytes: maxBatchSizeBytes
    , maxWriteBatchSize: maxWriteBatchSize
    // Namespace
    , namespace: namespace
    // BSON
    , bson: bson
    // Topology
    , topology: topology
    // Options
    , options: options
    // Current operation
    , currentOp: currentOp
    // Executed
    , executed: executed
    // Collection
    , collection: collection
    // Promise Library
    , promiseLibrary: promiseLibrary
    // Bypass validation
    , bypassDocumentValidation: typeof options.bypassDocumentValidation == 'boolean' ? options.bypassDocumentValidation : false
  }
}

var define = UnorderedBulkOperation.define = new Define('UnorderedBulkOperation', UnorderedBulkOperation, false);

/**
 * Add a single insert document to the bulk operation
 *
 * @param {object} doc the document to insert
 * @throws {MongoError}
 * @return {UnorderedBulkOperation}
 */
UnorderedBulkOperation.prototype.insert = function(document) {
  if(this.s.collection.s.db.options.forceServerObjectId !== true && document._id == null) document._id = new ObjectID();
  return addToOperationsList(this, common.INSERT, document);
}

/**
 * Initiate a find operation for an update/updateOne/remove/removeOne/replaceOne
 *
 * @method
 * @param {object} selector The selector for the bulk operation.
 * @throws {MongoError}
 * @return {FindOperatorsUnordered}
 */
UnorderedBulkOperation.prototype.find = function(selector) {
  if (!selector) {
    throw toError("Bulk find operation must specify a selector");
  }

  // Save a current selector
  this.s.currentOp = {
    selector: selector
  }

  return new FindOperatorsUnordered(this);
}

Object.defineProperty(UnorderedBulkOperation.prototype, 'length', {
  enumerable: true,
  get: function() {
    return this.s.currentIndex;
  }
});

UnorderedBulkOperation.prototype.raw = function(op) {
  var key = Object.keys(op)[0];

  // Set up the force server object id
  var forceServerObjectId = typeof this.s.options.forceServerObjectId == 'boolean'
    ? this.s.options.forceServerObjectId : this.s.collection.s.db.options.forceServerObjectId;

  // Update operations
  if((op.updateOne && op.updateOne.q)
    || (op.updateMany && op.updateMany.q)
    || (op.replaceOne && op.replaceOne.q)) {
    op[key].multi = op.updateOne || op.replaceOne ? false : true;
    return addToOperationsList(this, common.UPDATE, op[key]);
  }

  // Crud spec update format
  if(op.updateOne || op.updateMany || op.replaceOne) {
    var multi = op.updateOne || op.replaceOne ? false : true;
    var operation = {q: op[key].filter, u: op[key].update || op[key].replacement, multi: multi}
    if(op[key].upsert) operation.upsert = true;
    return addToOperationsList(this, common.UPDATE, operation);
  }

  // Remove operations
  if(op.removeOne || op.removeMany || (op.deleteOne && op.deleteOne.q) || op.deleteMany && op.deleteMany.q) {
    op[key].limit = op.removeOne ? 1 : 0;
    return addToOperationsList(this, common.REMOVE, op[key]);
  }

  // Crud spec delete operations, less efficient
  if(op.deleteOne || op.deleteMany) {
    var limit = op.deleteOne ? 1 : 0;
    var operation = {q: op[key].filter, limit: limit}
    return addToOperationsList(this, common.REMOVE, operation);
  }

  // Insert operations
  if(op.insertOne && op.insertOne.document == null) {
    if(forceServerObjectId !== true && op.insertOne._id == null) op.insertOne._id = new ObjectID();
    return addToOperationsList(this, common.INSERT, op.insertOne);
  } else if(op.insertOne && op.insertOne.document) {
    if(forceServerObjectId !== true && op.insertOne.document._id == null) op.insertOne.document._id = new ObjectID();
    return addToOperationsList(this, common.INSERT, op.insertOne.document);
  }

  if(op.insertMany) {
    for(var i = 0; i < op.insertMany.length; i++) {
      if(forceServerObjectId !== true && op.insertMany[i]._id == null) op.insertMany[i]._id = new ObjectID();
      addToOperationsList(this, common.INSERT, op.insertMany[i]);
    }

    return;
  }

  // No valid type of operation
  throw toError("bulkWrite only supports insertOne, insertMany, updateOne, updateMany, removeOne, removeMany, deleteOne, deleteMany");
}

//
// Execute the command
var executeBatch = function(self, batch, callback) {
  var finalOptions = {ordered: false}
  if(self.s.writeConcern != null) {
    finalOptions.writeConcern = self.s.writeConcern;
  }

  var resultHandler = function(err, result) {
		// Error is a driver related error not a bulk op error, terminate
		if(err && err.driver || err && err.message) {
			return handleCallback(callback, err);
		}

    // If we have and error
    if(err) err.ok = 0;
    handleCallback(callback, null, mergeBatchResults(false, batch, self.s.bulkResult, err, result));
  }

	// Set an operationIf if provided
	if(self.operationId) {
		resultHandler.operationId = self.operationId;
	}

	// Serialize functions
	if(self.s.options.serializeFunctions) {
		finalOptions.serializeFunctions = true
	}

  // Is the bypassDocumentValidation options specific
  if(self.s.bypassDocumentValidation == true) {
    finalOptions.bypassDocumentValidation = true;
  }

  try {
    if(batch.batchType == common.INSERT) {
      self.s.topology.insert(self.s.collection.namespace, batch.operations, finalOptions, resultHandler);
    } else if(batch.batchType == common.UPDATE) {
      self.s.topology.update(self.s.collection.namespace, batch.operations, finalOptions, resultHandler);
    } else if(batch.batchType == common.REMOVE) {
      self.s.topology.remove(self.s.collection.namespace, batch.operations, finalOptions, resultHandler);
    }
  } catch(err) {
    // Force top level error
    err.ok = 0;
    // Merge top level error and return
    handleCallback(callback, null, mergeBatchResults(false, batch, self.s.bulkResult, err, null));
  }
}

//
// Execute all the commands
var executeBatches = function(self, callback) {
  var numberOfCommandsToExecute = self.s.batches.length;
	var error = null;
  // Execute over all the batches
  for(var i = 0; i < self.s.batches.length; i++) {
    executeBatch(self, self.s.batches[i], function(err, result) {
			// Driver layer error capture it
			if(err) error = err;
			// Count down the number of commands left to execute
      numberOfCommandsToExecute = numberOfCommandsToExecute - 1;

      // Execute
      if(numberOfCommandsToExecute == 0) {
				// Driver level error
				if(error) return handleCallback(callback, error);
				// Treat write errors
        var error = self.s.bulkResult.writeErrors.length > 0 ? toError(self.s.bulkResult.writeErrors[0]) : null;
        handleCallback(callback, error, new BulkWriteResult(self.s.bulkResult));
      }
    });
  }
}

/**
 * The callback format for results
 * @callback UnorderedBulkOperation~resultCallback
 * @param {MongoError} error An error instance representing the error during the execution.
 * @param {BulkWriteResult} result The bulk write result.
 */

/**
 * Execute the ordered bulk operation
 *
 * @method
 * @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 {UnorderedBulkOperation~resultCallback} [callback] The result callback
 * @throws {MongoError}
 * @return {Promise} returns Promise if no callback passed
 */
UnorderedBulkOperation.prototype.execute = function(_writeConcern, callback) {
  var self = this;
  if(this.s.executed) throw toError("batch cannot be re-executed");
  if(typeof _writeConcern == 'function') {
    callback = _writeConcern;
  } else {
    this.s.writeConcern = _writeConcern;
  }

  // If we have current batch
  if(this.s.currentInsertBatch) this.s.batches.push(this.s.currentInsertBatch);
  if(this.s.currentUpdateBatch) this.s.batches.push(this.s.currentUpdateBatch);
  if(this.s.currentRemoveBatch) this.s.batches.push(this.s.currentRemoveBatch);

  // If we have no operations in the bulk raise an error
  if(this.s.batches.length == 0) {
    throw toError("Invalid Operation, No operations in bulk");
  }

  // Execute using callback
  if(typeof callback == 'function') return executeBatches(this, callback);

  // Return a Promise
  return new this.s.promiseLibrary(function(resolve, reject) {
    executeBatches(self, function(err, r) {
      if(err) return reject(err);
      resolve(r);
    });
  });
}

define.classMethod('execute', {callback: true, promise:false});

/**
 * Returns an unordered batch object
 * @ignore
 */
var initializeUnorderedBulkOp = function(topology, collection, options) {
	return new UnorderedBulkOperation(topology, collection, options);
}

initializeUnorderedBulkOp.UnorderedBulkOperation = UnorderedBulkOperation;
module.exports = initializeUnorderedBulkOp;
module.exports.Bulk = UnorderedBulkOperation;
