using MongoDB.Driver;
using MongoDbGenericRepository.DataAccess.Create;
using MongoDbGenericRepository.DataAccess.Update;
using MongoDbGenericRepository.Models;
using MongoDbGenericRepository.Utils;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Threading.Tasks;

namespace MongoDbGenericRepository
{
    /// <summary>
    /// The base Repository, it is meant to be inherited from by your custom custom MongoRepository implementation.
    /// Its constructor must be given a connection string and a database name.
    /// </summary>
    public abstract partial class BaseMongoRepository : ReadOnlyMongoRepository, IBaseMongoRepository
    {
        private object _initLock;
        private MongoDbCreator _mongoDbCreator;
        protected MongoDbCreator MongoDbCreator
        {
            get
            {
                if (_mongoDbCreator != null) { return _mongoDbCreator; }

                lock (_initLock)
                {
                    if (_mongoDbCreator == null)
                    {
                        _mongoDbCreator = new MongoDbCreator(MongoDbContext);
                    }
                }

                return _mongoDbCreator;
            }
        }

        private MongoDbUpdater _mongoDbUpdater;
        protected MongoDbUpdater MongoDbUpdater
        {
            get
            {
                if (_mongoDbUpdater != null) { return _mongoDbUpdater; }

                lock (_initLock)
                {
                    if (_mongoDbUpdater == null)
                    {
                        _mongoDbUpdater = new MongoDbUpdater(MongoDbContext);
                    }
                }

                return _mongoDbUpdater;
            }
        }

        /// <summary>
        /// The constructor taking a connection string and a database name.
        /// </summary>
        /// <param name="connectionString">The connection string of the MongoDb server.</param>
        /// <param name="databaseName">The name of the database against which you want to perform operations.</param>
        protected BaseMongoRepository(string connectionString, string databaseName = null) : base(connectionString, databaseName)
        {
        }

        /// <summary>
        /// The contructor taking a <see cref="IMongoDbContext"/>.
        /// </summary>
        /// <param name="mongoDbContext">A mongodb context implementing <see cref="IMongoDbContext"/></param>
        protected BaseMongoRepository(IMongoDbContext mongoDbContext) : base(mongoDbContext)
        {
        }

        /// <summary>
        /// The contructor taking a <see cref="IMongoDatabase"/>.
        /// </summary>
        /// <param name="mongoDatabase">A mongodb context implementing <see cref="IMongoDatabase"/></param>
        protected BaseMongoRepository(IMongoDatabase mongoDatabase) : base(mongoDatabase)
        {
        }

        #region Create TKey

        /// <summary>
        /// Asynchronously adds a document to the collection.
        /// Populates the Id and AddedAtUtc fields if necessary.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <param name="document">The document you want to add.</param>
        public virtual async Task AddOneAsync<TDocument, TKey>(TDocument document)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            await MongoDbCreator.AddOneAsync<TDocument, TKey>(document);
        }

        /// <summary>
        /// Adds a document to the collection.
        /// Populates the Id and AddedAtUtc fields if necessary.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <param name="document">The document you want to add.</param>
        public virtual void AddOne<TDocument, TKey>(TDocument document)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            MongoDbCreator.AddOne<TDocument, TKey>(document);
        }

        /// <summary>
        /// Asynchronously adds a list of documents to the collection.
        /// Populates the Id and AddedAtUtc fields if necessary.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <param name="documents">The documents you want to add.</param>
        public virtual async Task AddManyAsync<TDocument, TKey>(IEnumerable<TDocument> documents)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            await MongoDbCreator.AddManyAsync<TDocument, TKey>(documents);
        }

        /// <summary>
        /// Adds a list of documents to the collection.
        /// Populates the Id and AddedAtUtc fields if necessary.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <param name="documents">The documents you want to add.</param>
        public virtual void AddMany<TDocument, TKey>(IEnumerable<TDocument> documents)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            MongoDbCreator.AddMany<TDocument, TKey>(documents);
        }

        #endregion 

        #region Update

        /// <summary>
        /// Asynchronously Updates a document.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <param name="modifiedDocument">The document with the modifications you want to persist.</param>
        public virtual async Task<bool> UpdateOneAsync<TDocument>(TDocument modifiedDocument) where TDocument : IDocument
        {
            return await MongoDbUpdater.UpdateOneAsync<TDocument, Guid>(modifiedDocument);
        }

        /// <summary>
        /// Updates a document.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <param name="modifiedDocument">The document with the modifications you want to persist.</param>
        public virtual bool UpdateOne<TDocument>(TDocument modifiedDocument) where TDocument : IDocument
        {
            return MongoDbUpdater.UpdateOne<TDocument, Guid>(modifiedDocument);
        }

        /// <summary>
        /// Takes a document you want to modify and applies the update you have defined in MongoDb.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <param name="documentToModify">The document you want to modify.</param>
        /// <param name="update">The update definition for the document.</param>
        public virtual async Task<bool> UpdateOneAsync<TDocument>(TDocument documentToModify, UpdateDefinition<TDocument> update)
            where TDocument : IDocument
        {
            return await MongoDbUpdater.UpdateOneAsync<TDocument, Guid>(documentToModify, update);

        }

        /// <summary>
        /// Takes a document you want to modify and applies the update you have defined in MongoDb.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <param name="documentToModify">The document you want to modify.</param>
        /// <param name="update">The update definition for the document.</param>
        public virtual bool UpdateOne<TDocument>(TDocument documentToModify, UpdateDefinition<TDocument> update)
            where TDocument : IDocument
        {
            return MongoDbUpdater.UpdateOne<TDocument, Guid>(documentToModify, update);
        }

        /// <summary>
        /// Updates the property field with the given value update a property field in entities.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TField">The type of the field.</typeparam>
        /// <param name="documentToModify">The document you want to modify.</param>
        /// <param name="field">The field selector.</param>
        /// <param name="value">The new value of the property field.</param>
        public virtual bool UpdateOne<TDocument, TField>(TDocument documentToModify, Expression<Func<TDocument, TField>> field, TField value)
            where TDocument : IDocument
        {
            return MongoDbUpdater.UpdateOne<TDocument, Guid, TField>(documentToModify, field, value);
        }

        /// <summary>
        /// Updates the property field with the given value update a property field in entities.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TField">The type of the field.</typeparam>
        /// <param name="documentToModify">The document you want to modify.</param>
        /// <param name="field">The field selector.</param>
        /// <param name="value">The new value of the property field.</param>
        public virtual async Task<bool> UpdateOneAsync<TDocument, TField>(TDocument documentToModify, Expression<Func<TDocument, TField>> field, TField value)
            where TDocument : IDocument
        {
            return await MongoDbUpdater.UpdateOneAsync<TDocument, Guid, TField>(documentToModify, field, value);
        }

        /// <summary>
        /// Updates the property field with the given value update a property field in entities.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TField">The type of the field.</typeparam>
        /// <param name="filter">The document filter.</param>
        /// <param name="field">The field selector.</param>
        /// <param name="value">The new value of the property field.</param>
        /// <param name="partitionKey">The value of the partition key.</param>
        public virtual bool UpdateOne<TDocument, TField>(FilterDefinition<TDocument> filter, Expression<Func<TDocument, TField>> field, TField value, string partitionKey = null)
            where TDocument : IDocument
        {
            return MongoDbUpdater.UpdateOne<TDocument, Guid, TField>(filter, field, value, partitionKey);
        }

        /// <summary>
        /// For the entity selected by the filter, updates the property field with the given value.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TField">The type of the field.</typeparam>
        /// <param name="filter">The document filter.</param>
        /// <param name="field">The field selector.</param>
        /// <param name="value">The new value of the property field.</param>
        /// <param name="partitionKey">The partition key for the document.</param>
        public virtual bool UpdateOne<TDocument, TField>(Expression<Func<TDocument, bool>> filter, Expression<Func<TDocument, TField>> field, TField value, string partitionKey = null)
            where TDocument : IDocument
        {
            return MongoDbUpdater.UpdateOne<TDocument, Guid, TField>(filter, field, value, partitionKey);
        }

        /// <summary>
        /// Updates the property field with the given value update a property field in entities.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TField">The type of the field.</typeparam>
        /// <param name="filter">The document filter.</param>
        /// <param name="field">The field selector.</param>
        /// <param name="value">The new value of the property field.</param>
        /// <param name="partitionKey">The value of the partition key.</param>
        public virtual async Task<bool> UpdateOneAsync<TDocument, TField>(FilterDefinition<TDocument> filter, Expression<Func<TDocument, TField>> field, TField value, string partitionKey = null)
            where TDocument : IDocument
        {
            return await MongoDbUpdater.UpdateOneAsync<TDocument, Guid, TField>(filter, field, value, partitionKey);
        }

        /// <summary>
        /// For the entity selected by the filter, updates the property field with the given value.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TField">The type of the field.</typeparam>
        /// <param name="filter">The document filter.</param>
        /// <param name="field">The field selector.</param>
        /// <param name="value">The new value of the property field.</param>
        /// <param name="partitionKey">The partition key for the document.</param>
        public virtual async Task<bool> UpdateOneAsync<TDocument, TField>(Expression<Func<TDocument, bool>> filter, Expression<Func<TDocument, TField>> field, TField value, string partitionKey = null)
            where TDocument : IDocument
        {
            return await MongoDbUpdater.UpdateOneAsync<TDocument, Guid, TField>(filter, field, value, partitionKey);
        }


        #endregion Update

        #region Update TKey

        /// <summary>
        /// Asynchronously Updates a document.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <param name="modifiedDocument">The document with the modifications you want to persist.</param>
        public virtual async Task<bool> UpdateOneAsync<TDocument, TKey>(TDocument modifiedDocument)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            return await MongoDbUpdater.UpdateOneAsync<TDocument, TKey>(modifiedDocument);
        }

        /// <summary>
        /// Updates a document.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <param name="modifiedDocument">The document with the modifications you want to persist.</param>
        public virtual bool UpdateOne<TDocument, TKey>(TDocument modifiedDocument)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            return MongoDbUpdater.UpdateOne<TDocument, TKey>(modifiedDocument);
        }

        /// <summary>
        /// Takes a document you want to modify and applies the update you have defined in MongoDb.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <param name="documentToModify">The document you want to modify.</param>
        /// <param name="update">The update definition for the document.</param>
        public virtual async Task<bool> UpdateOneAsync<TDocument, TKey>(TDocument documentToModify, UpdateDefinition<TDocument> update)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            return await MongoDbUpdater.UpdateOneAsync<TDocument, TKey>(documentToModify, update);
        }

        /// <summary>
        /// Takes a document you want to modify and applies the update you have defined in MongoDb.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <param name="documentToModify">The document you want to modify.</param>
        /// <param name="update">The update definition for the document.</param>
        public virtual bool UpdateOne<TDocument, TKey>(TDocument documentToModify, UpdateDefinition<TDocument> update)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            return MongoDbUpdater.UpdateOne<TDocument, TKey>(documentToModify, update);
        }

        /// <summary>
        /// Updates the property field with the given value update a property field in entities.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <typeparam name="TField">The type of the field.</typeparam>
        /// <param name="documentToModify">The document you want to modify.</param>
        /// <param name="field">The field selector.</param>
        /// <param name="value">The new value of the property field.</param>
        public virtual bool UpdateOne<TDocument, TKey, TField>(TDocument documentToModify, Expression<Func<TDocument, TField>> field, TField value)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            return MongoDbUpdater.UpdateOne<TDocument, TKey, TField>(documentToModify, field, value);
        }

        /// <summary>
        /// Updates the property field with the given value update a property field in entities.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <typeparam name="TField">The type of the field.</typeparam>
        /// <param name="documentToModify">The document you want to modify.</param>
        /// <param name="field">The field selector.</param>
        /// <param name="value">The new value of the property field.</param>
        public virtual async Task<bool> UpdateOneAsync<TDocument, TKey, TField>(TDocument documentToModify, Expression<Func<TDocument, TField>> field, TField value)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            return await MongoDbUpdater.UpdateOneAsync<TDocument, TKey, TField>(documentToModify, field, value);
        }

        /// <summary>
        /// Updates the property field with the given value.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <typeparam name="TField">The type of the field.</typeparam>
        /// <param name="filter">The document filter.</param>
        /// <param name="field">The field selector.</param>
        /// <param name="value">The new value of the property field.</param>
        /// <param name="partitionKey">The value of the partition key.</param>
        public virtual bool UpdateOne<TDocument, TKey, TField>(FilterDefinition<TDocument> filter, Expression<Func<TDocument, TField>> field, TField value, string partitionKey = null)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            return MongoDbUpdater.UpdateOne<TDocument, TKey, TField>(filter, field, value, partitionKey);
        }

        /// <summary>
        /// For the entity selected by the filter, updates the property field with the given value.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <typeparam name="TField">The type of the field.</typeparam>
        /// <param name="filter">The document filter.</param>
        /// <param name="field">The field selector.</param>
        /// <param name="value">The new value of the property field.</param>
        /// <param name="partitionKey">The partition key for the document.</param>
        public virtual bool UpdateOne<TDocument, TKey, TField>(Expression<Func<TDocument, bool>> filter, Expression<Func<TDocument, TField>> field, TField value, string partitionKey = null)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            return MongoDbUpdater.UpdateOne<TDocument, TKey, TField>(filter, field, value, partitionKey);
        }

        /// <summary>
        /// Updates the property field with the given value update a property field in entities.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <typeparam name="TField">The type of the field.</typeparam>
        /// <param name="filter">The document filter.</param>
        /// <param name="field">The field selector.</param>
        /// <param name="value">The new value of the property field.</param>
        /// <param name="partitionKey">The value of the partition key.</param>
        public virtual async Task<bool> UpdateOneAsync<TDocument, TKey, TField>(FilterDefinition<TDocument> filter, Expression<Func<TDocument, TField>> field, TField value, string partitionKey = null)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            return await MongoDbUpdater.UpdateOneAsync<TDocument, TKey, TField>(filter, field, value, partitionKey);
        }

        /// <summary>
        /// For the entity selected by the filter, updates the property field with the given value.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <typeparam name="TField">The type of the field.</typeparam>
        /// <param name="filter">The document filter.</param>
        /// <param name="field">The field selector.</param>
        /// <param name="value">The new value of the property field.</param>
        /// <param name="partitionKey">The partition key for the document.</param>
        public virtual async Task<bool> UpdateOneAsync<TDocument, TKey, TField>(Expression<Func<TDocument, bool>> filter, Expression<Func<TDocument, TField>> field, TField value, string partitionKey = null)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            return await UpdateOneAsync<TDocument, TKey, TField>(Builders<TDocument>.Filter.Where(filter), field, value, partitionKey);
        }

        #endregion Update

        #region Delete

        /// <summary>
        /// Asynchronously deletes a document.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <param name="document">The document you want to delete.</param>
        /// <returns>The number of documents deleted.</returns>
        public virtual async Task<long> DeleteOneAsync<TDocument>(TDocument document) where TDocument : IDocument
        {
            return await DeleteOneAsync<TDocument, Guid>(document);
        }

        /// <summary>
        /// Deletes a document.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <param name="document">The document you want to delete.</param>
        /// <returns>The number of documents deleted.</returns>
        public virtual long DeleteOne<TDocument>(TDocument document) where TDocument : IDocument
        {
            return DeleteOne<TDocument, Guid>(document);
        }

        /// <summary>
        /// Deletes a document matching the condition of the LINQ expression filter.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="partitionKey">An optional partition key.</param>
        /// <returns>The number of documents deleted.</returns>
        public virtual long DeleteOne<TDocument>(Expression<Func<TDocument, bool>> filter, string partitionKey = null) where TDocument : IDocument
        {
            return DeleteOne<TDocument, Guid>(filter, partitionKey);
        }

        /// <summary>
        /// Asynchronously deletes a document matching the condition of the LINQ expression filter.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="partitionKey">An optional partition key.</param>
        /// <returns>The number of documents deleted.</returns>
        public virtual async Task<long> DeleteOneAsync<TDocument>(Expression<Func<TDocument, bool>> filter, string partitionKey = null) where TDocument : IDocument
        {
            return await DeleteOneAsync<TDocument, Guid>(filter, partitionKey);
        }

        /// <summary>
        /// Asynchronously deletes the documents matching the condition of the LINQ expression filter.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="partitionKey">An optional partition key.</param>
        /// <returns>The number of documents deleted.</returns>
        public virtual async Task<long> DeleteManyAsync<TDocument>(Expression<Func<TDocument, bool>> filter, string partitionKey = null) where TDocument : IDocument
        {
            return (await HandlePartitioned<TDocument>(partitionKey).DeleteManyAsync(filter)).DeletedCount;
        }

        /// <summary>
        /// Asynchronously deletes a list of documents.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <param name="documents">The list of documents to delete.</param>
        /// <returns>The number of documents deleted.</returns>
        public virtual async Task<long> DeleteManyAsync<TDocument>(IEnumerable<TDocument> documents) where TDocument : IDocument
        {
            return await DeleteManyAsync<TDocument, Guid>(documents);
        }

        /// <summary>
        /// Deletes a list of documents.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <param name="documents">The list of documents to delete.</param>
        /// <returns>The number of documents deleted.</returns>
        public virtual long DeleteMany<TDocument>(IEnumerable<TDocument> documents) where TDocument : IDocument
        {
            return DeleteMany<TDocument, Guid>(documents);
        }

        /// <summary>
        /// Deletes the documents matching the condition of the LINQ expression filter.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="partitionKey">An optional partition key.</param>
        /// <returns>The number of documents deleted.</returns>
        public virtual long DeleteMany<TDocument>(Expression<Func<TDocument, bool>> filter, string partitionKey = null) where TDocument : IDocument
        {
            return HandlePartitioned<TDocument>(partitionKey).DeleteMany(filter).DeletedCount;
        }

        #endregion Delete

        #region Delete TKey

        /// <summary>
        /// Deletes a document.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <param name="document">The document you want to delete.</param>
        /// <returns>The number of documents deleted.</returns>
        public virtual long DeleteOne<TDocument, TKey>(TDocument document)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            var filter = Builders<TDocument>.Filter.Eq("Id", document.Id);
            return HandlePartitioned<TDocument, TKey>(document).DeleteOne(filter).DeletedCount;
        }

        /// <summary>
        /// Asynchronously deletes a document matching the condition of the LINQ expression filter.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <param name="document">The document you want to delete.</param>
        /// <returns>The number of documents deleted.</returns>
        public virtual async Task<long> DeleteOneAsync<TDocument, TKey>(TDocument document)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            var filter = Builders<TDocument>.Filter.Eq("Id", document.Id);
            return (await HandlePartitioned<TDocument, TKey>(document).DeleteOneAsync(filter)).DeletedCount;
        }

        /// <summary>
        /// Deletes a document matching the condition of the LINQ expression filter.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="partitionKey">An optional partition key.</param>
        /// <returns>The number of documents deleted.</returns>
        public virtual long DeleteOne<TDocument, TKey>(Expression<Func<TDocument, bool>> filter, string partitionKey = null)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            return HandlePartitioned<TDocument, TKey>(partitionKey).DeleteOne(filter).DeletedCount;
        }

        /// <summary>
        /// Asynchronously deletes a document matching the condition of the LINQ expression filter.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="partitionKey">An optional partition key.</param>
        /// <returns>The number of documents deleted.</returns>
        public virtual async Task<long> DeleteOneAsync<TDocument, TKey>(Expression<Func<TDocument, bool>> filter, string partitionKey = null)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            return (await HandlePartitioned<TDocument, TKey>(partitionKey).DeleteOneAsync(filter)).DeletedCount;
        }

        /// <summary>
        /// Asynchronously deletes the documents matching the condition of the LINQ expression filter.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="partitionKey">An optional partition key.</param>
        /// <returns>The number of documents deleted.</returns>
        public virtual async Task<long> DeleteManyAsync<TDocument, TKey>(Expression<Func<TDocument, bool>> filter, string partitionKey = null)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            return (await HandlePartitioned<TDocument, TKey>(partitionKey).DeleteManyAsync(filter)).DeletedCount;
        }

        /// <summary>
        /// Asynchronously deletes a list of documents.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <param name="documents">The list of documents to delete.</param>
        /// <returns>The number of documents deleted.</returns>
        public virtual async Task<long> DeleteManyAsync<TDocument, TKey>(IEnumerable<TDocument> documents)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            if (!documents.Any())
            {
                return 0;
            }
            // cannot use typeof(IPartitionedDocument).IsAssignableFrom(typeof(TDocument)), not available in netstandard 1.5
            if (documents.Any(e => e is IPartitionedDocument))
            {
                long deleteCount = 0;
                foreach (var group in documents.GroupBy(e => ((IPartitionedDocument)e).PartitionKey))
                {
                    var groupIdsTodelete = group.Select(e => e.Id).ToArray();
                    deleteCount += (await HandlePartitioned<TDocument, TKey>(group.FirstOrDefault()).DeleteManyAsync(x => groupIdsTodelete.Contains(x.Id))).DeletedCount;
                }
                return deleteCount;
            }
            else
            {
                var idsTodelete = documents.Select(e => e.Id).ToArray();
                return (await HandlePartitioned<TDocument, TKey>(documents.FirstOrDefault()).DeleteManyAsync(x => idsTodelete.Contains(x.Id))).DeletedCount;
            }
        }

        /// <summary>
        /// Deletes a list of documents.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <param name="documents">The list of documents to delete.</param>
        /// <returns>The number of documents deleted.</returns>
        public virtual long DeleteMany<TDocument, TKey>(IEnumerable<TDocument> documents)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            if (!documents.Any())
            {
                return 0;
            }
            // cannot use typeof(IPartitionedDocument).IsAssignableFrom(typeof(TDocument)), not available in netstandard 1.5
            if (documents.Any(e => e is IPartitionedDocument))
            {
                long deleteCount = 0;
                foreach (var group in documents.GroupBy(e => ((IPartitionedDocument)e).PartitionKey))
                {
                    var groupIdsTodelete = group.Select(e => e.Id).ToArray();
                    deleteCount += (HandlePartitioned<TDocument, TKey>(group.FirstOrDefault()).DeleteMany(x => groupIdsTodelete.Contains(x.Id))).DeletedCount;
                }
                return deleteCount;
            }
            else
            {
                var idsTodelete = documents.Select(e => e.Id).ToArray();
                return (HandlePartitioned<TDocument, TKey>(documents.FirstOrDefault()).DeleteMany(x => idsTodelete.Contains(x.Id))).DeletedCount;
            }
        }

        /// <summary>
        /// Deletes the documents matching the condition of the LINQ expression filter.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="partitionKey">An optional partition key.</param>
        /// <returns>The number of documents deleted.</returns>
        public virtual long DeleteMany<TDocument, TKey>(Expression<Func<TDocument, bool>> filter, string partitionKey = null)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            return HandlePartitioned<TDocument, TKey>(partitionKey).DeleteMany(filter).DeletedCount;
        }

        #endregion

        #region Project

        /// <summary>
        /// Asynchronously returns a projected document matching the filter condition.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TProjection">The type representing the model you want to project to.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="projection">The projection expression.</param>
        /// <param name="partitionKey">An optional partition key.</param>
        public virtual async Task<TProjection> ProjectOneAsync<TDocument, TProjection>(Expression<Func<TDocument, bool>> filter, Expression<Func<TDocument, TProjection>> projection, string partitionKey = null)
            where TDocument : IDocument
            where TProjection : class
        {
            return await HandlePartitioned<TDocument>(partitionKey).Find(filter)
                                                                   .Project(projection)
                                                                   .FirstOrDefaultAsync();
        }

        /// <summary>
        /// Asynchronously returns a projected document matching the filter condition.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <typeparam name="TProjection">The type representing the model you want to project to.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="projection">The projection expression.</param>
        /// <param name="partitionKey">An optional partition key.</param>
        public virtual async Task<TProjection> ProjectOneAsync<TDocument, TProjection, TKey>(Expression<Func<TDocument, bool>> filter, Expression<Func<TDocument, TProjection>> projection, string partitionKey = null)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
            where TProjection : class
        {
            return await HandlePartitioned<TDocument, TKey>(partitionKey).Find(filter)
                                                                         .Project(projection)
                                                                         .FirstOrDefaultAsync();
        }

        /// <summary>
        /// Returns a projected document matching the filter condition.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TProjection">The type representing the model you want to project to.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="projection">The projection expression.</param>
        /// <param name="partitionKey">An optional partition key.</param>
        public virtual TProjection ProjectOne<TDocument, TProjection>(Expression<Func<TDocument, bool>> filter, Expression<Func<TDocument, TProjection>> projection, string partitionKey = null)
            where TDocument : IDocument
            where TProjection : class
        {
            return HandlePartitioned<TDocument>(partitionKey).Find(filter)
                                                             .Project(projection)
                                                             .FirstOrDefault();
        }

        /// <summary>
        /// Returns a projected document matching the filter condition.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <typeparam name="TProjection">The type representing the model you want to project to.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="projection">The projection expression.</param>
        /// <param name="partitionKey">An optional partition key.</param>
        public virtual TProjection ProjectOne<TDocument, TProjection, TKey>(Expression<Func<TDocument, bool>> filter, Expression<Func<TDocument, TProjection>> projection, string partitionKey = null)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
            where TProjection : class
        {
            return HandlePartitioned<TDocument, TKey>(partitionKey).Find(filter)
                                                                   .Project(projection)
                                                                   .FirstOrDefault();
        }

        /// <summary>
        /// Asynchronously returns a list of projected documents matching the filter condition.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TProjection">The type representing the model you want to project to.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="projection">The projection expression.</param>
        /// <param name="partitionKey">An optional partition key.</param>
        public virtual async Task<List<TProjection>> ProjectManyAsync<TDocument, TProjection>(Expression<Func<TDocument, bool>> filter, Expression<Func<TDocument, TProjection>> projection, string partitionKey = null)
            where TDocument : IDocument
            where TProjection : class
        {
            return await HandlePartitioned<TDocument>(partitionKey).Find(filter)
                                                                   .Project(projection)
                                                                   .ToListAsync();
        }

        /// <summary>
        /// Asynchronously returns a list of projected documents matching the filter condition.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <typeparam name="TProjection">The type representing the model you want to project to.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="projection">The projection expression.</param>
        /// <param name="partitionKey">An optional partition key.</param>
        public virtual async Task<List<TProjection>> ProjectManyAsync<TDocument, TProjection, TKey>(Expression<Func<TDocument, bool>> filter, Expression<Func<TDocument, TProjection>> projection, string partitionKey = null)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
            where TProjection : class
        {
            return await HandlePartitioned<TDocument, TKey>(partitionKey).Find(filter)
                                                                   .Project(projection)
                                                                   .ToListAsync();
        }

        /// <summary>
        /// Asynchronously returns a list of projected documents matching the filter condition.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TProjection">The type representing the model you want to project to.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="projection">The projection expression.</param>
        /// <param name="partitionKey">An optional partition key.</param>
        public virtual List<TProjection> ProjectMany<TDocument, TProjection>(Expression<Func<TDocument, bool>> filter, Expression<Func<TDocument, TProjection>> projection, string partitionKey = null)
            where TDocument : IDocument
            where TProjection : class
        {
            return HandlePartitioned<TDocument>(partitionKey).Find(filter)
                                                             .Project(projection)
                                                             .ToList();
        }

        /// <summary>
        /// Asynchronously returns a list of projected documents matching the filter condition.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <typeparam name="TProjection">The type representing the model you want to project to.</typeparam>
        /// <param name="filter">The document filter.</param>
        /// <param name="projection">The projection expression.</param>
        /// <param name="partitionKey">An optional partition key.</param>
        public virtual List<TProjection> ProjectMany<TDocument, TProjection, TKey>(Expression<Func<TDocument, bool>> filter, Expression<Func<TDocument, TProjection>> projection, string partitionKey = null)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
            where TProjection : class
        {
            return HandlePartitioned<TDocument, TKey>(partitionKey).Find(filter)
                                                             .Project(projection)
                                                             .ToList();
        }

        #endregion

        #region Grouping

        /// <summary>
        /// Groups a collection of documents given a grouping criteria, 
        /// and returns a dictionary of listed document groups with keys having the different values of the grouping criteria.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TGroupKey">The type of the grouping criteria.</typeparam>
        /// <typeparam name="TProjection">The type of the projected group.</typeparam>
        /// <param name="groupingCriteria">The grouping criteria.</param>
        /// <param name="groupProjection">The projected group result.</param>
        /// <param name="partitionKey">The partition key of your document, if any.</param>
        public virtual List<TProjection> GroupBy<TDocument, TGroupKey, TProjection>(
            Expression<Func<TDocument, TGroupKey>> groupingCriteria,
            Expression<Func<IGrouping<TGroupKey, TDocument>, TProjection>> groupProjection,
            string partitionKey = null)
            where TDocument : IDocument
            where TProjection : class, new()
        {
            var collection = string.IsNullOrEmpty(partitionKey) ? GetCollection<TDocument>() : GetCollection<TDocument>(partitionKey);
            return collection.Aggregate()
                             .Group(groupingCriteria, groupProjection)
                             .ToList();

        }

        /// <summary>
        /// Groups filtered a collection of documents given a grouping criteria, 
        /// and returns a dictionary of listed document groups with keys having the different values of the grouping criteria.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TGroupKey">The type of the grouping criteria.</typeparam>
        /// <typeparam name="TProjection">The type of the projected group.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="selector">The grouping criteria.</param>
        /// <param name="projection">The projected group result.</param>
        /// <param name="partitionKey">The partition key of your document, if any.</param>
        public virtual List<TProjection> GroupBy<TDocument, TGroupKey, TProjection>(Expression<Func<TDocument, bool>> filter,
                                                       Expression<Func<TDocument, TGroupKey>> selector,
                                                       Expression<Func<IGrouping<TGroupKey, TDocument>, TProjection>> projection,
                                                       string partitionKey = null)
                                                       where TDocument : IDocument
                                                       where TProjection : class, new()
        {
            var collection = string.IsNullOrEmpty(partitionKey) ? GetCollection<TDocument>() : GetCollection<TDocument>(partitionKey);
            return collection.Aggregate()
                             .Match(Builders<TDocument>.Filter.Where(filter))
                             .Group(selector, projection)
                             .ToList();
        }


        #endregion

        /// <summary>
        /// Asynchronously returns a paginated list of the documents matching the filter condition.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="sortSelector">The property selector.</param>
        /// <param name="ascending">Order of the sorting.</param>
        /// <param name="skipNumber">The number of documents you want to skip. Default value is 0.</param>
        /// <param name="takeNumber">The number of documents you want to take. Default value is 50.</param>
        /// <param name="partitionKey">An optional partition key.</param>
        public virtual async Task<List<TDocument>> GetSortedPaginatedAsync<TDocument>(
            Expression<Func<TDocument, bool>> filter,
            Expression<Func<TDocument, object>> sortSelector,
            bool ascending = true,
            int skipNumber = 0,
            int takeNumber = 50,
            string partitionKey = null)
            where TDocument : IDocument
        {
            var sorting = ascending
                ? Builders<TDocument>.Sort.Ascending(sortSelector)
                : Builders<TDocument>.Sort.Descending(sortSelector);

            return await HandlePartitioned<TDocument>(partitionKey)
                    .Find(filter)
                    .Sort(sorting)
                    .Skip(skipNumber)
                    .Limit(takeNumber)
                    .ToListAsync();
        }


        /// <summary>
        /// Asynchronously returns a paginated list of the documents matching the filter condition.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="skipNumber">The number of documents you want to skip. Default value is 0.</param>
        /// <param name="takeNumber">The number of documents you want to take. Default value is 50.</param>
        /// <param name="partitionKey">An optional partition key.</param>
        public virtual async Task<List<TDocument>> GetPaginatedAsync<TDocument>(
            Expression<Func<TDocument, bool>> filter,
            int skipNumber = 0,
            int takeNumber = 50,
            string partitionKey = null)
            where TDocument : IDocument
        {
            return await HandlePartitioned<TDocument>(partitionKey).Find(filter).Skip(skipNumber).Limit(takeNumber).ToListAsync();
        }

        /// <summary>
        /// Asynchronously returns a paginated list of the documents matching the filter condition.
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="skipNumber">The number of documents you want to skip. Default value is 0.</param>
        /// <param name="takeNumber">The number of documents you want to take. Default value is 50.</param>
        /// <param name="partitionKey">An optional partition key.</param>
        public virtual async Task<List<TDocument>> GetPaginatedAsync<TDocument, TKey>(Expression<Func<TDocument, bool>> filter, int skipNumber = 0, int takeNumber = 50, string partitionKey = null)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            return await HandlePartitioned<TDocument, TKey>(partitionKey).Find(filter).Skip(skipNumber).Limit(takeNumber).ToListAsync();
        }

        #region Find And Update

        /// <summary>
        /// GetAndUpdateOne with filter
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="update"></param>
        /// <param name="options"></param>
        /// <returns></returns>
        public virtual async Task<TDocument> GetAndUpdateOne<TDocument>(FilterDefinition<TDocument> filter, UpdateDefinition<TDocument> update, FindOneAndUpdateOptions<TDocument, TDocument> options) where TDocument : IDocument
        {
            return await GetCollection<TDocument>().FindOneAndUpdateAsync(filter, update, options);
        }

        /// <summary>
        /// GetAndUpdateOne with filter
        /// </summary>
        /// <typeparam name="TDocument">The type representing a Document.</typeparam>
        /// <typeparam name="TKey">The type of the primary key for a Document.</typeparam>
        /// <param name="filter">A LINQ expression filter.</param>
        /// <param name="update"></param>
        /// <param name="options"></param>
        /// <returns></returns>
        public virtual async Task<TDocument> GetAndUpdateOne<TDocument, TKey>(FilterDefinition<TDocument> filter, UpdateDefinition<TDocument> update, FindOneAndUpdateOptions<TDocument, TDocument> options)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            return await GetCollection<TDocument, TKey>().FindOneAndUpdateAsync(filter, update, options);
        }

        #endregion Find And Update

        /// <summary>
        /// Sets the value of the document Id if it is not set already.
        /// </summary>
        /// <typeparam name="TDocument">The document type.</typeparam>
        /// <typeparam name="TKey">The type of the primary key.</typeparam>
        /// <param name="document">The document.</param>
        protected void FormatDocument<TDocument, TKey>(TDocument document)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
        {
            if (document == null)
            {
                throw new ArgumentNullException(nameof(document));
            }
            var defaultTKey = default(TKey);
            if (document.Id == null
                || (defaultTKey != null
                    && defaultTKey.Equals(document.Id)))
            {
                document.Id = IdGenerator.GetId<TKey>();
            }
        }

        /// <summary>
        /// Sets the value of the document Id if it is not set already.
        /// </summary>
        /// <typeparam name="TDocument">The document type.</typeparam>
        /// <param name="document">The document.</param>
        protected void FormatDocument<TDocument>(TDocument document) where TDocument : IDocument
        {
            if (document == null)
            {
                throw new ArgumentNullException(nameof(document));
            }
            if (document.Id == default(Guid))
            {
                document.Id = Guid.NewGuid();
            }
        }
    }
}