using System;
using System.Collections.Generic;
using System.Configuration;
using System.Linq;
using System.Web;
using EnVisage.Code.BLL;
using EnVisage.Code.DAL.Mongo;
using EnVisage.Properties;
using MongoDB.Bson;
using MongoDB.Driver;
using MongoDB.Driver.Builders;

namespace EnVisage.Code.DAL
{
	public class MongoDataContext
	{
		#region Fields and Constants
		private static readonly MongoDataContext Instance = new MongoDataContext();
		private static IMongoClient _client;
		private static IMongoDatabase _db;

		#region Collection Names
		public const string COLL_NAME_MIXES = "Mix";
		public const string COLL_NAME_TRANSACTIONS = "Transaction";
		public const string COLL_NAME_EXP_ALLOCATIONS = "ExpAllocation";
		public const string COLL_NAME_TEAM_ALLOCATIONS = "TeamAllocation";
		public const string COLL_NAME_RESOURCE_ALLOCATIONS = "ResourceAllocation";
		#endregion

		#endregion

		#region Constructors
		private MongoDataContext()
		{
            if (string.IsNullOrEmpty(AppSettingsManager.MongoDBConnectionString))
				throw new ConfigurationErrorsException("There is no MongoDBConnectionString configuration key.");

            _client = new MongoClient(AppSettingsManager.MongoDBConnectionString);
			_db = _client.GetDatabase(Settings.Default.MongoDBName);
		}
		// Explicit static constructor to tell C# compiler
		// not to mark type as beforefieldinit
		static MongoDataContext()
		{
			//RecreateIndexes();
		}
		#endregion

		#region Generic methods
		public static async void InsertOneAsync<T>(T entity, string collectionName) where T : class, new()
		{
			var collecion = GetCollection<T>(collectionName);
			if (collecion == null)
				throw new MongoCollectionNotExistsException(collectionName);
			await collecion.InsertOneAsync(entity);
		}
		public static void InsertOne<T>(T entity, string collectionName) where T : class, new()
		{
			var collecion = GetCollection<T>(collectionName);
			if (collecion == null)
				throw new MongoCollectionNotExistsException(collectionName);
			collecion.InsertOneAsync(entity).GetAwaiter().GetResult();
		}
		public static async void DropCollectionAsync<T>()
		{
			await _db.DropCollectionAsync(typeof(T).Name);
		}
		public static void DropCollection<T>()
		{
			_db.DropCollectionAsync(typeof(T).Name).GetAwaiter().GetResult();
		}
		public static IMongoCollection<T> GetCollection<T>(string name)
		{
			if (string.IsNullOrEmpty(name))
				throw new ArgumentNullException(nameof(name));

			return string.IsNullOrEmpty(name) ? null : _db.GetCollection<T>(name);
		}

		#endregion

		#region Collections
		public static IMongoCollection<Mongo.Mix> Mixes
		{
			get
			{
				var collection = GetCollection<Mongo.Mix>(COLL_NAME_MIXES);
				if (collection == null)
					throw new MongoCollectionNotExistsException(COLL_NAME_MIXES);
				return collection;
			}
		}
		public static IMongoCollection<MixExpenditureAllocation> ExpenditureAllocations
		{
			get
			{
				var collection = GetCollection<MixExpenditureAllocation>(COLL_NAME_EXP_ALLOCATIONS);
				if (collection == null)
					throw new MongoCollectionNotExistsException(COLL_NAME_EXP_ALLOCATIONS);
				return collection;
			}
		}
		public static IMongoCollection<MixTeamAllocation> TeamAllocations
		{
			get
			{
				var collection = GetCollection<MixTeamAllocation>(COLL_NAME_TEAM_ALLOCATIONS);
				if (collection == null)
					throw new MongoCollectionNotExistsException(COLL_NAME_TEAM_ALLOCATIONS);
				return collection;
			}
		}
		public static IMongoCollection<MixResourceAllocation> ResourceAllocations
		{
			get
			{
				var collection = GetCollection<MixResourceAllocation>(COLL_NAME_RESOURCE_ALLOCATIONS);
				if (collection == null)
					throw new MongoCollectionNotExistsException(COLL_NAME_RESOURCE_ALLOCATIONS);
				return collection;
			}
		}
		#endregion

		#region Index Management
		private static void CreateIndexes()
		{
			//#region NGramms
			//var collection = GetCollection<Mix>(COLL_NAME_MIXES);
			//collection.Indexes.CreateOneAsync(new BsonDocumentIndexKeysDefinition<Mix>(), new IndexOptionsBuilder().SetUnique(true).SetName("hash"));

			//#endregion
		}
		private static void DropIndexes()
		{
			var collection = GetCollection<Mongo.Mix>(COLL_NAME_MIXES);
			collection.Indexes.DropAllAsync().GetAwaiter().GetResult();
		}
		/// <summary>
		/// Drops and recreates indexes. Call it only once, do not call it in context constructor all the time.
		/// </summary>
		private static void RecreateIndexes()
		{
			DropIndexes();
			CreateIndexes();
		}
		#endregion
	}
}