using MongoDB.Driver;
using RouteGuideContracts.BindingModels;
using RouteGuideContracts.SearchModels;
using RouteGuideContracts.StoragesContracts;
using RouteGuideContracts.ViewModels;
using RouteGuideMongoDBImplement.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace RouteGuideMongoDBImplement.Implements
{
	/// <summary>
	/// Хранилище для сущности "Маршрут"
	/// </summary>
	public class RouteStorage : IRouteStorage
	{
		/// <summary>
		/// Получение полного списка
		/// </summary>
		/// <returns></returns>
		public List<RouteViewModel> GetFullList()
		{
			using var context = new RouteGuideDatabase();

			var filterBuilder = Builders<Route>.Filter;
			var filter = filterBuilder.Empty;

			return context.Routes
				.Find(filter)
				.ToList()
				.Select(x => x.GetViewModel)
				.ToList();
		}

		/// <summary>
		/// Получение фильтрованного списка
		/// </summary>
		/// <param name="model"></param>
		/// <returns></returns>
		public List<RouteViewModel> GetFilteredList(RouteSearchModel model)
		{
			if (string.IsNullOrEmpty(model.Name))
			{
				return new();
			}

			using var context = new RouteGuideDatabase();

			var filterBuilder = Builders<Route>.Filter;
			var filter = filterBuilder.Eq(x => x.Name, model.Name);

			return context.Routes
				.Find(filter)
				.ToList()
				.Select(x => x.GetViewModel)
				.ToList();
		}

		/// <summary>
		/// Получить список из заданного количества элементов
		/// </summary>
		/// <param name="count"></param>
		/// <returns></returns>
		public List<RouteViewModel> GetList(int count)
		{
			if (count <= 0)
			{
				return new();
			}

			using var context = new RouteGuideDatabase();

			var filterBuilder = Builders<Route>.Filter;
			var filter = filterBuilder.Empty;

			return context.Routes
				.Find(filter)
				.Limit(count)
				.ToList()
				.Select(x => x.GetViewModel)
				.ToList();
		}

		/// <summary>
		/// Получение элемента
		/// </summary>
		/// <param name="model"></param>
		/// <returns></returns>
		public RouteViewModel? GetElement(RouteSearchModel model)
		{
			if (string.IsNullOrEmpty(model.Id?.ToString()) && string.IsNullOrEmpty(model.Name))
			{
				return null;
			}

			using var context = new RouteGuideDatabase();

			var filterBuilder = Builders<Route>.Filter;
			var filter = filterBuilder.Empty;
			if (!string.IsNullOrEmpty(model.Name))
			{
				filter &= filterBuilder.Eq(x => x.Name, model.Name);
			}
			if (!string.IsNullOrEmpty(model.Id?.ToString()))
			{
				filter &= filterBuilder.Eq(x => x.Id, model.Id);
			}

			return context.Routes
				.Find(filter)
				.FirstOrDefault()
				?.GetViewModel;
		}

		/// <summary>
		/// Добавление элемента
		/// </summary>
		/// <param name="model"></param>
		/// <returns></returns>
		public RouteViewModel? Insert(RouteBindingModel model)
		{
			using var context = new RouteGuideDatabase();
			var newRoute = Route.Create(context, model);
			if (newRoute == null)
			{
				return null;
			}

			context.Routes.InsertOne(newRoute);
			return newRoute.GetViewModel;
		}

		/// <summary>
		/// Редактирование элемента
		/// </summary>
		/// <param name="model"></param>
		/// <returns></returns>
		public RouteViewModel? Update(RouteBindingModel model)
		{
			using var context = new RouteGuideDatabase();
			using var session = context._client.StartSession();
			try
			{
				var filterBuilder = Builders<Route>.Filter;
				var filter = filterBuilder.Eq(x => x.Id, model.Id);

				var route = context.Routes.Find(filter).FirstOrDefault();
				if (route == null)
				{
					return null;
				}

				route.Update(model);
				route.UpdateStops(context, model);
				context.Routes.ReplaceOne(filter, route);
				session.CommitTransaction();
				return route.GetViewModel;
			}
			catch
			{
				session.AbortTransaction();
				throw;
			}
		}

		/// <summary>
		/// Удаление элемента
		/// </summary>
		/// <param name="model"></param>
		/// <returns></returns>
		public RouteViewModel? Delete(RouteBindingModel model)
		{
			using var context = new RouteGuideDatabase();

			var filterBuilder = Builders<Route>.Filter;
			var filter = filterBuilder.Eq(x => x.Id, model.Id);

			var route = context.Routes.Find(filter).FirstOrDefault();
			if (route == null)
			{
				return null;
			}

			context.Routes.FindOneAndDelete(filter);
			return route.GetViewModel;
		}

		/// <summary>
		/// Удаление записи
		/// </summary>
		/// <returns></returns>
		public RouteViewModel? Delete()
		{
			if (!GetFullList().Any())
			{
				return null;
			}

			using var context = new RouteGuideDatabase();

			var filterBuilder = Builders<Route>.Filter;
			var filter = filterBuilder.Empty;

			var element = context.Routes.FindOneAndDelete(filter);
			return element.GetViewModel;
		}

		/// <summary>
		/// Удаление всех элементов
		/// </summary>
		/// <returns></returns>
		public int Clear()
		{
			using var context = new RouteGuideDatabase();
			int count = GetFullList().Count;
			if (count <= 0)
			{
				return 0;
			}

			var filterBuilder = Builders<Route>.Filter;
			var filter = filterBuilder.Empty;

			context.Routes.DeleteMany(filter);
			return count;
		}
	}
}