using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata;
using Microsoft.EntityFrameworkCore.Metadata.Internal;
using PersonnelDepartmentContracts.BindingModels;
using PersonnelDepartmentContracts.SearchModels;
using PersonnelDepartmentContracts.StoragesContracts;
using PersonnelDepartmentContracts.ViewModels;
using PersonnelDepartmentDatabaseImplement.Models;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace PersonnelDepartmentDatabaseImplement.Implements
{
	public class DealStorage : IDealStorage
	{
		public bool ClearList()
		{
			try
			{
				using var context = new PersonnelDepartmentDatabase();
				var tableName = context.Model.FindEntityType(typeof(Deal)).GetTableName();
				context.Database.ExecuteSqlRaw($"DELETE FROM \"{ tableName }\"");
			}
			catch (Exception)
			{
				return false;
			}
			return true;
		}

		public DealViewModel? Delete(DealBindingModel model)
		{
			using var context = new PersonnelDepartmentDatabase();
			var element = context.Deals
				.Include(x => x.Employee)
				.Include(x => x.Department)
				.Include(x => x.Type)
				.Include(x => x.Position)
				.FirstOrDefault(x => x.Id == model.Id);
			if (element == null)
			{
				return null;
			}
			context.Deals.Remove(element);
			context.SaveChanges();
			return element.GetViewModel;
		}

		public string DiffGetTest(int count)
		{
			using var context = new PersonnelDepartmentDatabase();
			Stopwatch stopwatch = new();	
			stopwatch.Start();
			var list = context.Deals
				.Include(x => x.Department)
				.Include(x => x.Employee)
				.Include(x => x.Type)
				.Include(x => x.Position)
				.Join(context.Departments,
				deal => deal.DepartmentId,
				department => department.Id,
				(deal, department) => new { Deal = deal, Department = department })
				.Join(context.Employees,
				deal => deal.Deal.EmployeeId,
				employee => employee.Id,
				(deal, employee) => new { deal.Deal, deal.Department, Employee = employee })
				.Join(context.Positions,
				deal => deal.Deal.PositionId,
				position => position.Id,
				(deal, position) => new { deal.Deal, deal.Department, deal.Employee, Position = position })
				.Join(context.Types,
				deal => deal.Deal.TypeId,
				type => type.Id,
				(deal, type) => new { deal.Deal, deal.Department, deal.Employee, deal.Position, Type = type })
				.Select(deal => new
				{
					Deal = deal.Deal.GetViewModel,
					Department = deal.Department.GetViewModel,
					Type = deal.Type.GetViewModel,
					Position = deal.Position.GetViewModel
				})
				.Take(count)
				.ToList();
			stopwatch.Stop();
			return stopwatch.ElapsedMilliseconds.ToString();
		}

		public DealViewModel? GetElement(DealSearchModel model)
		{
			if (!model.Id.HasValue)
			{
				return null;
			}
			using var context = new PersonnelDepartmentDatabase();
			return context.Deals
				.Include(x => x.Employee)
				.Include(x => x.Department)
				.Include(x => x.Type)
				.Include(x => x.Position)
				.FirstOrDefault(x => (model.Id.HasValue && model.Id == x.Id) ||
				(model.DateFrom != null && x.DateFrom == model.DateFrom) ||
				(model.DateTo != null && x.DateTo == model.DateTo) ||
				(model.EmployeeId.HasValue && x.EmployeeId == model.EmployeeId) ||
				(model.DepartmentId.HasValue && x.DepartmentId == model.DepartmentId) ||
				(model.PositionId.HasValue && x.PositionId == model.PositionId) ||
				(model.TypeId.HasValue && x.TypeId == model.TypeId))?.GetViewModel;
		}

		public List<DealViewModel> GetFilteredList(DealSearchModel model)
		{
			using var context = new PersonnelDepartmentDatabase();
			return context.Deals
				.Include(x => x.Employee)
				.Include(x => x.Department)
				.Include(x => x.Type)
				.Include(x => x.Position)
				.Where(x => (model.Id.HasValue && model.Id == x.Id) ||
				(model.DateFrom != null && x.DateFrom == model.DateFrom) ||
				(model.DateTo != null && x.DateTo == model.DateTo) ||
				(model.EmployeeId.HasValue && x.EmployeeId == model.EmployeeId) ||
				(model.DepartmentId.HasValue && x.DepartmentId == model.DepartmentId) ||
				(model.PositionId.HasValue && x.PositionId == model.PositionId) ||
				(model.TypeId.HasValue && x.TypeId == model.TypeId))
				.Select(x => x.GetViewModel) .ToList();
		}

		public List<DealViewModel> GetFullList()
		{
			using var context = new PersonnelDepartmentDatabase();
			return context.Deals
				.Include(x => x.Department)
				.Include(x => x.Position)
				.Include(x => x.Employee)
				.Include(x => x.Type)
				.Select(x => x.GetViewModel)
				.ToList();
		}

		public string GetTest(int count)
		{
			using var context = new PersonnelDepartmentDatabase();
			Stopwatch stopwatch = new();
			stopwatch.Start();
			var list = context.Deals
				.Include(x => x.Department)
				.Include(x => x.Employee)
				.Include(x => x.Type)
				.Include(x => x.Position)
				.Take(count)
				.Select(x => x.GetViewModel)
				.ToList();
			stopwatch.Stop();
			return stopwatch.ElapsedMilliseconds.ToString();
		}

		public DealViewModel? Insert(DealBindingModel model)
		{
			var newElement = Deal.Create(model);
			if (newElement == null)
			{
				return null;
			}
			using var context = new PersonnelDepartmentDatabase();
			context.Deals.Add(newElement);
			context.SaveChanges();
			return GetElement(new DealSearchModel { Id = newElement.Id } );
		}

		public string SetTest(int count)
		{
			Random rnd = new Random();
			using var context = new PersonnelDepartmentDatabase();
			var listDepartments = context.Departments.Select(x => x.GetViewModel).ToList();
			var listEmployees = context.Employees.Select(x => x.GetViewModel).ToList();
			var listPositions = context.Positions.Select(x => x.GetViewModel).ToList();
			var listTypes = context.Types.Select(x => x.GetViewModel).ToList();
			if (listDepartments.Count < 1 || listEmployees.Count < 1 || listPositions.Count < 1 || listTypes.Count < 1)
			{
				throw new Exception("Недостаточно для генерации!");
			}
			for (int i = 0; i < count; ++i)
			{
				context.Deals.Add(Deal.Create(new DealBindingModel
				{
					Id = 0,
					DateFrom = DateTime.SpecifyKind(DateTime.Now, DateTimeKind.Utc),
					DateTo = DateTime.SpecifyKind(DateTime.Now, DateTimeKind.Utc),
					DepartmentId = listDepartments[rnd.Next(listDepartments.Count)].Id,
					EmployeeId = listEmployees[rnd.Next(listEmployees.Count)].Id,
					TypeId = listTypes[rnd.Next(listTypes.Count)].Id,
					PositionId = listPositions[rnd.Next(listPositions.Count)].Id
				}));
			}
			Stopwatch stopwatch = new();
			stopwatch.Start();
			context.SaveChanges();
			stopwatch.Stop();
			return stopwatch.ElapsedMilliseconds.ToString();
		}

		public DealViewModel? Update(DealBindingModel model)
		{
			using var context = new PersonnelDepartmentDatabase();
			var element = context.Deals
				.Include(x => x.Department)
				.Include(x => x.Employee)
				.Include(x => x.Type)
				.Include (x => x.Position)
				.FirstOrDefault(x => x.Id == model.Id);
			if (element == null)
			{
				return null;
			}
			element.Update(model);
			context.SaveChanges();
			return GetElement(new DealSearchModel { Id = element.Id });
		}
	}
}