using DatabaseCore;
using DatabaseCore.Models.Department;
using DepartmentBusinessLogic.BindingModels;
using DepartmentBusinessLogic.Interfaces;
using DepartmentBusinessLogic.ViewModels;
using Microsoft.EntityFrameworkCore;
using ModuleTools.BusinessLogics;
using ModuleTools.Enums;
using ModuleTools.Models;
using System;
using System.Linq;

namespace DepartmentDatabaseImplementation.Implementations
{
	/// <summary>
	/// Реализация ILecturerService
	/// </summary>
	public class LecturerService : ILecturerService
	{
		public OperationResultModel Create(LecturerSetBindingModel model)
		{
			using var context = DatabaseManager.GetContext;

			var exsistEntity = context.Lecturers.FirstOrDefault(x => x.LastName == model.LastName && x.FirstName == model.FirstName &&
					x.Patronymic == model.Patronymic);
			if (exsistEntity == null)
			{
				var entity = Mapper.MapToClass<LecturerSetBindingModel, Lecturer>(model, true);
				context.Lecturers.Add(entity);
				context.SaveChanges();
				return OperationResultModel.Success(Mapper.MapToClass<Lecturer, LecturerViewModel>(entity, true));
			}
			else
			{
				if (exsistEntity.IsDeleted)
				{
					exsistEntity = Mapper.MapToClass(model, exsistEntity, true);
					exsistEntity.IsDeleted = false;
					context.SaveChanges();
					return OperationResultModel.Success(Mapper.MapToClass<Lecturer, LecturerViewModel>(exsistEntity, true));
				}
				else
				{
					return OperationResultModel.Error("Error:", "Элемент уже существует", ResultServiceStatusCode.ExsistItem);
				}
			}
		}

		public OperationResultModel Delete(LecturerGetBindingModel model)
		{
			using var context = DatabaseManager.GetContext;
			using var transaction = context.Database.BeginTransaction();
			try
			{
				var entity = context.Lecturers.Include(x => x.User).FirstOrDefault(x => x.Id == model.Id);
				if (entity == null)
				{
					return OperationResultModel.Error("Error:", "Элемент не найден", ResultServiceStatusCode.NotFound);
				}
				else if (entity.IsDeleted)
				{
					return OperationResultModel.Error("Error:", "Элемент был удален", ResultServiceStatusCode.WasDelete);
				}
				else if (entity.User == null)
				{
					return OperationResultModel.Error("Error:", "Не найден пользователь от сотрудника", ResultServiceStatusCode.NotFound);
				}
				entity.IsDeleted = true;
				entity.DateDelete = DateTime.Now;
				entity.User.IsDeleted = true;
				entity.User.DateDelete = DateTime.Now;

				context.SaveChanges();

				var links = context.LecturerEmployeePosts.Where(x => x.LecturerId == model.Id);
				foreach (var link in links)
				{
					link.IsDeleted = true;
					link.DateDelete = DateTime.Now;
				}
				context.SaveChanges();


				transaction.Commit();
			}
			catch (Exception)
			{
				transaction.Rollback();
				throw;
			}

			return OperationResultModel.Success(true);
		}

		public OperationResultModel Read(LecturerGetBindingModel model)
		{
			int countPages = 0;
			using var context = DatabaseManager.GetContext;

			// для одной записи
			if (model.Id.HasValue)
			{
				var entity = context.Lecturers.FirstOrDefault(x => x.Id == model.Id.Value);
				if (entity == null)
				{
					return OperationResultModel.Error("Error:", "Элемент не найден", ResultServiceStatusCode.NotFound);
				}
				return OperationResultModel.Success(Mapper.MapToClass<Lecturer, LecturerViewModel>(entity, model.HaveRight));
			}

			var query = context.Lecturers.Where(x => !x.IsDeleted).AsQueryable();
			if(model.UserId.HasValue)
			{
				query = query.Where(x => x.UserId == model.UserId);
			}
			if (model.LecturerAcademicDegreeId.HasValue)
			{
				query = query.Where(x => x.LecturerAcademicDegreeId == model.LecturerAcademicDegreeId);
			}
			if (model.LecturerAcademicRankId.HasValue)
			{
				query = query.Where(x => x.LecturerAcademicRankId == model.LecturerAcademicRankId);
			}
			if (model.LecturerPostId.HasValue)
			{
				query = query.Where(x => x.LecturerPostId == model.LecturerPostId);
			}

			query = query.OrderBy(x => x.LastName);

			if (model.PageNumber.HasValue && model.PageSize.HasValue)
			{
				countPages = (int)Math.Ceiling((double)query.Count() / model.PageSize.Value);
				query = query
							.Skip(model.PageSize.Value * model.PageNumber.Value)
							.Take(model.PageSize.Value);
			}

			var result = new LecturerListViewModel
			{
				MaxCount = countPages,
				List = query.Select(x => Mapper.MapToClass<Lecturer, LecturerViewModel>(x, model.HaveRight)).ToList()
			};

			return OperationResultModel.Success(result);
		}

		public OperationResultModel Update(LecturerSetBindingModel model)
		{
			using var context = DatabaseManager.GetContext;

			var entity = context.Lecturers.FirstOrDefault(x => x.Id == model.Id);
			if (entity == null)
			{
				return OperationResultModel.Error("Error:", "Элемент не найден", ResultServiceStatusCode.NotFound);
			}
			else if (entity.IsDeleted)
			{
				return OperationResultModel.Error("Error:", "Элемент был удален", ResultServiceStatusCode.WasDelete);
			}
			entity = Mapper.MapToClass(model, entity, true);

			context.SaveChanges();

			return OperationResultModel.Success(Mapper.MapToClass<Lecturer, LecturerViewModel>(entity, true));
		}
	}
}