using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using TaskTrackerContracts.BindingModels;
using TaskTrackerContracts.SearchModels;
using TaskTrackerContracts.StoragesContracts;
using TaskTrackerContracts.ViewModels;
using TaskTrackerDatabase.Models;

namespace TaskTrackerDatabase.Implements
{
    public class ExamStorage : IExamStorage
    {
        public List<ExamViewModel> GetFullList()
		{
			using var context = new TaskTrackerDatabase();
			return context.Exams
                    .Include(x => x.Subject)
                    .Select(x => x.GetViewModel)
                    .ToList();
        }

        public List<ExamViewModel> GetFilteredList(ExamSearchModel model)
        {
            using var context = new TaskTrackerDatabase();
            if (model.Id.HasValue)
            {
                return context.Exams
                    .Include(x => x.Subject)
                    .Where(x => x.Id == model.Id)
                    .Select(x => x.GetViewModel)
                    .ToList();
            }
            else if (!model.SubjectId.HasValue)
            {
                return context.Exams
                    .Include(x => x.Subject)
                    .Where(x => x.SubjectId == model.SubjectId)
                    .Select(x => x.GetViewModel)
                    .ToList();
            }
            return new();
        }

        public ExamViewModel? GetElement(ExamSearchModel model)
        {
            if (!model.Id.HasValue)
            {
                return null;
            }
            using var context = new TaskTrackerDatabase();
            return context.Exams
                    .Include(x => x.Subject)
                    .FirstOrDefault(x => x.Id == model.Id)
                    ?.GetViewModel;
        }

        public ExamViewModel? Insert(ExamBindingModel model)
        {
            var newExam = Exam.Create(model);
            if (newExam == null)
            {
                return null;
            }
            using var context = new TaskTrackerDatabase();
            context.Exams.Add(newExam);
            context.SaveChanges();
            return context.Exams
                      .Include(x => x.Subject)
                      .FirstOrDefault(x => x.Id == newExam.Id)
                      ?.GetViewModel;
        }

        public ExamViewModel? Update(ExamBindingModel model)
        {
            using var context = new TaskTrackerDatabase();
            var order = context.Exams.FirstOrDefault(x => x.Id == model.Id);
            if (order == null)
            {
                return null;
            }
            order.Update(model);
            context.SaveChanges();
            return context.Exams
                         .Include(x => x.Subject)
                         .FirstOrDefault(x => x.Id == model.Id)
                         ?.GetViewModel;
        }

        public ExamViewModel? Delete(ExamBindingModel model)
        {
            using var context = new TaskTrackerDatabase();
            var element = context.Exams.FirstOrDefault(rec => rec.Id == model.Id);
            if (element != null)
            {
                var deletedElement = context.Exams
                                           .Include(x => x.Subject)
                                           .FirstOrDefault(x => x.Id == model.Id)
                                           ?.GetViewModel;
                context.Exams.Remove(element);
                context.SaveChanges();
                return deletedElement;
            }
            return null;
        }
    }
}