using Microsoft.EntityFrameworkCore;
using SchoolAgainStudyContracts.BindingModel;
using SchoolAgainStudyContracts.SearchModel;
using SchoolAgainStudyContracts.StorageContracts;
using SchoolAgainStudyContracts.ViewModel;
using SchoolAgainStudyDataBaseImplements.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SchoolAgainStudyDataBaseImplements.Implements
{
    public class LessonStorage : ILessonStorage
    {
        public List<LessonViewModel> GetFullList()
        {
            using var context = new SchoolDataBase();
            return context.Lessons
                    .Include(x => x.Materials)
                    .ThenInclude(x => x.Material)
                    .ToList()
                    .Select(x => x.GetViewModel)
                    .ToList();
        }

        public List<LessonViewModel> GetFilteredList(LessonSearchModel model)
        {
            if (!model.TeacherId.HasValue)
            {
                return new();
            }
            using var context = new SchoolDataBase();
            if (model.TeacherId.HasValue && model.DateFrom.HasValue && model.DateTo.HasValue)
            {
                return context.Lessons
                    .Include(x => x.Materials)
                    .ThenInclude(x => x.Material)
                    .Where(x => x.DateEvent >= model.DateFrom && x.DateEvent <= model.DateTo && x.TeacherId == model.TeacherId)
                    .ToList()
                    .Select(x => x.GetViewModel)
                    .ToList();
            }
            return context.Lessons
                    .Include(x => x.Materials)
                    .ThenInclude(x => x.Material)
                    .Where(x => x.TeacherId == model.TeacherId)
                    .ToList()
                    .Select(x => x.GetViewModel)
                    .ToList();
        }

        public LessonViewModel? GetElement(LessonSearchModel model)
        {
            if (string.IsNullOrEmpty(model.Title) && !model.Id.HasValue && !model.TeacherId.HasValue && !model.DateCreate.HasValue)
            {
                return null;
            }
            using var context = new SchoolDataBase();
            if(!string.IsNullOrEmpty(model.Title)&& model.TeacherId.HasValue && model.DateCreate.HasValue)
            return context.Lessons
                .Include(x => x.Materials)
                .ThenInclude(x => x.Material)
                .FirstOrDefault(x =>  x.Title.Equals(model.Title) &&
                                x.DateEvent == model.DateCreate && x.TeacherId == model.TeacherId)
                ?.GetViewModel;
            return context.Lessons
                .Include(x => x.Materials)
                .ThenInclude(x => x.Material)
                .FirstOrDefault(x =>  x.Id == model.Id)
                ?.GetViewModel;
        }

        public LessonViewModel? Insert(LessonBindingModel model)
        {
            using var context = new SchoolDataBase();
            var newLesson = Lesson.Create(context, model);
            if (newLesson == null)
            {
                return null;
            }
            context.Lessons.Add(newLesson);
            context.SaveChanges();
            return newLesson.GetViewModel;
        }

        public LessonViewModel? Update(LessonBindingModel model)
        {
            using var context = new SchoolDataBase();
            using var transaction = context.Database.BeginTransaction();
            try
            {
                var lesson = context.Lessons.FirstOrDefault(rec => rec.Id == model.Id);
                if (lesson == null)
                {
                    return null;
                }
                lesson.Update(model);
                context.SaveChanges();
                lesson.UpdateMaterials(context, model);
                transaction.Commit();
                return lesson.GetViewModel;
            }
            catch
            {
                transaction.Rollback();
                throw;
            }
        }

        public LessonViewModel? Delete(LessonBindingModel model)
        {
            using var context = new SchoolDataBase();
            var element = context.Lessons
                .Include(x => x.Materials)
                .FirstOrDefault(rec => rec.Id == model.Id);
            if (element != null)
            {
                context.Lessons.Remove(element);
                context.SaveChanges();
                return element.GetViewModel;
            }
            return null;
        }
    }
}