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;
using Task = SchoolAgainStudyDataBaseImplements.Models.Task;

namespace SchoolAgainStudyDataBaseImplements.Implements
{
    public class TaskStorage : ITaskStorage
    {
        public List<TaskViewModel> GetFullList()
        {
            using var context = new SchoolDataBase();
            return context.Tasks
                    .Include(x => x.Materials)
                    .ThenInclude(x => x.Material)
                    .ToList()
                    .Select(x => x.GetViewModel)
                    .ToList();
        }

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

        public TaskViewModel? GetElement(TaskSearchModel model)
        {
            if (string.IsNullOrEmpty(model.Title) && !model.Id.HasValue)
            {
                return null;
            }
            using var context = new SchoolDataBase();
            return context.Tasks
                .Include(x => x.Materials)
                .ThenInclude(x => x.Material)
                .FirstOrDefault(x => (!string.IsNullOrEmpty(model.Title) && x.Title == model.Title) ||
                                (model.Id.HasValue && x.Id == model.Id))
                ?.GetViewModel;
        }

        public TaskViewModel? Insert(TaskBindingModel model)
        {
            using var context = new SchoolDataBase();
            var newTask = Task.Create(context, model);
            if (newTask == null)
            {
                return null;
            }
            context.Tasks.Add(newTask);
            context.SaveChanges();
            return newTask.GetViewModel;
        }

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

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