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 StudentStorage : IStudentStorage
    {
        public List<StudentViewModel> GetFullList()
        {
            using var context = new TaskTrackerDatabase();
            return context.Students
                    .Select(x => x.GetViewModel)
                    .ToList();
        }

        public List<StudentViewModel> GetFilteredList(StudentSearchModel model)
        {
            if (string.IsNullOrEmpty(model.Name))
            {
                return new();
            }
            using var context = new TaskTrackerDatabase();
            return context.Students
                    .Where(x => x.Name.Contains(model.Name))
                    .Select(x => x.GetViewModel)
                    .ToList();
        }

        public StudentViewModel? GetElement(StudentSearchModel model)
        {
            if (string.IsNullOrEmpty(model.Name) && !model.Id.HasValue)
            {
                return null;
            }
            using var context = new TaskTrackerDatabase();
            return context.Students.FirstOrDefault(x =>
            (!string.IsNullOrEmpty(model.Name) && x.Name == model.Name || (model.Id.HasValue && x.Id == model.Id)))?.GetViewModel;
        }

        public StudentViewModel? Insert(StudentBindingModel model)
        {
            var newStudent = Student.Create(model);
            if (newStudent == null)
            {
                return null;
            }
            using var context = new TaskTrackerDatabase();
            context.Students.Add(newStudent);
            context.SaveChanges();
            return newStudent.GetViewModel;
        }

        public StudentViewModel? Update(StudentBindingModel model)
        {
            using var context = new TaskTrackerDatabase();
            var user = context.Students.FirstOrDefault(x => x.Id == model.Id);
            if (user == null)
            {
                return null;
            }
            user.Update(model);
            context.SaveChanges();
            return user.GetViewModel;
        }

        public StudentViewModel? Delete(StudentBindingModel model)
        {
            using var context = new TaskTrackerDatabase();
            var element = context.Students.FirstOrDefault(x => x.Id == model.Id);
            if (element != null)
            {
                context.Students.Remove(element);
                context.SaveChanges();
                return element.GetViewModel;
            }
            return null;
        }
    }
}