using UniversityContracts.BindingModels;
using UniversityContracts.StoragesContracts;
using UniversityContracts.ViewModels;
using UniversityDatabaseImplement;
using UniversityDatabaseImplement.Models;

namespace UniversityUniversityDatabaseImplement.Implements
{
    public class StudentStorage : IStudentStorage
    {
        public void Delete(StudentBindingModel model)
        {
            var context = new UniversityDatabase();
            var student = context.Students.FirstOrDefault(rec => rec.Id == model.Id);
            if (student != null)
            {
                context.Students.Remove(student);
                context.SaveChanges();
            }
            else
            {
                throw new Exception("Студент не найден");
            }
        }

        public StudentViewModel GetElement(StudentBindingModel model)
        {
            if (model == null)
            {
                return null;
            }
            using var context = new UniversityDatabase();
            var student = context.Students
                    .ToList()
                    .FirstOrDefault(rec => rec.Id == model.Id);
            return student != null ? CreateModel(student) : null;
        }

        public List<StudentViewModel> GetFilteredList(StudentBindingModel model)
        {
            var context = new UniversityDatabase();
            return context.Students
                .Where(student => student.FIO.Contains(model.FIO))
                .ToList()
                .Select(CreateModel)
                .ToList();
        }

        public List<StudentViewModel> GetFullList()
        {
            using var context = new UniversityDatabase();
            return context.Students
            .ToList()
            .Select(CreateModel)
            .ToList();
        }

        public void Insert(StudentBindingModel model)
        {
            var context = new UniversityDatabase();
            var transaction = context.Database.BeginTransaction();
            try
            {
                context.Students.Add(CreateModel(model, new Student()));
                context.SaveChanges();
                transaction.Commit();
            }
            catch
            {
                transaction.Rollback();
                throw;
            }
        }

        public void Update(StudentBindingModel model)
        {
            var context = new UniversityDatabase();
            var transaction = context.Database.BeginTransaction();
            try
            {
                var student = context.Students.FirstOrDefault(rec => rec.Id == model.Id);
                if (student == null)
                {
                    throw new Exception("Студент не найден");
                }
                CreateModel(model, student);
                context.SaveChanges();
                transaction.Commit();
            }
            catch
            {
                transaction.Rollback();
                throw;
            }
        }

        private static Student CreateModel(StudentBindingModel model, Student student)
        {
            student.FIO = model.FIO;
            student.PhotoFilePath = model.PhotoFilePath;
            student.Email = model.Email;            
            student.DirectionName = model.DirectionName;

            return student;
        }

        private StudentViewModel CreateModel(Student student)
        {
            return new StudentViewModel
            {
                Id = student.Id,
                FIO = student.FIO,                
                PhotoFilePath = student.PhotoFilePath,
                Email = student.Email,
                DirectionName = student.DirectionName,
            };
        }
    }
}