using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using UniversityContracts.BindingModels;
using UniversityContracts.ViewModels;
using UniversityModels.Models;

namespace UniversityDataBaseImplemet.Models
{
    public class Stream : IStreamModel
    {
        [Required]
        public string Name { get; set; } = string.Empty;
        [Required]
        public int Course { get; set; }
        [Required]
        public int UserId { get; set; }

        public int Id { get; private set; }
        [ForeignKey("StreamId")]
        public virtual List<EducationGroupStream> EducationGroupStream { get; set; } = new();
        [ForeignKey("StreamId")]
        public virtual List<StudentStream> StreamStudents { get; set; } = new();
        public virtual User User { get; set; }
        private List<StudentViewModel>? _studentStream = null;
        private List<EducationGroupViewModel>? _educationGroupStream = null;
        [NotMapped]
        public List<StudentViewModel> StudentStream
        {
            get
            {
                if (_studentStream == null)
                {
                    _studentStream = StreamStudents.Select(x => new StudentViewModel(x.Student)).ToList();
                }
                return _studentStream;
            }
        }
        public List<EducationGroupViewModel> StreamEdGroups
        {
            get
            {
                if (_educationGroupStream == null)
                {
                    _educationGroupStream = EducationGroupStream.Select(x => new EducationGroupViewModel(x.EducationGroup)).ToList();
                }
                return _educationGroupStream;
            }
        }
        public static Stream Create(Database context, StreamBindingModel model)
        {
            return new Stream()
            {
                Id = model.Id,
                Name = model.Name,
                Course = model.Course,
                UserId = model.UserId,
                EducationGroupStream = model.GroupStream.Select(x => new EducationGroupStream()
                {
                    EducationGroup = context.EducationGroups.First(y => y.Id == x.Id),
                }).ToList()
            };
        }
        public void Update(StreamBindingModel model)
        {
            Name = model.Name;
            Course = model.Course;
            UserId = model.UserId;
        }
        public void UpdateStreamStudents(Database context, StreamBindingModel model)
        {
            var documentStudents = context.StudentStreams.Where(x => x.StreamId == model.Id).ToList();
            List<int> currentStudents = documentStudents.Select(x => x.StudentId).ToList();
            List<int> modelStudents = model.StudentStream.Select(x => x.Id).ToList();
            if (documentStudents != null && documentStudents.Count > 0)
            {
                context.StudentStreams.RemoveRange(documentStudents.Where(x => !modelStudents.Contains(x.StreamId)));
                model.StudentStream.RemoveAll(x => currentStudents.Contains(x.Id));
                context.SaveChanges();
            }
            var document = context.Streams.First(x => x.Id == Id);
            foreach (var record in model.StudentStream)
            {
                context.StudentStreams.Add(new StudentStream
                {
                    Stream = document,
                    Student = context.Students.First(x => x.Id == record.Id),
                });
                context.SaveChanges();
            }
            _studentStream = null;
        }
        public void UpdateGroups(Database context, StreamBindingModel model)
        {
            var documentGroups = context.EducationGroupsStreams.Where(x => x.StreamId == model.Id).ToList();
            List<int> currentGroups = documentGroups.Select(x => x.EducationGroupId).ToList();
            List<int> modelGroups = model.GroupStream.Select(x => x.Id).ToList();
            if (documentGroups != null && documentGroups.Count > 0)
            {
                context.EducationGroupsStreams.RemoveRange(documentGroups.Where(x => !modelGroups.Contains(x.EducationGroupId)));
                model.GroupStream.RemoveAll(x => currentGroups.Contains(x.Id));
                context.SaveChanges();
            }
            var document = context.Streams.First(x => x.Id == Id);
            foreach (var record in model.GroupStream)
            {
                context.EducationGroupsStreams.Add(new EducationGroupStream
                {
                    Stream = document,
                    EducationGroup = context.EducationGroups.First(x => x.Id == record.Id),
                });
                context.SaveChanges();
            }
            _educationGroupStream = null;
        }
        public StreamViewModel GetViewModel => new StreamViewModel()
        {
            Id = Id,
            Name = Name,
            UserId = UserId,
            Course= Course,
            StudentStream = StudentStream,
            StreamEdGroups = StreamEdGroups
        };
    }
}