using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;
using System.Numerics;
using System.Text;
using System.Threading.Tasks;
using VeterinaryClinicContracts.BindingModels;
using VeterinaryClinicContracts.ViewModels;
using VeterinaryClinicDataModels.Models;

namespace VeterinaryClinicDatabaseImplement.Models
{
    public class Animal: IAnimalModel
    {
        public int Id { get; set; }

        [Required]
        public string Type { get; set; } = string.Empty;

        [Required]
        public string Breed { get; set; } = string.Empty;

        [Required]
        public int Age { get; set; }

        [ForeignKey("UserId")]
        public int UserId { get; set; }

        public virtual User User { get; set; } = new();

        [ForeignKey("AnimalId")]
        public virtual List<AnimalMedication> Medications { get; set; } = new();

        private Dictionary<int, IMedicationModel>? _animalMedications = null;

        [NotMapped]
        public Dictionary<int, IMedicationModel> AnimalMedications { get 
            { 
                if(_animalMedications == null)
                    _animalMedications = Medications.ToDictionary(recAM => recAM.MedicationId, recAM => (recAM.Medication as IMedicationModel));

                return _animalMedications;
            } 
        }

        public static Animal? Create(VeterinaryClinicDatabase context, AnimalBindingModel model)
        {
            if (model == null)
            {
                return null;
            }

            return new Animal()
            {
                Id = model.Id,
                Type = model.Type,
                Breed = model.Breed,
                Age = model.Age,
                UserId = model.UserId,
                User = context.Users
                    .First(x => x.Id == model.UserId),
                Medications = model.AnimalMedications.Select(x => new AnimalMedication
                {
                    Medication = context.Medications.First(y => y.Id == x.Key)
                }).ToList()
            };
        }

        public void Update(AnimalBindingModel model)
        {
            if (model == null)
            {
                return;
            }

            Type = model.Type;
            Breed = model.Breed;
            Age = model.Age;
        }

        public AnimalViewModel GetViewModel => new()
        {
            Id = Id,
            Type = Type,
            Breed = Breed,
            Age = Age,
            UserId = UserId,
            UserFullName = User.FullName,
            AnimalMedications = AnimalMedications
        };

        public void UpdateMedications(VeterinaryClinicDatabase context, AnimalBindingModel model)
        {
            var animalMedications = context.AnimalMedications.Where(rec => rec.AnimalId == model.Id).ToList();
            context.AnimalMedications.RemoveRange(animalMedications);
            context.SaveChanges();

            var animal = context.Animals.First(x => x.Id == Id);
            foreach (var pr in model.AnimalMedications)
            {
                context.AnimalMedications.Add(new AnimalMedication
                {
                    Animal = animal,
                    Medication = context.Medications.First(x => x.Id == pr.Key)
                });
                context.SaveChanges();
            }
            _animalMedications = null;
        }
    }
}