using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Runtime.CompilerServices;
using FluentValidation;
using FluentValidation.Attributes;
using FluentValidation.Results;


namespace aluTransport.App
{
    public class ValidatableBindableBase : BindableBase, INotifyDataErrorInfo
    {
        private IValidator Validator => new AttributedValidatorFactory().GetValidator(GetType());

        private readonly Dictionary<string, List<string>> _errors = new Dictionary<string, List<string>>();

        public event EventHandler<DataErrorsChangedEventArgs> ErrorsChanged = delegate { };

        public System.Collections.IEnumerable GetErrors(string propertyName)
        {
            if (propertyName == null) return null;
            if (_errors.ContainsKey(propertyName))
                return _errors[propertyName];
            else
                return null;
        }

        //public IList<string> GetAllErrors()
        //{
        //    return _errors.SelectMany(err=> err.Value).ToList();
        //}

        public bool HasErrors => _errors.Count > 0;

        protected override void SetProperty<T>(ref T member, T val, [CallerMemberName] string propertyName = null)
        {
            //
            base.SetProperty<T>(ref member, val, propertyName);
            ValidateProperty(propertyName, val);
        }

        private void ValidateProperty<T>(string propertyName, T value)
        {
            ValidationResult results = Validator?.Validate(this);

            if (results == null) return;

            bool validationSucceeded = results.IsValid;
            IList<ValidationFailure> failures = results.Errors;

            if (!validationSucceeded)
            {

                _errors[propertyName] = failures.Where(p=>p.PropertyName == propertyName).Select(c => c.ErrorMessage).ToList();
            }
            else
            {
                _errors.Remove(propertyName);
            }
            ErrorsChanged(this, new DataErrorsChangedEventArgs(propertyName));
        }

        public void ValidateAll()
        {
            ValidationResult results = Validator?.Validate(this);

            if (results == null) return;

            bool validationSucceeded = results.IsValid;
            IList<ValidationFailure> failures = results.Errors;

            if (!validationSucceeded)
            {
                _errors.Clear();
                foreach (var validationFailure in failures)
                {
                    _errors[validationFailure.PropertyName] = failures.Where(p => p.PropertyName == validationFailure.PropertyName).Select(c => c.ErrorMessage).ToList();
                    ErrorsChanged(this, new DataErrorsChangedEventArgs(validationFailure.PropertyName));
                }
            }
        }

    }
}