using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using Kreta.Core;
using Kreta.Resources;
using KretaValidate = Kreta.Core.Validation.Exceptions;
using KretaValidateEnum = Kreta.Core.Validation.Exceptions.Enum;

namespace Kreta.BusinessLogic.Validation
{
    /// <summary>
    /// Validates the models with "DataAnnotationAttributes" and gives You the option
    /// to create custom validation if model implements the "IValidatableObject" interface.
    /// </summary>
    public class BlValidator
    {
        public static implicit operator string(BlValidator blValidator)
            => blValidator.GetFirstUserFriendlyError();

        public readonly List<ValidationResult> ErrorList = new List<ValidationResult>();
        public readonly bool IsValid;

        //TODO devkornel: Megcsinálni List<object>-re is vagy Singleton-ra!!!!
        public BlValidator(object coInstance)
        {
            var context = new ValidationContext(coInstance, serviceProvider: null, items: null);
            IsValid = Validator.TryValidateObject(coInstance, context, ErrorList, true);
        }
        public string GetUserFriendlyError()
            => string.Join(Constants.General.LineSeparator, ErrorList.Select(x => x.ErrorMessage).ToArray());
        public string GetFirstUserFriendlyError()
            => ErrorList.Count > 0 ? ErrorList[0].ErrorMessage : string.Empty;

        public KretaValidate.ValidationException ConvertToValidationException()
        {
            var validationException = new KretaValidate.ValidationException(KretaValidateEnum.ValidationErrorType.Undefined, ErrorResource.ValidaciosHiba);
            var count = 1;
            foreach (var error in ErrorList)
            {
                var name = error.MemberNames.FirstOrDefault() ?? "custom_" + count;
                validationException.AddValidationItem(new KretaValidate.ValidationExceptionItem(name, error.ErrorMessage));
                count++;
            }

            return validationException;
        }
    }
}