// Copyright (C) Stichting Deltares 2017. All rights reserved.
//
// This file is part of the application DAM - UI.
//
// DAM - UI is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
// All names, logos, and references to "Deltares" are registered trademarks of
// Stichting Deltares and remain full property of Stichting Deltares at all times.
// All rights reserved.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using Deltares.Standard.Validation;

namespace Deltares.Standard.Specifications.Extensions
{
    public static class SpecificationExtensions
    {
        public static IEnumerable<T> GetBySpecification<T>(this IEnumerable<T> collection, ISpecification<T> specification)
        {
            return collection.Where(specification.IsSatisfiedBy);
        }

        public static bool IsSatisfiedBySpecification<T>(this T source, ISpecification<T> specification)
        {
            return specification.IsSatisfiedBy(source);
        }

        public static bool IsNotSatisfiedBySpecification<T>(this T source, ISpecification<T> specification)
        {
            return !IsSatisfiedBySpecification(source, specification);
        }

        public static IEnumerable<ValidationResult> Validate<T>(this T source, string groupName)
        {
            throw new NotImplementedException();
        }

        public static IEnumerable<ValidationResult> Validate<T>(this T source)
        {
            var validationResults = new List<ValidationResult>();

            foreach (var attribute in source.GetType().GetCustomAttributes(false))
            {
                var specAttr = attribute as SpecificationBaseAttribute;
                if (specAttr != null)
                {
                    if (IsNotSatisfiedBySpecification(source, (ISpecification<T>)specAttr.Specification))
                        AddValidationResult(source, validationResults, specAttr);
                }                
            }
            
            foreach (PropertyInfo property in source.GetType().GetProperties())
            {
                foreach (object attribute in property.GetCustomAttributes(true))
                {
                    var specAttr = attribute as SpecificationBaseAttribute;
                    if (specAttr != null)
                    {
                        object candidateValue = property.GetValue(source, null);
                        if (!specAttr.Specification.IsSatisfiedBy(candidateValue))
                            AddValidationResult(property, validationResults, specAttr);
                    }
                    else
                    {
                        var minAttr = attribute as MinimumAttribute;
                        if (minAttr != null)
                        {
                            var gte =
                                new GreaterThanOrEqualToSpecification<T, double>(property.Name, minAttr.AttributeValue);
                            if (!gte.IsSatisfiedBy(source))
                            {
                                validationResults.Add(new ValidationResult()
                                                      {
                                                          Subject = property,
                                                          MessageType = ValidationResultType.Error,
                                                          Error = new ValidationException(string.Format("The property or field {0} has the value {1} which is less then the specification {2}",
                                                                                                        property.Name, gte.CandidateValue, minAttr.AttributeValue))
                                                      });
                            }
                        }
                        else
                        {
                            var maxAttr = attribute as MaximumAttribute;
                            if (maxAttr != null)
                            {
                                var lte =
                                    new LessThanOrEqualToSpecification<T, double>(property.Name, maxAttr.AttributeValue);
                                if (!lte.IsSatisfiedBy(source))
                                {
                                    validationResults.Add(new ValidationResult()
                                                          {
                                                              Subject = property,
                                                              MessageType = ValidationResultType.Error,
                                                              Error = new ValidationException(string.Format("The property or field {0} has the value {1} which is greater then the specification {2}",
                                                                                                            property.Name, lte.CandidateValue, maxAttr.AttributeValue))
                                                          });
                                }
                            }
                        }
                    }
                }
            }

            return validationResults;
        }

        private static void AddValidationResult(object subject, ICollection<ValidationResult> validationResults, SpecificationBaseAttribute specAttr)
        {
            string message = specAttr.NotSatisfiedText;

            if (string.IsNullOrWhiteSpace(message))
                message = specAttr.Specification.Description;

            if (string.IsNullOrWhiteSpace(message))
                message = specAttr.Specification.Name;

            if (string.IsNullOrWhiteSpace(message))
                message = specAttr.Specification.ToString();

            validationResults.Add(new ValidationResult()
                                  {
                                      Subject = subject,
                                      MessageType = ValidationResultType.Error,
                                      Error = new ValidationException(message)
                                  });
        }
    }
}