// The MIT License (MIT)

//

// Copyright (c) 2015-2025 Rasmus Mikkelsen

// https://github.com/eventflow/EventFlow

//

// Permission is hereby granted, free of charge, to any person obtaining a copy of

// this software and associated documentation files (the "Software"), to deal in

// the Software without restriction, including without limitation the rights to

// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of

// the Software, and to permit persons to whom the Software is furnished to do so,

// subject to the following conditions:

//

// The above copyright notice and this permission notice shall be included in all

// copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS

// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR

// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER

// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN

// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

using System;

using System.Collections.Concurrent;

using System.Collections.Generic;

using System.Linq;

using System.Reflection;

namespace EventFlow.ValueObjects

{

public abstract class ValueObject

{

private static readonly ConcurrentDictionary<Type, IReadOnlyCollection<PropertyInfo>> TypeProperties = new ConcurrentDictionary<Type, IReadOnlyCollection<PropertyInfo>>();

public override bool Equals(object obj)

{

if (ReferenceEquals(this, obj)) return true;

if (ReferenceEquals(null, obj)) return false;

if (GetType() != obj.GetType()) return false;

var other = obj as ValueObject;

return other != null && GetEqualityComponents().SequenceEqual(other.GetEqualityComponents());

}

public override int GetHashCode()

{

unchecked

{

return GetEqualityComponents().Aggregate(17, (current, obj) => current * 23 + (obj?.GetHashCode() ?? 0));

}

}

public static bool operator ==(ValueObject left, ValueObject right)

{

return Equals(left, right);

}

public static bool operator !=(ValueObject left, ValueObject right)

{

return !Equals(left, right);

}

public override string ToString()

{

return $"{{{string.Join(", ", GetProperties().Select(f => $"{f.Name}: {f.GetValue(this)}"))}}}";

}

protected virtual IEnumerable<object> GetEqualityComponents()

{

return GetProperties().Select(x => x.GetValue(this));

}

protected virtual IEnumerable<PropertyInfo> GetProperties()

{

return TypeProperties.GetOrAdd(

GetType(),

t => t

.GetTypeInfo()

.GetProperties(BindingFlags.Instance | BindingFlags.Public)

.OrderBy(p => p.Name)

.ToList());

}

}

}