using System;

using System.Collections.Generic;

using System.ComponentModel.DataAnnotations.Schema;

using System.Diagnostics.CodeAnalysis;

using System.Linq;

using System.Runtime.Serialization;

namespace SmartStore.Core

{

/// <summary>

/// Base class for entities

/// </summary>

[DataContract]

public abstract partial class BaseEntity

{

/// <summary>

/// Gets or sets the entity identifier

/// </summary>

[DataMember]

[DatabaseGenerated(DatabaseGeneratedOption.Identity)]

public int Id { get; set; }

[SuppressMessage("ReSharper", "PossibleNullReferenceException")]

public Type GetUnproxiedType()

{

var t = GetType();

if (t.AssemblyQualifiedName.StartsWith("System.Data.Entity."))

{

// it's a proxied type

t = t.BaseType;

}

return t;

}

/// <summary>

/// Transient objects are not associated with an item already in storage. For instance,

/// a Product entity is transient if its Id is 0.

/// </summary>

public virtual bool IsTransientRecord()

{

return Id == 0;

}

public override bool Equals(object obj)

{

return Equals(obj as BaseEntity);

}

protected virtual bool Equals(BaseEntity other)

{

if (other == null)

return false;

if (ReferenceEquals(this, other))

return true;

if (HasSameNonDefaultIds(other))

{

var otherType = other.GetUnproxiedType();

var thisType = GetUnproxiedType();

return thisType.Equals(otherType);

}

return false;

}

[SuppressMessage("ReSharper", "NonReadonlyMemberInGetHashCode")]

public override int GetHashCode()

{

if (IsTransientRecord())

{

return base.GetHashCode();

}

else

{

unchecked

{

// It's possible for two objects to return the same hash code based on

// identically valued properties, even if they're of two different types,

// so we include the object's type in the hash calculation

var hashCode = GetUnproxiedType().GetHashCode();

return (hashCode * 31) ^ Id.GetHashCode();

}

}

}

public static bool operator ==(BaseEntity x, BaseEntity y)

{

return Equals(x, y);

}

public static bool operator !=(BaseEntity x, BaseEntity y)

{

return !(x == y);

}

private bool HasSameNonDefaultIds(BaseEntity other)

{

return !this.IsTransientRecord() && !other.IsTransientRecord() && this.Id == other.Id;

}

}

}