// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System.Diagnostics;
using System.Globalization;
using System.Runtime.CompilerServices;

namespace System.Reflection
{
    public abstract partial class FieldInfo : MemberInfo
    {
        protected FieldInfo() { }

        public override MemberTypes MemberType => MemberTypes.Field;

        public abstract FieldAttributes Attributes { get; }
        public abstract Type FieldType { get; }

        public bool IsInitOnly => (Attributes & FieldAttributes.InitOnly) != 0;
        public bool IsLiteral => (Attributes & FieldAttributes.Literal) != 0;
        public bool IsNotSerialized => (Attributes & FieldAttributes.NotSerialized) != 0;
        public bool IsPinvokeImpl => (Attributes & FieldAttributes.PinvokeImpl) != 0;
        public bool IsSpecialName => (Attributes & FieldAttributes.SpecialName) != 0;
        public bool IsStatic => (Attributes & FieldAttributes.Static) != 0;

        public bool IsAssembly => (Attributes & FieldAttributes.FieldAccessMask) == FieldAttributes.Assembly;
        public bool IsFamily => (Attributes & FieldAttributes.FieldAccessMask) == FieldAttributes.Family;
        public bool IsFamilyAndAssembly => (Attributes & FieldAttributes.FieldAccessMask) == FieldAttributes.FamANDAssem;
        public bool IsFamilyOrAssembly => (Attributes & FieldAttributes.FieldAccessMask) == FieldAttributes.FamORAssem;
        public bool IsPrivate => (Attributes & FieldAttributes.FieldAccessMask) == FieldAttributes.Private;
        public bool IsPublic => (Attributes & FieldAttributes.FieldAccessMask) == FieldAttributes.Public;

        public virtual bool IsSecurityCritical => true;
        public virtual bool IsSecuritySafeCritical => false;
        public virtual bool IsSecurityTransparent => false;

        public abstract RuntimeFieldHandle FieldHandle { get; }

        public override bool Equals(object? obj) => base.Equals(obj);
        public override int GetHashCode() => base.GetHashCode();

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static bool operator ==(FieldInfo? left, FieldInfo? right)
        {
            // Test "right" first to allow branch elimination when inlined for null checks (== null)
            // so it can become a simple test
            if (right is null)
            {
                // return true/false not the test result https://github.com/dotnet/coreclr/issues/914
                return (left is null) ? true : false;
            }

            // Try fast reference equality and opposite null check prior to calling the slower virtual Equals
            if ((object?)left == (object)right)
            {
                return true;
            }

            return (left is null) ? false : left.Equals(right);
        }

        public static bool operator !=(FieldInfo? left, FieldInfo? right) => !(left == right);

        public abstract object? GetValue(object? obj);

        [DebuggerHidden]
        [DebuggerStepThrough]
        public void SetValue(object? obj, object? value) => SetValue(obj, value, BindingFlags.Default, Type.DefaultBinder, null);
        public abstract void SetValue(object? obj, object? value, BindingFlags invokeAttr, Binder? binder, CultureInfo? culture);

        [CLSCompliant(false)]
        public virtual void SetValueDirect(TypedReference obj, object value) { throw new NotSupportedException(SR.NotSupported_AbstractNonCLS); }
        [CLSCompliant(false)]
        public virtual object? GetValueDirect(TypedReference obj) { throw new NotSupportedException(SR.NotSupported_AbstractNonCLS); }

        public virtual object? GetRawConstantValue() { throw new NotSupportedException(SR.NotSupported_AbstractNonCLS); }

        public virtual Type[] GetOptionalCustomModifiers() { throw NotImplemented.ByDesign; }
        public virtual Type[] GetRequiredCustomModifiers() { throw NotImplemented.ByDesign; }
    }
}