#nullable disable
using System.Collections.Generic;
using System.Globalization;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Diagnostics;

namespace System.Reflection
{
	abstract class RtFieldInfo : FieldInfo
	{
		internal abstract object UnsafeGetValue (object obj);
		internal abstract void UnsafeSetValue (Object obj, Object value, BindingFlags invokeAttr, Binder binder, CultureInfo culture);
        internal abstract void CheckConsistency(Object target);
	}

	[StructLayout (LayoutKind.Sequential)]
	class RuntimeFieldInfo : RtFieldInfo
	{
#pragma warning disable 649
		internal IntPtr klass;
		internal RuntimeFieldHandle fhandle;
		string name;
		Type type;
		FieldAttributes attrs;
#pragma warning restore 649

		internal BindingFlags BindingFlags {
			get {
				return 0;
			}
		}

		public override Module Module {
			get {
				return GetRuntimeModule ();
			}
		}

		internal RuntimeType GetDeclaringTypeInternal ()
		{
			return (RuntimeType) DeclaringType;
		}

		RuntimeType ReflectedTypeInternal {
			get {
				return (RuntimeType) ReflectedType;
			}
		}

		internal RuntimeModule GetRuntimeModule ()
		{
			return GetDeclaringTypeInternal ().GetRuntimeModule ();
		}

		[MethodImplAttribute(MethodImplOptions.InternalCall)]
		internal override extern object UnsafeGetValue (object obj);

        internal override void CheckConsistency(Object target)
        {
            // only test instance fields
            if ((Attributes & FieldAttributes.Static) != FieldAttributes.Static)
            {
                if (!DeclaringType.IsInstanceOfType(target))
                {
                    if (target == null)
                    {
                        throw new TargetException(Environment.GetResourceString("RFLCT.Targ_StatFldReqTarg"));
                    }
                    else
                    {
                        throw new ArgumentException(
                            String.Format(CultureInfo.CurrentUICulture, Environment.GetResourceString("Arg_FieldDeclTarget"),
                                Name, DeclaringType, target.GetType()));
                    }
                }
            }
        }

		[DebuggerStepThroughAttribute]
		[Diagnostics.DebuggerHidden]
		internal override void UnsafeSetValue (Object obj, Object value, BindingFlags invokeAttr, Binder binder, CultureInfo culture)
		{
			bool domainInitialized = false;
			RuntimeFieldHandle.SetValue (this, obj, value, null, Attributes, null, ref domainInitialized);
		}

        [DebuggerStepThroughAttribute]
        [Diagnostics.DebuggerHidden]
        public override void SetValueDirect(TypedReference obj, Object value)
        {
            if (obj.IsNull)
                throw new ArgumentException(Environment.GetResourceString("Arg_TypedReference_Null"));

            unsafe
            {
                // Passing TypedReference by reference is easier to make correct in native code
                RuntimeFieldHandle.SetValueDirect(this, (RuntimeType)FieldType, &obj, value, (RuntimeType)DeclaringType);
            }
        }

        [DebuggerStepThroughAttribute]
        [Diagnostics.DebuggerHidden]
        public override Object GetValueDirect(TypedReference obj)
        {
            if (obj.IsNull)
                throw new ArgumentException(Environment.GetResourceString("Arg_TypedReference_Null"));

            unsafe
            {
                // Passing TypedReference by reference is easier to make correct in native code
                return RuntimeFieldHandle.GetValueDirect(this, (RuntimeType)FieldType, &obj, (RuntimeType)DeclaringType);
            }
        }
		
		public override FieldAttributes Attributes {
			get {
				return attrs;
			}
		}
		public override RuntimeFieldHandle FieldHandle {
			get {
				return fhandle;
			}
		}

		[MethodImplAttribute(MethodImplOptions.InternalCall)]
		extern Type ResolveType ();

		public override Type FieldType { 
			get {
				if (type == null)
					type = ResolveType ();
				return type;
			}
		}

		[MethodImplAttribute(MethodImplOptions.InternalCall)]
		private extern Type GetParentType (bool declaring);

		public override Type ReflectedType {
			get {
				return GetParentType (false);
			}
		}
		public override Type DeclaringType {
			get {
				return GetParentType (true);
			}
		}
		public override string Name {
			get {
				return name;
			}
		}

		public override bool IsDefined (Type attributeType, bool inherit) {
			return MonoCustomAttrs.IsDefined (this, attributeType, inherit);
		}

		public override object[] GetCustomAttributes( bool inherit) {
			return MonoCustomAttrs.GetCustomAttributes (this, inherit);
		}
		public override object[] GetCustomAttributes( Type attributeType, bool inherit) {
			return MonoCustomAttrs.GetCustomAttributes (this, attributeType, inherit);
		}

		[MethodImplAttribute(MethodImplOptions.InternalCall)]
		internal override extern int GetFieldOffset ();

		[MethodImplAttribute(MethodImplOptions.InternalCall)]
		private extern object GetValueInternal (object obj);

		public override object GetValue (object obj)
		{
			if (!IsStatic) {
				if (obj == null)
					throw new TargetException ("Non-static field requires a target");
				if (!DeclaringType.IsAssignableFrom (obj.GetType ()))
					throw new ArgumentException (string.Format (
						"Field {0} defined on type {1} is not a field on the target object which is of type {2}.",
					 	Name, DeclaringType, obj.GetType ()),
					 	"obj");
			}
			
			if (!IsLiteral)
				CheckGeneric ();
			return GetValueInternal (obj);
		}

		public override string ToString () {
			return String.Format ("{0} {1}", FieldType, name);
		}

		[MethodImplAttribute(MethodImplOptions.InternalCall)]
		private static extern void SetValueInternal (FieldInfo fi, object obj, object value);

		public override void SetValue (object obj, object val, BindingFlags invokeAttr, Binder binder, CultureInfo culture)
		{
			if (!IsStatic) {
				if (obj == null)
					throw new TargetException ("Non-static field requires a target");
				if (!DeclaringType.IsAssignableFrom (obj.GetType ()))
					throw new ArgumentException (string.Format (
						"Field {0} defined on type {1} is not a field on the target object which is of type {2}.",
					 	Name, DeclaringType, obj.GetType ()),
					 	"obj");
			}
			if (IsLiteral)
				throw new FieldAccessException ("Cannot set a constant field");
			if (binder == null)
				binder = Type.DefaultBinder;
			CheckGeneric ();
			if (val != null) {
				RuntimeType fieldType = (RuntimeType) FieldType;
				val = fieldType.CheckValue (val, binder, culture, invokeAttr);
			}
			SetValueInternal (this, obj, val);
		}
		
		internal RuntimeFieldInfo Clone (string newName)
		{
			RuntimeFieldInfo field = new RuntimeFieldInfo ();
			field.name = newName;
			field.type = type;
			field.attrs = attrs;
			field.klass = klass;
			field.fhandle = fhandle;
			return field;
		}

		[MethodImplAttribute(MethodImplOptions.InternalCall)]
		public override extern object GetRawConstantValue ();

		public override IList<CustomAttributeData> GetCustomAttributesData () {
			return CustomAttributeData.GetCustomAttributes (this);
		}

		void CheckGeneric () {
			if (DeclaringType.ContainsGenericParameters)
				throw new InvalidOperationException ("Late bound operations cannot be performed on fields with types for which Type.ContainsGenericParameters is true.");
	    }

		public sealed override bool HasSameMetadataDefinitionAs (MemberInfo other) => HasSameMetadataDefinitionAsCore<RuntimeFieldInfo> (other);

		public override int MetadataToken {
			get {
				return get_metadata_token (this);
			}
		}
		
		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		internal static extern int get_metadata_token (RuntimeFieldInfo monoField);

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		extern Type[] GetTypeModifiers (bool optional);

		public override Type[] GetOptionalCustomModifiers () => GetCustomModifiers (true);

		public override Type[] GetRequiredCustomModifiers () => GetCustomModifiers (false);

		private Type[] GetCustomModifiers (bool optional) => GetTypeModifiers (optional) ?? Type.EmptyTypes;
	}
}