/*
    Copyright (C) 2014-2019 de4dot@gmail.com

    This file is part of dnSpy

    dnSpy 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.

    dnSpy 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 dnSpy.  If not, see <http://www.gnu.org/licenses/>.
*/

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.Threading;

namespace dnSpy.Debugger.DotNet.Metadata.Impl {
	abstract class DmdMethodRef : DmdMethodInfoBase {
		public override DmdAppDomain AppDomain => declaringTypeRef.AppDomain;
		public override string Name { get; }
		public override DmdType? DeclaringType => __resolvedMethod_DONT_USE?.DeclaringType ?? declaringTypeRef;
		public override DmdType? ReflectedType => DeclaringType;
		public override bool IsMetadataReference => true;
		public override int MetadataToken => ResolvedMethod.MetadataToken;
		public override DmdMethodImplAttributes MethodImplementationFlags => ResolvedMethod.MethodImplementationFlags;
		public override DmdMethodAttributes Attributes => ResolvedMethod.Attributes;
		public override uint RVA => ResolvedMethod.RVA;
		public override bool IsGenericMethodDefinition => methodSignature.GenericParameterCount != 0;
		public override bool IsGenericMethod => methodSignature.GenericParameterCount != 0;

		DmdMethodDef ResolvedMethod => GetResolvedMethod(throwOnError: true)!;
		DmdMethodDef? GetResolvedMethod(bool throwOnError) {
			if (__resolvedMethod_DONT_USE is not null)
				return __resolvedMethod_DONT_USE;

			DmdMethodDef? newResolvedMethod = null;
			var declType = declaringTypeRef.Resolve(throwOnError);
			if (declType is not null) {
				var nonGenericInstDeclType = declType.IsGenericType ? declType.GetGenericTypeDefinition() : declType;
				var nonGenericInstDeclTypeMethod = nonGenericInstDeclType?.GetMethod(Name, rawMethodSignature, throwOnError: false) as DmdMethodDef;
				if (nonGenericInstDeclTypeMethod is not null) {
					newResolvedMethod = (object?)nonGenericInstDeclTypeMethod.DeclaringType == declType ?
						nonGenericInstDeclTypeMethod :
						declType.GetMethod(nonGenericInstDeclTypeMethod.Module, nonGenericInstDeclTypeMethod.MetadataToken) as DmdMethodDef;
					Debug2.Assert(newResolvedMethod is not null);
				}
			}
			if (newResolvedMethod is not null) {
				Interlocked.CompareExchange(ref __resolvedMethod_DONT_USE, newResolvedMethod, null);
				Debug.Assert(DmdMemberInfoEqualityComparer.DefaultMember.Equals(__resolvedMethod_DONT_USE!.ReflectedType, declaringTypeRef));
				return __resolvedMethod_DONT_USE;
			}
			if (throwOnError)
				throw new MethodResolveException(this);
			return null;
		}
		volatile DmdMethodDef? __resolvedMethod_DONT_USE;

		readonly DmdType declaringTypeRef;
		readonly DmdMethodSignature rawMethodSignature;
		readonly DmdMethodSignature methodSignature;

		protected DmdMethodRef(DmdType declaringTypeRef, string name, DmdMethodSignature rawMethodSignature, DmdMethodSignature methodSignature) {
			this.declaringTypeRef = declaringTypeRef ?? throw new ArgumentNullException(nameof(declaringTypeRef));
			Name = name ?? throw new ArgumentNullException(nameof(name));
			this.rawMethodSignature = rawMethodSignature ?? throw new ArgumentNullException(nameof(rawMethodSignature));
			this.methodSignature = methodSignature ?? throw new ArgumentNullException(nameof(methodSignature));
		}

		public override DmdMethodInfo? Resolve(bool throwOnError) => GetResolvedMethod(throwOnError);
		public override ReadOnlyCollection<DmdParameterInfo> GetParameters() => ResolvedMethod.GetParameters();
		public override ReadOnlyCollection<DmdType> GetGenericArguments() => methodSignature.GenericParameterCount == 0 ? ReadOnlyCollectionHelpers.Empty<DmdType>() : ResolvedMethod.GetGenericArguments();
		public override DmdMethodBody? GetMethodBody() => ResolvedMethod.GetMethodBody();
		internal override DmdMethodBody? GetMethodBody(IList<DmdType> genericMethodArguments) => ResolvedMethod.GetMethodBody(genericMethodArguments);
		public override DmdMethodSignature GetMethodSignature() => methodSignature;
		public override ReadOnlyCollection<DmdCustomAttributeData> GetCustomAttributesData() => ResolvedMethod.GetCustomAttributesData();
		public override ReadOnlyCollection<DmdCustomAttributeData> GetSecurityAttributesData() => ResolvedMethod.GetSecurityAttributesData();
		public override DmdParameterInfo ReturnParameter => ResolvedMethod.ReturnParameter;
		internal override DmdMethodInfo? GetParentDefinition() => ResolvedMethod.GetParentDefinition();
		public override DmdMethodInfo GetGenericMethodDefinition() => methodSignature.GenericParameterCount == 0 ? throw new InvalidOperationException() : ResolvedMethod.GetGenericMethodDefinition();
		public override DmdMethodInfo MakeGenericMethod(IList<DmdType> typeArguments) => AppDomain.MakeGenericMethod(this, typeArguments);
	}
}