//
// Author:
//   Jb Evain (jbevain@gmail.com)
//
// Copyright (c) 2008 - 2015 Jb Evain
// Copyright (c) 2008 - 2011 Novell, Inc.
//
// Licensed under the MIT/X11 license.
//

using System;
using System.Threading;
using Mono.Cecil.Cil;
using Mono.Collections.Generic;

using RVA = System.UInt32;

namespace Mono.Cecil {

	public sealed class MethodDefinition : MethodReference, IMemberDefinition, ISecurityDeclarationProvider, ICustomDebugInformationProvider {

		ushort attributes;
		ushort impl_attributes;
		internal volatile bool sem_attrs_ready;
		internal MethodSemanticsAttributes sem_attrs;
		Collection<CustomAttribute> custom_attributes;
		Collection<SecurityDeclaration> security_declarations;

		internal RVA rva;
		internal PInvokeInfo pinvoke;
		Collection<MethodReference> overrides;

		internal MethodBody body;
		internal MethodDebugInformation debug_info;
		internal Collection<CustomDebugInformation> custom_infos;

		public override string Name {
			get { return base.Name; }
			set {
				if (IsWindowsRuntimeProjection && value != base.Name)
					throw new InvalidOperationException ();

				base.Name = value;
			}
		}

		public MethodAttributes Attributes {
			get { return (MethodAttributes) attributes; }
			set {
				if (IsWindowsRuntimeProjection && (ushort) value != attributes)
					throw new InvalidOperationException ();

				attributes = (ushort) value;
			}
		}

		public MethodImplAttributes ImplAttributes {
			get { return (MethodImplAttributes) impl_attributes; }
			set {
				if (IsWindowsRuntimeProjection && (ushort) value != impl_attributes)
					throw new InvalidOperationException ();

				impl_attributes = (ushort) value;
			}
		}

		public MethodSemanticsAttributes SemanticsAttributes {
			get {
				if (sem_attrs_ready)
					return sem_attrs;

				if (HasImage) {
					ReadSemantics ();
					return sem_attrs;
				}

				sem_attrs = MethodSemanticsAttributes.None;
				sem_attrs_ready = true;
				return sem_attrs;
			}
			set { sem_attrs = value; }
		}

		internal new MethodDefinitionProjection WindowsRuntimeProjection {
			get { return (MethodDefinitionProjection) projection; }
			set { projection = value; }
		}

		internal void ReadSemantics ()
		{
			if (sem_attrs_ready)
				return;

			var module = this.Module;
			if (module == null)
				return;

			if (!module.HasImage)
				return;

			lock (module.SyncRoot) {
				if (sem_attrs_ready)
					return;

				module.Read (this, (method, reader) => reader.ReadAllSemantics (method));
			}
		}

		public bool HasSecurityDeclarations {
			get {
				if (security_declarations != null)
					return security_declarations.Count > 0;

				return this.GetHasSecurityDeclarations (Module);
			}
		}

		public Collection<SecurityDeclaration> SecurityDeclarations {
			get { return security_declarations ?? (this.GetSecurityDeclarations (ref security_declarations, Module)); }
		}

		public bool HasCustomAttributes {
			get {
				if (custom_attributes != null)
					return custom_attributes.Count > 0;

				return this.GetHasCustomAttributes (Module);
			}
		}

		public Collection<CustomAttribute> CustomAttributes {
			get { return custom_attributes ?? (this.GetCustomAttributes (ref custom_attributes, Module)); }
		}

		public int RVA {
			get { return (int) rva; }
		}

		public bool HasBody {
			get {
				return (attributes & (ushort) MethodAttributes.Abstract) == 0 &&
					(attributes & (ushort) MethodAttributes.PInvokeImpl) == 0 &&
					(impl_attributes & (ushort) MethodImplAttributes.InternalCall) == 0 &&
					(impl_attributes & (ushort) MethodImplAttributes.Native) == 0 &&
					(impl_attributes & (ushort) MethodImplAttributes.Unmanaged) == 0 &&
					(impl_attributes & (ushort) MethodImplAttributes.Runtime) == 0;
			}
		}

		public MethodBody Body {
			get {
				var local = this.body;
				if (local != null)
					return local;

				if (!HasBody)
					return null;

				if (HasImage && rva != 0)
					return Module.Read (ref body, this, (method, reader) => reader.ReadMethodBody (method));

				Interlocked.CompareExchange (ref body, new MethodBody (this) , null);

				return body;
			}
			set {
				var module = this.Module;
				if (module == null) {
					body = value;
					return;
				}

				// we reset Body to null in ILSpy to save memory; so we need that operation to be thread-safe
				lock (module.SyncRoot) {
					body = value;
					if (value == null)
						this.debug_info = null;
				}
			}
		}

		public MethodDebugInformation DebugInformation {
			get {
				Mixin.Read (Body);

				if (debug_info == null) {
					Interlocked.CompareExchange (ref debug_info, new MethodDebugInformation (this), null);
				}

				return debug_info;
			}
			set {
				debug_info = value;
			}
		}

		public bool HasPInvokeInfo {
			get {
				if (pinvoke != null)
					return true;

				return IsPInvokeImpl;
			}
		}

		public PInvokeInfo PInvokeInfo {
			get {
				if (pinvoke != null)
					return pinvoke;

				if (HasImage && IsPInvokeImpl)
					return Module.Read (ref pinvoke, this, (method, reader) => reader.ReadPInvokeInfo (method));

				return null;
			}
			set {
				IsPInvokeImpl = true;
				pinvoke = value;
			}
		}

		public bool HasOverrides {
			get {
				if (overrides != null)
					return overrides.Count > 0;

				return HasImage && Module.Read (this, (method, reader) => reader.HasOverrides (method));
			}
		}

		public Collection<MethodReference> Overrides {
			get {
				if (overrides != null)
					return overrides;

				if (HasImage)
					return Module.Read (ref overrides, this, (method, reader) => reader.ReadOverrides (method));

				Interlocked.CompareExchange (ref overrides, new Collection<MethodReference> (), null);

				return overrides;
			}
		}

		public override bool HasGenericParameters {
			get {
				if (generic_parameters != null)
					return generic_parameters.Count > 0;

				return this.GetHasGenericParameters (Module);
			}
		}

		public override Collection<GenericParameter> GenericParameters {
			get { return generic_parameters ?? (this.GetGenericParameters (ref generic_parameters, Module)); }
		}

		public bool HasCustomDebugInformations {
			get {
				Mixin.Read (Body);

				return !custom_infos.IsNullOrEmpty ();
			}
		}

		public Collection<CustomDebugInformation> CustomDebugInformations {
			get {
				Mixin.Read (Body);

				if (custom_infos == null)
					Interlocked.CompareExchange (ref custom_infos, new Collection<CustomDebugInformation> (), null);

				return custom_infos;
			}
		}

		#region MethodAttributes

		public bool IsCompilerControlled {
			get { return attributes.GetMaskedAttributes ((ushort) MethodAttributes.MemberAccessMask, (ushort) MethodAttributes.CompilerControlled); }
			set { attributes = attributes.SetMaskedAttributes ((ushort) MethodAttributes.MemberAccessMask, (ushort) MethodAttributes.CompilerControlled, value); }
		}

		public bool IsPrivate {
			get { return attributes.GetMaskedAttributes ((ushort) MethodAttributes.MemberAccessMask, (ushort) MethodAttributes.Private); }
			set { attributes = attributes.SetMaskedAttributes ((ushort) MethodAttributes.MemberAccessMask, (ushort) MethodAttributes.Private, value); }
		}

		public bool IsFamilyAndAssembly {
			get { return attributes.GetMaskedAttributes ((ushort) MethodAttributes.MemberAccessMask, (ushort) MethodAttributes.FamANDAssem); }
			set { attributes = attributes.SetMaskedAttributes ((ushort) MethodAttributes.MemberAccessMask, (ushort) MethodAttributes.FamANDAssem, value); }
		}

		public bool IsAssembly {
			get { return attributes.GetMaskedAttributes ((ushort) MethodAttributes.MemberAccessMask, (ushort) MethodAttributes.Assembly); }
			set { attributes = attributes.SetMaskedAttributes ((ushort) MethodAttributes.MemberAccessMask, (ushort) MethodAttributes.Assembly, value); }
		}

		public bool IsFamily {
			get { return attributes.GetMaskedAttributes ((ushort) MethodAttributes.MemberAccessMask, (ushort) MethodAttributes.Family); }
			set { attributes = attributes.SetMaskedAttributes ((ushort) MethodAttributes.MemberAccessMask, (ushort) MethodAttributes.Family, value); }
		}

		public bool IsFamilyOrAssembly {
			get { return attributes.GetMaskedAttributes ((ushort) MethodAttributes.MemberAccessMask, (ushort) MethodAttributes.FamORAssem); }
			set { attributes = attributes.SetMaskedAttributes ((ushort) MethodAttributes.MemberAccessMask, (ushort) MethodAttributes.FamORAssem, value); }
		}

		public bool IsPublic {
			get { return attributes.GetMaskedAttributes ((ushort) MethodAttributes.MemberAccessMask, (ushort) MethodAttributes.Public); }
			set { attributes = attributes.SetMaskedAttributes ((ushort) MethodAttributes.MemberAccessMask, (ushort) MethodAttributes.Public, value); }
		}

		public bool IsStatic {
			get { return attributes.GetAttributes ((ushort) MethodAttributes.Static); }
			set { attributes = attributes.SetAttributes ((ushort) MethodAttributes.Static, value); }
		}

		public bool IsFinal {
			get { return attributes.GetAttributes ((ushort) MethodAttributes.Final); }
			set { attributes = attributes.SetAttributes ((ushort) MethodAttributes.Final, value); }
		}

		public bool IsVirtual {
			get { return attributes.GetAttributes ((ushort) MethodAttributes.Virtual); }
			set { attributes = attributes.SetAttributes ((ushort) MethodAttributes.Virtual, value); }
		}

		public bool IsHideBySig {
			get { return attributes.GetAttributes ((ushort) MethodAttributes.HideBySig); }
			set { attributes = attributes.SetAttributes ((ushort) MethodAttributes.HideBySig, value); }
		}

		public bool IsReuseSlot {
			get { return attributes.GetMaskedAttributes ((ushort) MethodAttributes.VtableLayoutMask, (ushort) MethodAttributes.ReuseSlot); }
			set { attributes = attributes.SetMaskedAttributes ((ushort) MethodAttributes.VtableLayoutMask, (ushort) MethodAttributes.ReuseSlot, value); }
		}

		public bool IsNewSlot {
			get { return attributes.GetMaskedAttributes ((ushort) MethodAttributes.VtableLayoutMask, (ushort) MethodAttributes.NewSlot); }
			set { attributes = attributes.SetMaskedAttributes ((ushort) MethodAttributes.VtableLayoutMask, (ushort) MethodAttributes.NewSlot, value); }
		}

		public bool IsCheckAccessOnOverride {
			get { return attributes.GetAttributes ((ushort) MethodAttributes.CheckAccessOnOverride); }
			set { attributes = attributes.SetAttributes ((ushort) MethodAttributes.CheckAccessOnOverride, value); }
		}

		public bool IsAbstract {
			get { return attributes.GetAttributes ((ushort) MethodAttributes.Abstract); }
			set { attributes = attributes.SetAttributes ((ushort) MethodAttributes.Abstract, value); }
		}

		public bool IsSpecialName {
			get { return attributes.GetAttributes ((ushort) MethodAttributes.SpecialName); }
			set { attributes = attributes.SetAttributes ((ushort) MethodAttributes.SpecialName, value); }
		}

		public bool IsPInvokeImpl {
			get { return attributes.GetAttributes ((ushort) MethodAttributes.PInvokeImpl); }
			set { attributes = attributes.SetAttributes ((ushort) MethodAttributes.PInvokeImpl, value); }
		}

		public bool IsUnmanagedExport {
			get { return attributes.GetAttributes ((ushort) MethodAttributes.UnmanagedExport); }
			set { attributes = attributes.SetAttributes ((ushort) MethodAttributes.UnmanagedExport, value); }
		}

		public bool IsRuntimeSpecialName {
			get { return attributes.GetAttributes ((ushort) MethodAttributes.RTSpecialName); }
			set { attributes = attributes.SetAttributes ((ushort) MethodAttributes.RTSpecialName, value); }
		}

		public bool HasSecurity {
			get { return attributes.GetAttributes ((ushort) MethodAttributes.HasSecurity); }
			set { attributes = attributes.SetAttributes ((ushort) MethodAttributes.HasSecurity, value); }
		}

		#endregion

		#region MethodImplAttributes

		public bool IsIL {
			get { return impl_attributes.GetMaskedAttributes ((ushort) MethodImplAttributes.CodeTypeMask, (ushort) MethodImplAttributes.IL); }
			set { impl_attributes = impl_attributes.SetMaskedAttributes ((ushort) MethodImplAttributes.CodeTypeMask, (ushort) MethodImplAttributes.IL, value); }
		}

		public bool IsNative {
			get { return impl_attributes.GetMaskedAttributes ((ushort) MethodImplAttributes.CodeTypeMask, (ushort) MethodImplAttributes.Native); }
			set { impl_attributes = impl_attributes.SetMaskedAttributes ((ushort) MethodImplAttributes.CodeTypeMask, (ushort) MethodImplAttributes.Native, value); }
		}

		public bool IsRuntime {
			get { return impl_attributes.GetMaskedAttributes ((ushort) MethodImplAttributes.CodeTypeMask, (ushort) MethodImplAttributes.Runtime); }
			set { impl_attributes = impl_attributes.SetMaskedAttributes ((ushort) MethodImplAttributes.CodeTypeMask, (ushort) MethodImplAttributes.Runtime, value); }
		}

		public bool IsUnmanaged {
			get { return impl_attributes.GetMaskedAttributes ((ushort) MethodImplAttributes.ManagedMask, (ushort) MethodImplAttributes.Unmanaged); }
			set { impl_attributes = impl_attributes.SetMaskedAttributes ((ushort) MethodImplAttributes.ManagedMask, (ushort) MethodImplAttributes.Unmanaged, value); }
		}

		public bool IsManaged {
			get { return impl_attributes.GetMaskedAttributes ((ushort) MethodImplAttributes.ManagedMask, (ushort) MethodImplAttributes.Managed); }
			set { impl_attributes = impl_attributes.SetMaskedAttributes ((ushort) MethodImplAttributes.ManagedMask, (ushort) MethodImplAttributes.Managed, value); }
		}

		public bool IsForwardRef {
			get { return impl_attributes.GetAttributes ((ushort) MethodImplAttributes.ForwardRef); }
			set { impl_attributes = impl_attributes.SetAttributes ((ushort) MethodImplAttributes.ForwardRef, value); }
		}

		public bool IsPreserveSig {
			get { return impl_attributes.GetAttributes ((ushort) MethodImplAttributes.PreserveSig); }
			set { impl_attributes = impl_attributes.SetAttributes ((ushort) MethodImplAttributes.PreserveSig, value); }
		}

		public bool IsInternalCall {
			get { return impl_attributes.GetAttributes ((ushort) MethodImplAttributes.InternalCall); }
			set { impl_attributes = impl_attributes.SetAttributes ((ushort) MethodImplAttributes.InternalCall, value); }
		}

		public bool IsSynchronized {
			get { return impl_attributes.GetAttributes ((ushort) MethodImplAttributes.Synchronized); }
			set { impl_attributes = impl_attributes.SetAttributes ((ushort) MethodImplAttributes.Synchronized, value); }
		}

		public bool NoInlining {
			get { return impl_attributes.GetAttributes ((ushort) MethodImplAttributes.NoInlining); }
			set { impl_attributes = impl_attributes.SetAttributes ((ushort) MethodImplAttributes.NoInlining, value); }
		}

		public bool NoOptimization {
			get { return impl_attributes.GetAttributes ((ushort) MethodImplAttributes.NoOptimization); }
			set { impl_attributes = impl_attributes.SetAttributes ((ushort) MethodImplAttributes.NoOptimization, value); }
		}

		public bool AggressiveInlining {
			get { return impl_attributes.GetAttributes ((ushort) MethodImplAttributes.AggressiveInlining); }
			set { impl_attributes = impl_attributes.SetAttributes ((ushort) MethodImplAttributes.AggressiveInlining, value); }
		}

		#endregion

		#region MethodSemanticsAttributes

		public bool IsSetter {
			get { return this.GetSemantics (MethodSemanticsAttributes.Setter); }
			set { this.SetSemantics (MethodSemanticsAttributes.Setter, value); }
		}

		public bool IsGetter {
			get { return this.GetSemantics (MethodSemanticsAttributes.Getter); }
			set { this.SetSemantics (MethodSemanticsAttributes.Getter, value); }
		}

		public bool IsOther {
			get { return this.GetSemantics (MethodSemanticsAttributes.Other); }
			set { this.SetSemantics (MethodSemanticsAttributes.Other, value); }
		}

		public bool IsAddOn {
			get { return this.GetSemantics (MethodSemanticsAttributes.AddOn); }
			set { this.SetSemantics (MethodSemanticsAttributes.AddOn, value); }
		}

		public bool IsRemoveOn {
			get { return this.GetSemantics (MethodSemanticsAttributes.RemoveOn); }
			set { this.SetSemantics (MethodSemanticsAttributes.RemoveOn, value); }
		}

		public bool IsFire {
			get { return this.GetSemantics (MethodSemanticsAttributes.Fire); }
			set { this.SetSemantics (MethodSemanticsAttributes.Fire, value); }
		}

		#endregion

		public new TypeDefinition DeclaringType {
			get { return (TypeDefinition) base.DeclaringType; }
			set { base.DeclaringType = value; }
		}

		public bool IsConstructor {
			get {
				return this.IsRuntimeSpecialName
					&& this.IsSpecialName
					&& (this.Name == ".cctor" || this.Name == ".ctor");
			}
		}

		public override bool IsDefinition {
			get { return true; }
		}

		internal MethodDefinition ()
		{
			this.token = new MetadataToken (TokenType.Method);
		}

		public MethodDefinition (string name, MethodAttributes attributes, TypeReference returnType)
			: base (name, returnType)
		{
			this.attributes = (ushort) attributes;
			this.HasThis = !this.IsStatic;
			this.token = new MetadataToken (TokenType.Method);
		}

		public override MethodDefinition Resolve ()
		{
			return this;
		}
	}

	static partial class Mixin {

		public static ParameterDefinition GetParameter (this MethodBody self, int index)
		{
			var method = self.method;

			if (method.HasThis) {
				if (index == 0)
					return self.ThisParameter;

				index--;
			}

			var parameters = method.Parameters;

			if (index < 0 || index >= parameters.size)
				return null;

			return parameters [index];
		}

		public static VariableDefinition GetVariable (this MethodBody self, int index)
		{
			var variables = self.Variables;

			if (index < 0 || index >= variables.size)
				return null;

			return variables [index];
		}

		public static bool GetSemantics (this MethodDefinition self, MethodSemanticsAttributes semantics)
		{
			return (self.SemanticsAttributes & semantics) != 0;
		}

		public static void SetSemantics (this MethodDefinition self, MethodSemanticsAttributes semantics, bool value)
		{
			if (value)
				self.SemanticsAttributes |= semantics;
			else
				self.SemanticsAttributes &= ~semantics;
		}
	}
}