// 
// FieldValueReference.cs
//  
// Authors: Lluis Sanchez Gual <lluis@novell.com>
//          Jeffrey Stedfast <jeff@xamarin.com>
// 
// Copyright (c) 2009 Novell, Inc (http://www.novell.com)
// Copyright (c) 2012 Xamarin Inc. (http://www.xamarin.com)
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

using System;
using System.Reflection;
using Mono.Debugging.Evaluation;
using Mono.Debugger.Soft;
using Mono.Debugging.Client;
using System.Collections.Generic;
using System.Linq;

namespace Mono.Debugging.Soft
{
	public class FieldValueReference: SoftValueReference
	{
		FieldInfoMirror field;
		object obj;
		TypeMirror declaringType;
		ObjectValueFlags flags;
		string vname;
		FieldReferenceBatch batch;
		
		public FieldValueReference (EvaluationContext ctx, FieldInfoMirror field, object obj, TypeMirror declaringType, FieldReferenceBatch batch = null)
			: this (ctx, field, obj, declaringType, null, ObjectValueFlags.Field, batch)
		{
		}
		
		public FieldValueReference (EvaluationContext ctx, FieldInfoMirror field, object obj, TypeMirror declaringType, string vname, ObjectValueFlags vflags, FieldReferenceBatch batch = null): base (ctx)
		{
			this.field = field;
			this.obj = obj;
			this.declaringType = declaringType;
			this.vname = vname;
			this.batch = batch;

			if (field.IsStatic)
				this.obj = null;

			var objectMirror = obj as ObjectMirror;
			if (objectMirror != null)
				EnsureContextHasDomain (objectMirror.Domain);

			flags = GetFlags (field);

			// if `vflags` already has an origin specified, we need to unset the `Field` flag which is always returned by GetFlags().
			if ((vflags & ObjectValueFlags.OriginMask) != 0)
				flags &= ~ObjectValueFlags.Field;

			flags |= vflags;

			if (obj is PrimitiveValue)
				flags |= ObjectValueFlags.ReadOnly;
		}

		internal static ObjectValueFlags GetFlags (FieldInfoMirror field)
		{
			var flags = ObjectValueFlags.Field;

			if (field.IsStatic)
				flags |= ObjectValueFlags.Global;

			if (field.IsPublic)
				flags |= ObjectValueFlags.Public;
			else if (field.IsPrivate)
				flags |= ObjectValueFlags.Private;
			else if (field.IsFamily)
				flags |= ObjectValueFlags.Protected;
			else if (field.IsFamilyAndAssembly)
				flags |= ObjectValueFlags.Internal;
			else if (field.IsFamilyOrAssembly)
				flags |= ObjectValueFlags.InternalProtected;

			return flags;
		}
		
		public override ObjectValueFlags Flags {
			get {
				return flags;
			}
		}

		public override string Name {
			get {
				return vname ?? field.Name;
			}
		}

		public override object Type {
			get {
				return field.FieldType;
			}
		}
		
		public override object DeclaringType {
			get {
				return field.DeclaringType;
			}
		}

		public override object Value {
			get {
				if (obj == null) {
					// If the type hasn't already been loaded, invoke the .cctor() for types w/ the BeforeFieldInit attribute.
					Context.Adapter.ForceLoadType (Context, declaringType);

					return declaringType.GetValue (field, ((SoftEvaluationContext)Context).Thread);
				} else if (obj is ObjectMirror) {
					if (batch != null)
						return batch.GetValue (field);
					return ((ObjectMirror)obj).GetValue (field);
				} else if (obj is StructMirror) {
					StructMirror sm = (StructMirror)obj;
					int idx = 0;
					foreach (FieldInfoMirror f in sm.Type.GetFields ()) {
						if (f.IsStatic) continue;
						if (f == field)
							break;
						idx++;
					}
					return sm.Fields [idx];
				} else if (obj is StringMirror) {
					SoftEvaluationContext cx = (SoftEvaluationContext) Context;
					StringMirror val = (StringMirror) obj;
					FieldInfo rfield = typeof(string).GetField (field.Name, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
					return cx.Session.VirtualMachine.CreateValue (rfield.GetValue (val.Value));
				} else {
					SoftEvaluationContext cx = (SoftEvaluationContext) Context;
					PrimitiveValue val = (PrimitiveValue) obj;
					if (val.Value == null)
						return null;
					FieldInfo rfield = val.Value.GetType ().GetField (field.Name, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
					return cx.Session.VirtualMachine.CreateValue (rfield.GetValue (val.Value));
				}
			}
			set {
				if (obj == null)
					declaringType.SetValue (field, (Value)value);
				else if (obj is ObjectMirror) {
					if (batch != null)
						batch.Invalidate ();
					((ObjectMirror)obj).SetValue (field, (Value)value);
				}
				else if (obj is StructMirror) {
					StructMirror sm = (StructMirror)obj;
					int idx = 0;
					foreach (FieldInfoMirror f in sm.Type.GetFields ()) {
						if (f.IsStatic) continue;
						if (f == field)
							break;
						idx++;
					}
					if (idx != -1) {
						sm.Fields [idx] = (Value)value;
						// Structs are handled by-value in the debugger, so the source of the object has to be updated
						if (ParentSource != null && obj != null)
							ParentSource.Value = obj;
					}
				}
				else
					throw new NotSupportedException ();
			}
		}

		internal string [] GetTupleElementNames ()
		{
			return GetTupleElementNames (field.GetCustomAttributes (true));
		}

		internal static string [] GetTupleElementNames (CustomAttributeDataMirror [] attrs)
		{
			var attr = attrs.FirstOrDefault (at => at.Constructor.DeclaringType.Name == "TupleElementNamesAttribute");
			if (attr == null)
				return null;
			var attributeValue = attr.ConstructorArguments.Single ().Value;
			var array = attributeValue as ArrayMirror;
			if (array == null)
				return null;
			var values = array.GetValues (0, array.Length);
			if (!values.Any ())
				return null;
			var result = new string [values.Count];
			for (int i = 0; i < result.Length; i++) {
				if (values [i] is StringMirror s)//other than string is null
					result [i] = s.Value;
			}
			return result;
		}
	}
}