using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Reflection.Metadata;
using System.Text;


namespace Cosmos.IL2CPU.ILOpCodes
{
    public class OpField : ILOpCode
    {
        public readonly FieldInfo Value;

        public OpField(Code aOpCode, int aPos, int aNextPos, FieldInfo aValue, _ExceptionRegionInfo aCurrentExceptionRegion)
          : base(aOpCode, aPos, aNextPos, aCurrentExceptionRegion)
        {
            Value = aValue;
        }

        public override int GetNumberOfStackPops(MethodBase aMethod)
        {
            switch (OpCode)
            {
                case Code.Stsfld:
                    return 1;
                case Code.Ldsfld:
                    return 0;
                case Code.Stfld:
                    return 2;
                case Code.Ldfld:
                    return 1;
                case Code.Ldsflda:
                    return 0;
                case Code.Ldflda:
                    return 1;
                default:
                    throw new NotImplementedException("OpCode '" + OpCode + "' not implemented!");
            }
        }

        public override int GetNumberOfStackPushes(MethodBase aMethod)
        {
            switch (OpCode)
            {
                case Code.Stsfld:
                    return 0;
                case Code.Ldsfld:
                    return 1;
                case Code.Stfld:
                    return 0;
                case Code.Ldfld:
                    return 1;
                case Code.Ldsflda:
                    return 1;
                case Code.Ldflda:
                    return 1;
                default:
                    throw new NotImplementedException("OpCode '" + OpCode + "' not implemented!");
            }
        }

        protected override void DoInitStackAnalysis(MethodBase aMethod)
        {
            base.DoInitStackAnalysis(aMethod);

            switch (OpCode)
            {
                case Code.Ldsfld:
                    StackPushTypes[0] = Value.FieldType;
                    if (StackPushTypes[0].GetTypeInfo().IsEnum)
                    {
                        StackPushTypes[0] = StackPushTypes[0].GetTypeInfo().GetEnumUnderlyingType();
                    }
                    return;
                case Code.Ldsflda:
                    StackPushTypes[0] = typeof(IntPtr);
                    return;
                case Code.Ldfld:
                    StackPushTypes[0] = Value.FieldType;
                    if (StackPushTypes[0].GetTypeInfo().IsEnum)
                    {
                        StackPushTypes[0] = StackPushTypes[0].GetTypeInfo().GetEnumUnderlyingType();
                    }
                    if (!Value.DeclaringType.GetTypeInfo().IsValueType)
                    {
                        StackPopTypes[0] = Value.DeclaringType;
                    }
                    return;
                case Code.Ldflda:
                    StackPopTypes[0] = Value.DeclaringType;
                    if (StackPopTypes[0].GetTypeInfo().IsEnum)
                    {
                        StackPopTypes[0] = StackPopTypes[0].GetTypeInfo().GetEnumUnderlyingType();
                    }
                    if (StackPopTypes[0].GetTypeInfo().IsValueType &&
                        !StackPopTypes[0].GetTypeInfo().IsPrimitive)
                    {
                        StackPopTypes[0] = StackPopTypes[0].MakeByRefType();
                    }
                    StackPushTypes[0] = typeof(IntPtr);
                    return;
            }
        }

        protected override void DoInterpretStackTypes(ref bool aSituationChanged)
        {
            base.DoInterpretStackTypes(ref aSituationChanged);
            switch (OpCode)
            {
                case Code.Stfld:
                    if (StackPopTypes[1] == null)
                    {
                        return;
                    }
                    var expectedType = Value.FieldType;
                    if (expectedType.GetTypeInfo().IsEnum)
                    {
                        expectedType = expectedType.GetTypeInfo().GetEnumUnderlyingType();
                    }
                    else if (Value.DeclaringType.GetTypeInfo().IsValueType && !Value.DeclaringType.GetTypeInfo().IsPrimitive)
                    {
                        expectedType = typeof(void*);
                    }
                    if (StackPopTypes[1] == expectedType ||
                        StackPopTypes[1] == Value.FieldType)
                    {
                        return;
                    }
                    if (ILOp.IsIntegralType(expectedType) &&
                        ILOp.IsIntegralType(StackPopTypes[1]))
                    {
                        return;
                    }
                    if (expectedType == typeof(bool))
                    {
                        if (StackPopTypes[1] == typeof(int))
                        {
                            return;
                        }
                    }
                    if (StackPopTypes[1] == typeof(NullRef))
                    {
                        return;
                    }
                    if (expectedType.IsAssignableFrom(StackPopTypes[1]))
                    {
                        return;
                    }
                    if (StackPopTypes[0] == null)
                    {
                        return;
                    }

                    if (Value.FieldType.IsAssignableFrom(StackPopTypes[0]))
                    {
                        return;
                    }
                    if (ILOp.IsIntegralType(Value.FieldType) &&
                        ILOp.IsIntegralType(StackPopTypes[0]))
                    {
                        return;
                    }
                    if (Value.FieldType == typeof(bool) &&
                        ILOp.IsIntegralType(StackPopTypes[0]))
                    {
                        return;
                    }
                    if (Value.FieldType.GetTypeInfo().IsEnum)
                    {
                        if (ILOp.IsIntegralType(StackPopTypes[0]))
                        {
                            return;
                        }
                    }
                    if (ILOp.IsPointer(Value.FieldType) &&
                        ILOp.IsPointer(StackPopTypes[0]))
                    {
                        return;
                    }
                    if (Value.FieldType.GetTypeInfo().IsClass &&
                        StackPopTypes[0] == typeof(NullRef))
                    {
                        return;
                    }
                    throw new Exception("Wrong Poptype encountered! (Type = " + StackPopTypes[0].FullName + ", expected = " + expectedType.FullName + ")");
                // throw new Exception("Wrong Poptype encountered!");
                case Code.Stsfld:
                    if (StackPopTypes[0] == null)
                    {
                        return;
                    }
                    expectedType = Value.FieldType;
                    if (expectedType.GetTypeInfo().IsEnum)
                    {
                        expectedType = expectedType.GetTypeInfo().GetEnumUnderlyingType();
                    }
                    if (StackPopTypes[0] == expectedType ||
                        StackPopTypes[0] == Value.FieldType)
                    {
                        return;
                    }
                    if (ILOp.IsIntegralType(expectedType) &&
                        ILOp.IsIntegralType(StackPopTypes[0]))
                    {
                        return;
                    }
                    if (expectedType == typeof(bool))
                    {
                        if (StackPopTypes[0] == typeof(int))
                        {
                            return;
                        }
                    }
                    if (expectedType.IsAssignableFrom(StackPopTypes[0]))
                    {
                        return;
                    }
                    if (StackPopTypes[0] == typeof(NullRef))
                    {
                        return;
                    }
                    if ((StackPopTypes[0] == typeof(IntPtr)
                         || StackPopTypes[0] == typeof(UIntPtr))
                        & expectedType.IsPointer)
                    {
                        return;
                    }
                    throw new Exception("Wrong Poptype encountered! (Type = " + StackPopTypes[0].FullName + ", expected = " + expectedType.FullName + ")");
                case Code.Ldfld:
                    if (StackPopTypes[0] == null)
                    {
                        return;
                    }
                    if (!Value.DeclaringType.GetTypeInfo().IsValueType)
                    {
                        return;
                    }
                    if (StackPopTypes[0] == Value.DeclaringType.MakePointerType() ||
                        StackPopTypes[0] == Value.DeclaringType.MakeByRefType() ||
                        StackPopTypes[0] == typeof(void*) ||
                        StackPopTypes[0] == typeof(IntPtr))
                    {
                        return;
                    }
                    if (StackPopTypes[0] == Value.DeclaringType)
                    {
                        return;
                    }
                    throw new Exception("Wrong Poptype encountered! (Type = " + StackPopTypes[0].FullName + ", expected = " + Value.DeclaringType.FullName + ")");
            }
        }
    }
}