using System;
using System.Diagnostics;
using System.Globalization;
using System.Text;
using Cxxi.Types;

namespace Cxxi.Generators.CLI
{
    public class CLIMarshalNativeToManagedPrinter : ITypeVisitor<bool>,
                                                    IDeclVisitor<bool>
    {
        public TextGenerator Support;
        public TextGenerator Return;

        Generator Generator { get; set; }
        MarshalContext Context { get; set; }

        public CLIMarshalNativeToManagedPrinter(Generator gen, MarshalContext ctx)
        {
            Generator = gen;
            Context = ctx;
            Support = new TextGenerator();
            Return = new TextGenerator();
        }

        public bool VisitTagType(TagType tag, TypeQualifiers quals)
        {
            var decl = tag.Declaration;
            return decl.Visit(this);
        }

        public bool VisitArrayType(ArrayType array, TypeQualifiers quals)
        {
            return false;
        }

        public bool VisitFunctionType(FunctionType function, TypeQualifiers quals)
        {
            var returnType = function.ReturnType;
            return returnType.Visit(this, quals);
        }

        public bool VisitPointerType(PointerType pointer, TypeQualifiers quals)
        {
            var pointee = pointer.Pointee;

            if (pointee.IsPrimitiveType(PrimitiveType.Void))
            {
                Return.Write("IntPtr()");
                return true;
            }

            if (pointee.IsPrimitiveType(PrimitiveType.Char))
            {
                Return.Write("clix::marshalString<clix::E_UTF8>({0})",
                             Context.ReturnVarName);
                return true;
            }

            PrimitiveType primitive;
            if (pointee.IsPrimitiveType(out primitive, walkTypedefs: true))
                Return.Write("*");

            if (!pointee.Visit(this, quals))
                return false;

            return true;
        }

        public bool VisitMemberPointerType(MemberPointerType member,
            TypeQualifiers quals)
        {
            return false;
        }

        public bool VisitBuiltinType(BuiltinType builtin, TypeQualifiers quals)
        {
            return VisitPrimitiveType(builtin.Type);
        }

        public bool VisitPrimitiveType(PrimitiveType primitive)
        {
            switch (primitive)
            {
                case PrimitiveType.Void:
                    return true;
                case PrimitiveType.Bool:
                case PrimitiveType.Int8:
                case PrimitiveType.UInt8:
                case PrimitiveType.Int16:
                case PrimitiveType.UInt16:
                case PrimitiveType.Int32:
                case PrimitiveType.UInt32:
                case PrimitiveType.Int64:
                case PrimitiveType.UInt64:
                case PrimitiveType.Float:
                case PrimitiveType.Double:
                    Return.Write(Context.ReturnVarName);
                    return true;
                case PrimitiveType.WideChar:
                    return false;
            }

            return false;
        }

        public bool VisitTypedefType(TypedefType typedef, TypeQualifiers quals)
        {
            var decl = typedef.Declaration;

            TypeMap typeMap = null;
            if (Generator.TypeMapDatabase.FindTypeMap(decl, out typeMap))
            {
                Return.Write(typeMap.MarshalFromNative(Context));
                return typeMap.IsValueType;
            }

            // TODO: How should function pointers behave here?

            return decl.Type.Visit(this);
        }

        public bool VisitTemplateSpecializationType(TemplateSpecializationType template,
                                                    TypeQualifiers quals)
        {
            return template.Template.Visit(this);
        }

        public bool VisitDeclaration(Declaration decl, TypeQualifiers quals)
        {
            throw new NotImplementedException();
        }

        public bool VisitDeclaration(Declaration decl)
        {
            throw new NotImplementedException();
        }

        public bool VisitClassDecl(Class @class)
        {
            if (@class.IsRefType)
                Return.Write("gcnew ");

            Return.Write("{0}::{1}(", Generator.Library.Name,
                @class.Name);

            Return.Write("(::{0}*)", @class.QualifiedOriginalName);

            if (@class.IsValueType && !this.Context.ReturnType.IsPointer())
                Return.Write("&");

            Return.Write("{0})", this.Context.ReturnVarName);
            return true;
        }

        public bool VisitFieldDecl(Field field)
        {
            throw new NotImplementedException();
        }

        public bool VisitFunctionDecl(Function function)
        {
            throw new NotImplementedException();
        }

        public bool VisitMethodDecl(Method method)
        {
            throw new NotImplementedException();
        }

        public bool VisitParameterDecl(Parameter parameter)
        {
            throw new NotImplementedException();
        }

        public bool VisitTypedefDecl(TypedefDecl typedef)
        {
            throw new NotImplementedException();
        }

        public bool VisitEnumDecl(Enumeration @enum)
        {
            Return.Write("({0}){1}", ToCLITypeName(@enum),
                Context.ReturnVarName);
            return true;
        }

        private string ToCLITypeName(Declaration decl)
        {
            var typePrinter = new CLITypePrinter(Generator);
            return typePrinter.VisitDeclaration(decl);
        }

        public bool VisitClassTemplateDecl(ClassTemplate template)
        {
            return template.TemplatedClass.Visit(this);
        }

        public bool VisitFunctionTemplateDecl(FunctionTemplate template)
        {
            throw new NotImplementedException();
        }

        public bool VisitMacroDefinition(MacroDefinition macro)
        {
            throw new NotImplementedException();
        }

        public bool VisitNamespace(Namespace @namespace)
        {
            throw new NotImplementedException();
        }

        public bool VisitDelegate(Delegate @delegate)
        {
            throw new NotImplementedException();
        }
    }

    public class CLIMarshalManagedToNativePrinter : ITypeVisitor<bool>,
                                                    IDeclVisitor<bool>
    {
        public TextGenerator SupportBefore;
        public TextGenerator SupportAfter;
        public TextGenerator Return;
        public TextGenerator ArgumentPrefix;

        Generator Generator { get; set; }
        MarshalContext Context { get; set; }

        public CLIMarshalManagedToNativePrinter(Generator gen, MarshalContext ctx)
        {
            Generator = gen;
            Context = ctx;

            SupportBefore = new TextGenerator();
            SupportAfter = new TextGenerator();
            Return = new TextGenerator();
            ArgumentPrefix = new TextGenerator();
        }

        public bool VisitTagType(TagType tag, TypeQualifiers quals)
        {
            var decl = tag.Declaration;
            return decl.Visit(this);
        }

        public bool VisitArrayType(ArrayType array, TypeQualifiers quals)
        {
            return false;
        }

        public bool VisitFunctionType(FunctionType function, TypeQualifiers quals)
        {
            var returnType = function.ReturnType;
            return returnType.Visit(this, quals);
        }

        public bool VisitDelegateType(FunctionType function, string type)
        {
            // We marshal function pointer types by calling
            // GetFunctionPointerForDelegate to get a native function
            // pointer ouf of the delegate. Then we can pass it in the
            // native call. Since references are not tracked in the
            // native side, we need to be careful and protect it with an
            // explicit GCHandle if necessary.

            var sb = new StringBuilder();
            sb.AppendFormat("static_cast<::{0}>(", type);
            sb.Append("System::Runtime::InteropServices::Marshal::");
            sb.Append("GetFunctionPointerForDelegate(");
            sb.AppendFormat("{0}).ToPointer())", Context.Parameter.Name);
            Return.Write(sb.ToString());

            return true;
        }

        public bool VisitPointerType(PointerType pointer, TypeQualifiers quals)
        {
            var pointee = pointer.Pointee;

            var isVoidPtr = pointee.IsPrimitiveType(PrimitiveType.Void,
                walkTypedefs: true);

            var isUInt8Ptr = pointee.IsPrimitiveType(PrimitiveType.UInt8,
                walkTypedefs: true);

            if (isVoidPtr || isUInt8Ptr)
            {
                if (isUInt8Ptr)
                    Return.Write("({0})", "uint8*");
                Return.Write("{0}.ToPointer()", Context.Parameter.Name);
                return true;
            }

            if (pointee.IsPrimitiveType(PrimitiveType.Char))
            {
                SupportBefore.Write(
                    "auto _{0} = clix::marshalString<clix::E_UTF8>({1});",
                    Context.ArgName, Context.Parameter.Name);

                Return.Write("_{0}.c_str()", Context.ArgName);
                return true;
            }

            if (pointee is FunctionType)
            {
                var function = pointee as FunctionType;
                // TODO: We have to translate the function type typedef to C/C++
                return VisitDelegateType(function, function.ToString());
            }

            return pointee.Visit(this, quals);
        }

        public bool VisitMemberPointerType(MemberPointerType member,
            TypeQualifiers quals)
        {
            return false;
        }

        public bool VisitBuiltinType(BuiltinType builtin, TypeQualifiers quals)
        {
            return VisitPrimitiveType(builtin.Type);
        }

        public bool VisitPrimitiveType(PrimitiveType primitive)
        {
            switch (primitive)
            {
                case PrimitiveType.Void:
                    return true;
                case PrimitiveType.Bool:
                case PrimitiveType.Int8:
                case PrimitiveType.UInt8:
                case PrimitiveType.Int16:
                case PrimitiveType.UInt16:
                case PrimitiveType.Int32:
                case PrimitiveType.UInt32:
                case PrimitiveType.Int64:
                case PrimitiveType.UInt64:
                case PrimitiveType.Float:
                case PrimitiveType.Double:
                    Return.Write(Context.Parameter.Name);
                    return true;
                case PrimitiveType.WideChar:
                    return false;
            }

            return false;
        }

        public bool VisitTypedefType(TypedefType typedef, TypeQualifiers quals)
        {
            var decl = typedef.Declaration;

            TypeMap typeMap = null;
            if (Generator.TypeMapDatabase.FindTypeMap(decl, out typeMap))
            {
                Return.Write(typeMap.MarshalToNative(Context));
                return typeMap.IsValueType;
            }

            FunctionType func;
            if (decl.Type.IsPointerTo<FunctionType>(out func))
            {
                VisitDelegateType(func, typedef.Declaration.OriginalName);
                return true;
            }

            PrimitiveType primitive;
            if (decl.Type.IsPrimitiveType(out primitive, walkTypedefs: true))
            {
                Return.Write("({0})", typedef.Declaration.Name);
            }

            return decl.Type.Visit(this);
        }

        public bool VisitTemplateSpecializationType(TemplateSpecializationType template,
                                                    TypeQualifiers quals)
        {
            return template.Template.Visit(this);
        }

        public bool VisitDeclaration(Declaration decl, TypeQualifiers quals)
        {
            throw new NotImplementedException();
        }

        public bool VisitDeclaration(Declaration decl)
        {
            throw new NotImplementedException();
        }

        public bool VisitClassDecl(Class @class)
        {
            if (@class.IsValueType)
            {
                if (Context.Parameter.Type.IsReference())
                {
                    var argName = string.Format("_{0}", Context.ArgName);
                    SupportBefore.Write("auto {0} = (::{1}*)&{2};",
                                  argName, @class.OriginalName,
                                  Context.Parameter.Name);
                    Return.Write("*{0}", argName);
                }
                else
                {
                    SupportAfter.PushIndent();

                    foreach (var field in @class.Fields)
                    {
                        SupportAfter.Write("{0}.{1} = ", Context.ArgName,
                            field.OriginalName);

                        var fieldRef = string.Format("{0}.{1}", Context.Parameter.Name,
                                                     field.Name);

                        var marshalCtx = new MarshalContext() { ArgName = fieldRef };
                        var marshal = new CLIMarshalManagedToNativePrinter(Generator,
                            marshalCtx);
                        field.Visit(marshal);

                        SupportAfter.WriteLine("{0};", marshal.Return);
                    }

                    Return.Write("::{0}()", @class.QualifiedOriginalName);

                    if (Context.Parameter.Type.IsPointer())
                        ArgumentPrefix.Write("&");
                }
            }
            else
            {
                if (!Context.Parameter.Type.IsPointer())
                    Return.Write("*");

                var method = Context.Function as Method;
                if (method != null
                    && method.Conversion == MethodConversionType.FunctionToInstanceMethod
                    && Context.ParameterIndex == 0)
                {
                    Return.Write("NativePtr");
                    return true;
                }

                Return.Write("{0}->NativePtr", Context.Parameter.Name);
            }

            return true;
        }

        public bool VisitFieldDecl(Field field)
        {
            Context.Parameter = new Parameter
                {
                    Name = Context.ArgName, Type = field.Type
                };

            return field.Type.Visit(this);
        }

        public bool VisitFunctionDecl(Function function)
        {
            throw new NotImplementedException();
        }

        public bool VisitMethodDecl(Method method)
        {
            throw new NotImplementedException();
        }

        public bool VisitParameterDecl(Parameter parameter)
        {
            return parameter.Type.Visit(this);
        }

        public bool VisitTypedefDecl(TypedefDecl typedef)
        {
            throw new NotImplementedException();
        }

        public bool VisitEnumDecl(Enumeration @enum)
        {
            Return.Write("(::{0}){1}", @enum.QualifiedOriginalName,
                         Context.Parameter.Name);
            return true;
        }

        public bool VisitClassTemplateDecl(ClassTemplate template)
        {
            return template.TemplatedClass.Visit(this);
        }

        public bool VisitFunctionTemplateDecl(FunctionTemplate template)
        {
            throw new NotImplementedException();
        }

        public bool VisitMacroDefinition(MacroDefinition macro)
        {
            throw new NotImplementedException();
        }

        public bool VisitNamespace(Namespace @namespace)
        {
            throw new NotImplementedException();
        }

        public bool VisitDelegate(Delegate @delegate)
        {
            throw new NotImplementedException();
        }
    }
}