using EpicGames.Core;
using EpicGames.UHT.Types;
using UnrealSharpScriptGenerator.PropertyTranslators;
using UnrealSharpScriptGenerator.Utilities;

namespace UnrealSharpScriptGenerator.Exporters;

public static class DelegateExporter
{
    public static void ExportDelegate(UhtFunction function)
    {
        string delegateName = DelegateBasePropertyTranslator.GetDelegateName(function);
        string delegateNamespace = function.GetNamespace();
        
        GeneratorStringBuilder builder = new();
        
        builder.GenerateTypeSkeleton(delegateNamespace);
        builder.AppendLine();
        
        string superClass;
        if (function.HasAllFlags(EFunctionFlags.MulticastDelegate))
        {
            superClass = $"MulticastDelegate<{delegateName}>";
        }
        else
        {
            superClass = $"Delegate<{delegateName}>";
        }
        
        FunctionExporter functionExporter = FunctionExporter.ExportDelegateSignature(builder, function, delegateName);
        
        builder.DeclareType(function, "class", $"U{delegateName}", superClass);
        
        FunctionExporter.ExportDelegateGlue(builder, functionExporter);
        
        builder.AppendLine("static public void InitializeUnrealDelegate(IntPtr nativeDelegateProperty)");
        builder.OpenBrace();
        ExportDelegateFunctionStaticConstruction(builder, function);
        builder.CloseBrace();
        builder.CloseBrace();
        
        FileExporter.SaveGlueToDisk(function, builder);
    }

    private static void ExportDelegateFunctionStaticConstruction(GeneratorStringBuilder builder, UhtFunction function)
    {
        string delegateName = function.SourceName;
        builder.AppendLine($"{delegateName}_NativeFunction = FMulticastDelegatePropertyExporter.CallGetSignatureFunction(nativeDelegateProperty);");
        if (function.HasParameters)
        {
            builder.AppendLine($"{delegateName}_ParamsSize = {ExporterCallbacks.UFunctionCallbacks}.CallGetNativeFunctionParamsSize({delegateName}_NativeFunction);");
        }
        
        foreach (UhtProperty parameter in function.Properties)
        {
            PropertyTranslator propertyTranslator = PropertyTranslatorManager.GetTranslator(parameter)!;
            propertyTranslator.ExportParameterStaticConstructor(builder, parameter, function, parameter.SourceName, delegateName);
        }
    }
}