CodeFileGenerator.h

//  
// Copyright (c) 2023 articy Software GmbH & Co. KG. All rights reserved.  
//
 
#pragma once
 
#include "CodeGenerator.h"

class CodeFileGenerator
{
public:

    template<typename Lambda>
    void SafeExecute(Lambda Lamb);

    template<typename Lambda>
    CodeFileGenerator(const FString& Path, const bool bHeader, Lambda ContentGenerator);

    void Line(const FString& Line = "", const bool bSemicolon = false, const bool bIndent = true, const int IndentOffset = 0);

    void Comment(const FString& Text);

    void AccessModifier(const FString& Text);

    void UPropertyMacro(const FString& Specifiers);

    void UFunctionMacro(const FString& Specifiers);
 
    //========================================//

    template<typename Lambda>
    void Block(const bool bIndent, Lambda Content, const bool bSemicolonAtEnd = false);

    template<typename Lambda>
    void Class(const FString& Classname, const FString& Comment, const bool bUClass, Lambda Content, const FString& UClassSpecifiers = "BlueprintType");

    template<typename Lambda>
    void Struct(const FString& Structname, const FString& Comment, const bool bUStruct, Lambda Content, const FString& InlineDeclaration = "");

    template<typename Lambda>
    void UInterface(const FString& Classname, const FString& UInterfaceSpecifiers, const FString& Comment, Lambda Content);

    template<typename Type>
    void Enum(const FString& Enumname, const FString& Comment, const bool bUEnum, TArray<Type> Values);
 
    //========================================//

    void Variable(const FString& Type, const FString& Name, const FString& Value = "", const FString& Comment = "",
        const bool bUProperty = false, const FString& UPropertySpecifiers = "VisibleAnywhere, BlueprintReadOnly");

    template<typename Lambda>
    void Method(const FString& ReturnType, const FString& Name, const FString& Parameters = "", Lambda Definition = nullptr, const FString& Comment = "",
        const bool bUFunction = false, const FString& UFunctionSpecifiers = "", const FString& MethodSpecifiers = "");
 
 
private:
 
    const FString Path; 
    FString FileContent = ""; 
 
    int IndentCount = 0; 
    uint8 BlockCount = 0; 

    void PushIndent() { ++IndentCount; }

    void PopIndent() { IndentCount = FMath::Max(0, IndentCount - 1); }

    void StartBlock(const bool bIndent = true);

    void EndBlock(const bool bUnindent = true, const bool bSemicolon = false);

    void StartClass(const FString& Classname, const FString& Comment, const bool bUClass, const FString& UClassSpecifiers = "BlueprintType");

    void EndClass() { EndBlock(true, true); }

    void StartStruct(const FString& Structname, const FString& Comment, const bool bUStruct);

    void EndStruct(const FString& InlineDeclaration);

    void AddEnumEntry(FString Name);

    template <typename TNameValuePair>
    void AddEnumEntry(TNameValuePair Pair);

    static FString GetExportMacro();

    void WriteToFile() const;

    FString SplitName(const FString& Name);
};
 
//---------------------------------------------------------------------------//
//---------------------------------------------------------------------------//
 
template<typename Lambda>
void CodeFileGenerator::SafeExecute(Lambda Lamb)
{
    Lamb();
}
 
template<>
inline void CodeFileGenerator::SafeExecute(nullptr_t Lamb)
{
}

template <typename Lambda>
CodeFileGenerator::CodeFileGenerator(const FString& Path, const bool bHeader, Lambda ContentGenerator) : Path(CodeGenerator::GetSourceFolder() / Path)
{
    Line("// articy Software GmbH & Co. KG");
    Comment("This code file was generated by ArticyImporter. Changes to this file will get lost once the code is regenerated.");
 
    if (bHeader)
    {
        Line();
        Line("#pragma once");
    }
 
    Line();
 
    if (ensure(!std::is_null_pointer<Lambda>::value))
        ContentGenerator(this);
 
    WriteToFile();
}

template <typename Lambda>
void CodeFileGenerator::Block(const bool bIndent, Lambda Content, const bool bSemicolonAtEnd)
{
    StartBlock(bIndent);
    {
        // Add the content
        SafeExecute(Content);
    }
    EndBlock(bIndent, bSemicolonAtEnd);
}

template <typename Lambda>
void CodeFileGenerator::Class(const FString& Classname, const FString& Comment, const bool bUClass, Lambda Content, const FString& UClassSpecifiers)
{
    StartClass(Classname, Comment, bUClass, UClassSpecifiers);
    {
        // Add the content
        SafeExecute(Content);
    }
    EndClass();
}

template <typename Lambda>
void CodeFileGenerator::Struct(const FString& Structname, const FString& Comment, const bool bUStruct, Lambda Content, const FString& InlineDeclaration)
{
    StartStruct(Structname, Comment, bUStruct);
    {
        // Add the content
        SafeExecute(Content);
    }
    EndStruct(InlineDeclaration);
}

template <typename Lambda>
void CodeFileGenerator::UInterface(const FString& Classname, const FString& UInterfaceSpecifiers, const FString& Comment, Lambda Content)
{
    if (!Comment.IsEmpty())
        this->Comment(Comment);
    Line(FString::Printf(TEXT("UINTERFACE(%s)"), *UInterfaceSpecifiers));
    Line(FString::Printf(TEXT("class U%s : public UInterface { GENERATED_BODY() };"), *Classname));
    Class("I" + Classname, "", false, [&]
        {
            Line("GENERATED_BODY()");
            Line();
            SafeExecute(Content);
        });
}
 
//---------------------------------------------------------------------------//

template <typename Type>
void CodeFileGenerator::Enum(const FString& Enumname, const FString& Comment, const bool bUEnum, TArray<Type> Values)
{
    if (bUEnum)
        Line("UENUM(BlueprintType)");
 
    Line("enum");
    StartClass(Enumname + (bUEnum ? " : uint8" : ""), Comment, false);
    {
        // Add the values
        for (auto val : Values)
            AddEnumEntry(val);
    }
    EndClass();
}

inline void CodeFileGenerator::AddEnumEntry(FString Name)
{
    Line(FString::Printf(TEXT("%s,"), *Name));
}

template <typename TNameValuePair>
void CodeFileGenerator::AddEnumEntry(TNameValuePair Pair)
{
    Line(FString::Printf(TEXT("%s = %d,"), *Pair.Name, Pair.Value));
}
 
//---------------------------------------------------------------------------//

template<typename Lambda>
void CodeFileGenerator::Method(const FString& ReturnType, const FString& Name, const FString& Parameters, Lambda Definition, const FString& Comment, const bool bUFunction, const FString& UFunctionSpecifiers, const FString& MethodSpecifiers)
{
    if (!ensure(!Name.IsEmpty()))
        return;
 
    if (!Comment.IsEmpty())
        this->Comment(Comment);
 
    if (bUFunction)
        this->UFunctionMacro(UFunctionSpecifiers);
 
    // Check if nullptr was passed as Definition
    constexpr auto hasDefinition = !std::is_null_pointer<Lambda>::value;
 
    // ReturnType Name(Parameters..)
    // Only add the semicolon if there is no definition
    Line(FString::Printf(TEXT("%s %s(%s) %s"), *ReturnType, *Name, *Parameters, *MethodSpecifiers), !hasDefinition);
 
    // Add definition, if any
    if (hasDefinition)
        Block(true, Definition, false);
}