o3de/Gems/EditorPythonBindings/Code/Source/PythonUtility.h

/*
 * Copyright (c) Contributors to the Open 3D Engine Project.
 * For complete copyright and license terms please see the LICENSE at the root of this distribution.
 *
 * SPDX-License-Identifier: Apache-2.0 OR MIT
 *
 */
#pragma once

#include <Source/PythonCommon.h>
#include <pybind11/pybind11.h>
#include <AzCore/RTTI/BehaviorContext.h>
#include <AzCore/RTTI/AttributeReader.h>
#include <AzCore/std/string/string_view.h>
#include <AzCore/std/optional.h>

namespace AZ
{
    struct BehaviorParameter;
    struct BehaviorValueParameter;
    class BehaviorMethod;
}

namespace EditorPythonBindings
{
    namespace Scope
    {
        inline bool IsBehaviorFlaggedForEditor(const AZ::AttributeArray& attributes)
        {
            // defaults to Launcher
            AZ::Script::Attributes::ScopeFlags scopeType = AZ::Script::Attributes::ScopeFlags::Launcher;
            AZ::Attribute* scopeAttribute = AZ::FindAttribute(AZ::Script::Attributes::Scope, attributes);
            if (scopeAttribute)
            {
                AZ::AttributeReader scopeAttributeReader(nullptr, scopeAttribute);
                scopeAttributeReader.Read<AZ::Script::Attributes::ScopeFlags>(scopeType);
            }
            return (scopeType == AZ::Script::Attributes::ScopeFlags::Automation || scopeType == AZ::Script::Attributes::ScopeFlags::Common);
        }
    
        inline void FetchScriptName(const AZ::AttributeArray& attributes, AZStd::string& baseName)
        {
            AZ::Attribute* scriptNameAttribute = AZ::FindAttribute(AZ::Script::Attributes::Alias, attributes);
            if (scriptNameAttribute)
            {
                AZ::AttributeReader scopeAttributeReader(nullptr, scriptNameAttribute);
                scopeAttributeReader.Read<AZStd::string>(baseName);
            }
        }
    }

    namespace Module
    {
        using PackageMapType = AZStd::unordered_map<AZStd::string, pybind11::module>;

        //! Finds or creates a sub-module to add a base parent module; create all the sub-modules as well
        //! @param modulePackageMap keeps track of the known modules 
        //! @param moduleName can be a dot separated string such as "mygen.mypackage.mymodule"
        //! @param parentModule the module to add new sub-modules
        //! @param fallbackModule the module to add new sub-modules
        //! @param alertUsingFallback issue a warning if using the fallback module
        //! @return the new submodule
        pybind11::module DeterminePackageModule(PackageMapType& modulePackageMap, AZStd::string_view moduleName, pybind11::module parentModule, pybind11::module fallbackModule, bool alertUsingFallback);

        inline AZStd::optional<AZStd::string_view> GetName(const AZ::AttributeArray& attributes)
        {
            AZ::Attribute* moduleAttribute = AZ::FindAttribute(AZ::Script::Attributes::Module, attributes);
            if (moduleAttribute)
            {
                const char* moduleName = nullptr;
                AZ::AttributeReader scopeAttributeReader(nullptr, moduleAttribute);
                scopeAttributeReader.Read<const char*>(moduleName);
                if (moduleName)
                {
                    return { moduleName };
                }
            }
            return {};
        }
    }

    namespace Convert
    {
        // allocation pattern for BehaviorValueParameters being stored in the stack and needs to be cleaned at the end of a block
        using VariableDeleter = AZStd::function<void()>;

        struct StackVariableAllocator final
            : public AZStd::static_buffer_allocator<256, 16>
        {
        public:
            ~StackVariableAllocator();
            void StoreVariableDeleter(VariableDeleter&& deleter);

        private:
            AZStd::vector<VariableDeleter> m_cleanUpItems;
        };

        //! Converts a behavior value parameter to a Python object
        //! @param behaviorValue is a parameter that came from a result or some prepared behavior value
        //! @param stackVariableAllocator manages the allocated parameter while in scope
        //! @return a valid Python object or None if no conversion was possible
        pybind11::object BehaviorValueParameterToPython(AZ::BehaviorValueParameter& behaviorValue, Convert::StackVariableAllocator& stackVariableAllocator);

        //! Converts Python object to a behavior value parameter using an existing behaviorArgument from a Behavior Method
        //! @param behaviorArgument the stored argument slot from a Behavior Method to match with the pyObj to covert in the parameter
        //! @param parameter is the output of the conversion from Python to a Behavior value
        //! @param stackVariableAllocator manages the allocated parameter while in scope
        //! @return true if the conversion happened
        bool PythonToBehaviorValueParameter(const AZ::BehaviorParameter& behaviorArgument, pybind11::object pyObj, AZ::BehaviorValueParameter& parameter, Convert::StackVariableAllocator& stackVariableAllocator);
    
        //! Converts Python object to a PythonProxyObject, if possible 
        //! @param behaviorArgument A stored PythonProxyObject in Python, returns FALSE if the Python object does not point to a PythonProxyObject
        //! @param parameter is the output of the conversion from Python to a Behavior value
        //! @return true if the conversion happened
        bool PythonProxyObjectToBehaviorValueParameter(const AZ::BehaviorParameter& behaviorArgument, pybind11::object pyObj, AZ::BehaviorValueParameter& parameter);

        //! Gets a readable type name for the Python object; this will unwrap a PythonProxyObject to find its underlying type name
        //! @param pyObj any valid Python object value
        //! @return text form of the Python object value type
        AZStd::string GetPythonTypeName(pybind11::object pyObj);
    }

    namespace Call
    {
        //! Calls a BehaviorMethod with a tuple of arguments for non-member functions
        pybind11::object StaticMethod(AZ::BehaviorMethod* behaviorMethod, pybind11::args args);

        //! Calls a BehaviorMethod with a tuple of arguments for member class level functions
        pybind11::object ClassMethod(AZ::BehaviorMethod* behaviorMethod, AZ::BehaviorObject self, pybind11::args args);
    }
}