/*************************************************************************/
/*  gd_mono_internals.cpp                                                */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
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#include "gd_mono_internals.h"

#include "../csharp_script.h"
#include "../mono_gc_handle.h"
#include "../utils/macros.h"
#include "gd_mono_class.h"
#include "gd_mono_marshal.h"
#include "gd_mono_utils.h"

#include "core/debugger/engine_debugger.h"
#include "core/debugger/script_debugger.h"

#include <mono/metadata/exception.h>

namespace GDMonoInternals {
void tie_managed_to_unmanaged(MonoObject *managed, Object *unmanaged) {
	// This method should not fail

	CRASH_COND(!unmanaged);

	// All mono objects created from the managed world (e.g.: 'new Player()')
	// need to have a CSharpScript in order for their methods to be callable from the unmanaged side

	RefCounted *rc = Object::cast_to<RefCounted>(unmanaged);

	GDMonoClass *klass = GDMonoUtils::get_object_class(managed);

	CRASH_COND(!klass);

	GDMonoClass *native = GDMonoUtils::get_class_native_base(klass);

	CRASH_COND(native == nullptr);

	if (native == klass) {
		// If it's just a wrapper Godot class and not a custom inheriting class, then attach a
		// script binding instead. One of the advantages of this is that if a script is attached
		// later and it's not a C# script, then the managed object won't have to be disposed.
		// Another reason for doing this is that this instance could outlive CSharpLanguage, which would
		// be problematic when using a script. See: https://github.com/godotengine/godot/issues/25621

		CSharpScriptBinding script_binding;

		script_binding.inited = true;
		script_binding.type_name = NATIVE_GDMONOCLASS_NAME(klass);
		script_binding.wrapper_class = klass;
		script_binding.gchandle = rc ? MonoGCHandleData::new_weak_handle(managed) : MonoGCHandleData::new_strong_handle(managed);
		script_binding.owner = unmanaged;

		if (rc) {
			// Unsafe refcount increment. The managed instance also counts as a reference.
			// This way if the unmanaged world has no references to our owner
			// but the managed instance is alive, the refcount will be 1 instead of 0.
			// See: godot_icall_RefCounted_Dtor(MonoObject *p_obj, Object *p_ptr)

			// May not me referenced yet, so we must use init_ref() instead of reference()
			if (rc->init_ref()) {
				CSharpLanguage::get_singleton()->post_unsafe_reference(rc);
			}
		}

		// The object was just created, no script instance binding should have been attached
		CRASH_COND(CSharpLanguage::has_instance_binding(unmanaged));

		void *data;
		{
			MutexLock lock(CSharpLanguage::get_singleton()->get_language_bind_mutex());
			data = (void *)CSharpLanguage::get_singleton()->insert_script_binding(unmanaged, script_binding);
		}

		// Should be thread safe because the object was just created and nothing else should be referencing it
		CSharpLanguage::set_instance_binding(unmanaged, data);

		return;
	}

	MonoGCHandleData gchandle = rc ? MonoGCHandleData::new_weak_handle(managed) : MonoGCHandleData::new_strong_handle(managed);

	Ref<CSharpScript> script = CSharpScript::create_for_managed_type(klass, native);

	CRASH_COND(script.is_null());

	CSharpInstance *csharp_instance = CSharpInstance::create_for_managed_type(unmanaged, script.ptr(), gchandle);

	unmanaged->set_script_and_instance(script, csharp_instance);
}

void unhandled_exception(MonoException *p_exc) {
	mono_print_unhandled_exception((MonoObject *)p_exc);
	gd_unhandled_exception_event(p_exc);

	if (GDMono::get_singleton()->get_unhandled_exception_policy() == GDMono::POLICY_TERMINATE_APP) {
		// Too bad 'mono_invoke_unhandled_exception_hook' is not exposed to embedders
		mono_unhandled_exception((MonoObject *)p_exc);
		GDMono::unhandled_exception_hook((MonoObject *)p_exc, nullptr);
		GD_UNREACHABLE();
	} else {
#ifdef DEBUG_ENABLED
		GDMonoUtils::debug_send_unhandled_exception_error(p_exc);
		if (EngineDebugger::is_active()) {
			EngineDebugger::get_singleton()->poll_events(false);
		}
#endif
	}
}

void gd_unhandled_exception_event(MonoException *p_exc) {
	MonoImage *mono_image = GDMono::get_singleton()->get_core_api_assembly()->get_image();

	MonoClass *gd_klass = mono_class_from_name(mono_image, "Godot", "GD");
	MonoMethod *unhandled_exception_method = mono_class_get_method_from_name(gd_klass, "OnUnhandledException", -1);
	void *args[1];
	args[0] = p_exc;
	mono_runtime_invoke(unhandled_exception_method, nullptr, (void **)args, nullptr);
}
} // namespace GDMonoInternals