/*************************************************************************/
/*  javascript_singleton.cpp                                             */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
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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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/* a copy of this software and associated documentation files (the       */
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/* without limitation the rights to use, copy, modify, merge, publish,   */
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#ifdef JAVASCRIPT_EVAL_ENABLED

#include "api/javascript_singleton.h"
#include "emscripten.h"

extern "C" {
typedef union {
	int64_t i;
	double r;
	void *p;
} godot_js_wrapper_ex;

typedef int (*GodotJSWrapperVariant2JSCallback)(const void **p_args, int p_pos, godot_js_wrapper_ex *r_val, void **p_lock);
typedef void (*GodotJSWrapperFreeLockCallback)(void **p_lock, int p_type);
extern int godot_js_wrapper_interface_get(const char *p_name);
extern int godot_js_wrapper_object_call(int p_id, const char *p_method, void **p_args, int p_argc, GodotJSWrapperVariant2JSCallback p_variant2js_callback, godot_js_wrapper_ex *p_cb_rval, void **p_lock, GodotJSWrapperFreeLockCallback p_lock_callback);
extern int godot_js_wrapper_object_get(int p_id, godot_js_wrapper_ex *p_val, const char *p_prop);
extern int godot_js_wrapper_object_getvar(int p_id, int p_type, godot_js_wrapper_ex *p_val);
extern int godot_js_wrapper_object_setvar(int p_id, int p_key_type, godot_js_wrapper_ex *p_key_ex, int p_val_type, godot_js_wrapper_ex *p_val_ex);
extern void godot_js_wrapper_object_set(int p_id, const char *p_name, int p_type, godot_js_wrapper_ex *p_val);
extern void godot_js_wrapper_object_unref(int p_id);
extern int godot_js_wrapper_create_cb(void *p_ref, void (*p_callback)(void *p_ref, int p_arg_id, int p_argc));
extern int godot_js_wrapper_create_object(const char *p_method, void **p_args, int p_argc, GodotJSWrapperVariant2JSCallback p_variant2js_callback, godot_js_wrapper_ex *p_cb_rval, void **p_lock, GodotJSWrapperFreeLockCallback p_lock_callback);
};

class JavaScriptObjectImpl : public JavaScriptObject {
private:
	friend class JavaScript;

	int _js_id = 0;
	Callable _callable;

	static int _variant2js(const void **p_args, int p_pos, godot_js_wrapper_ex *r_val, void **p_lock);
	static void _free_lock(void **p_lock, int p_type);
	static Variant _js2variant(int p_type, godot_js_wrapper_ex *p_val);
	static void *_alloc_variants(int p_size);
	static void _callback(void *p_ref, int p_arg_id, int p_argc);

protected:
	bool _set(const StringName &p_name, const Variant &p_value) override;
	bool _get(const StringName &p_name, Variant &r_ret) const override;
	void _get_property_list(List<PropertyInfo> *p_list) const override;

public:
	Variant getvar(const Variant &p_key, bool *r_valid = nullptr) const override;
	void setvar(const Variant &p_key, const Variant &p_value, bool *r_valid = nullptr) override;
	Variant call(const StringName &p_method, const Variant **p_args, int p_argc, Callable::CallError &r_error) override;
	JavaScriptObjectImpl() {}
	JavaScriptObjectImpl(int p_id) { _js_id = p_id; }
	~JavaScriptObjectImpl() {
		if (_js_id) {
			godot_js_wrapper_object_unref(_js_id);
		}
	}
};

bool JavaScriptObjectImpl::_set(const StringName &p_name, const Variant &p_value) {
	ERR_FAIL_COND_V_MSG(!_js_id, false, "Invalid JS instance");
	const String name = p_name;
	godot_js_wrapper_ex exchange;
	void *lock = nullptr;
	const Variant *v = &p_value;
	int type = _variant2js((const void **)&v, 0, &exchange, &lock);
	godot_js_wrapper_object_set(_js_id, name.utf8().get_data(), type, &exchange);
	if (lock) {
		_free_lock(&lock, type);
	}
	return true;
}

bool JavaScriptObjectImpl::_get(const StringName &p_name, Variant &r_ret) const {
	ERR_FAIL_COND_V_MSG(!_js_id, false, "Invalid JS instance");
	const String name = p_name;
	godot_js_wrapper_ex exchange;
	int type = godot_js_wrapper_object_get(_js_id, &exchange, name.utf8().get_data());
	r_ret = _js2variant(type, &exchange);
	return true;
}

Variant JavaScriptObjectImpl::getvar(const Variant &p_key, bool *r_valid) const {
	if (r_valid) {
		*r_valid = false;
	}
	godot_js_wrapper_ex exchange;
	void *lock = nullptr;
	const Variant *v = &p_key;
	int prop_type = _variant2js((const void **)&v, 0, &exchange, &lock);
	int type = godot_js_wrapper_object_getvar(_js_id, prop_type, &exchange);
	if (lock) {
		_free_lock(&lock, prop_type);
	}
	if (type < 0) {
		return Variant();
	}
	if (r_valid) {
		*r_valid = true;
	}
	return _js2variant(type, &exchange);
}

void JavaScriptObjectImpl::setvar(const Variant &p_key, const Variant &p_value, bool *r_valid) {
	if (r_valid) {
		*r_valid = false;
	}
	godot_js_wrapper_ex kex, vex;
	void *klock = nullptr;
	void *vlock = nullptr;
	const Variant *kv = &p_key;
	const Variant *vv = &p_value;
	int ktype = _variant2js((const void **)&kv, 0, &kex, &klock);
	int vtype = _variant2js((const void **)&vv, 0, &vex, &vlock);
	int ret = godot_js_wrapper_object_setvar(_js_id, ktype, &kex, vtype, &vex);
	if (klock) {
		_free_lock(&klock, ktype);
	}
	if (vlock) {
		_free_lock(&vlock, vtype);
	}
	if (ret == 0 && r_valid) {
		*r_valid = true;
	}
}

void JavaScriptObjectImpl::_get_property_list(List<PropertyInfo> *p_list) const {
}

void JavaScriptObjectImpl::_free_lock(void **p_lock, int p_type) {
	ERR_FAIL_COND_MSG(*p_lock == nullptr, "No lock to free!");
	const Variant::Type type = (Variant::Type)p_type;
	switch (type) {
		case Variant::STRING: {
			CharString *cs = (CharString *)(*p_lock);
			memdelete(cs);
			*p_lock = nullptr;
		} break;
		default:
			ERR_FAIL_MSG("Unknown lock type to free. Likely a bug.");
	}
}

Variant JavaScriptObjectImpl::_js2variant(int p_type, godot_js_wrapper_ex *p_val) {
	Variant::Type type = (Variant::Type)p_type;
	switch (type) {
		case Variant::BOOL:
			return Variant((bool)p_val->i);
		case Variant::INT:
			return p_val->i;
		case Variant::FLOAT:
			return p_val->r;
		case Variant::STRING: {
			String out((const char *)p_val->p);
			free(p_val->p);
			return out;
		}
		case Variant::OBJECT: {
			return memnew(JavaScriptObjectImpl(p_val->i));
		}
		default:
			return Variant();
	}
}

int JavaScriptObjectImpl::_variant2js(const void **p_args, int p_pos, godot_js_wrapper_ex *r_val, void **p_lock) {
	const Variant **args = (const Variant **)p_args;
	const Variant *v = args[p_pos];
	Variant::Type type = v->get_type();
	switch (type) {
		case Variant::BOOL:
			r_val->i = v->operator bool() ? 1 : 0;
			break;
		case Variant::INT: {
			const int64_t tmp = v->operator int64_t();
			if (tmp >= 1 << 31) {
				r_val->r = (double)tmp;
				return Variant::FLOAT;
			}
			r_val->i = v->operator int64_t();
		} break;
		case Variant::FLOAT:
			r_val->r = v->operator real_t();
			break;
		case Variant::STRING: {
			CharString *cs = memnew(CharString(v->operator String().utf8()));
			r_val->p = (void *)cs->get_data();
			*p_lock = (void *)cs;
		} break;
		case Variant::OBJECT: {
			JavaScriptObject *js_obj = Object::cast_to<JavaScriptObject>(v->operator Object *());
			r_val->i = js_obj != nullptr ? ((JavaScriptObjectImpl *)js_obj)->_js_id : 0;
		} break;
		default:
			break;
	}
	return type;
}

Variant JavaScriptObjectImpl::call(const StringName &p_method, const Variant **p_args, int p_argc, Callable::CallError &r_error) {
	godot_js_wrapper_ex exchange;
	const String method = p_method;
	void *lock = nullptr;
	const int type = godot_js_wrapper_object_call(_js_id, method.utf8().get_data(), (void **)p_args, p_argc, &_variant2js, &exchange, &lock, &_free_lock);
	r_error.error = Callable::CallError::CALL_OK;
	if (type < 0) {
		r_error.error = Callable::CallError::CALL_ERROR_INSTANCE_IS_NULL;
		return Variant();
	}
	return _js2variant(type, &exchange);
}

void JavaScriptObjectImpl::_callback(void *p_ref, int p_args_id, int p_argc) {
	const JavaScriptObjectImpl *obj = (JavaScriptObjectImpl *)p_ref;
	ERR_FAIL_COND_MSG(obj->_callable.is_null(), "JavaScript callback failed.");
	Vector<const Variant *> argp;
	Array arg_arr;
	for (int i = 0; i < p_argc; i++) {
		godot_js_wrapper_ex exchange;
		exchange.i = i;
		int type = godot_js_wrapper_object_getvar(p_args_id, Variant::INT, &exchange);
		arg_arr.push_back(_js2variant(type, &exchange));
	}
	Variant arg = arg_arr;
	const Variant *argv[1] = { &arg };
	Callable::CallError err;
	Variant ret;
	obj->_callable.call(argv, 1, ret, err);
}

Ref<JavaScriptObject> JavaScript::create_callback(const Callable &p_callable) {
	Ref<JavaScriptObjectImpl> out = memnew(JavaScriptObjectImpl);
	out->_callable = p_callable;
	out->_js_id = godot_js_wrapper_create_cb(out.ptr(), JavaScriptObjectImpl::_callback);
	return out;
}

Ref<JavaScriptObject> JavaScript::get_interface(const String &p_interface) {
	int js_id = godot_js_wrapper_interface_get(p_interface.utf8().get_data());
	ERR_FAIL_COND_V_MSG(!js_id, Ref<JavaScriptObject>(), "No interface '" + p_interface + "' registered.");
	return Ref<JavaScriptObject>(memnew(JavaScriptObjectImpl(js_id)));
}

Variant JavaScript::_create_object_bind(const Variant **p_args, int p_argcount, Callable::CallError &r_error) {
	if (p_argcount < 1) {
		r_error.error = Callable::CallError::CALL_ERROR_TOO_FEW_ARGUMENTS;
		r_error.argument = 0;
		return Ref<JavaScriptObject>();
	}
	if (p_args[0]->get_type() != Variant::STRING) {
		r_error.error = Callable::CallError::CALL_ERROR_INVALID_ARGUMENT;
		r_error.argument = 0;
		r_error.expected = Variant::STRING;
		return Ref<JavaScriptObject>();
	}
	godot_js_wrapper_ex exchange;
	const String object = *p_args[0];
	void *lock = nullptr;
	const Variant **args = p_argcount > 1 ? &p_args[1] : nullptr;
	const int type = godot_js_wrapper_create_object(object.utf8().get_data(), (void **)args, p_argcount - 1, &JavaScriptObjectImpl::_variant2js, &exchange, &lock, &JavaScriptObjectImpl::_free_lock);
	r_error.error = Callable::CallError::CALL_OK;
	if (type < 0) {
		r_error.error = Callable::CallError::CALL_ERROR_INSTANCE_IS_NULL;
		return Ref<JavaScriptObject>();
	}
	return JavaScriptObjectImpl::_js2variant(type, &exchange);
}

extern "C" {
union js_eval_ret {
	uint32_t b;
	double d;
	char *s;
};

extern int godot_js_eval(const char *p_js, int p_use_global_ctx, union js_eval_ret *p_union_ptr, void *p_byte_arr, void *p_byte_arr_write, void *(*p_callback)(void *p_ptr, void *p_ptr2, int p_len));
}

void *resize_PackedByteArray_and_open_write(void *p_arr, void *r_write, int p_len) {
	PackedByteArray *arr = (PackedByteArray *)p_arr;
	VectorWriteProxy<uint8_t> *write = (VectorWriteProxy<uint8_t> *)r_write;
	arr->resize(p_len);
	*write = arr->write;
	return arr->ptrw();
}

Variant JavaScript::eval(const String &p_code, bool p_use_global_exec_context) {
	union js_eval_ret js_data;
	PackedByteArray arr;
	VectorWriteProxy<uint8_t> arr_write;

	Variant::Type return_type = static_cast<Variant::Type>(godot_js_eval(p_code.utf8().get_data(), p_use_global_exec_context, &js_data, &arr, &arr_write, resize_PackedByteArray_and_open_write));

	switch (return_type) {
		case Variant::BOOL:
			return js_data.b;
		case Variant::FLOAT:
			return js_data.d;
		case Variant::STRING: {
			String str = String::utf8(js_data.s);
			free(js_data.s); // Must free the string allocated in JS.
			return str;
		}
		case Variant::PACKED_BYTE_ARRAY:
			arr_write = VectorWriteProxy<uint8_t>();
			return arr;
		default:
			return Variant();
	}
}
#endif // JAVASCRIPT_EVAL_ENABLED