/*************************************************************************/
/*  callable.cpp                                                         */
/*************************************************************************/
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/*                           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 "callable.h"

#include "callable_bind.h"
#include "core/object/message_queue.h"
#include "core/object/object.h"
#include "core/object/reference.h"
#include "core/object/script_language.h"

void Callable::call_deferred(const Variant **p_arguments, int p_argcount) const {
	MessageQueue::get_singleton()->push_callable(*this, p_arguments, p_argcount);
}

void Callable::call(const Variant **p_arguments, int p_argcount, Variant &r_return_value, CallError &r_call_error) const {
	if (is_null()) {
		r_call_error.error = CallError::CALL_ERROR_INSTANCE_IS_NULL;
		r_call_error.argument = 0;
		r_call_error.expected = 0;
		r_return_value = Variant();
	} else if (is_custom()) {
		custom->call(p_arguments, p_argcount, r_return_value, r_call_error);
	} else {
		Object *obj = ObjectDB::get_instance(ObjectID(object));
		r_return_value = obj->call(method, p_arguments, p_argcount, r_call_error);
	}
}

Callable Callable::bind(const Variant **p_arguments, int p_argcount) const {
	Vector<Variant> args;
	args.resize(p_argcount);
	for (int i = 0; i < p_argcount; i++) {
		args.write[i] = *p_arguments[i];
	}
	return Callable(memnew(CallableCustomBind(*this, args)));
}
Callable Callable::unbind(int p_argcount) const {
	return Callable(memnew(CallableCustomUnbind(*this, p_argcount)));
}

Object *Callable::get_object() const {
	if (is_null()) {
		return nullptr;
	} else if (is_custom()) {
		return ObjectDB::get_instance(custom->get_object());
	} else {
		return ObjectDB::get_instance(ObjectID(object));
	}
}

ObjectID Callable::get_object_id() const {
	if (is_null()) {
		return ObjectID();
	} else if (is_custom()) {
		return custom->get_object();
	} else {
		return ObjectID(object);
	}
}

StringName Callable::get_method() const {
	ERR_FAIL_COND_V_MSG(is_custom(), StringName(),
			vformat("Can't get method on CallableCustom \"%s\".", operator String()));
	return method;
}

CallableCustom *Callable::get_custom() const {
	ERR_FAIL_COND_V_MSG(!is_custom(), nullptr,
			vformat("Can't get custom on non-CallableCustom \"%s\".", operator String()));
	return custom;
}

const Callable *Callable::get_base_comparator() const {
	const Callable *comparator = nullptr;
	if (is_custom()) {
		comparator = custom->get_base_comparator();
	}
	if (comparator) {
		return comparator;
	} else {
		return this;
	}
}

uint32_t Callable::hash() const {
	if (is_custom()) {
		return custom->hash();
	} else {
		uint32_t hash = method.hash();
		return hash_djb2_one_64(object, hash);
	}
}

bool Callable::operator==(const Callable &p_callable) const {
	bool custom_a = is_custom();
	bool custom_b = p_callable.is_custom();

	if (custom_a == custom_b) {
		if (custom_a) {
			if (custom == p_callable.custom) {
				return true; //same pointer, don't even compare
			}

			CallableCustom::CompareEqualFunc eq_a = custom->get_compare_equal_func();
			CallableCustom::CompareEqualFunc eq_b = p_callable.custom->get_compare_equal_func();
			if (eq_a == eq_b) {
				return eq_a(custom, p_callable.custom);
			} else {
				return false;
			}
		} else {
			return object == p_callable.object && method == p_callable.method;
		}
	} else {
		return false;
	}
}

bool Callable::operator!=(const Callable &p_callable) const {
	return !(*this == p_callable);
}

bool Callable::operator<(const Callable &p_callable) const {
	bool custom_a = is_custom();
	bool custom_b = p_callable.is_custom();

	if (custom_a == custom_b) {
		if (custom_a) {
			if (custom == p_callable.custom) {
				return false; //same pointer, don't even compare
			}

			CallableCustom::CompareLessFunc less_a = custom->get_compare_less_func();
			CallableCustom::CompareLessFunc less_b = p_callable.custom->get_compare_less_func();
			if (less_a == less_b) {
				return less_a(custom, p_callable.custom);
			} else {
				return less_a < less_b; //it's something..
			}

		} else {
			if (object == p_callable.object) {
				return method < p_callable.method;
			} else {
				return object < p_callable.object;
			}
		}
	} else {
		return int(custom_a ? 1 : 0) < int(custom_b ? 1 : 0);
	}
}

void Callable::operator=(const Callable &p_callable) {
	if (is_custom()) {
		if (p_callable.is_custom()) {
			if (custom == p_callable.custom) {
				return;
			}
		}

		if (custom->ref_count.unref()) {
			memdelete(custom);
		}
	}

	if (p_callable.is_custom()) {
		method = StringName();
		if (!p_callable.custom->ref_count.ref()) {
			object = 0;
		} else {
			object = 0;
			custom = p_callable.custom;
		}
	} else {
		method = p_callable.method;
		object = p_callable.object;
	}
}

Callable::operator String() const {
	if (is_custom()) {
		return custom->get_as_text();
	} else {
		if (is_null()) {
			return "null::null";
		}

		Object *base = get_object();
		if (base) {
			String class_name = base->get_class();
			Ref<Script> script = base->get_script();
			if (script.is_valid() && script->get_path().is_resource_file()) {
				class_name += "(" + script->get_path().get_file() + ")";
			}
			return class_name + "::" + String(method);
		} else {
			return "null::" + String(method);
		}
	}
}

Callable::Callable(const Object *p_object, const StringName &p_method) {
	if (p_method == StringName()) {
		object = 0;
		ERR_FAIL_MSG("Method argument to Callable constructor must be a non-empty string");
	}
	if (p_object == nullptr) {
		object = 0;
		ERR_FAIL_MSG("Object argument to Callable constructor must be non-null");
	}

	object = p_object->get_instance_id();
	method = p_method;
}

Callable::Callable(ObjectID p_object, const StringName &p_method) {
	if (p_method == StringName()) {
		object = 0;
		ERR_FAIL_MSG("Method argument to Callable constructor must be a non-empty string");
	}

	object = p_object;
	method = p_method;
}

Callable::Callable(CallableCustom *p_custom) {
	if (p_custom->referenced) {
		object = 0;
		ERR_FAIL_MSG("Callable custom is already referenced");
	}
	p_custom->referenced = true;
	object = 0; //ensure object is all zero, since pointer may be 32 bits
	custom = p_custom;
}

Callable::Callable(const Callable &p_callable) {
	if (p_callable.is_custom()) {
		if (!p_callable.custom->ref_count.ref()) {
			object = 0;
		} else {
			object = 0;
			custom = p_callable.custom;
		}
	} else {
		method = p_callable.method;
		object = p_callable.object;
	}
}

Callable::~Callable() {
	if (is_custom()) {
		if (custom->ref_count.unref()) {
			memdelete(custom);
		}
	}
}

const Callable *CallableCustom::get_base_comparator() const {
	return nullptr;
}

CallableCustom::CallableCustom() {
	ref_count.init();
}

//////////////////////////////////

Object *Signal::get_object() const {
	return ObjectDB::get_instance(object);
}

ObjectID Signal::get_object_id() const {
	return object;
}

StringName Signal::get_name() const {
	return name;
}

bool Signal::operator==(const Signal &p_signal) const {
	return object == p_signal.object && name == p_signal.name;
}

bool Signal::operator!=(const Signal &p_signal) const {
	return object != p_signal.object || name != p_signal.name;
}

bool Signal::operator<(const Signal &p_signal) const {
	if (object == p_signal.object) {
		return name < p_signal.name;
	} else {
		return object < p_signal.object;
	}
}

Signal::operator String() const {
	Object *base = get_object();
	if (base) {
		String class_name = base->get_class();
		Ref<Script> script = base->get_script();
		if (script.is_valid() && script->get_path().is_resource_file()) {
			class_name += "(" + script->get_path().get_file() + ")";
		}
		return class_name + "::[signal]" + String(name);
	} else {
		return "null::[signal]" + String(name);
	}
}

Error Signal::emit(const Variant **p_arguments, int p_argcount) const {
	Object *obj = ObjectDB::get_instance(object);
	if (!obj) {
		return ERR_INVALID_DATA;
	}

	return obj->emit_signal(name, p_arguments, p_argcount);
}

Error Signal::connect(const Callable &p_callable, const Vector<Variant> &p_binds, uint32_t p_flags) {
	Object *object = get_object();
	ERR_FAIL_COND_V(!object, ERR_UNCONFIGURED);

	return object->connect(name, p_callable, p_binds, p_flags);
}

void Signal::disconnect(const Callable &p_callable) {
	Object *object = get_object();
	ERR_FAIL_COND(!object);
	object->disconnect(name, p_callable);
}

bool Signal::is_connected(const Callable &p_callable) const {
	Object *object = get_object();
	ERR_FAIL_COND_V(!object, false);

	return object->is_connected(name, p_callable);
}

Array Signal::get_connections() const {
	Object *object = get_object();
	if (!object) {
		return Array();
	}

	List<Object::Connection> connections;
	object->get_signal_connection_list(name, &connections);

	Array arr;
	for (List<Object::Connection>::Element *E = connections.front(); E; E = E->next()) {
		arr.push_back(E->get());
	}
	return arr;
}

Signal::Signal(const Object *p_object, const StringName &p_name) {
	ERR_FAIL_COND_MSG(p_object == nullptr, "Object argument to Signal constructor must be non-null");

	object = p_object->get_instance_id();
	name = p_name;
}

Signal::Signal(ObjectID p_object, const StringName &p_name) {
	object = p_object;
	name = p_name;
}