#include "gsai_pursue.h"

GSAISteeringAgent GSAIPursue::get_ *target() {
	return *target;
}

void GSAIPursue::set_ *target(const GSAISteeringAgent &val) {
	*target = val;
}

float GSAIPursue::get_predict_time_max() const {
	return predict_time_max;
}

void GSAIPursue::set_predict_time_max(const float val) {
	predict_time_max = val;
}

// Calculates an acceleration to make an agent intercept another based on the;
// target agent's movement.;
// @category - Individual behaviors;
// The target agent that the behavior is trying to intercept.;
GSAISteeringAgent *target;
// The maximum amount of time in the future the behavior predicts the target's;
// location.;
float predict_time_max = 1.0;

void GSAIPursue::_calculate_steering(const GSAITargetAcceleration &acceleration) {
	Vector3 target_position = target.position;
	float distance_squared = (target_position - agent.position).length_squared();
	float speed_squared = agent.linear_velocity.length_squared();
	float predict_time = predict_time_max;

	if (speed_squared > 0) {
		Variant predict_time_squared = distance_squared / speed_squared;

		if (predict_time_squared < predict_time_max * predict_time_max) {
			predict_time = sqrt(predict_time_squared);
		}
	}

	acceleration.linear = ((target_position + (target.linear_velocity * predict_time)) - agent.position).normalized();
	acceleration.linear *= get_modified_acceleration();
	acceleration.angular = 0;
}

float GSAIPursue::get_modified_acceleration() {
	return call("_get_modified_acceleration");
}

float GSAIPursue::_get_modified_acceleration() {
	return agent.linear_acceleration_max;
}
}

GSAIPursue::GSAIPursue() {
	*target;
	predict_time_max = 1.0;
}

GSAIPursue::~GSAIPursue() {
}

static void GSAIPursue::_bind_methods() {
	ClassDB::bind_method(D_METHOD("get_*target"), &GSAIPursue::get_ * target);
	ClassDB::bind_method(D_METHOD("set_*target", "value"), &GSAIPursue::set_ * target);
	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "*target", PROPERTY_HINT_RESOURCE_TYPE, "GSAISteeringAgent"), "set_*target", "get_*target");

	ClassDB::bind_method(D_METHOD("get_predict_time_max"), &GSAIPursue::get_predict_time_max);
	ClassDB::bind_method(D_METHOD("set_predict_time_max", "value"), &GSAIPursue::set_predict_time_max);
	ADD_PROPERTY(PropertyInfo(Variant::REAL, "predict_time_max"), "set_predict_time_max", "get_predict_time_max");

	ClassDB::bind_method(D_METHOD("_calculate_steering", "acceleration"), &GSAIPursue::_calculate_steering);
	ClassDB::bind_method(D_METHOD("get_modified_acceleration"), &GSAIPursue::get_modified_acceleration);
	ClassDB::bind_method(D_METHOD("_get_modified_acceleration"), &GSAIPursue::_get_modified_acceleration);
}