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/**
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 * Copyright (c) 2011 Colony Project
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 * 
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 * Permission is hereby granted, free of charge, to any person
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 * obtaining a copy of this software and associated documentation
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 * files (the "Software"), to deal in the Software without
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 * restriction, including without limitation the rights to use,
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 * copy, modify, merge, publish, distribute, sublicense, and/or sell
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 * copies of the Software, and to permit persons to whom the
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 * Software is furnished to do so, subject to the following
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 * conditions:
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 * 
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 * The above copyright notice and this permission notice shall be
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 * included in all copies or substantial portions of the Software.
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 * 
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 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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 * OTHER DEALINGS IN THE SOFTWARE.
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 */
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/**
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 * @file motors.cpp
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 * @brief Contains code to control the motors.
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 *
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 * Implementation of functions for motor use.
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 *
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 * @author Colony Project, CMU Robotics Club
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 * @author Ben Wasserman
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 */
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#include <ros/ros.h>
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#include <cstdlib>
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#include <fstream>
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#include "motors.h"
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using namespace std;
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/**
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 * @defgroup motors Motors
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 * @brief Functions for using the motors
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 *
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 * @{
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 */
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/* Motor state variables
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 * Speeds expressed as absolute speed out of max speed (0 - +-MAXSPEED)
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 * Absolute speed is the speed written to the hardware to move the motors
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 */
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static int motor_fl_speed; /**< The current speed of the front left motor. */
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static int motor_fr_speed; /**< The current speed of the front right motor. */
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static int motor_bl_speed; /**< The current speed of the back left motor. */
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static int motor_br_speed; /**< The current speed of the back right motor. */
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static fstream motor_fl_file; /**< The device file for the front left motor. */
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static fstream motor_fr_file; /**< The device file for the front right motor. */
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static fstream motor_bl_file; /**< The device file for the back left motor. */
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static fstream motor_br_file; /**< The device file for the back right motor. */
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/**
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 * @brief Sets motor speed
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 *
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 * Sets the motor speeds based on subscription to the set_motors topic.
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 *
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 * @param msg The message from the set_motors topic, containing speeds and
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 *  motor configuration settings.
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 */
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void motors_set(const motors::set_motors::ConstPtr& msg)
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{
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    if(msg->fl_set)
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    {
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      motor_fl_speed = msg->fl_speed;
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      motor_fl_file << motor_fl_speed;
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    }
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    if(msg->fr_set)
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    {
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      motor_fr_speed = msg->fr_speed;
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      motor_fr_file << motor_fr_speed;
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    }
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    if(msg->bl_set)
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    {
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      motor_bl_speed = msg->bl_speed;
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      motor_bl_file << motor_bl_speed;
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    }
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    if(msg->br_set)
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    {
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      motor_br_speed = msg->br_speed;
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      motor_br_file << motor_br_speed;
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    }
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    ROS_DEBUG("Motor speeds set");
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}
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/**
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 * @brief Outputs current motor speeds
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 *
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 * Serves the service query_motors by responding to service requests with the
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 * speeds of the motors.
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 * @param req The request. The only field is the units requested.
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 * @param res The response. The fields will be filled with values.
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 */
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bool motors_query(motors::query_motors::Request &req,
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                  motors::query_motors::Response &res)
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{
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    /** @todo Are we checking hardware or just using the saved values?
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     *  Saved values sound fine to me (Alex). Pleas confirm.
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     *  I think saved values are ok; they're read in from hardware at the
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     *  beginning (Tom). */
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    res.fl_speed = motor_fl_speed;
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    res.fr_speed = motor_fr_speed;
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    res.bl_speed = motor_bl_speed;
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    res.br_speed = motor_br_speed;
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    ROS_DEBUG("Motor speeds queried");
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    return true;
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}
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/**
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 * @brief Motors driver. This is a ROS node that controls motor speeds.
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 *
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 * This is the main function for the motors node. It is run when the node
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 * starts and initializes the motors. It then subscribes to the
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 * set_motors, and set_motor_speeds topics, and advertises the
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 * query_motors service.
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 * 
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 * @param argc The number of command line arguments (should be 1)
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 * @param argv The array of command line arguments
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 */
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int main(int argc, char **argv)
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{
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    /* Initialize in ROS the motors driver node */
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    ros::init(argc, argv, "motors_driver");
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    /* Advertise that this serves the query_motors service */
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    ros::NodeHandle node;
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    ros::ServiceServer service = node.advertiseService("query_motors",
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                                                       motors_query);
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    /* Subscribe to the set_motors topic */
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    ros::Subscriber sub0 = node.subscribe("set_motors", QUEUE_SIZE, motors_set);
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    /* Open device files for PWM values */
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    /** @todo These are probably not the correct order */
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    motor_fl_file.open("/dev/pwm8");
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    motor_fr_file.open("/dev/pwm9");
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    motor_bl_file.open("/dev/pwm10");
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    motor_br_file.open("/dev/pwm11");
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    /* Get initial values, for motor queries */
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    motor_fl_file >> motor_fl_speed;
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    motor_fr_file >> motor_fr_speed;
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    motor_bl_file >> motor_bl_speed;
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    motor_br_file >> motor_br_speed;
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    ROS_INFO("Motors node ready.");
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    ros::spin();
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    return 0;
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}
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/** @} */