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/* Author: Wim Meeussen */

#include "robot_state_publisher/robot_state_publisher.h"
#include <kdl/frames_io.hpp>
#include <tf_conversions/tf_kdl.h>

using namespace std;
using namespace ros;
using namespace KDL;



namespace robot_state_publisher{

RobotStatePublisher::RobotStatePublisher(const Tree& tree)
   :tree_(tree)
{
  // get tf prefix
  NodeHandle n_local("~");
  n_local.param("tf_prefix", tf_prefix_, string());

  // build tree solver
  solver_.reset(new TreeFkSolverPosFull_recursive(tree_));

  // advertise tf message
  NodeHandle n;
  tf_publisher_ = n.advertise<tf::tfMessage>("/tf", 5);

  // get the 'real' root segment of the tree, which is the first child of "root"
  SegmentMap::const_iterator root = tree.getRootSegment();
  if (root->second.children.empty())
    throw empty_tree_ex;

  root_ = (*root->second.children.begin())->first;
}



bool RobotStatePublisher::publishTransforms(const map<string, double>& joint_positions, const Time& time)
{
  // calculate transforms form root to every segment in tree
  map<string, Frame> link_poses;
  solver_->JntToCart(joint_positions, link_poses);
  if (link_poses.size() < 2){
    ROS_ERROR("Could not compute link poses. The tree or the state is invalid.");
    return false;
  }
  tf_msg_.transforms.resize(link_poses.size()-1);

  // publish the transforms to tf, converting the transforms from "root" to the 'real' root 
  geometry_msgs::TransformStamped trans; 
  map<string, Frame>::const_iterator root = link_poses.find(root_);
  if (root == link_poses.end()){
    ROS_ERROR("Did not find root of tree");
    return false;
  }

  // remove root from published poses
  Frame offset = root->second.Inverse();
  unsigned int i = 0;
  // send transforms to tf
  for (map<string, Frame>::const_iterator f=link_poses.begin(); f!=link_poses.end(); f++){
    if (f != root){
      Frame frame = offset * f->second;
      tf::Transform tf_frame;
      tf::TransformKDLToTF(frame, tf_frame);
      trans.header.stamp = time;
      trans.header.frame_id = tf::remap(tf_prefix_, root->first);
      trans.child_frame_id = tf::remap(tf_prefix_, f->first);
      tf::transformTFToMsg(tf_frame, trans.transform);
	tf_msg_.transforms[i++] = trans;
    }
  }
  tf_publisher_.publish(tf_msg_);

  return true;
}
}