// vi:ft=cpp
/*
 * (c) 2010 Adam Lackorzynski <adam@os.inf.tu-dresden.de>,
 *          Alexander Warg <warg@os.inf.tu-dresden.de>
 *     economic rights: Technische Universität Dresden (Germany)
 *
 * This file is part of TUD:OS and distributed under the terms of the
 * GNU General Public License 2.
 * Please see the COPYING-GPL-2 file for details.
 */
#pragma once

#include <l4/mag/server/user_state>
#include <l4/mag/server/plugin>

#include <l4/re/event_enums.h>

namespace Mag_server {

template<int Max_axis>
class Motion_merger
{
private:
  unsigned long _changed;
  int _v[Max_axis];

  enum Type
  {
    T_none = 0,
    T_abs  = 1,
    T_rel  = 2,
  };

  Type axis_inf(unsigned char axis) const
  { return Type((_changed >> (2*axis)) & 3); }

  void set_axis_inf(unsigned char axis, Type t)
  { _changed |= ((unsigned long)t) << (axis*2); }

public:
  Motion_merger() : _changed(0) {}

  void reset() { _changed = 0; }



  bool handle(User_state::Event const &e)
  {
    if (!(e.payload.type == L4RE_EV_REL || e.payload.type == L4RE_EV_ABS))
      return false;

    if (e.payload.code >= Max_axis)
      return false;

    unsigned char ax = e.payload.code;

    if (axis_inf(ax) == T_none && e.payload.type == L4RE_EV_REL)
      {
        _v[ax] = 0;
	set_axis_inf(ax, T_rel);
      }

    switch (e.payload.type)
      {
      case L4RE_EV_REL:
	_v[ax] += e.payload.value;
	break;
      case L4RE_EV_ABS:
	_v[ax] = e.payload.value;
	set_axis_inf(ax, T_abs);
	break;
      }

    return true;
  }

  bool set_event(unsigned char axis, User_state::Event *e)
  {
    unsigned i = axis_inf(axis);
    if (!i)
      return false;

    if (i & T_abs)
      e->payload.type = L4RE_EV_ABS;
    else
      e->payload.type = L4RE_EV_REL;

    e->payload.code = axis;
    e->payload.value = _v[axis];

    return true;
  }

  template< typename I, typename T >
  I merge(I const &s, I const &e, T *last_time)
  {
    for (I i = s; i != e; ++i)
      if (handle(*i))
	{
	  *last_time = i->time;
	  i->free();
	}
      else
	return i;

    return e;
  }

  template< typename E, typename I, typename F >
  void process(I const &s, I const &end, F const &f)
  {
    for (I e = s; e != end; ++e)
      {
	E me;
	me.payload.stream_id = e->payload.stream_id;
	e = merge(e, end, &me.time);

	for (unsigned i = 0; i < Max_axis; ++i)
	  if (set_event(i, &me))
	    f(me);

	if (e != end)
	  {
	    reset();
	    f(*e);
	  }
	else
	  break;
	e->free();
      }
  }
};

class Motion_fwd
{
public:
  template< /*typename E,*/ typename I, typename F >
  void process(I const &s, I const &end, F const &f)
  {
    for (I e = s; e != end; ++e)
      {
	f(*e);
	e->free();
      }
  }
};

class Input_driver : public Plugin
{
public:
  explicit Input_driver(char const *name)
  : Plugin(name)
  {}

  char const *type() const { return "input-driver"; }
  virtual ~Input_driver() {}
};

}