/* 
    Copyright (C) 2001 Brett Viren & Paul Davis

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

    $Id$
*/

#include <iostream>
#include <string>
#include <sstream>

#include <pbd/undo.h>
#include <pbd/xml++.h>

#include <sigc++/bind.h>

using namespace std;
using namespace sigc;

/* grrr, strict C++ says that static member functions are not C functions, but we also want
   to be able to pack this into a sigc::ptr_fun and not sigc::mem_fun, so we have to make
   it a genuine function rather than a member.
*/

static void command_death (UndoTransaction* ut, Command* c)
{
	if (ut->clearing()) {
		return;
	}

	ut->remove_command (c);

	if (ut->empty()) {
		delete ut;
	}
}


UndoTransaction::UndoTransaction ()
{
	_clearing = false;
}

UndoTransaction::UndoTransaction (const UndoTransaction& rhs)
{
	_name = rhs._name;
	_clearing = false;
	clear ();
	actions.insert(actions.end(),rhs.actions.begin(),rhs.actions.end());
}

UndoTransaction::~UndoTransaction ()
{
	GoingAway ();
	clear ();
}

UndoTransaction& 
UndoTransaction::operator= (const UndoTransaction& rhs)
{
	if (this == &rhs) return *this;
	_name = rhs._name;
	clear ();
	actions.insert(actions.end(),rhs.actions.begin(),rhs.actions.end());
	return *this;
}

void
UndoTransaction::add_command (Command *const action)
{
	action->GoingAway.connect (bind (sigc::ptr_fun (command_death), this, const_cast<Command*>(action)));
	actions.push_back (action);
}

void
UndoTransaction::remove_command (Command* const action)
{
	actions.remove (action);
}

bool
UndoTransaction::empty () const
{
	return actions.empty();
}

void
UndoTransaction::clear ()
{
	_clearing = true;
	for (list<Command*>::iterator i = actions.begin(); i != actions.end(); ++i) {
		delete *i;
	}
	actions.clear ();
	_clearing = false;
}

void
UndoTransaction::operator() ()
{
	for (list<Command*>::iterator i = actions.begin(); i != actions.end(); ++i) {
		(*(*i))();
	}
}

void
UndoTransaction::undo ()
{
	for (list<Command*>::reverse_iterator i = actions.rbegin(); i != actions.rend(); ++i) {
		(*i)->undo();
	}
}

void
UndoTransaction::redo ()
{
        (*this)();
}

XMLNode &UndoTransaction::get_state()
{
    XMLNode *node = new XMLNode ("UndoTransaction");
    stringstream ss;
    ss << _timestamp.tv_sec;
    node->add_property("tv_sec", ss.str());
    ss.str("");
    ss << _timestamp.tv_usec;
    node->add_property("tv_usec", ss.str());
    node->add_property("name", _name);

    list<Command*>::iterator it;
    for (it=actions.begin(); it!=actions.end(); it++)
        node->add_child_nocopy((*it)->get_state());

    return *node;
}

UndoHistory::UndoHistory ()
{
	_clearing = false;
}

void
UndoHistory::add (UndoTransaction* const ut)
{
	ut->GoingAway.connect (bind (mem_fun (*this, &UndoHistory::remove), ut));
	UndoList.push_back (ut);

	/* we are now owners of the transaction */
}

void
UndoHistory::remove (UndoTransaction* const ut)
{
	if (_clearing) {
		return;
	}

	UndoList.remove (ut);
	RedoList.remove (ut);
}

void
UndoHistory::undo (unsigned int n)
{
	while (n--) {
		if (UndoList.size() == 0) {
			return;
		}
		UndoTransaction* ut = UndoList.back ();
		UndoList.pop_back ();
		ut->undo ();
		RedoList.push_back (ut);
	}
}

void
UndoHistory::redo (unsigned int n)
{
	while (n--) {
		if (RedoList.size() == 0) {
			return;
		}
		UndoTransaction* ut = RedoList.back ();
		RedoList.pop_back ();
		ut->redo ();
		UndoList.push_back (ut);
	}
}

void
UndoHistory::clear_redo ()
{
	_clearing = true;
	RedoList.clear ();
	_clearing = false;
}

void
UndoHistory::clear_undo ()
{
	_clearing = true;
	UndoList.clear ();
	_clearing = false;
}

void
UndoHistory::clear ()
{
	clear_undo ();
	clear_redo ();
}

XMLNode & UndoHistory::get_state()
{
    XMLNode *node = new XMLNode ("UndoHistory");

    list<UndoTransaction*>::iterator it;
    for (it = UndoList.begin(); it != UndoList.end(); it++) {
	    node->add_child_nocopy((*it)->get_state());
    }

    return *node;
}