/*
    Copyright (C) 2012 Carl Hetherington <cth@carlh.net>

    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.

*/

/** @file src/job.cc
 *  @brief A parent class to represent long-running tasks which are run in their own thread.
 */

#include <boost/thread.hpp>
#include <boost/filesystem.hpp>
#include <libdcp/exceptions.h>
#include "job.h"
#include "util.h"
#include "cross.h"
#include "ui_signaller.h"
#include "exceptions.h"

#include "i18n.h"

using std::string;
using std::list;
using std::cout;
using std::stringstream;
using boost::shared_ptr;

Job::Job (shared_ptr<const Film> f)
	: _film (f)
	, _thread (0)
	, _state (NEW)
	, _start_time (0)
	, _progress (0)
	, _ran_for (0)
{

}

/** Start the job in a separate thread, returning immediately */
void
Job::start ()
{
	set_state (RUNNING);
	_start_time = time (0);
	_thread = new boost::thread (boost::bind (&Job::run_wrapper, this));
}

/** A wrapper for the ::run() method to catch exceptions */
void
Job::run_wrapper ()
{
	try {

		run ();

	} catch (libdcp::FileError& e) {
		
		string m = String::compose (_("An error occurred whilst handling the file %1."), boost::filesystem::path (e.filename()).leaf());

		try {
			boost::filesystem::space_info const s = boost::filesystem::space (e.filename());
			if (s.available < pow (1024, 3)) {
				m += N_("\n\n");
				m += _("The drive that the film is stored on is low in disc space.  Free some more space and try again.");
			}
		} catch (...) {

		}

		set_error (e.what(), m);
		set_progress (1);
		set_state (FINISHED_ERROR);
		
	} catch (OpenFileError& e) {

		set_error (
			String::compose (_("Could not open %1"), e.file().string()),
			String::compose (_("DCP-o-matic could not open the file %1.  Perhaps it does not exist or is in an unexpected format."), e.file().string())
			);

		set_progress (1);
		set_state (FINISHED_ERROR);

	} catch (boost::thread_interrupted &) {

		set_state (FINISHED_CANCELLED);

	} catch (std::bad_alloc& e) {

		set_error (_("Out of memory"), _("There was not enough memory to do this."));
		set_progress (1);
		set_state (FINISHED_ERROR);
		
	} catch (std::exception& e) {

		set_error (
			e.what (),
			_("It is not known what caused this error.  The best idea is to report the problem to the DCP-o-matic mailing list (carl@dcpomatic.com)")
			);

		set_progress (1);
		set_state (FINISHED_ERROR);
		
	} catch (...) {

		set_error (
			_("Unknown error"),
			_("It is not known what caused this error.  The best idea is to report the problem to the DCP-o-matic mailing list (carl@dcpomatic.com)")
			);

		set_progress (1);
		set_state (FINISHED_ERROR);
	}
}

/** @return true if this job is new (ie has not started running) */
bool
Job::is_new () const
{
	boost::mutex::scoped_lock lm (_state_mutex);
	return _state == NEW;
}

/** @return true if the job is running */
bool
Job::running () const
{
	boost::mutex::scoped_lock lm (_state_mutex);
	return _state == RUNNING;
}

/** @return true if the job has finished (either successfully or unsuccessfully) */
bool
Job::finished () const
{
	boost::mutex::scoped_lock lm (_state_mutex);
	return _state == FINISHED_OK || _state == FINISHED_ERROR || _state == FINISHED_CANCELLED;
}

/** @return true if the job has finished successfully */
bool
Job::finished_ok () const
{
	boost::mutex::scoped_lock lm (_state_mutex);
	return _state == FINISHED_OK;
}

/** @return true if the job has finished unsuccessfully */
bool
Job::finished_in_error () const
{
	boost::mutex::scoped_lock lm (_state_mutex);
	return _state == FINISHED_ERROR;
}

bool
Job::finished_cancelled () const
{
	boost::mutex::scoped_lock lm (_state_mutex);
	return _state == FINISHED_CANCELLED;
}

bool
Job::paused () const
{
	boost::mutex::scoped_lock lm (_state_mutex);
	return _state == PAUSED;
}
	
/** Set the state of this job.
 *  @param s New state.
 */
void
Job::set_state (State s)
{
	bool finished = false;
	
	{
		boost::mutex::scoped_lock lm (_state_mutex);
		_state = s;

		if (_state == FINISHED_OK || _state == FINISHED_ERROR || _state == FINISHED_CANCELLED) {
			_ran_for = elapsed_time ();
			finished = true;
			_sub_name.clear ();
		}
	}

	if (finished && ui_signaller) {
		ui_signaller->emit (boost::bind (boost::ref (Finished)));
	}
}

/** @return Time (in seconds) that this sub-job has been running */
int
Job::elapsed_time () const
{
	if (_start_time == 0) {
		return 0;
	}
	
	return time (0) - _start_time;
}

/** Set the progress of the current part of the job.
 *  @param p Progress (from 0 to 1)
 */
void
Job::set_progress (float p, bool force)
{
	if (!force && fabs (p - progress()) < 0.01) {
		/* Calm excessive progress reporting */
		return;
	}

	boost::mutex::scoped_lock lm (_progress_mutex);
	_progress = p;
	boost::this_thread::interruption_point ();

	if (paused ()) {
		dcpomatic_sleep (1);
	}

	if (ui_signaller) {
		ui_signaller->emit (boost::bind (boost::ref (Progress)));
	}
}

/** @return fractional progress of the current sub-job, or -1 if not known */
float
Job::progress () const
{
	boost::mutex::scoped_lock lm (_progress_mutex);
	return _progress.get_value_or (-1);
}

void
Job::sub (string n)
{
	{
		boost::mutex::scoped_lock lm (_progress_mutex);
		_sub_name = n;
	}
	
	set_progress (0, true);
}

string
Job::error_details () const
{
	boost::mutex::scoped_lock lm (_state_mutex);
	return _error_details;
}

/** @return A summary of any error that the job has generated */
string
Job::error_summary () const
{
	boost::mutex::scoped_lock lm (_state_mutex);
	return _error_summary;
}

/** Set the current error string.
 *  @param e New error string.
 */
void
Job::set_error (string s, string d)
{
	boost::mutex::scoped_lock lm (_state_mutex);
	_error_summary = s;
	_error_details = d;
}

/** Say that this job's progress will be unknown until further notice */
void
Job::set_progress_unknown ()
{
	boost::mutex::scoped_lock lm (_progress_mutex);
	_progress.reset ();
}

/** @return Human-readable status of this job */
string
Job::status () const
{
	float const p = progress ();
	int const t = elapsed_time ();
	int const r = remaining_time ();

	int pc = rint (p * 100);
	if (pc == 100) {
		/* 100% makes it sound like we've finished when we haven't */
		pc = 99;
	}

	stringstream s;
	if (!finished ()) {
		s << pc << N_("%");
		if (p >= 0 && t > 10 && r > 0) {
			/// TRANSLATORS: remaining here follows an amount of time that is remaining
			/// on an operation.
			s << "; " << seconds_to_approximate_hms (r) << " " << _("remaining");
		}
	} else if (finished_ok ()) {
		s << String::compose (_("OK (ran for %1)"), seconds_to_hms (_ran_for));
	} else if (finished_in_error ()) {
		s << String::compose (_("Error (%1)"), error_summary());
	} else if (finished_cancelled ()) {
		s << _("Cancelled");
	}

	return s.str ();
}

string
Job::json_status () const
{
	boost::mutex::scoped_lock lm (_state_mutex);

	switch (_state) {
	case NEW:
		return N_("new");
	case RUNNING:
		return N_("running");
	case PAUSED:
		return N_("paused");
	case FINISHED_OK:
		return N_("finished_ok");
	case FINISHED_ERROR:
		return N_("finished_error");
	case FINISHED_CANCELLED:
		return N_("finished_cancelled");
	}

	return "";
}

/** @return An estimate of the remaining time for this sub-job, in seconds */
int
Job::remaining_time () const
{
	return elapsed_time() / progress() - elapsed_time();
}

void
Job::cancel ()
{
	if (!_thread) {
		return;
	}

	_thread->interrupt ();
	_thread->join ();
}

void
Job::pause ()
{
	if (running ()) {
		set_state (PAUSED);
	}
}

void
Job::resume ()
{
	if (paused ()) {
		set_state (RUNNING);
	}
}