/*
    Copyright (C) 2000-2003 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.
*/

#include <fstream>
#include <cstdio>
#include <unistd.h>
#include <cmath>
#include <cerrno>
#include <string>
#include <climits>
#include <fcntl.h>
#include <cstdlib>
#include <ctime>
#include <sys/stat.h>
#include <sys/mman.h>

#include "pbd/error.h"
#include "pbd/basename.h"
#include <glibmm/thread.h>
#include "pbd/xml++.h"
#include "pbd/memento_command.h"
#include "pbd/enumwriter.h"
#include "pbd/stateful_diff_command.h"
#include "pbd/stacktrace.h"

#include "ardour/ardour.h"
#include "ardour/audioengine.h"
#include "ardour/butler.h"
#include "ardour/configuration.h"
#include "ardour/cycle_timer.h"
#include "ardour/debug.h"
#include "ardour/io.h"
#include "ardour/midi_diskstream.h"
#include "ardour/midi_playlist.h"
#include "ardour/midi_port.h"
#include "ardour/midi_region.h"
#include "ardour/playlist_factory.h"
#include "ardour/region_factory.h"
#include "ardour/send.h"
#include "ardour/session.h"
#include "ardour/smf_source.h"
#include "ardour/utils.h"
#include "ardour/session_playlists.h"
#include "ardour/route.h"

#include "midi++/types.h"

#include "i18n.h"
#include <locale.h>

using namespace std;
using namespace ARDOUR;
using namespace PBD;

framecnt_t MidiDiskstream::midi_readahead = 4096;

MidiDiskstream::MidiDiskstream (Session &sess, const string &name, Diskstream::Flag flag)
	: Diskstream(sess, name, flag)
	, _playback_buf(0)
	, _capture_buf(0)
	, _source_port(0)
	, _last_flush_frame(0)
	, _note_mode(Sustained)
	, _frames_written_to_ringbuffer(0)
	, _frames_read_from_ringbuffer(0)
{
	/* prevent any write sources from being created */

	in_set_state = true;

	init ();
	use_new_playlist ();
	use_new_write_source (0);

	in_set_state = false;

	assert(!destructive());
}

MidiDiskstream::MidiDiskstream (Session& sess, const XMLNode& node)
	: Diskstream(sess, node)
	, _playback_buf(0)
	, _capture_buf(0)
	, _source_port(0)
	, _last_flush_frame(0)
	, _note_mode(Sustained)
	, _frames_written_to_ringbuffer(0)
	, _frames_read_from_ringbuffer(0)
{
	in_set_state = true;

	init ();

	if (set_state (node, Stateful::loading_state_version)) {
		in_set_state = false;
		throw failed_constructor();
	}

	use_new_write_source (0);

	in_set_state = false;
}

void
MidiDiskstream::init ()
{
	/* there are no channels at this point, so these
	   two calls just get speed_buffer_size and wrap_buffer
	   size setup without duplicating their code.
	*/

	set_block_size (_session.get_block_size());
	allocate_temporary_buffers ();

	const size_t size = _session.butler()->midi_diskstream_buffer_size();
	_playback_buf = new MidiRingBuffer<framepos_t>(size);
	_capture_buf = new MidiRingBuffer<framepos_t>(size);

	_n_channels = ChanCount(DataType::MIDI, 1);

	assert(recordable());
}

MidiDiskstream::~MidiDiskstream ()
{
	Glib::Mutex::Lock lm (state_lock);
}


void
MidiDiskstream::non_realtime_locate (framepos_t position)
{
	if (_write_source) {
		_write_source->set_timeline_position (position);
	}
	seek(position, false);
}


void
MidiDiskstream::non_realtime_input_change ()
{
	{
		Glib::Mutex::Lock lm (state_lock);

		if (input_change_pending.type == IOChange::NoChange) {
			return;
		}

		if (input_change_pending.type & IOChange::ConfigurationChanged) {
			if (_io->n_ports().n_midi() != _n_channels.n_midi()) {
				error << "Can not feed IO " << _io->n_ports()
					<< " with diskstream " << _n_channels << endl;
			}
		}

		get_input_sources ();
		set_capture_offset ();

		if (first_input_change) {
			set_align_style (_persistent_alignment_style);
			first_input_change = false;
		} else {
			set_align_style_from_io ();
		}

		input_change_pending.type = IOChange::NoChange;

		/* implicit unlock */
	}

	/* unlike with audio, there is never any need to reset write sources
	   based on input configuration changes because ... a MIDI track
	   has just 1 MIDI port as input, always.
	*/

	/* now refill channel buffers */

	if (speed() != 1.0f || speed() != -1.0f) {
		seek ((framepos_t) (_session.transport_frame() * (double) speed()));
	}
	else {
		seek (_session.transport_frame());
	}

	_last_flush_frame = _session.transport_frame();
}

void
MidiDiskstream::get_input_sources ()
{
	uint32_t ni = _io->n_ports().n_midi();

	if (ni == 0) {
		return;
	}

	// This is all we do for now at least
	assert(ni == 1);

	_source_port = _io->midi(0);

	// do... stuff?
}

int
MidiDiskstream::find_and_use_playlist (const string& name)
{
	boost::shared_ptr<MidiPlaylist> playlist;

	if ((playlist = boost::dynamic_pointer_cast<MidiPlaylist> (_session.playlists->by_name (name))) == 0) {
		playlist = boost::dynamic_pointer_cast<MidiPlaylist> (PlaylistFactory::create (DataType::MIDI, _session, name));
	}

	if (!playlist) {
		error << string_compose(_("MidiDiskstream: Playlist \"%1\" isn't an midi playlist"), name) << endmsg;
		return -1;
	}

	return use_playlist (playlist);
}

int
MidiDiskstream::use_playlist (boost::shared_ptr<Playlist> playlist)
{
	assert(boost::dynamic_pointer_cast<MidiPlaylist>(playlist));

	Diskstream::use_playlist(playlist);

	return 0;
}

int
MidiDiskstream::use_new_playlist ()
{
	string newname;
	boost::shared_ptr<MidiPlaylist> playlist;

	if (!in_set_state && destructive()) {
		return 0;
	}

	if (_playlist) {
		newname = Playlist::bump_name (_playlist->name(), _session);
	} else {
		newname = Playlist::bump_name (_name, _session);
	}

	if ((playlist = boost::dynamic_pointer_cast<MidiPlaylist> (PlaylistFactory::create (
			DataType::MIDI, _session, newname, hidden()))) != 0) {

		playlist->set_orig_diskstream_id (id());
		return use_playlist (playlist);

	} else {
		return -1;
	}
}

int
MidiDiskstream::use_copy_playlist ()
{
	assert(midi_playlist());

	if (destructive()) {
		return 0;
	}

	if (_playlist == 0) {
		error << string_compose(_("MidiDiskstream %1: there is no existing playlist to make a copy of!"), _name) << endmsg;
		return -1;
	}

	string newname;
	boost::shared_ptr<MidiPlaylist> playlist;

	newname = Playlist::bump_name (_playlist->name(), _session);

	if ((playlist  = boost::dynamic_pointer_cast<MidiPlaylist>(PlaylistFactory::create (midi_playlist(), newname))) != 0) {
		playlist->set_orig_diskstream_id (id());
		return use_playlist (playlist);
	} else {
		return -1;
	}
}

/** Overloaded from parent to die horribly
 */
int
MidiDiskstream::set_destructive (bool yn)
{
	assert( ! destructive());
	assert( ! yn);
	return -1;
}

void
MidiDiskstream::set_note_mode (NoteMode m)
{
	_note_mode = m;
	midi_playlist()->set_note_mode(m);
	if (_write_source && _write_source->model())
		_write_source->model()->set_note_mode(m);
}

#if 0
static void
trace_midi (ostream& o, MIDI::byte *msg, size_t len)
{
	using namespace MIDI;
	eventType type;
	const char trace_prefix = ':';

	type = (eventType) (msg[0]&0xF0);

	switch (type) {
	case off:
		o << trace_prefix
		   << "Channel "
		   << (msg[0]&0xF)+1
		   << " NoteOff NoteNum "
		   << (int) msg[1]
		   << " Vel "
		   << (int) msg[2]
		   << endl;
		break;

	case on:
		o << trace_prefix
		   << "Channel "
		   << (msg[0]&0xF)+1
		   << " NoteOn NoteNum "
		   << (int) msg[1]
		   << " Vel "
		   << (int) msg[2]
		   << endl;
		break;

	case polypress:
		o << trace_prefix
		   << "Channel "
		   << (msg[0]&0xF)+1
		   << " PolyPressure"
		   << (int) msg[1]
		   << endl;
		break;

	case MIDI::controller:
		o << trace_prefix
		   << "Channel "
		   << (msg[0]&0xF)+1
		   << " Controller "
		   << (int) msg[1]
		   << " Value "
		   << (int) msg[2]
		   << endl;
		break;

	case program:
		o << trace_prefix
		   << "Channel "
		   << (msg[0]&0xF)+1
		   <<  " Program Change ProgNum "
		   << (int) msg[1]
		   << endl;
		break;

	case chanpress:
		o << trace_prefix
		   << "Channel "
		   << (msg[0]&0xF)+1
		   << " Channel Pressure "
		   << (int) msg[1]
		   << endl;
		break;

	case MIDI::pitchbend:
		o << trace_prefix
		   << "Channel "
		   << (msg[0]&0xF)+1
		   << " Pitch Bend "
		   << ((msg[2]<<7)|msg[1])
		   << endl;
		break;

	case MIDI::sysex:
		if (len == 1) {
			switch (msg[0]) {
			case 0xf8:
				o << trace_prefix
				   << "Clock"
				   << endl;
				break;
			case 0xfa:
				o << trace_prefix
				   << "Start"
				   << endl;
				break;
			case 0xfb:
				o << trace_prefix
				   << "Continue"
				   << endl;
				break;
			case 0xfc:
				o << trace_prefix
				   << "Stop"
				   << endl;
				break;
			case 0xfe:
				o << trace_prefix
				   << "Active Sense"
				   << endl;
				break;
			case 0xff:
				o << trace_prefix
				   << "System Reset"
				   << endl;
				break;
			default:
				o << trace_prefix
				   << "System Exclusive (1 byte : " << hex << (int) *msg << dec << ')'
				   << endl;
				break;
			}
		} else {
			o << trace_prefix
			   << "System Exclusive (" << len << ") = [ " << hex;
			for (unsigned int i = 0; i < len; ++i) {
				o << (int) msg[i] << ' ';
			}
			o << dec << ']' << endl;

		}
		break;

	case MIDI::song:
		o << trace_prefix << "Song" << endl;
		break;

	case MIDI::tune:
		o << trace_prefix << "Tune" << endl;
		break;

	case MIDI::eox:
		o << trace_prefix << "End-of-System Exclusive" << endl;
		break;

	case MIDI::timing:
		o << trace_prefix << "Timing" << endl;
		break;

	case MIDI::start:
		o << trace_prefix << "Start" << endl;
		break;

	case MIDI::stop:
		o << trace_prefix << "Stop" << endl;
		break;

	case MIDI::contineu:
		o << trace_prefix << "Continue" << endl;
		break;

	case active:
		o << trace_prefix << "Active Sense" << endl;
		break;

	default:
		o << trace_prefix << "Unrecognized MIDI message" << endl;
		break;
	}
}
#endif

int
MidiDiskstream::process (framepos_t transport_frame, pframes_t nframes, bool can_record, bool rec_monitors_input, bool& need_butler)
{
	int       ret = -1;
	framecnt_t rec_offset = 0;
	framecnt_t rec_nframes = 0;
	bool      nominally_recording;
	bool      re = record_enabled ();

	playback_distance = 0;

	check_record_status (transport_frame, can_record);

	nominally_recording = (can_record && re);

	if (nframes == 0) {
		return 0;
	}

	Glib::Mutex::Lock sm (state_lock, Glib::TRY_LOCK);

	if (!sm.locked()) {
		return 1;
	}

	adjust_capture_position = 0;

	if (nominally_recording || (re && was_recording && _session.get_record_enabled() && _session.config.get_punch_in())) {
		OverlapType ot = coverage (first_recordable_frame, last_recordable_frame, transport_frame, transport_frame + nframes);

		calculate_record_range(ot, transport_frame, nframes, rec_nframes, rec_offset);

		if (rec_nframes && !was_recording) {
			capture_captured = 0;
			was_recording = true;
		}
	}


	if (can_record && !_last_capture_sources.empty()) {
		_last_capture_sources.clear ();
	}

	if (nominally_recording || rec_nframes) {

		// Pump entire port buffer into the ring buffer (FIXME: split cycles?)
		MidiBuffer& buf = _source_port->get_midi_buffer(nframes);
		for (MidiBuffer::iterator i = buf.begin(); i != buf.end(); ++i) {
			const Evoral::MIDIEvent<MidiBuffer::TimeType> ev(*i, false);
			assert(ev.buffer());
			_capture_buf->write(ev.time() + transport_frame, ev.type(), ev.size(), ev.buffer());
		}

		if (buf.size() != 0) {
			/* Make a copy of this data and emit it for the GUI to see */
			boost::shared_ptr<MidiBuffer> copy (new MidiBuffer (buf.capacity ()));
			for (MidiBuffer::iterator i = buf.begin(); i != buf.end(); ++i) {
				copy->push_back ((*i).time() + transport_frame, (*i).size(), (*i).buffer());
			}

			DataRecorded (copy, _write_source); /* EMIT SIGNAL */
		}

	} else {

		if (was_recording) {
			finish_capture (rec_monitors_input);
		}

	}

	if (rec_nframes) {

		/* data will be written to disk */

		if (rec_nframes == nframes && rec_offset == 0) {
			playback_distance = nframes;
		}

		adjust_capture_position = rec_nframes;

	} else if (nominally_recording) {

		/* XXXX do this for MIDI !!!
		   can't do actual capture yet - waiting for latency effects to finish before we start
		   */

		playback_distance = nframes;

	}

	ret = 0;

	if (commit (nframes)) {
		need_butler = true;
	}

	return ret;
}

bool
MidiDiskstream::commit (framecnt_t nframes)
{
	bool need_butler = false;

	if (_actual_speed < 0.0) {
		playback_sample -= playback_distance;
	} else {
		playback_sample += playback_distance;
	}

	if (adjust_capture_position != 0) {
		capture_captured += adjust_capture_position;
		adjust_capture_position = 0;
	}

	uint32_t frames_read = g_atomic_int_get(&_frames_read_from_ringbuffer);
	uint32_t frames_written = g_atomic_int_get(&_frames_written_to_ringbuffer);
	if ((frames_written - frames_read) + nframes < midi_readahead) {
		need_butler = true;
	}

	/*cerr << "MDS written: " << frames_written << " - read: " << frames_read <<
		" = " << frames_written - frames_read
		<< " + " << nframes << " < " << midi_readahead << " = " << need_butler << ")" << endl;*/

	return need_butler;
}

void
MidiDiskstream::set_pending_overwrite (bool yn)
{
	/* called from audio thread, so we can use the read ptr and playback sample as we wish */

	_pending_overwrite = yn;

	overwrite_frame = playback_sample;
}

int
MidiDiskstream::overwrite_existing_buffers ()
{
	/* This is safe as long as the butler thread is suspended, which it should be */
	_playback_buf->reset ();

	g_atomic_int_set (&_frames_read_from_ringbuffer, 0);
	g_atomic_int_set (&_frames_written_to_ringbuffer, 0);

	read (overwrite_frame, disk_io_chunk_frames, false);
	overwrite_queued = false;
	_pending_overwrite = false;

	return 0;
}

int
MidiDiskstream::seek (framepos_t frame, bool complete_refill)
{
	Glib::Mutex::Lock lm (state_lock);
	int ret = -1;

	_playback_buf->reset();
	_capture_buf->reset();
	g_atomic_int_set(&_frames_read_from_ringbuffer, 0);
	g_atomic_int_set(&_frames_written_to_ringbuffer, 0);

	playback_sample = frame;
	file_frame = frame;

	if (complete_refill) {
		while ((ret = do_refill_with_alloc ()) > 0) ;
	} else {
		ret = do_refill_with_alloc ();
	}

	return ret;
}

int
MidiDiskstream::can_internal_playback_seek (framecnt_t distance)
{
	uint32_t frames_read    = g_atomic_int_get(&_frames_read_from_ringbuffer);
	uint32_t frames_written = g_atomic_int_get(&_frames_written_to_ringbuffer);
	return ((frames_written - frames_read) < distance);
}

int
MidiDiskstream::internal_playback_seek (framecnt_t distance)
{
	first_recordable_frame += distance;
	playback_sample += distance;

	return 0;
}

/** @a start is set to the new frame position (TIME) read up to */
int
MidiDiskstream::read (framepos_t& start, framecnt_t dur, bool reversed)
{
	framecnt_t this_read = 0;
	bool reloop = false;
	framepos_t loop_end = 0;
	framepos_t loop_start = 0;
	Location *loc = 0;

	if (!reversed) {

		framecnt_t loop_length = 0;

		/* Make the use of a Location atomic for this read operation.

		   Note: Locations don't get deleted, so all we care about
		   when I say "atomic" is that we are always pointing to
		   the same one and using a start/length values obtained
		   just once.
		*/

		if ((loc = loop_location) != 0) {
			loop_start = loc->start();
			loop_end = loc->end();
			loop_length = loop_end - loop_start;
		}

		/* if we are looping, ensure that the first frame we read is at the correct
		   position within the loop.
		*/

		if (loc && (start >= loop_end)) {
			//cerr << "start adjusted from " << start;
			start = loop_start + ((start - loop_start) % loop_length);
			//cerr << "to " << start << endl;
		}
		//cerr << "start is " << start << "  loopstart: " << loop_start << "  loopend: " << loop_end << endl;
	}

	while (dur) {

		/* take any loop into account. we can't read past the end of the loop. */

		if (loc && (loop_end - start < dur)) {
			this_read = loop_end - start;
			//cerr << "reloop true: thisread: " << this_read << "  dur: " << dur << endl;
			reloop = true;
		} else {
			reloop = false;
			this_read = dur;
		}

		if (this_read == 0) {
			break;
		}

		this_read = min(dur,this_read);

		if (midi_playlist()->read (*_playback_buf, start, this_read) != this_read) {
			error << string_compose(
					_("MidiDiskstream %1: cannot read %2 from playlist at frame %3"),
					_id, this_read, start) << endmsg;
			return -1;
		}

		g_atomic_int_add(&_frames_written_to_ringbuffer, this_read);

		_read_data_count = _playlist->read_data_count();

		if (reversed) {

			// Swap note ons with note offs here.  etc?
			// Fully reversing MIDI requires look-ahead (well, behind) to find previous
			// CC values etc.  hard.

		} else {

			/* if we read to the end of the loop, go back to the beginning */

			if (reloop) {
				// Synthesize LoopEvent here, because the next events
				// written will have non-monotonic timestamps.
				_playback_buf->write(loop_end - 1, LoopEventType, sizeof (framepos_t), (uint8_t *) &loop_start);
				start = loop_start;
			} else {
				start += this_read;
			}
		}

		dur -= this_read;
		//offset += this_read;
	}

	return 0;
}

int
MidiDiskstream::do_refill_with_alloc ()
{
	return do_refill();
}

int
MidiDiskstream::do_refill ()
{
	int     ret         = 0;
	size_t  write_space = _playback_buf->write_space();
	bool    reversed    = (_visible_speed * _session.transport_speed()) < 0.0f;

	if (write_space == 0) {
		return 0;
	}

	if (reversed) {
		return 0;
	}

	/* at end: nothing to do */
	if (file_frame == max_framepos) {
		return 0;
	}

	// At this point we...
	assert(_playback_buf->write_space() > 0); // ... have something to write to, and
	assert(file_frame <= max_framepos); // ... something to write

	// now calculate how much time is in the ringbuffer.
	// and lets write as much as we need to get this to be midi_readahead;
	uint32_t frames_read = g_atomic_int_get(&_frames_read_from_ringbuffer);
	uint32_t frames_written = g_atomic_int_get(&_frames_written_to_ringbuffer);
	if ((frames_written - frames_read) >= midi_readahead) {
		//cout << "MDS Nothing to do. all fine" << endl;
		return 0;
	}

	framecnt_t to_read = midi_readahead - (frames_written - frames_read);

	//cout << "MDS read for midi_readahead " << to_read << "  rb_contains: "
	//	<< frames_written - frames_read << endl;

	to_read = (framecnt_t) min ((framecnt_t) to_read, (framecnt_t) (max_framepos - file_frame));

	if (read (file_frame, to_read, reversed)) {
		ret = -1;
	}

	return ret;
}

/** Flush pending data to disk.
 *
 * Important note: this function will write *AT MOST* disk_io_chunk_frames
 * of data to disk. it will never write more than that.  If it writes that
 * much and there is more than that waiting to be written, it will return 1,
 * otherwise 0 on success or -1 on failure.
 *
 * If there is less than disk_io_chunk_frames to be written, no data will be
 * written at all unless @a force_flush is true.
 */
int
MidiDiskstream::do_flush (RunContext /*context*/, bool force_flush)
{
	uint32_t to_write;
	int32_t ret = 0;
	framecnt_t total;

	_write_data_count = 0;

	total = _session.transport_frame() - _last_flush_frame;

	if (_last_flush_frame > _session.transport_frame() || _last_flush_frame < capture_start_frame) {
		_last_flush_frame = _session.transport_frame();
	}

	if (total == 0 || _capture_buf->read_space() == 0
			|| (!force_flush && (total < disk_io_chunk_frames && was_recording))) {
		goto out;
	}

	/* if there are 2+ chunks of disk i/o possible for
	   this track, let the caller know so that it can arrange
	   for us to be called again, ASAP.

	   if we are forcing a flush, then if there is* any* extra
	   work, let the caller know.

	   if we are no longer recording and there is any extra work,
	   let the caller know too.
	   */

	if (total >= 2 * disk_io_chunk_frames || ((force_flush || !was_recording) && total > disk_io_chunk_frames)) {
		ret = 1;
	}

	to_write = disk_io_chunk_frames;

	assert(!destructive());

	if (record_enabled() &&
            ((_session.transport_frame() - _last_flush_frame > disk_io_chunk_frames) ||
             force_flush)) {
		if ((!_write_source) || _write_source->midi_write (*_capture_buf, get_capture_start_frame (0), to_write) != to_write) {
			error << string_compose(_("MidiDiskstream %1: cannot write to disk"), _id) << endmsg;
			return -1;
		} else {
			_last_flush_frame = _session.transport_frame();
		}
	}

out:
	return ret;
}

void
MidiDiskstream::transport_stopped_wallclock (struct tm& /*when*/, time_t /*twhen*/, bool abort_capture)
{
	bool more_work = true;
	int err = 0;
	boost::shared_ptr<MidiRegion> region;
	MidiRegion::SourceList srcs;
	MidiRegion::SourceList::iterator src;
	vector<CaptureInfo*>::iterator ci;
	bool mark_write_completed = false;

	finish_capture (true);

	/* butler is already stopped, but there may be work to do
	   to flush remaining data to disk.
	   */

	while (more_work && !err) {
		switch (do_flush (TransportContext, true)) {
		case 0:
			more_work = false;
			break;
		case 1:
			break;
		case -1:
			error << string_compose(_("MidiDiskstream \"%1\": cannot flush captured data to disk!"), _name) << endmsg;
			err++;
		}
	}

	/* XXX is there anything we can do if err != 0 ? */
	Glib::Mutex::Lock lm (capture_info_lock);

	if (capture_info.empty()) {
		return;
	}

	if (abort_capture) {

		if (_write_source) {
			_write_source->mark_for_remove ();
			_write_source.reset();
		}

		/* new source set up in "out" below */

	} else {

		assert(_write_source);

		framecnt_t total_capture = 0;
		for (ci = capture_info.begin(); ci != capture_info.end(); ++ci) {
			total_capture += (*ci)->frames;
		}

		if (_write_source->length (capture_info.front()->start) != 0) {

			/* phew, we have data */

			/* figure out the name for this take */

			srcs.push_back (_write_source);

			_write_source->set_timeline_position (capture_info.front()->start);
			_write_source->set_captured_for (_name);

			/* flush to disk: this step differs from the audio path,
			   where all the data is already on disk.
			*/

			_write_source->mark_streaming_write_completed ();

			/* set length in beats to entire capture length */

			BeatsFramesConverter converter (_session.tempo_map(), capture_info.front()->start);
			const double total_capture_beats = converter.from(total_capture);
			_write_source->set_length_beats(total_capture_beats);

			/* make it not a stub anymore */

			_write_source->unstubify ();

			/* we will want to be able to keep (over)writing the source
			   but we don't want it to be removable. this also differs
			   from the audio situation, where the source at this point
			   must be considered immutable. luckily, we can rely on
			   MidiSource::mark_streaming_write_completed() to have
			   already done the necessary work for that.
			*/

			string whole_file_region_name;
			whole_file_region_name = region_name_from_path (_write_source->name(), true);

			/* Register a new region with the Session that
			   describes the entire source. Do this first
			   so that any sub-regions will obviously be
			   children of this one (later!)
			*/

			try {
				PropertyList plist;

				plist.add (Properties::name, whole_file_region_name);
				plist.add (Properties::whole_file, true);
				plist.add (Properties::automatic, true);
				plist.add (Properties::start, 0);
				plist.add (Properties::length, total_capture);
				plist.add (Properties::layer, 0);

				boost::shared_ptr<Region> rx (RegionFactory::create (srcs, plist));

				region = boost::dynamic_pointer_cast<MidiRegion> (rx);
				region->special_set_position (capture_info.front()->start);
			}


			catch (failed_constructor& err) {
				error << string_compose(_("%1: could not create region for complete midi file"), _name) << endmsg;
				/* XXX what now? */
			}

			_last_capture_sources.insert (_last_capture_sources.end(), srcs.begin(), srcs.end());

			_playlist->clear_changes ();
			_playlist->freeze ();

			/* Session frame time of the initial capture in this pass, which is where the source starts */
			framepos_t initial_capture = 0;
			if (!capture_info.empty()) {
				initial_capture = capture_info.front()->start;
			}

			for (ci = capture_info.begin(); ci != capture_info.end(); ++ci) {

				string region_name;

				RegionFactory::region_name (region_name, _write_source->name(), false);

				// cerr << _name << ": based on ci of " << (*ci)->start << " for " << (*ci)->frames << " add a region\n";

				try {
					PropertyList plist;

					/* start of this region is the offset between the start of its capture and the start of the whole pass */
					plist.add (Properties::start, (*ci)->start - initial_capture);
					plist.add (Properties::length, (*ci)->frames);
					plist.add (Properties::length_beats, converter.from((*ci)->frames));
					plist.add (Properties::name, region_name);

					boost::shared_ptr<Region> rx (RegionFactory::create (srcs, plist));
					region = boost::dynamic_pointer_cast<MidiRegion> (rx);
				}

				catch (failed_constructor& err) {
					error << _("MidiDiskstream: could not create region for captured midi!") << endmsg;
					continue; /* XXX is this OK? */
				}

				// cerr << "add new region, buffer position = " << buffer_position << " @ " << (*ci)->start << endl;

				i_am_the_modifier++;
				_playlist->add_region (region, (*ci)->start);
				i_am_the_modifier--;
			}

			_playlist->thaw ();
			_session.add_command (new StatefulDiffCommand(_playlist));
		}

		mark_write_completed = true;
	}

	use_new_write_source (0);

	for (ci = capture_info.begin(); ci != capture_info.end(); ++ci) {
		delete *ci;
	}

	if (_playlist) {
		midi_playlist()->clear_note_trackers ();
	}

	capture_info.clear ();
	capture_start_frame = 0;
}

void
MidiDiskstream::transport_looped (framepos_t transport_frame)
{
	if (was_recording) {

		// adjust the capture length knowing that the data will be recorded to disk
		// only necessary after the first loop where we're recording
		if (capture_info.size() == 0) {
			capture_captured += _capture_offset;

			if (_alignment_style == ExistingMaterial) {
				capture_captured += _session.worst_output_latency();
			} else {
				capture_captured += _roll_delay;
			}
		}

		finish_capture (true);

		// the next region will start recording via the normal mechanism
		// we'll set the start position to the current transport pos
		// no latency adjustment or capture offset needs to be made, as that already happened the first time
		capture_start_frame = transport_frame;
		first_recordable_frame = transport_frame; // mild lie
		last_recordable_frame = max_framepos;
		was_recording = true;
	}
}

void
MidiDiskstream::finish_capture (bool /*rec_monitors_input*/)
{
	was_recording = false;

	if (capture_captured == 0) {
		return;
	}

	// Why must we destroy?
	assert(!destructive());

	CaptureInfo* ci = new CaptureInfo;

	ci->start  = capture_start_frame;
	ci->frames = capture_captured;

	/* XXX theoretical race condition here. Need atomic exchange ?
	   However, the circumstances when this is called right
	   now (either on record-disable or transport_stopped)
	   mean that no actual race exists. I think ...
	   We now have a capture_info_lock, but it is only to be used
	   to synchronize in the transport_stop and the capture info
	   accessors, so that invalidation will not occur (both non-realtime).
	*/

	// cerr << "Finish capture, add new CI, " << ci->start << '+' << ci->frames << endl;

	capture_info.push_back (ci);
	capture_captured = 0;
}

void
MidiDiskstream::set_record_enabled (bool yn)
{
	if (!recordable() || !_session.record_enabling_legal()) {
		return;
	}

	assert(!destructive());

	/* yes, i know that this not proof against race conditions, but its
	   good enough. i think.
	*/

	if (record_enabled() != yn) {
		if (yn) {
			engage_record_enable ();
		} else {
			disengage_record_enable ();
		}
	}
}

void
MidiDiskstream::engage_record_enable ()
{
	bool const rolling = _session.transport_speed() != 0.0f;

	g_atomic_int_set (&_record_enabled, 1);

	if (_source_port && Config->get_monitoring_model() == HardwareMonitoring) {
		_source_port->request_monitor_input (!(_session.config.get_auto_input() && rolling));
	}

	RecordEnableChanged (); /* EMIT SIGNAL */
}

void
MidiDiskstream::disengage_record_enable ()
{
	g_atomic_int_set (&_record_enabled, 0);
	if (_source_port && Config->get_monitoring_model() == HardwareMonitoring) {
		if (_source_port) {
			_source_port->request_monitor_input (false);
		}
	}

	RecordEnableChanged (); /* EMIT SIGNAL */
}

XMLNode&
MidiDiskstream::get_state ()
{
	XMLNode* node = new XMLNode ("Diskstream");
	char buf[64];
	LocaleGuard lg (X_("POSIX"));

	snprintf (buf, sizeof(buf), "0x%x", _flags);
	node->add_property ("flags", buf);

	node->add_property("channel-mode", enum_2_string(get_channel_mode()));

	snprintf (buf, sizeof(buf), "0x%x", get_channel_mask());
	node->add_property("channel-mask", buf);

	node->add_property ("playlist", _playlist->name());

	snprintf (buf, sizeof(buf), "%f", _visible_speed);
	node->add_property ("speed", buf);

	node->add_property("name", _name);
	id().print(buf, sizeof(buf));
	node->add_property("id", buf);

	if (_write_source && _session.get_record_enabled()) {

		XMLNode* cs_child = new XMLNode (X_("CapturingSources"));
		XMLNode* cs_grandchild;

		cs_grandchild = new XMLNode (X_("file"));
		cs_grandchild->add_property (X_("path"), _write_source->path());
		cs_child->add_child_nocopy (*cs_grandchild);

		/* store the location where capture will start */

		Location* pi;

		if (_session.config.get_punch_in() && ((pi = _session.locations()->auto_punch_location()) != 0)) {
			snprintf (buf, sizeof (buf), "%" PRId64, pi->start());
		} else {
			snprintf (buf, sizeof (buf), "%" PRId64, _session.transport_frame());
		}

		cs_child->add_property (X_("at"), buf);
		node->add_child_nocopy (*cs_child);
	}

	if (_extra_xml) {
		node->add_child_copy (*_extra_xml);
	}

	return* node;
}

int
MidiDiskstream::set_state (const XMLNode& node, int /*version*/)
{
	const XMLProperty* prop;
	XMLNodeList nlist = node.children();
	XMLNodeIterator niter;
	XMLNode* capture_pending_node = 0;
	LocaleGuard lg (X_("POSIX"));

	in_set_state = true;

	for (niter = nlist.begin(); niter != nlist.end(); ++niter) {
		/*if ((*niter)->name() == IO::state_node_name) {
			deprecated_io_node = new XMLNode (**niter);
		}*/
		assert ((*niter)->name() != IO::state_node_name);

		if ((*niter)->name() == X_("CapturingSources")) {
			capture_pending_node = *niter;
		}
	}

	/* prevent write sources from being created */

	in_set_state = true;

	if ((prop = node.property ("name")) != 0) {
		_name = prop->value();
	}

	if ((prop = node.property ("id")) != 0) {
		_id = prop->value ();
	}

	if ((prop = node.property ("flags")) != 0) {
		_flags = Flag (string_2_enum (prop->value(), _flags));
	}

	ChannelMode channel_mode = AllChannels;
	if ((prop = node.property ("channel-mode")) != 0) {
		channel_mode = ChannelMode (string_2_enum(prop->value(), channel_mode));
	}

	unsigned int channel_mask = 0xFFFF;
	if ((prop = node.property ("channel-mask")) != 0) {
		sscanf (prop->value().c_str(), "0x%x", &channel_mask);
		if (channel_mask & (~0xFFFF)) {
			warning << _("MidiDiskstream: XML property channel-mask out of range") << endmsg;
		}
	}

	set_channel_mode(channel_mode, channel_mask);

	if ((prop = node.property ("playlist")) == 0) {
		return -1;
	}

	{
		bool had_playlist = (_playlist != 0);

		if (find_and_use_playlist (prop->value())) {
			return -1;
		}

		if (!had_playlist) {
			_playlist->set_orig_diskstream_id (id());
		}

		if (capture_pending_node) {
			use_pending_capture_data (*capture_pending_node);
		}

	}

	if ((prop = node.property ("speed")) != 0) {
		double sp = atof (prop->value().c_str());

		if (realtime_set_speed (sp, false)) {
			non_realtime_set_speed ();
		}
	}

	in_set_state = false;

	return 0;
}

int
MidiDiskstream::use_new_write_source (uint32_t n)
{
	if (!_session.writable() || !recordable()) {
		return 1;
	}

	assert(n == 0);

	_write_source.reset();

	try {
		/* file starts off as a stub file, it will be converted
		   when we're done with a capture pass, or when "stolen"
		   by the GUI.
		*/

		_write_source = boost::dynamic_pointer_cast<SMFSource>(
			_session.create_midi_source_for_session (0, name (), true));

		if (!_write_source) {
			throw failed_constructor();
		}
	}

	catch (failed_constructor &err) {
		error << string_compose (_("%1:%2 new capture file not initialized correctly"), _name, n) << endmsg;
		_write_source.reset();
		return -1;
	}

	_write_source->mark_streaming_midi_write_started (_note_mode, _session.transport_frame());

	return 0;
}

list<boost::shared_ptr<Source> >
MidiDiskstream::steal_write_sources()
{
	list<boost::shared_ptr<Source> > ret;

	/* put some data on the disk, even if its just a header for an empty file.
	   XXX should we not have a more direct method for doing this? Maybe not
	   since we don't want to mess around with the model/disk relationship
	   that the Source has to pay attention to.
	*/

	boost::dynamic_pointer_cast<MidiSource>(_write_source)->session_saved ();

	/* make it visible/present */
	_write_source->unstubify ();
	/* never let it go away */
	_write_source->mark_nonremovable ();

	ret.push_back (_write_source);

	/* get a new one */

	use_new_write_source (0);

	return ret;
}

void
MidiDiskstream::reset_write_sources (bool mark_write_complete, bool /*force*/)
{
	if (!_session.writable() || !recordable()) {
		return;
	}

	if (_write_source && mark_write_complete) {
		_write_source->mark_streaming_write_completed ();
	}
	use_new_write_source (0);
}

int
MidiDiskstream::rename_write_sources ()
{
	if (_write_source != 0) {
		_write_source->set_source_name (_name.val(), destructive());
		/* XXX what to do if this fails ? */
	}
	return 0;
}

void
MidiDiskstream::set_block_size (pframes_t /*nframes*/)
{
}

void
MidiDiskstream::allocate_temporary_buffers ()
{
}

void
MidiDiskstream::monitor_input (bool yn)
{
	if (_source_port)
		_source_port->ensure_monitor_input (yn);
}

void
MidiDiskstream::set_align_style_from_io ()
{
	bool have_physical = false;

	if (_io == 0) {
		return;
	}

	get_input_sources ();

	if (_source_port && _source_port->flags() & JackPortIsPhysical) {
		have_physical = true;
	}

	if (have_physical) {
		set_align_style (ExistingMaterial);
	} else {
		set_align_style (CaptureTime);
	}
}


float
MidiDiskstream::playback_buffer_load () const
{
	return (float) ((double) _playback_buf->read_space()/
			(double) _playback_buf->capacity());
}

float
MidiDiskstream::capture_buffer_load () const
{
	return (float) ((double) _capture_buf->write_space()/
			(double) _capture_buf->capacity());
}

int
MidiDiskstream::use_pending_capture_data (XMLNode& /*node*/)
{
	return 0;
}

/** Writes playback events in the given range to \a dst, translating time stamps
 * so that an event at \a start has time = 0
 */
void
MidiDiskstream::get_playback (MidiBuffer& dst, framepos_t start, framepos_t end)
{
	dst.clear();
	assert(dst.size() == 0);

	// Reverse.  ... We just don't do reverse, ok?  Back off.
	if (end <= start) {
		return;
	}

	// Translates stamps to be relative to start


#ifndef NDEBUG
	const size_t events_read = _playback_buf->read(dst, start, end);
	DEBUG_TRACE (DEBUG::MidiDiskstreamIO, string_compose ("%1 MDS events read %2 range %3 .. %4 rspace %5 wspace %6\n", _name, events_read, start, end,
							      _playback_buf->read_space(), _playback_buf->write_space()));
#else
	_playback_buf->read(dst, start, end);
#endif

	gint32 frames_read = end - start;
	g_atomic_int_add(&_frames_read_from_ringbuffer, frames_read);
}