tek/src/device/sampler.rs

#![allow(unused)]
use crate::*;
pub(crate) use symphonia::{
    default::get_codecs,
    core::{//errors::Error as SymphoniaError,
        audio::SampleBuffer, formats::Packet, io::MediaSourceStream, probe::Hint,
        codecs::{Decoder, CODEC_TYPE_NULL},
    },
};

pub trait HasSampler: AsRef<Sampler> + AsMut<Sampler> {
    fn sampler (&self) -> &Sampler {
        self.as_ref()
    }
    fn sampler_mut (&mut self) -> &mut Sampler {
        self.as_mut()
    }
}

impl<T: AsRef<Sampler> + AsMut<Sampler>> HasSampler for T {}

#[tek_proc::commands(SamplerCommand = "sampler")]
pub trait SamplerController: HasSampler
    + Namespace<usize>
{

    #[command(RecordToggle = "rec-toggle")]
    fn record_toggle (&mut self, slot: usize) -> Perhaps<SamplerCommand>
        where Self: Sized
    {
        let sampler = self.sampler_mut();
        let recording = sampler.recording.as_ref().map(|x|x.0);
        let _ = SamplerCommand::RecordFinish.dispatch(self)?;
        // autoslice: continue recording at next slot
        if recording != Some(slot) {
            SamplerCommand::RecordBegin { slot }.dispatch(self)
        } else {
            Ok(None)
        }
    }

    #[command(RecordBegin = "rec-begin")]
    fn record_begin (&mut self, slot: usize) -> Perhaps<SamplerCommand> {
        let sampler = self.sampler_mut();
        sampler.recording = Some((
            slot,
            Some(Arc::new(RwLock::new(Sample::new(
                "Sample", 0, 0, vec![vec![]; sampler.audio_ins.len()]
            ))))
        ));
        Ok(None)
    }

    #[command(RecordFinish = "rec-finish")]
    fn record_finish (&mut self) -> Perhaps<SamplerCommand> {
        let sampler = self.sampler_mut();
        let _prev_sample = sampler.recording.as_mut().map(|(index, sample)|{
            std::mem::swap(sample, &mut sampler.samples.0[*index]);
            sample
        }); // TODO: undo
        Ok(None)
    }

    #[command(RecordCancel = "rec-cancel")]
    fn record_cancel (&mut self) -> Perhaps<SamplerCommand> {
        self.sampler_mut().recording = None;
        Ok(None)
    }

    #[command(PlaySample = "sample-play")]
    fn sample_play (&mut self, slot: usize) -> Perhaps<SamplerCommand> {
        let sampler = self.sampler_mut();
        if let Some(ref sample) = sampler.samples.0[slot] {
            sampler.voices.write().unwrap().push(Sample::play(sample, 0, &u7::from(128)));
        }
        Ok(None)
    }

    #[command(StopSample = "sample-stop")]
    fn sample_stop (&mut self, slot: usize) -> Perhaps<SamplerCommand> {
        todo!();
        //Ok(None)
    }
}

/// Plays [Voice]s from [Sample]s.
/// 
/// ```
/// let sampler = tek::Sampler::default();
/// ```
#[derive(Debug, Default)] pub struct Sampler {
    /// Name of sampler.
    pub name: Arc<str>,
    /// Device color.
    pub color: ItemTheme,
    /// Sample currently being recorded.
    pub recording: Option<(usize, Option<Arc<RwLock<Sample>>>)>,
    /// Recording buffer.
    pub buffer: Vec<Vec<f32>>,
    /// Samples mapped to MIDI notes.
    pub samples: SampleKit<128>,
    /// Collection of currently playing instances of samples.
    pub voices: Arc<RwLock<Vec<Voice>>>,
    /// Samples that are not mapped to MIDI notes.
    pub unmapped: Vec<Arc<RwLock<Sample>>>,
    /// Sample currently being edited.
    pub editing: Option<Arc<RwLock<Sample>>>,
    /// How to mix the voices.
    pub mixing_mode: MixingMode,
    /// How to meter the inputs and outputs.
    pub metering_mode: MeteringMode,
    /// Fixed gain applied to all output.
    pub output_gain: f32,
    /// Currently active modal, if any.
    pub mode: Option<SamplerMode>,
    /// Size of rendered sampler.
    pub size: Sizer,
    /// Lowest note displayed.
    pub note_lo: AtomicUsize,
    /// Currently selected note.
    pub note_pt: AtomicUsize,
    /// Selected note as row/col.
    pub cursor: (AtomicUsize, AtomicUsize),
    /// Audio input meters.
    #[cfg(feature = "meter")] pub input_meters: Vec<f32>,
    /// Audio input ports. Samples are recorded from here.
    #[cfg(feature = "port")] pub audio_ins: Vec<AudioInput>,
    /// MIDI input port. Sampler are triggered from here.
    #[cfg(feature = "port")] pub midi_in: Option<MidiInput>,
    /// Audio output ports. Voices are played into here.
    #[cfg(feature = "port")] pub audio_outs: Vec<AudioOutput>,
    /// Audio output meters.
    #[cfg(feature = "meter")] pub output_meters: Vec<f32>,
}

impl_audio!(Sampler: sampler_jack_process);

pub(crate) fn sampler_jack_process (state: &mut Sampler, _: &Client, scope: &ProcessScope) -> Control {
    if let Some(midi_in) = &state.midi_in {
        for midi in midi_in.port().iter(scope) {
            sampler_midi_in(&state.samples, &state.voices, midi)
        }
    }
    state.process_audio_out(scope);
    state.process_audio_in(scope);
    Control::Continue
}

#[derive(Debug)] pub enum SamplerMode {
    // Load sample from path
    Import(usize, Browse),
}

pub type MidiSample =
    (Option<u7>, Arc<RwLock<crate::Sample>>);

impl NoteRange for Sampler {
    fn note_lo (&self) -> &AtomicUsize {
        &self.note_lo
    }
    fn note_axis (&self) -> &AtomicUsize {
        &self.size.1
    }
}

impl NotePoint for Sampler {
    fn note_len (&self) -> &AtomicUsize {
        unreachable!();
    }
    fn get_note_len (&self) -> usize {
        0
    }
    fn set_note_len (&self, _x: usize) -> usize {
        0 /*TODO?*/
    }
    fn note_pos (&self) -> &AtomicUsize {
        &self.note_pt
    }
    fn get_note_pos (&self) -> usize {
        self.note_pt.load(Relaxed)
    }
    fn set_note_pos (&self, x: usize) -> usize {
        let old = self.note_pt.swap(x, Relaxed);
        self.cursor.0.store(x % 8, Relaxed);
        self.cursor.1.store(x / 8, Relaxed);
        old
    }
}

impl Sampler {
    pub fn new (
        jack: &Jack<'static>,
        name: impl AsRef<str>,
        #[cfg(feature = "port")] midi_from:  &[Connect],
        #[cfg(feature = "port")] audio_from: &[&[Connect];2],
        #[cfg(feature = "port")] audio_to:   &[&[Connect];2],
    ) -> Usually<Self> {
        let name = name.as_ref();
        Ok(Self {
            name: name.into(),
            input_meters:   vec![0.0;2],
            output_meters:  vec![0.0;2],
            output_gain:    1.,
            buffer:         vec![vec![0.0;16384];2],
            #[cfg(feature = "port")] midi_in: Some(
                MidiInput::new(jack, &format!("M/{name}"), midi_from)?
            ),
            #[cfg(feature = "port")] audio_ins: vec![
                AudioInput::new(jack, &format!("L/{name}"), audio_from[0])?,
                AudioInput::new(jack, &format!("R/{name}"), audio_from[1])?,
            ],
            #[cfg(feature = "port")] audio_outs: vec![
                AudioOutput::new(jack, &format!("{name}/L"), audio_to[0])?,
                AudioOutput::new(jack, &format!("{name}/R"), audio_to[1])?,
            ],
            ..Default::default()
        })
    }
    /// Value of cursor
    pub fn cursor (&self) -> (usize, usize) {
        (self.cursor.0.load(Relaxed), self.cursor.1.load(Relaxed))
    }
    fn sample_selected (&self) -> usize {
        (self.get_note_pos() as u8).into()
    }
    fn sample_selected_pitch (&self) -> u7 {
        (self.get_note_pos() as u8).into()
    }
    pub fn process_audio_in (&mut self, scope: &ProcessScope) {
        self.reset_input_meters();
        if self.recording.is_some() {
            self.record_into(scope);
        } else {
            self.update_input_meters(scope);
        }
    }
    /// Make sure that input meter count corresponds to input channel count
    fn reset_input_meters (&mut self) {
        let channels = self.audio_ins.len();
        if self.input_meters.len() != channels {
            self.input_meters = vec![f32::MIN;channels];
        }
    }
    /// Record from inputs to sample
    fn record_into (&mut self, scope: &ProcessScope) {
        if let Some(ref sample) = self.recording.as_ref().expect("no recording sample").1 {
            let mut sample = sample.write().unwrap();
            if sample.channels.len() != self.audio_ins.len() {
                panic!("channel count mismatch");
            }
            let samples_with_meters = self.audio_ins.iter()
                .zip(self.input_meters.iter_mut())
                .zip(sample.channels.iter_mut());
            let mut length = 0;
            for ((input, meter), channel) in samples_with_meters {
                let slice = input.port().as_slice(scope);
                length = length.max(slice.len());
                *meter = to_rms(slice);
                channel.extend_from_slice(slice);
            }
            sample.end += length;
        } else {
            panic!("tried to record into the void")
        }
    }
    /// Update input meters
    fn update_input_meters (&mut self, scope: &ProcessScope) {
        for (input, meter) in self.audio_ins.iter().zip(self.input_meters.iter_mut()) {
            let slice = input.port().as_slice(scope);
            *meter = to_rms(slice);
        }
    }
    /// Make sure that output meter count corresponds to input channel count
    fn reset_output_meters (&mut self) {
        let channels = self.audio_outs.len();
        if self.output_meters.len() != channels {
            self.output_meters = vec![f32::MIN;channels];
        }
    }
    /// Mix all currently playing samples into the output.
    pub fn process_audio_out (&mut self, scope: &ProcessScope) {
        self.clear_output_buffer();
        self.populate_output_buffer(scope.n_frames() as usize);
        self.write_output_buffer(scope);
    }
    /// Zero the output buffer.
    fn clear_output_buffer (&mut self) {
        for buffer in self.buffer.iter_mut() {
            buffer.fill(0.0);
        }
    }
    /// Write playing voices to output buffer
    fn populate_output_buffer (&mut self, frames: usize) {
        let Sampler { buffer, voices, output_gain, mixing_mode, .. } = self;
        let _channel_count = buffer.len();
        match mixing_mode {
            MixingMode::Summing => voices.write().unwrap().retain_mut(|voice|{
                mix_summing(buffer.as_mut_slice(), *output_gain, frames, ||voice.next())
            }),
            MixingMode::Average => voices.write().unwrap().retain_mut(|voice|{
                mix_average(buffer.as_mut_slice(), *output_gain, frames, ||voice.next())
            }),
        }
    }
    /// Write output buffer to output ports.
    fn write_output_buffer (&mut self, scope: &ProcessScope) {
        let Sampler { audio_outs, buffer, .. } = self;
        for (i, port) in audio_outs.iter_mut().enumerate() {
            let buffer = &buffer[i];
            for (i, value) in port.port_mut().as_mut_slice(scope).iter_mut().enumerate() {
                *value = *buffer.get(i).unwrap_or(&0.0);
            }
        }
    }
}

fn draw_list_item (sample: &Option<Arc<RwLock<Sample>>>) -> String {
    if let Some(sample) = sample {
        let sample = sample.read().unwrap();
        format!("{:8}", sample.name)
        //format!("{:8} {:3} {:6}-{:6}/{:6}",
            //sample.name,
            //sample.gain,
            //sample.start,
            //sample.end,
            //sample.channels[0].len()
        //)
    } else {
        String::from("........")
    }
}

fn draw_viewer (sample: Option<&Arc<RwLock<Sample>>>) -> impl Draw<'_, Tui> + use<'_> {
    let min_db = -64.0;
    draw(move|to: &mut Tui|{
        let xywh = to.area().into();
        let XYWH(x, y, width, height) = xywh;
        let area = Rect { x, y, width, height };
        if let Some(sample) = &sample {
            let sample = sample.read().unwrap();
            let start  = sample.start  as f64;
            let end    = sample.end    as f64;
            let length = end - start;
            let step   = length / width as f64;
            let mut t  = start;
            let mut lines = vec![];
            while t < end {
                let chunk = &sample.channels[0][t as usize..((t + step) as usize).min(sample.end)];
                let total: f32 = chunk.iter().map(|x|x.abs()).sum();
                let count = chunk.len() as f32;
                let meter = 10. * (total / count).log10();
                let x = t as f64;
                let y = meter as f64;
                lines.push(Line::new(x, min_db, x, y, Color::Green));
                t += step / 2.;
            }
            if let Tui::Draw(buf, ..) = to {
                Canvas::default()
                    .x_bounds([sample.start as f64, sample.end as f64])
                    .y_bounds([min_db, 0.])
                    .paint(|ctx| {
                        for line in lines.iter() {
                            ctx.draw(line);
                        }
                        //FIXME: proportions
                        //let text = "press record to finish sampling";
                        //ctx.print(
                            //(width - text.len() as u16) as f64 / 2.0,
                            //height as f64 / 2.0,
                            //text.red()
                        //);
                    })
                    .render(area, buf);
            }
        } else {
            if let Tui::Draw(buf, ..) = to {
                Canvas::default()
                    .x_bounds([0.0, width  as f64])
                    .y_bounds([0.0, height as f64])
                    .paint(|_ctx| {
                        //let text = "press record to begin sampling";
                        //ctx.print(
                            //(width - text.len() as u16) as f64 / 2.0,
                            //height as f64 / 2.0,
                            //text.red()
                        //);
                    })
                    .render(area, buf);
            }
        }
        Ok(Some(xywh))
    })
}

/// Create [Voice]s from [Sample]s in response to MIDI input.
fn sampler_midi_in (
    samples: &SampleKit<128>, voices: &Arc<RwLock<Vec<Voice>>>, RawMidi { time, bytes }: RawMidi
) {
    if let Ok(LiveEvent::Midi { message, .. }) = LiveEvent::parse(bytes) {
        match message {
            MidiMessage::NoteOn { ref key, ref vel } => {
                if let Some(sample) = samples.get(key.as_int() as usize) {
                    voices.write().unwrap().push(Sample::play(sample, time as usize, vel));
                }
            },
            MidiMessage::Controller { controller: _, value: _ } => {
                // TODO
            }
            _ => {}
        }
    }
}

fn draw_sample (
    to: &mut Tui, x: u16, y: u16, note: Option<&u7>, sample: &Sample, focus: bool
) -> Usually<usize> {
    let style = if focus { Style::default().green() } else { Style::default() };
    if focus {
        to.blit(&"🬴", x+1, y, Some(style.bold()));
    }
    let label1 = format!("{:3} {:12}",
        note.map(|n|n.to_string()).unwrap_or(String::default()),
        sample.name);
    let label2 = format!("{:>6} {:>6}  +0.0",
        sample.start,
        sample.end);
    to.blit(&label1, x+2, y, Some(style.bold()));
    to.blit(&label2, x+3+label1.len()as u16, y, Some(style));
    Ok(label1.len() + label2.len() + 4)
}

/// A currently playing instance of a sample.
#[derive(Default, Debug, Clone)] pub struct Voice {
    pub sample:   Arc<RwLock<Sample>>,
    pub after:    usize,
    pub position: usize,
    pub velocity: f32,
}

impl Iterator for Voice {
    type Item = [f32;2];
    fn next (&mut self) -> Option<Self::Item> {
        if self.after > 0 {
            self.after -= 1;
            return Some([0.0, 0.0])
        }
        let sample = self.sample.read().unwrap();
        if self.position < sample.end {
            let position = self.position;
            self.position += 1;
            return sample.channels[0].get(position).map(|_amplitude|[
                sample.channels[0][position] * self.velocity * sample.gain,
                sample.channels[0][position] * self.velocity * sample.gain,
            ])
        }
        None
    }
}

/// Collection of samples, one per slot, fixed number of slots.
///
/// History: Separated to cleanly implement [Default].
///
/// ```
/// let samples = tek::SampleKit([None, None, None, None]);
/// ```
#[derive(Debug)] pub struct SampleKit <const N: usize> (
    pub [Option<Arc<RwLock<Sample>>>;N]
);

impl<const N: usize> Default for SampleKit<N> {
    fn default () -> Self { Self([const { None }; N]) }
}

impl<const N: usize> SampleKit<N> {
    pub fn get (&self, index: usize) -> &Option<Arc<RwLock<Sample>>> {
        if index < self.0.len() {
            &self.0[index]
        } else {
            &None
        }
    }
}

/// A sound cut.
///
/// ```
/// let sample = tek::Sample::default();
/// let sample = tek::Sample::new("test", 0, 0, vec![]);
/// ```
#[derive(Default, Debug)] pub struct Sample {
    pub name:     Arc<str>,
    pub start:    usize,
    pub end:      usize,
    pub channels: Vec<Vec<f32>>,
    pub rate:     Option<usize>,
    pub gain:     f32,
    pub color:    ItemTheme,
}

impl Sample {
    pub fn new (name: impl AsRef<str>, start: usize, end: usize, channels: Vec<Vec<f32>>) -> Self {
        Self {
            name: name.as_ref().into(),
            start,
            end,
            channels,
            rate: None,
            gain: 1.0,
            color: ItemTheme::random(),
        }
    }
    pub fn play (sample: &Arc<RwLock<Self>>, after: usize, velocity: &u7) -> Voice {
        Voice {
            sample: sample.clone(),
            after,
            position: sample.read().unwrap().start,
            velocity: velocity.as_int() as f32 / 127.0,
        }
    }
    pub fn handle_cc (&mut self, controller: u7, value: u7) {
        let percentage = value.as_int() as f64 / 127.;
        match controller.as_int() {
            20 => {
                self.start = (percentage * self.end as f64) as usize;
            },
            21 => {
                let length = self.channels[0].len();
                self.end = length.min(
                    self.start + (percentage * (length as f64 - self.start as f64)) as usize
                );
            },
            22 => { /*attack*/ },
            23 => { /*decay*/  },
            24 => {
                self.gain = percentage as f32 * 2.0;
            },
            26 => { /* pan */ }
            25 => { /* pitch */ }
            _ => {}
        }
    }
    /// Read WAV from file
    pub fn read_data (src: &str) -> Usually<(usize, Vec<Vec<f32>>)> {
        let mut channels: Vec<wavers::Samples<f32>> = vec![];
        for channel in wavers::Wav::from_path(src)?.channels() {
            channels.push(channel);
        }
        let mut end = 0;
        let mut data: Vec<Vec<f32>> = vec![];
        for samples in channels.iter() {
            let channel = Vec::from(samples.as_ref());
            end = end.max(channel.len());
            data.push(channel);
        }
        Ok((end, data))
    }
    pub fn from_file (path: &PathBuf) -> Usually<Self> {
        let name = path.file_name().unwrap().to_string_lossy().into();
        let mut sample = Self { name, ..Default::default() };
        // Use file extension if present
        let mut hint = Hint::new();
        if let Some(ext) = path.extension() {
            hint.with_extension(&ext.to_string_lossy());
        }
        let probed = symphonia::default::get_probe().format(
            &hint,
            MediaSourceStream::new(
                Box::new(File::open(path)?),
                Default::default(),
            ),
            &Default::default(),
            &Default::default()
        )?;
        let mut format = probed.format;
        let params = &format.tracks().iter()
            .find(|t| t.codec_params.codec != CODEC_TYPE_NULL)
            .expect("no tracks found")
            .codec_params;
        let mut decoder = get_codecs().make(params, &Default::default())?;
        loop {
            match format.next_packet() {
                Ok(packet) => sample.decode_packet(&mut decoder, packet)?,
                Err(symphonia::core::errors::Error::IoError(_)) => break decoder.last_decoded(),
                Err(err) => return Err(err.into()),
            };
        };
        sample.end = sample.channels.iter().fold(0, |l, c|l + c.len());
        Ok(sample)
    }
    fn decode_packet (
        &mut self, decoder: &mut Box<dyn Decoder>, packet: Packet
    ) -> Usually<()> {
        // Decode a packet
        let decoded = decoder
            .decode(&packet)
            .map_err(|e|Box::<dyn std::error::Error>::from(e))?;
        // Determine sample rate
        let spec = *decoded.spec();
        if let Some(rate) = self.rate {
            if rate != spec.rate as usize {
                panic!("sample rate changed");
            }
        } else {
            self.rate = Some(spec.rate as usize);
        }
        // Determine channel count
        while self.channels.len() < spec.channels.count() {
            self.channels.push(vec![]);
        }
        // Load sample
        let mut samples = SampleBuffer::new(
            decoded.frames() as u64,
            spec
        );
        if samples.capacity() > 0 {
            samples.copy_interleaved_ref(decoded);
            for frame in samples.samples().chunks(spec.channels.count()) {
                for (chan, frame) in frame.iter().enumerate() {
                    self.channels[chan].push(*frame)
                }
            }
        }
        Ok(())
    }
}

#[derive(Default, Debug)] pub struct SampleAdd {
    pub exited:  bool,
    pub dir:     PathBuf,
    pub subdirs: Vec<OsString>,
    pub files:   Vec<OsString>,
    pub cursor:  usize,
    pub offset:  usize,
    pub sample:  Arc<RwLock<Sample>>,
    pub voices:  Arc<RwLock<Vec<Voice>>>,
    pub _search: Option<String>,
}

impl_draw!(|self: SampleAdd, to: Tui|{ todo!() });

impl SampleAdd {
    fn exited (&self) -> bool {
        self.exited
    }
    fn exit (&mut self) {
        self.exited = true
    }
    pub fn new (
        sample: &Arc<RwLock<Sample>>,
        voices: &Arc<RwLock<Vec<Voice>>>
    ) -> Usually<Self> {
        let dir = std::env::current_dir()?;
        let (subdirs, files) = scan(&dir)?;
        Ok(Self {
            exited: false,
            dir,
            subdirs,
            files,
            cursor: 0,
            offset: 0,
            sample: sample.clone(),
            voices: voices.clone(),
            _search: None
        })
    }
    fn rescan (&mut self) -> Usually<()> {
        scan(&self.dir).map(|(subdirs, files)|{
            self.subdirs = subdirs;
            self.files = files;
        })
    }
    fn prev (&mut self) {
        self.cursor = self.cursor.saturating_sub(1);
    }
    fn next (&mut self) {
        self.cursor = self.cursor + 1;
    }
    fn try_preview (&mut self) -> Usually<()> {
        if let Some(path) = self.cursor_file() {
            if let Ok(sample) = Sample::from_file(&path) {
                *self.sample.write().unwrap() = sample;
                self.voices.write().unwrap().push(
                    Sample::play(&self.sample, 0, &u7::from(100u8))
                );
            }
            //load_sample(&path)?;
            //let src = std::fs::File::open(&path)?;
            //let mss = MediaSourceStream::new(Box::new(src), Default::default());
            //let mut hint = Hint::new();
            //if let Some(ext) = path.extension() {
                //hint.with_extension(&ext.to_string_lossy());
            //}
            //let meta_opts: MetadataOptions = Default::default();
            //let fmt_opts: FormatOptions = Default::default();
            //if let Ok(mut probed) =  symphonia::default::get_probe()
                //.format(&hint, mss, &fmt_opts, &meta_opts)
            //{
                //panic!("{:?}", probed.format.metadata());
            //};
        }
        Ok(())
    }
    fn cursor_dir (&self) -> Option<PathBuf> {
        if self.cursor < self.subdirs.len() {
            Some(self.dir.join(&self.subdirs[self.cursor]))
        } else {
            None
        }
    }
    fn cursor_file (&self) -> Option<PathBuf> {
        if self.cursor < self.subdirs.len() {
            return None
        }
        let index = self.cursor.saturating_sub(self.subdirs.len());
        if index < self.files.len() {
            Some(self.dir.join(&self.files[index]))
        } else {
            None
        }
    }
    fn pick (&mut self) -> Usually<bool> {
        if self.cursor == 0 {
            if let Some(parent) = self.dir.parent() {
                self.dir = parent.into();
                self.rescan()?;
                self.cursor = 0;
                return Ok(false)
            }
        }
        if let Some(dir) = self.cursor_dir() {
            self.dir = dir;
            self.rescan()?;
            self.cursor = 0;
            return Ok(false)
        }
        if let Some(path) = self.cursor_file() {
            let (end, channels) = read_sample_data(&path.to_string_lossy())?;
            let mut sample = self.sample.write().unwrap();
            sample.name = path.file_name().unwrap().to_string_lossy().into();
            sample.end = end;
            sample.channels = channels;
            return Ok(true)
        }
        return Ok(false)
    }
}

fn read_sample_data (_: &str) -> Usually<(usize, Vec<Vec<f32>>)> {
    todo!();
}

pub fn view_sample_info (sample: Option<&Arc<RwLock<Sample>>>) -> impl Draw<'_, Tui> + use<'_> {
    when(sample.is_some(), draw(move|to: &mut Tui|{
        let sample = sample.unwrap().read().unwrap();
        let theme  = sample.color;
        east!(
            field_h(theme, "Name",   format!("{:<10}", sample.name.clone())),
            field_h(theme, "Length", format!("{:<8}",  sample.channels[0].len())),
            field_h(theme, "Start",  format!("{:<8}",  sample.start)),
            field_h(theme, "End",    format!("{:<8}",  sample.end)),
            field_h(theme, "Trans",  "0"),
            field_h(theme, "Gain",   format!("{}",     sample.gain)),
        ).draw(to)
    }))
}

pub fn view_sample_info_v (sample: Option<&Arc<RwLock<Sample>>>) -> impl Draw<'_, Tui> + use<'_> {
    let a = draw(move|to: &mut Tui|{
        let sample = sample.unwrap().read().unwrap();
        let theme  = sample.color;
        south!(
            field_h(theme, "Name  ", format!("{:<10}", sample.name.clone()))     .align_w().full_w(),
            field_h(theme, "Length", format!("{:<8}",  sample.channels[0].len())).align_w().full_w(),
            field_h(theme, "Start ", format!("{:<8}",  sample.start))            .align_w().full_w(),
            field_h(theme, "End   ", format!("{:<8}",  sample.end))              .align_w().full_w(),
            field_h(theme, "Trans ", "0")                                        .align_w().full_w(),
            field_h(theme, "Gain  ", format!("{}",     sample.gain))             .align_w().full_w(),
        ).exact_w(20).draw(to)
    });

    let b = draw(|to: &mut Tui|fg(Red, south!(
        bold(true, "× No sample."),
        "[r] record",
        "[Shift-F9] import",
    )).draw(to));

    either(sample.is_some(), a, b)
}

pub fn view_sample_status (sample: Option<&Arc<RwLock<Sample>>>) -> impl Draw<'_, Tui> {
    bold(true, fg(g(224), sample
        .map(|sample|{
            let sample = sample.read().unwrap();
            format!("Sample {}-{}", sample.start, sample.end)
        })
        .unwrap_or_else(||"No sample".to_string())))
}

#[cfg(feature = "track")]
impl Track {
    /// Create a new track connecting the [Sequencer] to a [Sampler].
    pub fn new_with_sampler (
        name:       &impl AsRef<str>,
        color:      Option<ItemTheme>,
        jack:       &Jack<'static>,
        clock:      Option<&Clock>,
        clip:       Option<&Arc<RwLock<MidiClip>>>,
        midi_from:  &[Connect],
        midi_to:    &[Connect],
        audio_from: &[&[Connect];2],
        audio_to:   &[&[Connect];2],
    ) -> Usually<Self> {
        let mut track = Self::new(name, color, jack, clock, clip, midi_from, midi_to)?;
        let client_name = jack.with_client(|c|c.name().to_string());
        let port_name = track.sequencer.midi_outs[0].port_name();
        let connect = [Connect::exact(format!("{client_name}:{}", port_name))];
        track.devices.push(Device::Sampler(Sampler::new(
            jack, &format!("{}/sampler", name.as_ref()), &connect, audio_from, audio_to
        )?));
        Ok(track)
    }

    pub fn sampler (&self, mut nth: usize) -> Option<&Sampler> {
        for device in self.devices.iter() {
            match device {
                Device::Sampler(s) => if nth == 0 { return Some(s); } else { nth -= 1; },
                _ => {}
            }
        }
        None
    }

    pub fn sampler_mut (&mut self, mut nth: usize) -> Option<&mut Sampler> {
        for device in self.devices.iter_mut() {
            match device {
                Device::Sampler(s) => if nth == 0 { return Some(s); } else { nth -= 1; },
                _ => {}
            }
        }
        None
    }
}