//! MIDI sequencer
//! ```
//! use crate::*;
//!
//! let clip = MidiClip::default();
//! println!("Empty clip: {clip:?}");
//!
//! let clip = MidiClip::stop_all();
//! println!("Panic clip: {clip:?}");
//!
//! let mut clip = MidiClip::new("clip", true, 1, None, None);
//! clip.set_length(96);
//! clip.toggle_loop();
//! clip.record_event(12, MidiMessage::NoteOn { key: 36.into(), vel: 100.into() });
//! assert!(clip.contains_note_on(36.into(), 6, 18));
//! assert_eq!(&clip.notes, &clip.duplicate().notes);
//!
//! let clip = std::sync::Arc::new(clip);
//! assert_eq!(clip.clone(), clip);
//!
//! let sequencer = Sequencer::default();
//! println!("{sequencer:?}");
//! ```

use crate::*;

impl<T: Has<Sequencer>> HasSequencer for T {
    fn sequencer (&self) -> &Sequencer {
        self.get()
    }
    fn sequencer_mut (&mut self) -> &mut Sequencer {
        self.get_mut()
    }
}

pub trait HasSequencer {
    fn sequencer (&self) -> &Sequencer;
    fn sequencer_mut (&mut self) -> &mut Sequencer;
}

/// Contains state for playing a clip
pub struct Sequencer {
    /// State of clock and playhead
    #[cfg(feature = "clock")] pub clock: Clock,
    /// Start time and clip being played
    #[cfg(feature = "clip")] pub play_clip: Option<(Moment, Option<Arc<RwLock<MidiClip>>>)>,
    /// Start time and next clip
    #[cfg(feature = "clip")] pub next_clip: Option<(Moment, Option<Arc<RwLock<MidiClip>>>)>,
    /// Record from MIDI ports to current sequence.
    #[cfg(feature = "port")] pub midi_ins: Vec<MidiInput>,
    /// Play from current sequence to MIDI ports
    #[cfg(feature = "port")] pub midi_outs: Vec<MidiOutput>,
    /// Play input through output.
    pub monitoring: bool,
    /// Write input to sequence.
    pub recording:  bool,
    /// Overdub input to sequence.
    pub overdub:    bool,
    /// Send all notes off
    pub reset:      bool, // TODO?: after Some(nframes)
    /// Notes currently held at input
    pub notes_in:   Arc<RwLock<[bool; 128]>>,
    /// Notes currently held at output
    pub notes_out:  Arc<RwLock<[bool; 128]>>,
    /// MIDI output buffer
    pub note_buf:   Vec<u8>,
    /// MIDI output buffer
    pub midi_buf:   Vec<Vec<Vec<u8>>>,
}

impl Default for Sequencer {
    fn default () -> Self {
        Self {
            #[cfg(feature = "clock")] clock:    Clock::default(),
            #[cfg(feature = "clip")] play_clip: None,
            #[cfg(feature = "clip")] next_clip: None,
            #[cfg(feature = "port")] midi_ins:  vec![],
            #[cfg(feature = "port")] midi_outs: vec![],

            recording:  false,
            monitoring: true,
            overdub:    false,
            notes_in:   RwLock::new([false;128]).into(),
            notes_out:  RwLock::new([false;128]).into(),
            note_buf:   vec![0;8],
            midi_buf:   vec![],
            reset:      true,
        }
    }
}

impl Sequencer {
    pub fn new (
        name:      impl AsRef<str>,
        jack:      &Jack<'static>,
        #[cfg(feature = "clock")] clock:     Option<&Clock>,
        #[cfg(feature = "clip")] clip:      Option<&Arc<RwLock<MidiClip>>>,
        #[cfg(feature = "port")] midi_from: &[Connect],
        #[cfg(feature = "port")] midi_to:   &[Connect],
    ) -> Usually<Self> {
        let _name = name.as_ref();
        #[cfg(feature = "clock")] let clock = clock.cloned().unwrap_or_default();
        Ok(Self {
            reset:     true,
            notes_in:  RwLock::new([false;128]).into(),
            notes_out: RwLock::new([false;128]).into(),
            #[cfg(feature = "port")] midi_ins:  vec![MidiInput::new(jack,  &format!("M/{}", name.as_ref()), midi_from)?,],
            #[cfg(feature = "port")] midi_outs: vec![MidiOutput::new(jack, &format!("{}/M", name.as_ref()), midi_to)?,  ],
            #[cfg(feature = "clip")] play_clip: clip.map(|clip|(Moment::zero(&clock.timebase), Some(clip.clone()))),
            #[cfg(feature = "clock")] clock,
            ..Default::default()
        })
    }
}

impl std::fmt::Debug for Sequencer {
    fn fmt (&self, f: &mut Formatter<'_>) -> std::result::Result<(), std::fmt::Error> {
        f.debug_struct("Sequencer")
            .field("clock",     &self.clock)
            .field("play_clip", &self.play_clip)
            .field("next_clip", &self.next_clip)
            .finish()
    }
}

#[cfg(feature = "clock")] has!(Clock:           |self:Sequencer|self.clock);
#[cfg(feature = "port")] has!(Vec<MidiInput>:  |self:Sequencer|self.midi_ins);
#[cfg(feature = "port")] has!(Vec<MidiOutput>: |self:Sequencer|self.midi_outs);

impl MidiMonitor for Sequencer {
    fn notes_in (&self) -> &Arc<RwLock<[bool; 128]>> {
        &self.notes_in
    }
    fn monitoring (&self) -> bool {
        self.monitoring
    }
    fn monitoring_mut (&mut self) -> &mut bool {
        &mut self.monitoring
    }
}

impl MidiRecord for Sequencer {
    fn recording (&self) -> bool {
        self.recording
    }
    fn recording_mut (&mut self) -> &mut bool {
        &mut self.recording
    }
    fn overdub (&self) -> bool {
        self.overdub
    }
    fn overdub_mut (&mut self) -> &mut bool {
        &mut self.overdub
    }
}

#[cfg(feature="clip")] impl HasPlayClip for Sequencer {
    fn reset (&self) -> bool {
        self.reset
    }
    fn reset_mut (&mut self) -> &mut bool {
        &mut self.reset
    }
    fn play_clip (&self) -> &Option<(Moment, Option<Arc<RwLock<MidiClip>>>)> {
        &self.play_clip
    }
    fn play_clip_mut (&mut self) -> &mut Option<(Moment, Option<Arc<RwLock<MidiClip>>>)> {
        &mut self.play_clip
    }
    fn next_clip (&self) -> &Option<(Moment, Option<Arc<RwLock<MidiClip>>>)> {
        &self.next_clip
    }
    fn next_clip_mut (&mut self) -> &mut Option<(Moment, Option<Arc<RwLock<MidiClip>>>)> {
        &mut self.next_clip
    }
}

/// JACK process callback for a sequencer's clip sequencer/recorder.
impl Audio for Sequencer {
    fn process (&mut self, _: &Client, scope: &ProcessScope) -> Control {
        if self.clock().is_rolling() {
            self.process_rolling(scope)
        } else {
            self.process_stopped(scope)
        }
    }
}

impl Sequencer {
    fn process_rolling (&mut self, scope: &ProcessScope) -> Control {
        self.process_clear(scope, false);
        // Write chunk of clip to output, handle switchover
        if self.process_playback(scope) {
            self.process_switchover(scope);
        }
        // Monitor input to output
        self.process_monitoring(scope);
        // Record and/or monitor input
        self.process_recording(scope);
        // Emit contents of MIDI buffers to JACK MIDI output ports.
        self.midi_outs_emit(scope);
        Control::Continue
    }
    fn process_stopped (&mut self, scope: &ProcessScope) -> Control {
        if self.monitoring() && self.midi_ins().len() > 0 && self.midi_outs().len() > 0 {
            self.process_monitoring(scope)
        }
        Control::Continue
    }
    fn process_monitoring (&mut self, scope: &ProcessScope) {
        let notes_in = self.notes_in().clone(); // For highlighting keys and note repeat
        let monitoring = self.monitoring();
        for input in self.midi_ins.iter() {
            for (sample, event, bytes) in input.parsed(scope) {
                if let LiveEvent::Midi { message, .. } = event {
                    if monitoring {
                        self.midi_buf[sample].push(bytes.to_vec());
                    }
                    // FIXME: don't lock on every event!
                    update_keys(&mut notes_in.write().unwrap(), &message);
                }
            }
        }
    }
    /// Clear the section of the output buffer that we will be using,
    /// emitting "all notes off" at start of buffer if requested.
    fn process_clear (&mut self, scope: &ProcessScope, reset: bool) {
        let n_frames = (scope.n_frames() as usize).min(self.midi_buf_mut().len());
        for frame in &mut self.midi_buf_mut()[0..n_frames] {
            frame.clear();
        }
        if reset {
            all_notes_off(self.midi_buf_mut());
        }
        for port in self.midi_outs_mut().iter_mut() {
            // Clear output buffer(s)
            port.buffer_clear(scope, false);
        }
    }
    fn process_recording (&mut self, scope: &ProcessScope) {
        if self.monitoring() {
            self.monitor(scope);
        }
        if let Some((started, ref clip)) = self.play_clip.clone() {
            self.record_clip(scope, started, clip);
        }
        if let Some((_start_at, _clip)) = &self.next_clip() {
            self.record_next();
        }
    }
    fn process_playback (&mut self, scope: &ProcessScope) -> bool {
        // If a clip is playing, write a chunk of MIDI events from it to the output buffer.
        // If no clip is playing, prepare for switchover immediately.
        if let Some((started, clip)) = &self.play_clip {
            // Length of clip, to repeat or stop on end.
            let length = clip.as_ref().map_or(0, |p|p.read().unwrap().length);
            // Index of first sample to populate.
            let offset = self.clock().get_sample_offset(scope, &started);
            // Write MIDI events from clip at sample offsets corresponding to pulses.
            for (sample, pulse) in self.clock().get_pulses(scope, offset) {
                // If a next clip is enqueued, and we're past the end of the current one,
                // break the loop here (FIXME count pulse correctly)
                let past_end = if clip.is_some() { pulse >= length } else { true };
                // Is it time for switchover?
                if self.next_clip().is_some() && past_end {
                    return true
                }
                // If there's a currently playing clip, output notes from it to buffer:
                if let Some(clip) = clip {
                    // Source clip from which the MIDI events will be taken.
                    let clip = clip.read().unwrap();
                    // Clip with zero length is not processed
                    if clip.length > 0 {
                        // Current pulse index in source clip
                        let pulse = pulse % clip.length;
                        // Output each MIDI event from clip at appropriate frames of output buffer:
                        for message in clip.notes[pulse].iter() {
                            for port in self.midi_outs.iter_mut() {
                                port.buffer_write(sample, LiveEvent::Midi {
                                    channel: 0.into(), /* TODO */
                                    message: *message
                                });
                            }
                        }
                    }
                }
            }
            false
        } else {
            true
        }
    }
    /// Handle switchover from current to next playing clip.
    fn process_switchover (&mut self, scope: &ProcessScope) {
        let midi_buf = self.midi_buf_mut();
        let sample0 = scope.last_frame_time() as usize;
        //let samples = scope.n_frames() as usize;
        if let Some((start_at, clip)) = &self.next_clip() {
            let start  = start_at.sample.get() as usize;
            let sample = self.clock().started.read().unwrap()
                .as_ref().unwrap().sample.get() as usize;
            // If it's time to switch to the next clip:
            if start <= sample0.saturating_sub(sample) {
                // Samples elapsed since clip was supposed to start
                let _skipped = sample0 - start;
                // Switch over to enqueued clip
                let started = Moment::from_sample(self.clock().timebase(), start as f64);
                // Launch enqueued clip
                *self.play_clip_mut() = Some((started, clip.clone()));
                // Unset enqueuement (TODO: where to implement looping?)
                *self.next_clip_mut() = None;
                // Fill in remaining ticks of chunk from next clip.
                self.process_playback(scope);
            }
        }
    }
}

pub trait HasMidiBuffers {
    fn note_buf_mut (&mut self) -> &mut Vec<u8>;
    fn midi_buf_mut (&mut self) -> &mut Vec<Vec<Vec<u8>>>;
}

impl HasMidiBuffers for Sequencer {
    fn note_buf_mut (&mut self) -> &mut Vec<u8> {
        &mut self.note_buf
    }
    fn midi_buf_mut (&mut self) -> &mut Vec<Vec<Vec<u8>>> {
        &mut self.midi_buf
    }
}

pub trait MidiMonitor: HasMidiIns + HasMidiBuffers {
    fn notes_in (&self) -> &Arc<RwLock<[bool;128]>>;
    fn monitoring (&self) -> bool;
    fn monitoring_mut (&mut self) -> &mut bool;
    fn toggle_monitor (&mut self) {
        *self.monitoring_mut() = !self.monitoring();
    }
    fn monitor (&mut self, scope: &ProcessScope) {
    }
}

pub trait MidiRecord: MidiMonitor + HasClock + HasPlayClip {
    fn recording (&self) -> bool;
    fn recording_mut (&mut self) -> &mut bool;
    fn toggle_record (&mut self) {
        *self.recording_mut() = !self.recording();
    }

    fn overdub (&self) -> bool;
    fn overdub_mut (&mut self) -> &mut bool;
    fn toggle_overdub (&mut self) {
        *self.overdub_mut() = !self.overdub();
    }

    fn record_clip (
        &mut self,
        scope:   &ProcessScope,
        started: Moment,
        clip:    &Option<Arc<RwLock<MidiClip>>>,
    ) {
        if let Some(clip) = clip {
            let sample0    = scope.last_frame_time() as usize;
            let start      = started.sample.get() as usize;
            let _recording = self.recording();
            let timebase   = self.clock().timebase().clone();
            let quant      = self.clock().quant.get();
            let mut clip   = clip.write().unwrap();
            let length     = clip.length;
            for input in self.midi_ins_mut().iter() {
                for (sample, event, _bytes) in parse_midi_input(input.port().iter(scope)) {
                    if let LiveEvent::Midi { message, .. } = event {
                        clip.record_event({
                            let sample    = (sample0 + sample - start) as f64;
                            let pulse     = timebase.samples_to_pulse(sample);
                            let quantized = (pulse / quant).round() * quant;
                            quantized as usize % length
                        }, message);
                    }
                }
            }
        }
    }

    fn record_next (&mut self) {
        // TODO switch to next clip and record into it
    }
}

pub trait MidiViewer: HasSize<TuiOut> + MidiRange + MidiPoint + Debug + Send + Sync {
    fn buffer_size (&self, clip: &MidiClip) -> (usize, usize);
    fn redraw (&self);
    fn clip (&self) -> &Option<Arc<RwLock<MidiClip>>>;
    fn clip_mut (&mut self) -> &mut Option<Arc<RwLock<MidiClip>>>;
    fn set_clip (&mut self, clip: Option<&Arc<RwLock<MidiClip>>>) {
        *self.clip_mut() = clip.cloned();
        self.redraw();
    }
    /// Make sure cursor is within note range
    fn autoscroll (&self) {
        let note_pos = self.get_note_pos().min(127);
        let note_lo  = self.get_note_lo();
        let note_hi  = self.get_note_hi();
        if note_pos < note_lo {
            self.note_lo().set(note_pos);
        } else if note_pos > note_hi {
            self.note_lo().set((note_lo + note_pos).saturating_sub(note_hi));
        }
    }
    /// Make sure time range is within display
    fn autozoom (&self) {
        if self.time_lock().get() {
            let time_len  = self.get_time_len();
            let time_axis = self.get_time_axis();
            let time_zoom = self.get_time_zoom();
            loop {
                let time_zoom = self.time_zoom().get();
                let time_area = time_axis * time_zoom;
                if time_area > time_len {
                    let next_time_zoom = NoteDuration::prev(time_zoom);
                    if next_time_zoom <= 1 {
                        break
                    }
                    let next_time_area = time_axis * next_time_zoom;
                    if next_time_area >= time_len {
                        self.time_zoom().set(next_time_zoom);
                    } else {
                        break
                    }
                } else if time_area < time_len {
                    let prev_time_zoom = NoteDuration::next(time_zoom);
                    if prev_time_zoom > 384 {
                        break
                    }
                    let prev_time_area = time_axis * prev_time_zoom;
                    if prev_time_area <= time_len {
                        self.time_zoom().set(prev_time_zoom);
                    } else {
                        break
                    }
                }
            }
            if time_zoom != self.time_zoom().get() {
                self.redraw()
            }
        }
        //while time_len.div_ceil(time_zoom) > time_axis {
            //println!("\r{time_len} {time_zoom} {time_axis}");
            //time_zoom = Note::next(time_zoom);
        //}
        //self.time_zoom().set(time_zoom);
    }
}

pub trait HasPlayClip: HasClock {

    fn reset (&self) -> bool;

    fn reset_mut (&mut self) -> &mut bool;

    fn play_clip (&self) -> &Option<(Moment, Option<Arc<RwLock<MidiClip>>>)>;

    fn play_clip_mut (&mut self) -> &mut Option<(Moment, Option<Arc<RwLock<MidiClip>>>)>;

    fn next_clip (&self) -> &Option<(Moment, Option<Arc<RwLock<MidiClip>>>)>;

    fn next_clip_mut (&mut self) -> &mut Option<(Moment, Option<Arc<RwLock<MidiClip>>>)>;

    fn pulses_since_start (&self) -> Option<f64> {
        if let Some((started, Some(_))) = self.play_clip().as_ref() {
            let elapsed = self.clock().playhead.pulse.get() - started.pulse.get();
            return Some(elapsed)
        }
        None
    }

    fn pulses_since_start_looped (&self) -> Option<(f64, f64)> {
        if let Some((started, Some(clip))) = self.play_clip().as_ref() {
            let elapsed = self.clock().playhead.pulse.get() - started.pulse.get();
            let length  = clip.read().unwrap().length.max(1); // prevent div0 on empty clip
            let times   = (elapsed as usize / length) as f64;
            let elapsed = (elapsed as usize % length) as f64;
            return Some((times, elapsed))
        }
        None
    }

    fn enqueue_next (&mut self, clip: Option<&Arc<RwLock<MidiClip>>>) {
        *self.next_clip_mut() = Some((self.clock().next_launch_instant(), clip.cloned()));
        *self.reset_mut() = true;
    }

    fn play_status (&self) -> impl Content<TuiOut> {
        let (name, color): (Arc<str>, ItemTheme) = if let Some((_, Some(clip))) = self.play_clip() {
            let MidiClip { ref name, color, .. } = *clip.read().unwrap();
            (name.clone(), color)
        } else {
            ("".into(), Tui::g(64).into())
        };
        let time: String = self.pulses_since_start_looped()
            .map(|(times, time)|format!("{:>3}x {:>}", times+1.0, self.clock().timebase.format_beats_1(time)))
            .unwrap_or_else(||String::from("        ")).into();
        FieldV(color, "Now:", format!("{} {}", time, name))
    }

    fn next_status (&self) -> impl Content<TuiOut> {
        let mut time: Arc<str> = String::from("--.-.--").into();
        let mut name: Arc<str> = String::from("").into();
        let mut color = ItemTheme::G[64];
        let clock = self.clock();
        if let Some((t, Some(clip))) = self.next_clip() {
            let clip = clip.read().unwrap();
            name  = clip.name.clone();
            color = clip.color.clone();
            time  = {
                let target  = t.pulse.get();
                let current = clock.playhead.pulse.get();
                if target > current {
                    let remaining = target - current;
                    format!("-{:>}", clock.timebase.format_beats_1(remaining))
                } else {
                    String::new()
                }
            }.into()
        } else if let Some((t, Some(clip))) = self.play_clip() {
            let clip = clip.read().unwrap();
            if clip.looped {
                name  = clip.name.clone();
                color = clip.color.clone();
                let target  = t.pulse.get() + clip.length as f64;
                let current = clock.playhead.pulse.get();
                if target > current {
                    time = format!("-{:>}", clock.timebase.format_beats_0(target - current)).into()
                }
            } else {
                name  = "Stop".to_string().into();
            }
        };
        FieldV(color, "Next:", format!("{} {}", time, name))
    }
}