use crate::*;

#[derive(Clone, PartialEq)]
pub enum SequencerCommand {
    Focus(FocusCommand),
    Transport(TransportCommand),
    Phrases(PhrasePoolCommand),
    Editor(PhraseEditorCommand),
}

#[derive(Clone, PartialEq)]
pub enum PhraseEditorCommand {
    // TODO: 1-9 seek markers that by default start every 8th of the phrase
    ToggleDirection,
    EnterEditMode,
    ExitEditMode,
    NoteAppend,
    NoteSet,
    NoteCursorSet(usize),
    NoteLengthSet(usize),
    NoteScrollSet(usize),
    TimeCursorSet(usize),
    TimeScrollSet(usize),
    TimeZoomSet(usize),
    Go(Direction),
}

#[derive(Debug)]
pub struct SequencerTrack {
    /// Name of track
    pub name:         Arc<RwLock<String>>,
    /// Preferred width of track column
    pub width:        usize,
    /// Identifying color of track
    pub color:        ItemColor,
    /// Global timebase
    pub clock:        Arc<Clock>,
    /// Start time and phrase being played
    pub phrase:       Option<(Instant, Option<Arc<RwLock<Phrase>>>)>,
    /// Start time and next phrase
    pub next_phrase:  Option<(Instant, Option<Arc<RwLock<Phrase>>>)>,
    /// 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)
    /// Record from MIDI ports to current sequence.
    pub midi_inputs:  Vec<Port<MidiIn>>,
    /// Play from current sequence to MIDI ports
    pub midi_outputs: Vec<Port<MidiOut>>,
    /// MIDI output buffer
    pub midi_note:    Vec<u8>,
    /// MIDI output buffer
    pub midi_chunk:   Vec<Vec<Vec<u8>>>,
    /// Notes currently held at input
    pub notes_in:     Arc<RwLock<[bool; 128]>>,
    /// Notes currently held at output
    pub notes_out:    Arc<RwLock<[bool; 128]>>,
}

/// JACK process callback for a sequencer's phrase player/recorder.
impl Audio for SequencerTrack {
    fn process (&mut self, _: &Client, scope: &ProcessScope) -> Control {
        let has_midi_outputs = self.has_midi_outputs();
        let has_midi_inputs = self.has_midi_inputs();
        // Clear output buffer(s)
        self.clear(scope, false);
        // Write chunk of phrase to output, handle switchover
        if self.play(scope) {
            self.switchover(scope);
        }
        if has_midi_inputs {
            if self.recording || self.monitoring {
                // Record and/or monitor input
                self.record(scope)
            } else if has_midi_outputs && self.monitoring {
                // Monitor input to output
                self.monitor(scope)
            }
        }
        // Write to output port(s)
        self.write(scope);
        Control::Continue
    }
}

/// Methods used primarily by the process callback
impl SequencerTrack {
    fn is_rolling (&self) -> bool {
        *self.clock.playing.read().unwrap() == Some(TransportState::Rolling)
    }
    fn has_midi_inputs (&self) -> bool {
        self.midi_inputs.len() > 0
    }
    fn has_midi_outputs (&self) -> bool {
        self.midi_outputs.len() > 0
    }
    /// Clear the section of the output buffer that we will be using,
    /// emitting "all notes off" at start of buffer if requested.
    fn clear (&mut self, scope: &ProcessScope, force_reset: bool) {
        for frame in &mut self.midi_chunk[0..scope.n_frames() as usize] {
            frame.clear();
        }
        if self.reset || force_reset {
            all_notes_off(&mut self.midi_chunk); self.reset = false;
        }
    }
    fn play (&mut self, scope: &ProcessScope) -> bool {
        let mut next = false;
        // Write MIDI events from currently playing phrase (if any) to MIDI output buffer
        if self.is_rolling() {
            let sample0 = scope.last_frame_time() as usize;
            let samples = scope.n_frames() as usize;
            // If no phrase is playing, prepare for switchover immediately
            next = self.phrase.is_none();
            if let Some((started, phrase)) = &self.phrase {
                // First sample to populate. Greater than 0 means that the first
                // pulse of the phrase falls somewhere in the middle of the chunk.
                let sample = started.sample.get() as usize;
                let sample = sample + self.clock.started.read().unwrap().unwrap().0;
                let sample = sample0.saturating_sub(sample);
                // Iterator that emits sample (index into output buffer at which to write MIDI event)
                // paired with pulse (index into phrase from which to take the MIDI event) for each
                // sample of the output buffer that corresponds to a MIDI pulse.
                let pulses = self.clock.timebase().pulses_between_samples(sample, sample + samples);
                // Notes active during current chunk.
                let notes  = &mut self.notes_out.write().unwrap();
                for (sample, pulse) in pulses {
                    // If a next phrase is enqueued, and we're past the end of the current one,
                    // break the loop here (FIXME count pulse correctly)
                    next = self.next_phrase.is_some() && if let Some(ref phrase) = phrase {
                        pulse >= phrase.read().unwrap().length
                    } else {
                        true
                    };
                    if next {
                        break
                    }
                    // If there's a currently playing phrase, output notes from it to buffer:
                    if let Some(ref phrase) = phrase {
                        // Source phrase from which the MIDI events will be taken.
                        let phrase = phrase.read().unwrap();
                        // Current pulse index in source phrase
                        let pulse = pulse % phrase.length;
                        // Output each MIDI event from phrase at appropriate frames of output buffer:
                        for message in phrase.notes[pulse].iter() {
                            // Clear output buffer for this MIDI event.
                            self.midi_note.clear();
                            // TODO: support MIDI channels other than CH1.
                            let channel = 0.into();
                            // Serialize MIDI event into message buffer.
                            LiveEvent::Midi { channel, message: *message }
                                .write(&mut self.midi_note)
                                .unwrap();
                            // Append serialized message to output buffer.
                            self.midi_chunk[sample].push(self.midi_note.clone());
                            // Update the list of currently held notes.
                            update_keys(notes, &message);
                        }
                    }
                }
            }
        }
        next
    }
    fn switchover (&mut self, scope: &ProcessScope) {
        if self.is_rolling() {
            let sample0 = scope.last_frame_time() as usize;
            //let samples = scope.n_frames() as usize;
            if let Some((start_at, phrase)) = &self.next_phrase {
                let start  = start_at.sample.get() as usize;
                let sample = self.clock.started.read().unwrap().unwrap().0;
                // If it's time to switch to the next phrase:
                if start <= sample0.saturating_sub(sample) {
                    // Samples elapsed since phrase was supposed to start
                    let skipped = sample0 - start;
                    // Switch over to enqueued phrase
                    let started = Instant::from_sample(&self.clock.timebase(), start as f64);
                    self.phrase = Some((started, phrase.clone()));
                    // Unset enqueuement (TODO: where to implement looping?)
                    self.next_phrase = None
                }
                // TODO fill in remaining ticks of chunk from next phrase.
                // ?? just call self.play(scope) again, since enqueuement is off ???
                self.play(scope);
                // ?? or must it be with modified scope ??
                // likely not because start time etc
            }
        }
    }
    fn record (&mut self, scope: &ProcessScope) {
        let sample0 = scope.last_frame_time() as usize;
        if let (true, Some((started, phrase))) = (self.is_rolling(), &self.phrase) {
            let start = started.sample.get() as usize;
            let quant = self.clock.quant.get();
            // For highlighting keys and note repeat
            let mut notes_in = self.notes_in.write().unwrap();
            // Record from each input
            for input in self.midi_inputs.iter() {
                for (sample, event, bytes) in parse_midi_input(input.iter(scope)) {
                    if let LiveEvent::Midi { message, .. } = event {
                        if self.monitoring {
                            self.midi_chunk[sample].push(bytes.to_vec())
                        }
                        if self.recording {
                            if let Some(phrase) = phrase {
                                let mut phrase = phrase.write().unwrap();
                                let length = phrase.length;
                                phrase.record_event({
                                    let sample    = (sample0 + sample - start) as f64;
                                    let pulse     = self.clock.timebase().samples_to_pulse(sample);
                                    let quantized = (pulse / quant).round() * quant;
                                    let looped    = quantized as usize % length;
                                    looped
                                }, message);
                            }
                        }
                        update_keys(&mut notes_in, &message);
                    }
                }
            }
        }
        if let (true, Some((start_at, phrase))) = (self.is_rolling(), &self.next_phrase) {
            // TODO switch to next phrase and record into it
        }
    }
    fn monitor (&mut self, scope: &ProcessScope) {
        let mut notes_in = self.notes_in.write().unwrap();
        for input in self.midi_inputs.iter() {
            for (sample, event, bytes) in parse_midi_input(input.iter(scope)) {
                if let LiveEvent::Midi { message, .. } = event {
                    self.midi_chunk[sample].push(bytes.to_vec());
                    update_keys(&mut notes_in, &message);
                }
            }
        }
    }
    fn write (&mut self, scope: &ProcessScope) {
        let samples = scope.n_frames() as usize;
        for port in self.midi_outputs.iter_mut() {
            let writer = &mut port.writer(scope);
            let output = &self.midi_chunk;
            for time in 0..samples {
                for event in output[time].iter() {
                    writer.write(&RawMidi { time: time as u32, bytes: &event })
                        .expect(&format!("{event:?}"));
                }
            }
        }
    }
}

/// Add "all notes off" to the start of a buffer.
pub fn all_notes_off (output: &mut PhraseChunk) {
    let mut buf = vec![];
    let msg = MidiMessage::Controller { controller: 123.into(), value: 0.into() };
    let evt = LiveEvent::Midi { channel: 0.into(), message: msg };
    evt.write(&mut buf).unwrap();
    output[0].push(buf);
}

/// Return boxed iterator of MIDI events
pub fn parse_midi_input (input: MidiIter) -> Box<dyn Iterator<Item=(usize, LiveEvent, &[u8])> + '_> {
    Box::new(input.map(|RawMidi { time, bytes }|(
        time as usize,
        LiveEvent::parse(bytes).unwrap(),
        bytes
    )))
}

/// Update notes_in array
pub fn update_keys (keys: &mut[bool;128], message: &MidiMessage) {
    match message {
        MidiMessage::NoteOn  { key, .. } => { keys[key.as_int() as usize] = true; }
        MidiMessage::NoteOff { key, .. } => { keys[key.as_int() as usize] = false; },
        _ => {}
    }
}