use crate::*;

pub trait HasPlayer: HasJack + HasClock {
    fn player (&self) -> &MIDIPlayer;
    fn player_mut (&mut self) -> &mut MIDIPlayer;
}

pub trait HasMidiBuffer {
    fn midi_buffer (&self) -> &mut Vec<Vec<Vec<u8>>>;

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

    /// 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_buffer()[0..scope.n_frames() as usize] {
            frame.clear();
        }
        if self.reset() || force_reset {
            all_notes_off(&mut self.midi_buffer());
            *self.reset_mut() = false;
        }
    }
}

pub trait HasPhrase {
    fn phrase (&self) -> &Option<(Instant, Arc<RwLock<Phrase>>)>;
    fn next_phrase (&self) -> &Option<(Instant, Arc<RwLock<Phrase>>)>;
    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 enqueue_next (&mut self, phrase: Option<&Arc<RwLock<Phrase>>>) {
        let start = self.clock.next_launch_pulse();
        self.next_phrase = Some((
            Instant::from_pulse(&self.clock.timebase(), start as f64),
            phrase.map(|p|p.clone())
        ));
        self.reset = true;
    }
    fn pulses_since_start (&self) -> Option<f64> {
        if let Some((started, Some(_))) = self.phrase.as_ref() {
            Some(self.clock.current.pulse.get() - started.pulse.get())
        } else {
            None
        }
    }
}

pub trait MidiInputApi: PlayheadApi + HasMidiBuffer + HasPhrase {
    fn midi_ins (&self) -> &Vec<Port<MidiIn>>;
    fn midi_ins_mut (&self) -> &mut Vec<Port<MidiIn>>;
    fn has_midi_ins (&self) -> bool {
        self.midi_ins().len() > 0
    }
    fn recording (&self) -> bool;
    fn recording_mut (&mut self) -> &mut bool;
    fn toggle_record (&mut self) {
        *self.recording_mut() = !self.recording();
    }

    fn monitoring (&self) -> bool;
    fn monitoring_mut (&mut self) -> &mut bool;
    fn toggle_monitor (&mut self) {
        *self.monitoring_mut() = !self.monitoring();
    }

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

    fn notes_in (&self) -> &Arc<RwLock<[bool;128]>>;

    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.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_ins_mut().iter() {
                for (sample, event, bytes) in parse_midi_input(input.iter(scope)) {
                    if let LiveEvent::Midi { message, .. } = event {
                        if self.monitoring() {
                            self.midi_buffer()[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.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_ins_mut().iter() {
            for (sample, event, bytes) in parse_midi_input(input.iter(scope)) {
                if let LiveEvent::Midi { message, .. } = event {
                    self.midi_buffer()[sample].push(bytes.to_vec());
                    update_keys(&mut notes_in, &message);
                }
            }
        }
    }

}

pub trait MidiOutputApi: PlayheadApi + HasMidiBuffer + HasPhrase + HasClock {
    fn midi_outs (&self) -> &Vec<Port<MidiOut>>;

    fn midi_outs_mut (&self) -> &mut Vec<Port<MidiOut>>;

    fn midi_note (&mut self) -> &mut Vec<u8>;

    fn notes_out (&mut self) -> &Arc<RwLock<Vec<[bool;128]>>>;

    fn has_midi_outs (&self) -> bool {
        self.midi_outs().len() > 0
    }

    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_buffer()[sample].push(self.midi_note().clone());
                            // Update the list of currently held notes.
                            update_keys(&mut*notes, &message);
                        }
                    }
                }
            }
        }
        next
    }

    fn write (&mut self, scope: &ProcessScope) {
        let samples = scope.n_frames() as usize;
        for port in self.midi_outs_mut().iter_mut() {
            let writer = &mut port.writer(scope);
            let output = &self.midi_buffer();
            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 [Vec<Vec<u8>>]) {
    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; },
        _ => {}
    }
}