use crate::core::*;

pub struct Sampler {
    pub name:    String,
    pub cursor:  (usize, usize),
    pub samples: BTreeMap<u7, Arc<Sample>>,
    pub voices:  Vec<Voice>,
    pub ports:   JackPorts,
    pub buffer:  Vec<Vec<f32>>,
    pub output_gain: f32
}

render!(Sampler = crate::view::sampler::render);
handle!(Sampler = crate::control::sampler::handle);
//jack!(Sampler {
    //process = Sampler::process,
    //audio = {
        //ins  = |s|Ok(s.jack.audio_ins.values().collect()),
        //outs = |s|Ok(s.jack.audio_outs.values().collect()),
    //}
    //midi = {
        //ins  = |s|Ok(s.jack.midi_ins.values().collect()),
        //outs = |s|Ok(s.jack.midi_outs.values().collect()),
    //}
//});
process!(Sampler = Sampler::process);
//ports!(Sampler {
    //audio: {
        //ins:  |s|Ok(s.ports.audio_ins.values().collect()),
        //outs: |s|Ok(s.ports.audio_outs.values().collect()),
    //}
    //midi: {
        //ins:  |s|Ok(s.ports.midi_ins.values().collect()),
        //outs: |s|Ok(s.ports.midi_outs.values().collect()),
    //}
//});

impl Sampler {
    pub fn new (
        name: &str, samples: Option<BTreeMap<u7, Arc<Sample>>>,
    ) -> Usually<JackDevice> {
        Jack::new(name)?
            .midi_in("midi")
            .audio_in("recL")
            .audio_in("recR")
            .audio_out("outL")
            .audio_out("outR")
            .run(|ports|Box::new(Self {
                name:    name.into(),
                cursor:  (0, 0),
                samples: samples.unwrap_or(BTreeMap::new()),
                voices:  vec![],
                ports,
                buffer:  vec![vec![0.0;16384];2],
                output_gain: 0.5,
            }))
    }

    pub fn process (&mut self, _: &Client, scope: &ProcessScope) -> Control {
        self.process_midi_in(scope);
        self.clear_output_buffer();
        self.process_audio_out(scope);
        self.write_output_buffer(scope);
        Control::Continue
    }

    fn process_midi_in (&mut self, scope: &ProcessScope) {
        for RawMidi { time, bytes } in self.ports.midi_ins.get("midi").unwrap().iter(scope) {
            if let LiveEvent::Midi { message, .. } = LiveEvent::parse(bytes).unwrap() {
                if let MidiMessage::NoteOn { ref key, .. } = message {
                    if let Some(sample) = self.samples.get(key) {
                        self.voices.push(sample.play(time as usize));
                    }
                }
            }
        }
    }

    fn clear_output_buffer (&mut self) {
        for buffer in self.buffer.iter_mut() {
            buffer.fill(0.0);
        }
    }

    fn process_audio_out (&mut self, scope: &ProcessScope) {
        let channel_count = self.buffer.len();
        self.voices.retain_mut(|voice|{
            for index in 0..scope.n_frames() as usize {
                if let Some(frame) = voice.next() {
                    for (channel, sample) in frame.iter().enumerate() {
                        self.buffer[channel % channel_count][index] += sample * self.output_gain;
                    }
                } else {
                    return false
                }
            }
            return true
        });
    }

    /// Write output buffer to output ports.
    fn write_output_buffer (&mut self, scope: &ProcessScope) {
        for (i, port) in self.ports.audio_outs.values_mut().enumerate() {
            let buffer = &self.buffer[i];
            for (i, value) in port.as_mut_slice(scope).iter_mut().enumerate() {
                *value = *buffer.get(i).unwrap_or(&0.0);
            }
        }
    }
}

/// Load sample from WAV and assign to MIDI note.
#[macro_export] macro_rules! sample {
    ($note:expr, $name:expr, $src:expr) => {
        {
            let mut channels: Vec<wavers::Samples<f32>> = vec![];
            for channel in wavers::Wav::from_path($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);
            }
            (u7::from_int_lossy($note).into(), Sample::new($name, 0, end, data).into())
        }
    };
}

pub struct Sample {
    pub name:     String,
    pub start:    usize,
    pub end:      usize,
    pub channels: Vec<Vec<f32>>,
}

impl Sample {
    pub fn new (name: &str, start: usize, end: usize, channels: Vec<Vec<f32>>) -> Arc<Self> {
        Arc::new(Self { name: name.to_string(), start, end, channels })
    }
    pub fn play (self: &Arc<Self>, after: usize) -> Voice {
        Voice {
            sample: self.clone(),
            after,
            position: self.start
        }
    }
}

pub struct Voice {
    pub sample:   Arc<Sample>,
    pub after:    usize,
    pub position: usize,
}

const BUFFER: [f32;64] = [0.0f32;64];

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