use crate::prelude::*;

pub struct Voice {
    sample:   Arc<Sample>,
    position: usize,
}
impl Voice {
    fn chunk (&mut self, frames: usize) -> Option<Vec<Vec<f32>>> {
        let mut chunk = vec![];
        if self.position < self.sample.end {
            let start = self.position.min(self.sample.end);
            let end   = (self.position + frames).min(self.sample.end);
            for channel in self.sample.channels.iter() {
                chunk.push(channel[start..end].into());
            };
            self.position = self.position + frames;
            Some(chunk)
        } else {
            None
        }
    }
}

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 })
    }
    fn play (self: &Arc<Self>) -> Voice {
        Voice { sample: self.clone(), position: self.start }
    }
}

pub struct Sampler {
    name:       String,
    cursor:     (usize, usize),
    samples:    BTreeMap<u7, Arc<Sample>>,
    voices:     Vec<Voice>,
    midi_in:    Port<MidiIn>,
    audio_ins:  Vec<Port<AudioIn>>,
    audio_outs: Vec<Port<AudioOut>>,
}

impl Sampler {
    pub fn new (
        name:    &str,
        samples: Option<BTreeMap<u7, Arc<Sample>>>,
    ) -> Result<DynamicDevice<Self>, Box<dyn Error>> {
        let (client, _) = Client::new(name, ClientOptions::NO_START_SERVER)?;
        DynamicDevice::new(render, handle, Self::process, Self {
            name: name.into(),
            cursor: (0, 0),
            samples: samples.unwrap_or(BTreeMap::new()),
            voices: vec![],
            midi_in: client.register_port("midi", ::jack::MidiIn::default())?,
            audio_ins: vec![
                client.register_port("recL", ::jack::AudioIn::default())?,
                client.register_port("recR", ::jack::AudioIn::default())?,
            ],
            audio_outs: vec![
                client.register_port("outL", ::jack::AudioOut::default())?,
                client.register_port("outR", ::jack::AudioOut::default())?,
            ],
        }).activate(client)
    }

    pub fn process (&mut self, _: &Client, scope:  &ProcessScope) -> Control {
        // Output buffer. This will be copied to the audio outs.
        let channel_count = self.audio_outs.len();
        let mut mixed = vec![vec![0.0;scope.n_frames() as usize];channel_count];

        // Emit next chunk of each currently playing voice,
        // dropping voices that have reached their ends.
        let mut voices = vec![];
        std::mem::swap(&mut voices, &mut self.voices);
        loop {
            if voices.len() < 1 {
                break
            }
            let mut voice = voices.swap_remove(0);
            if let Some(chunk) = voice.chunk(scope.n_frames() as usize) {
                for (i, channel) in chunk.iter().enumerate() {
                    let buffer = &mut mixed[i % channel_count];
                    for (i, sample) in channel.iter().enumerate() {
                        buffer[i] += sample;
                    }
                }
                self.voices.push(voice);
            }
        }

        // process midi in
        // add new voices
        // emit new voices starting from midi event frames
        //
        for (i, port) in self.audio_outs.iter_mut().enumerate() {
            let buffer = &mixed[i];
            for (i, value) in port.as_mut_slice(scope).iter_mut().enumerate() {
                *value = *buffer.get(i).unwrap_or(&0.0);
            }
        }
        Control::Continue

        //for event in self.midi_in.iter(scope) {
            //let len = 3.min(event.bytes.len());
            //let mut data = [0; 3];
            //data[..len].copy_from_slice(&event.bytes[..len]);
            //if (data[0] >> 4) == 0b1001 { // note on
                //let channel  = data[0] & 0b00001111;
                //let note     = data[1];
                //let velocity = data[2];
                //for sample in self.samples.iter_mut() {
                    //if sample.trigger.0 == channel && sample.trigger.1 == note {
                        //sample.play(velocity);
                    //}
                //}
            //}
            //for sample in self.samples.iter_mut() {
                //if let Some(playing) = sample.playing {
                    //for (index, value) in sample.port.as_mut_slice(scope).iter_mut().enumerate() {
                        //*value = *sample.data[0].get(playing + index).unwrap_or(&0f32);
                    //}
                    //if playing + scope.n_frames() as usize > sample.data[0].len() {
                        //sample.playing = None
                    //} else {
                        //sample.playing = Some(playing + scope.n_frames() as usize)
                    //}
                //}
            //}
        //}
    }

    fn load_sample (&mut self, _path: &str) {}
}

impl PortList for Sampler {
    fn midi_ins (&self) -> Usually<Vec<String>> {
        Ok(vec![self.midi_in.name()?])
    }
    fn audio_ins (&self) -> Usually<Vec<String>> {
        let mut ports = vec![];
        for port in self.audio_ins.iter() {
            ports.push(port.name()?);
        }
        Ok(ports)
    }
    fn audio_outs (&self) -> Usually<Vec<String>> {
        let mut ports = vec![];
        for port in self.audio_outs.iter() {
            ports.push(port.name()?);
        }
        Ok(ports)
    }
}

pub fn render (state: &Sampler, buf: &mut Buffer, Rect { x, y, height, .. }: Rect)
    -> Usually<Rect>
{
    let width = 40;
    let style = Style::default().gray();
    format!(" {} ({})", state.name, state.voices.len()).blit(buf, x+1, y, Some(style.white().bold().not_dim()));
    for (i, (note, sample)) in state.samples.iter().enumerate() {
        let style = if i == state.cursor.0 {
            Style::default().green()
        } else {
            Style::default()
        };
        let i = i as u16;
        let y1 = y+1+i;
        if y1 >= y + height {
            break
        }
        if i as usize == state.cursor.0 {
            "⯈".blit(buf, x+1, y1, Some(style.bold()));
        }
        let label1 = format!("{note:3}  {:10}", sample.name);
        let label2 = format!("{:>7} {:>7}", sample.start, sample.end);
        label1.blit(buf, x+2, y1, Some(style.bold()));
        label2.blit(buf, x+3+label1.len()as u16, y1, Some(style));
    }
    Ok(Rect { x, y, width, height })
}

//fn render_table (
    //state:  &mut Sampler,
    //stdout: &mut Stdout,
    //offset: (u16, u16),
//) -> Result<(), Box<dyn Error>> {
    //let move_to = |col, row| crossterm::cursor::MoveTo(offset.0 + col, offset.1 + row);
    //stdout.queue(move_to(0, 3))?.queue(
        //Print(" Name     Rate     Trigger      Route")
    //)?;
    //for (i, sample) in state.samples.lock().unwrap().iter().enumerate() {
        //let row = 4 + i as u16;
        //for (j, (column, field)) in [
            //(0,  format!(" {:7} ",    sample.name)),
            //(9,  format!(" {:.1}Hz ", sample.rate)),
            //(18, format!(" MIDI C{} {} ", sample.trigger.0, sample.trigger.1)),
            //(33, format!(" {:.1}dB -> Output ", sample.gain)),
            //(50, format!(" {} ", sample.playing.unwrap_or(0))),
        //].into_iter().enumerate() {
            //stdout.queue(move_to(column, row))?;
            //if state.selected_sample == i && state.selected_column == j {
                //stdout.queue(PrintStyledContent(field.to_string().bold().reverse()))?;
            //} else {
                //stdout.queue(PrintStyledContent(field.to_string().bold()))?;
            //}
        //}
    //}
    //Ok(())
//}

//fn render_meters (
    //state:  &mut Sampler,
    //stdout: &mut Stdout,
    //offset: (u16, u16),
//) -> Result<(), Box<dyn Error>> {
    //let move_to = |col, row| crossterm::cursor::MoveTo(offset.0 + col, offset.1 + row);
    //for (i, sample) in state.samples.lock().iter().enumerate() {
        //let row = 4 + i as u16;
        //stdout.queue(move_to(32, row))?.queue(
            //PrintStyledContent("▁".green())
        //)?;
    //}
    //Ok(())
//}

pub fn handle (state: &mut Sampler, event: &AppEvent) -> Usually<bool> {
    Ok(handle_keymap(state, event, KEYMAP)?)
}
pub const KEYMAP: &'static [KeyBinding<Sampler>] = keymap!(Sampler {
    [Up,    NONE, "cursor_up",   "move cursor up",           cursor_up],
    [Down,  NONE, "cursor_down", "move cursor down",         cursor_down],
    [Enter, NONE, "select",      "select item under cursor", select],
});
fn cursor_up (state: &mut Sampler) -> Usually<bool> {
    state.cursor.0 = if state.cursor.0 == 0 {
        state.samples.len() - 1
    } else {
        state.cursor.0 - 1
    };
    Ok(true)
}
fn cursor_down (state: &mut Sampler) -> Usually<bool> {
    state.cursor.0 = (state.cursor.0 + 1) % state.samples.len();
    Ok(true)
}
fn select (state: &mut Sampler) -> Usually<bool> {
    for (i, sample) in state.samples.values().enumerate() {
        if i == state.cursor.0 {
            state.voices.push(sample.play())
        }
    }
    Ok(true)
}