use crate::*;

/// A LV2 plugin.
#[derive(Debug)] #[cfg(feature = "lv2")] pub struct Lv2 {
    /// JACK client handle (needs to not be dropped for standalone mode to work).
    pub jack:       Jack<'static>,
    pub name:       Arc<str>,
    pub path:       Option<Arc<str>>,
    pub selected:   usize,
    pub mapping:    bool,
    pub midi_ins:   Vec<Port<MidiIn>>,
    pub midi_outs:  Vec<Port<MidiOut>>,
    pub audio_ins:  Vec<Port<AudioIn>>,
    pub audio_outs: Vec<Port<AudioOut>>,

    pub lv2_world:        livi::World,
    pub lv2_instance:     livi::Instance,
    pub lv2_plugin:       livi::Plugin,
    pub lv2_features:     Arc<livi::Features>,
    pub lv2_port_list:    Vec<livi::Port>,
    pub lv2_input_buffer: Vec<livi::event::LV2AtomSequence>,
    pub lv2_ui_thread:    Option<JoinHandle<()>>,
}

/// A LV2 plugin's X11 UI.
#[cfg(feature = "lv2_gui")] pub struct LV2PluginUI {
    pub window: Option<Window>
}

impl_audio!(Lv2: lv2_jack_process);

impl Lv2 {
    const INPUT_BUFFER: usize = 1024;
    pub fn new (
        jack: &Jack<'static>,
        name: &str,
        uri:  &str,
    ) -> Usually<Self> {
        let lv2_world = livi::World::with_load_bundle(&uri);
        let lv2_features = lv2_world.build_features(livi::FeaturesBuilder {
            min_block_length: 1,
            max_block_length: 65536,
        });
        let lv2_plugin = lv2_world.iter_plugins().nth(0)
            .unwrap_or_else(||panic!("plugin not found: {uri}"));
        Ok(Self {
            jack:       jack.clone(),
            name:       name.into(),
            path:       Some(String::from(uri).into()),
            selected:   0,
            mapping:    false,
            midi_ins:   vec![],
            midi_outs:  vec![],
            audio_ins:  vec![],
            audio_outs: vec![],
            lv2_instance: unsafe {
                lv2_plugin
                    .instantiate(lv2_features.clone(), 48000.0)
                    .expect(&format!("instantiate failed: {uri}"))
            },
            lv2_port_list: lv2_plugin.ports().collect::<Vec<_>>(),
            lv2_input_buffer: Vec::with_capacity(Self::INPUT_BUFFER),
            lv2_ui_thread: None,
            lv2_world,
            lv2_features,
            lv2_plugin,
        })
    }
}
fn lv2_jack_process (
    Lv2 {
        midi_ins, midi_outs, audio_ins, audio_outs,
        lv2_features, lv2_instance, lv2_input_buffer, ..
    }:       &mut Lv2,
    _client: &Client,
    scope:   &ProcessScope
) -> Control {
    let urid = lv2_features.midi_urid();
    lv2_input_buffer.clear();
    for port in midi_ins.iter() {
        let mut atom = ::livi::event::LV2AtomSequence::new(
            &lv2_features,
            scope.n_frames() as usize
        );
        for event in port.iter(scope) {
            match event.bytes.len() {
                3 => atom.push_midi_event::<3>(
                    event.time as i64,
                    urid,
                    &event.bytes[0..3]
                ).unwrap(),
                _ => {}
            }
        }
        lv2_input_buffer.push(atom);
    }
    let mut outputs = vec![];
    for _ in midi_outs.iter() {
        outputs.push(::livi::event::LV2AtomSequence::new(
            lv2_features,
            scope.n_frames() as usize
        ));
    }
    let ports = ::livi::EmptyPortConnections::new()
        .with_atom_sequence_inputs(lv2_input_buffer.iter())
        .with_atom_sequence_outputs(outputs.iter_mut())
        .with_audio_inputs(audio_ins.iter().map(|o|o.as_slice(scope)))
        .with_audio_outputs(audio_outs.iter_mut().map(|o|o.as_mut_slice(scope)));
    unsafe {
        lv2_instance.run(scope.n_frames() as usize, ports).unwrap()
    };
    Control::Continue
}

impl LV2PluginUI { pub fn new () -> Usually<Self> { Ok(Self { window: None }) } }

impl ApplicationHandler for LV2PluginUI {
    fn resumed (&mut self, event_loop: &ActiveEventLoop) {
        self.window = Some(event_loop.create_window(Window::default_attributes()).unwrap());
    }
    fn window_event (&mut self, event_loop: &ActiveEventLoop, id: WindowId, event: WindowEvent) {
        match event {
            WindowEvent::CloseRequested => {
                self.window.as_ref().unwrap().set_visible(false);
                event_loop.exit();
            },
            WindowEvent::RedrawRequested => {
                self.window.as_ref().unwrap().request_redraw();
            }
            _ => (),
        }
    }
}

impl Draw<Tui> for Lv2 {
    fn draw(self, to: &mut Tui) {
        let area = to.area();
        let XYWH(x, y, _, height) = area;
        let mut width = 20u16;
        let start = self.selected.saturating_sub((height as usize / 2).saturating_sub(1));
        let end   = start + height as usize - 2;
        //draw_box(buf, Rect { x, y, width, height });
        for i in start..end {
            if let Some(port) = self.lv2_port_list.get(i) {
                let value = if let Some(value) = self.lv2_instance.control_input(port.index) {
                    value
                } else {
                    port.default_value
                };
                //let label = &format!("C·· M·· {:25} = {value:.03}", port.name);
                let label = &format!("{:25} = {value:.03}", port.name);
                width = width.max(label.len() as u16 + 4);
                let style = if i == self.selected {
                    Some(Style::default().green())
                } else {
                    None
                } ;
                to.blit(&label, x + 2, y + 1 + i as u16 - start as u16, style);
            } else {
                break
            }
        }
        draw_header(self, to, x, y, width);
    }
}


fn draw_header (state: &Lv2, to: &mut Tui, x: u16, y: u16, w: u16) {
    let style  = Style::default().gray();
    let label1 = format!(" {}", state.name);
    to.blit(&label1, x + 1, y, Some(style.white().bold()));
    if let Some(ref path) = state.path {
        let label2 = format!("{}…", &path[..((w as usize - 10).min(path.len()))]);
        to.blit(&label2, x + 2 + label1.len() as u16, y, Some(style.not_dim()));
    }
    //Ok(Rect { x, y, width: w, height: 1 })
}

#[cfg(feature = "vst2")] impl<E: Engine> ::vst::host::Host for Plugin<E> {}


#[cfg(feature = "vst2")] fn set_vst_plugin <E: Engine> (
    host: &Arc<Mutex<Plugin<E>>>, _path: &str
) -> Usually<PluginKind> {
    let mut loader = ::vst::host::PluginLoader::load(
        &std::path::Path::new("/nix/store/ij3sz7nqg5l7v2dygdvzy3w6cj62bd6r-helm-0.9.0/lib/lxvst/helm.so"),
        host.clone()
    )?;
    Ok(PluginKind::VST2 {
        instance: loader.instance()?
    })
}

#[cfg(feature = "lv2_gui")]
pub fn run_lv2_ui (mut ui: LV2PluginUI) -> Usually<JoinHandle<()>> {
    Ok(spawn(move||{
        let event_loop = EventLoop::builder().with_x11().with_any_thread(true).build().unwrap();
        event_loop.set_control_flow(ControlFlow::Wait);
        event_loop.run_app(&mut ui).unwrap()
    }))
}

#[cfg(feature = "lv2_gui")]
fn lv2_ui_instantiate (kind: &str) {
    //let host = Suil
}