//! Clip launcher and arrangement editor.
use crate::*;

/// Represents the tracks and scenes of the composition.
pub struct Arranger<E: Engine> {
    /// Name of arranger
    pub name:     Arc<RwLock<String>>,
    /// Collection of tracks.
    pub tracks:   Vec<Sequencer<E>>,
    /// Collection of scenes.
    pub scenes:   Vec<Scene>,
    /// Currently selected element.
    pub selected: ArrangerFocus,
    /// Display mode of arranger
    pub mode:     ArrangerViewMode,
    /// Slot for modal dialog displayed on top of app.
    pub modal:    Option<Box<dyn ExitableComponent<E>>>,
    /// Whether the arranger is currently focused
    pub focused:  bool
}
impl<E: Engine> Arranger<E> {
    pub fn new (name: &str) -> Self {
        Self {
            name:     Arc::new(RwLock::new(name.into())),
            mode:     ArrangerViewMode::VerticalCompact2,
            selected: ArrangerFocus::Clip(0, 0),
            scenes:   vec![],
            tracks:   vec![],
            modal:    None,
            focused:  false
        }
    }
    pub fn activate (&mut self) {
        match self.selected {
            ArrangerFocus::Scene(s) => {
                for (track_index, track) in self.tracks.iter_mut().enumerate() {
                    track.sequence = self.scenes[s].clips[track_index];
                    track.reset = true;
                }
            },
            ArrangerFocus::Clip(t, s) => {
                self.tracks[t].sequence = self.scenes[s].clips[t];
                self.tracks[t].reset = true;
            },
            _ => {}
        }
    }
    pub fn sequencer (&self) -> Option<&Sequencer<E>> {
        self.selected.track()
            .map(|track|self.tracks.get(track))
            .flatten()
    }
    pub fn sequencer_mut (&mut self) -> Option<&mut Sequencer<E>> {
        self.selected.track()
            .map(|track|self.tracks.get_mut(track))
            .flatten()
    }
    pub fn show_phrase (&mut self) -> Usually<()> {
        //unimplemented!()
        //let phrase = self.phrase();
        //self.sequencer.show(phrase)
        Ok(())
    }
    pub fn is_first_row (&self) -> bool {
        let selected = self.selected;
        selected.is_mix() || selected.is_track() || match selected {
            ArrangerFocus::Clip(_, s) =>
                s == 0,
            _ => false
        }
    }
    pub fn is_last_row (&self) -> bool {
        let selected = self.selected;
        match selected {
            ArrangerFocus::Scene(s) =>
                s == self.scenes.len() - 1,
            ArrangerFocus::Clip(_, s) =>
                s == self.scenes.len() - 1,
            _ => false
        }
    }
    pub fn track (&self) -> Option<&Sequencer<E>> {
        self.selected.track().map(|t|self.tracks.get(t)).flatten()
    }
    pub fn track_mut (&mut self) -> Option<&mut Sequencer<E>> {
        self.selected.track().map(|t|self.tracks.get_mut(t)).flatten()
    }
    pub fn track_next (&mut self) {
        self.selected.track_next(self.tracks.len() - 1)
    }
    pub fn track_prev (&mut self) {
        self.selected.track_prev()
    }
    pub fn track_add (&mut self, name: Option<&str>) -> Usually<&mut Sequencer<E>> {
        self.tracks.push(name.map_or_else(
            || Sequencer::new(&self.track_default_name()),
            |name| Sequencer::new(name),
        ));
        let index = self.tracks.len() - 1;
        Ok(&mut self.tracks[index])
    }
    pub fn track_del (&mut self) {
        unimplemented!("Arranger::track_del");
    }
    pub fn track_default_name (&self) -> String {
        format!("Track {}", self.tracks.len() + 1)
    }
}
impl Arranger<Tui> {
    pub fn rename_selected (&mut self) {
        self.modal = Some(Box::new(ArrangerRenameModal::new(
            self.selected,
            &match self.selected {
                ArrangerFocus::Mix => self.name.clone(),
                ArrangerFocus::Track(t) => self.tracks[t].name.clone(),
                ArrangerFocus::Scene(s) => self.scenes[s].name.clone(),
                ArrangerFocus::Clip(t, s) => self.tracks[t].phrases[s].read().unwrap().name.clone(),
            }
        )));
    }
}
impl Handle<Tui> for Arranger<Tui> {
    fn handle (&mut self, from: &TuiInput) -> Perhaps<bool> {
        if let Some(modal) = self.modal.as_mut() {
            let result = modal.handle(from)?;
            if modal.exited() {
                self.modal = None;
            }
            return Ok(result)
        }
        match from.event() {
            // mode_switch: switch the display mode
            key!(KeyCode::Char('`')) => {
                self.mode.to_next()
            },
            // cursor_up: move cursor up
            key!(KeyCode::Up) => {
                match self.mode {
                    ArrangerViewMode::Horizontal => self.track_prev(),
                    _ => self.scene_prev(),
                };
                self.show_phrase()?;
            },
            // cursor_down
            key!(KeyCode::Down) => {
                match self.mode {
                    ArrangerViewMode::Horizontal => self.track_next(),
                    _ => self.scene_next(),
                };
                self.show_phrase()?;
            },
            // cursor left
            key!(KeyCode::Left) => {
                match self.mode {
                    ArrangerViewMode::Horizontal => self.scene_prev(),
                    _ => self.track_prev(),
                };
                self.show_phrase()?;
            },
            // cursor right
            key!(KeyCode::Right) => {
                match self.mode {
                    ArrangerViewMode::Horizontal => self.scene_next(),
                    _ => self.track_next(),
                };
                self.show_phrase()?;
            },
            // increment: use next clip here
            key!(KeyCode::Char('.')) => {
                self.phrase_next();
            },
            // decrement: use previous next clip here
            key!(KeyCode::Char(',')) => {
                self.phrase_prev();
            },
            // decrement: use previous clip here
            key!(KeyCode::Enter) => {
                self.activate();
            },
            // scene_add: add a new scene
            key!(Ctrl-KeyCode::Char('a')) => {
                self.scene_add(None)?;
            },
            // track_add: add a new scene
            key!(Ctrl-KeyCode::Char('t')) => {
                self.track_add(None)?;
            },
            // rename: add a new scene
            key!(KeyCode::Char('n')) => {
                self.rename_selected();
            },
            // length: add a new scene
            key!(KeyCode::Char('l')) => {
                todo!();
            },
            // color: set color of item at cursor
            key!(KeyCode::Char('c')) => {
                todo!();
            },
            _ => return Ok(None)
        }
        Ok(Some(true))
    }
}
impl Content for Arranger<Tui> {
    type Engine = Tui;
    fn content (&self) -> impl Widget<Engine = Tui> {
        Layers::new(move |add|{
            //Lozenge(Style::default().fg(Nord::BG2))
                //.draw(&mut to.alter_area(|[x, y, w, h]|[
                    //x.saturating_sub(1),
                    //y.saturating_sub(1),
                    //w + 2,
                    //h + 2,
                //]))
            match self.mode {
                ArrangerViewMode::Horizontal => add(&ArrangerViewHorizontal(&self)),
                ArrangerViewMode::VerticalCompact1 => add(&ArrangerViewVertical(
                    &self,
                    track_clip_name_lengths(self.tracks.as_slice()).as_slice(),
                    (0..=self.scenes.len()).map(|i|(96, 96*i)).collect::<Vec<_>>().as_slice(),
                )),
                ArrangerViewMode::VerticalCompact2 => add(&ArrangerViewVertical(
                    &self,
                    track_clip_name_lengths(self.tracks.as_slice()).as_slice(),
                    (0..=self.scenes.len()).map(|i|(192, 192*i)).collect::<Vec<_>>().as_slice()
                )),
                ArrangerViewMode::VerticalExpanded => add(&ArrangerViewVertical(
                    &self,
                    track_clip_name_lengths(self.tracks.as_slice()).as_slice(),
                    scene_ppqs(self.tracks.as_slice(), self.scenes.as_slice()).as_slice(),
                )),
            }
        })
    }
}
impl Focusable<Tui> for Arranger<Tui> {
    fn is_focused (&self) -> bool {
        self.focused
    }
    fn set_focused (&mut self, focused: bool) {
        self.focused = focused
    }
}

#[derive(PartialEq, Clone, Copy)]
/// Represents the current user selection in the arranger
pub enum ArrangerFocus {
    /** The whole mix is selected */
    Mix,
    /// A track is selected.
    Track(usize),
    /// A scene is selected.
    Scene(usize),
    /// A clip (track × scene) is selected.
    Clip(usize, usize),
}

/// Focus identification methods
impl ArrangerFocus {
    pub fn is_mix (&self) -> bool {
        match self { Self::Mix => true, _ => false }
    }
    pub fn is_track (&self) -> bool {
        match self { Self::Track(_) => true, _ => false }
    }
    pub fn is_scene (&self) -> bool {
        match self { Self::Scene(_) => true, _ => false }
    }
    pub fn is_clip (&self) -> bool {
        match self { Self::Clip(_, _) => true, _ => false }
    }
    pub fn track (&self) -> Option<usize> {
        match self {
            Self::Clip(t, _) => Some(*t),
            Self::Track(t)   => Some(*t),
            _ => None
        }
    }
    pub fn track_next (&mut self, last_track: usize) {
        *self = match self {
            Self::Mix        => Self::Track(0),
            Self::Track(t)   => Self::Track(last_track.min(*t + 1)),
            Self::Scene(s)   => Self::Clip(0, *s),
            Self::Clip(t, s) => Self::Clip(last_track.min(*t + 1), *s),
        }
    }
    pub fn track_prev (&mut self) {
        *self = match self {
            Self::Mix      => Self::Mix,
            Self::Scene(s) => Self::Scene(*s),
            Self::Track(t) => if *t == 0 {
                Self::Mix
            } else {
                Self::Track(*t - 1)
            },
            Self::Clip(t, s) => if *t == 0 {
                Self::Scene(*s)
            } else {
                Self::Clip(t.saturating_sub(1), *s)
            }
        }
    }
    pub fn scene (&self) -> Option<usize> {
        match self {
            Self::Clip(_, s) => Some(*s),
            Self::Scene(s)   => Some(*s),
            _ => None
        }
    }
    pub fn scene_next (&mut self, last_scene: usize) {
        *self = match self {
            Self::Mix        => Self::Scene(0),
            Self::Track(t)   => Self::Clip(*t, 0),
            Self::Scene(s)   => Self::Scene(last_scene.min(*s + 1)),
            Self::Clip(t, s) => Self::Clip(*t, last_scene.min(*s + 1)),
        }
    }
    pub fn scene_prev (&mut self) {
        *self = match self {
            Self::Mix      => Self::Mix,
            Self::Track(t) => Self::Track(*t),
            Self::Scene(s) => if *s == 0 {
                Self::Mix
            } else {
                Self::Scene(*s - 1)
            },
            Self::Clip(t, s) => if *s == 0 {
                Self::Track(*t)
            } else {
                Self::Clip(*t, s.saturating_sub(1))
            }
        }
    }
}
/// Display mode of arranger
#[derive(PartialEq)]
pub enum ArrangerViewMode { VerticalExpanded, VerticalCompact1, VerticalCompact2, Horizontal }
/// Arranger display mode can be cycled
impl ArrangerViewMode {
    /// Cycle arranger display mode
    pub fn to_next (&mut self) {
        *self = match self {
            Self::VerticalExpanded => Self::VerticalCompact1,
            Self::VerticalCompact1 => Self::VerticalCompact2,
            Self::VerticalCompact2 => Self::Horizontal,
            Self::Horizontal       => Self::VerticalExpanded,
        }
    }
}

struct ArrangerViewVertical<'a, 'b, E: Engine>(
    &'a Arranger<E>, &'b [(usize, usize)], &'b [(usize, usize)]
);

impl<'a, 'b> Content for ArrangerViewVertical<'a, 'b, Tui> {
    type Engine = Tui;
    fn content (&self) -> impl Widget<Engine = Tui> {
        let Self(state, cols, rows) = self;
        let tracks = state.tracks.as_ref();
        let scenes = state.scenes.as_ref();
        let offset = 4 + scene_name_max_len(scenes) as u16;
        Layers::new(move |add|{
            //.add_ref(&Background(Color::Rgb(30, 33, 36)))//COLOR_BG1))//bg_lo(state.focused, state.entered)))
            add(&ColumnSeparators(offset, cols))?;
            add(&RowSeparators(rows))?;
            add(&CursorFocus(state.focused, state.selected, offset, cols, rows))?;
            add(&Split::down(|add|{
                add(&TracksHeader(offset, cols, tracks))?;
                add(&SceneRows(offset, cols, rows, tracks, scenes))
            }))
        })
    }
}

struct ColumnSeparators<'a>(u16, &'a [(usize, usize)]);

impl<'a> Widget for ColumnSeparators<'a> {
    type Engine = Tui;
    fn render (&self, to: &mut TuiOutput) -> Usually<()> {
        let area = to.area();
        let Self(offset, cols) = self;
        let style = Some(Style::default().fg(Nord::SEPARATOR));
        for (_, x) in cols.iter() {
            let x = offset + area.x() + *x as u16 - 1;
            for y in area.y()..area.y2() {
                to.blit(&"▎", x, y, style);
            }
        }
        Ok(())
    }
}

struct RowSeparators<'a>(&'a [(usize, usize)]);

impl<'a> Widget for RowSeparators<'a> {
    type Engine = Tui;
    fn render (&self, to: &mut TuiOutput) -> Usually<()> {
        let area = to.area();
        let Self(rows) = self;
        for (_, y) in rows.iter() {
            let y = area.y() + (*y / 96) as u16 + 1;
            if y >= to.buffer.area.height {
                break
            }
            for x in area.x()..area.x2().saturating_sub(2) {
                if x < to.buffer.area.x && y < to.buffer.area.y {
                    let cell = to.buffer.get_mut(x, y);
                    cell.modifier = Modifier::UNDERLINED;
                    cell.underline_color = Nord::SEPARATOR;
                }
            }
        }
        Ok(())
    }
}

struct CursorFocus<'a>(
    bool, ArrangerFocus, u16, &'a [(usize, usize)], &'a [(usize, usize)]
);

impl<'a> Widget for CursorFocus<'a> {
    type Engine = Tui;
    fn render (&self, to: &mut TuiOutput) -> Usually<()> {
        let area = to.area();
        let Self(focused, selected, offset, cols, rows) = *self;
        let get_track_area = |t: usize| [
            offset + area.x() + cols[t].1 as u16 - 1,
            area.y(),
            cols[t].0 as u16,
            area.h()
        ];
        let get_scene_area = |s: usize| [
            area.x(),
            2 + area.y() + (rows[s].1 / 96) as u16,
            area.w(),
            (rows[s].0 / 96) as u16
        ];
        let get_clip_area = |t: usize, s: usize| [
            offset + area.x() + cols[t].1 as u16 - 1,
            2 + area.y() + (rows[s].1 / 96) as u16,
            cols[t].0 as u16,
            (rows[s].0 / 96) as u16
        ];
        let mut track_area: Option<[u16;4]> = None;
        let mut scene_area: Option<[u16;4]> = None;
        let mut clip_area:  Option<[u16;4]> = None;
        let area = match selected {
            ArrangerFocus::Mix => {
                if focused {
                    to.fill_bg(area, COLOR_BG0);
                }
                area
            },
            ArrangerFocus::Track(t) => {
                track_area = Some(get_track_area(t));
                area
            },
            ArrangerFocus::Scene(s) => {
                scene_area = Some(get_scene_area(s));
                area
            },
            ArrangerFocus::Clip(t, s) => {
                track_area = Some(get_track_area(t));
                scene_area = Some(get_scene_area(s));
                clip_area  = Some(get_clip_area(t, s));
                area
            },
        };
        if let Some([x, y, width, height]) = track_area {
            to.fill_fg([x, y, 1, height], COLOR_BG5);
            to.fill_fg([x + width, y, 1, height], COLOR_BG5);
        }
        if let Some([_, y, _, height]) = scene_area {
            to.fill_ul([area.x(), y - 1, area.w(), 1], COLOR_BG5);
            to.fill_ul([area.x(), y + height - 1, area.w(), 1], COLOR_BG5);
        }
        if focused {
            if let Some(clip_area) = clip_area {
                to.fill_bg(clip_area, COLOR_BG0);
            } else if let Some(track_area) = track_area {
                to.fill_bg(track_area, COLOR_BG0);
            } else if let Some(scene_area) = scene_area {
                to.fill_bg(scene_area, COLOR_BG0);
            }
        }
        //Ok(Some(area))
        Ok(())
    }
}

struct TracksHeader<'a>(
    u16, &'a[(usize, usize)], &'a [Sequencer<Tui>]
);

impl<'a> Content for TracksHeader<'a> {
    type Engine = Tui;
    fn content (&self) -> impl Widget<Engine = Tui> {
        let Self(offset, columns, tracks) = *self;
        Plus::X(offset, Split::right(move |add|{
            for (track, (w, _)) in tracks.iter().zip(columns) {
                add(&Min::XY(*w as u16, 2, Layers::new(|add|{
                    add(&Background(COLOR_BG1))?;
                    add(&track.name.read().unwrap().as_str())
                })))?;
            }
            Ok(())
        }))
    }
}

struct SceneRows<'a>(
    u16, &'a[(usize, usize)], &'a[(usize, usize)], &'a[Sequencer<Tui>], &'a[Scene]
);

impl<'a> Content for SceneRows<'a> {
    type Engine = Tui;
    fn content (&self) -> impl Widget<Engine = Tui> {
        let Self(offset, columns, rows, tracks, scenes) = *self;
        Split::down(move |add| {
            for (scene, (pulses, _)) in scenes.iter().zip(rows) {
                add(&SceneRow(tracks, scene, columns, offset, 1.max((pulses / 96) as u16)))?;
            }
            Ok(())
        })
    }
}

struct SceneRow<'a>(
    &'a[Sequencer<Tui>], &'a Scene, &'a[(usize, usize)], u16, u16
);

impl<'a> Content for SceneRow<'a> {
    type Engine = Tui;
    fn content (&self) -> impl Widget<Engine = Tui> {
        let Self(tracks, scene, columns, offset, height) = self;
        let playing = scene.is_playing(tracks);
        Fixed::Y(*height, Split::right(move |add| {
            add(&Fixed::XY(offset.saturating_sub(1), *height, Split::right(|add|{
                add(&if playing { "▶ " } else { "  " })?;
                add(&scene.name.read().unwrap().as_str())
            })))?;
            for (track, (_w, _x)) in columns.iter().enumerate() {
                add(&SceneClip(tracks.get(track), scene.clips.get(track)))?;
            }
            Ok(())
        }))
    }
}

struct SceneClip<'a>(Option<&'a Sequencer<Tui>>, Option<&'a Option<usize>>);

impl<'a> Content for SceneClip<'a> {
    type Engine = Tui;
    fn content (&self) -> impl Widget<Engine = Tui> {
        let Self(track, clip) = self;
        Layers::new(move |add|{
            let mut color = COLOR_BG0;
            if let (Some(track), Some(Some(clip))) = (track, clip) {
                if let Some(phrase) = track.phrases.get(*clip) {
                    add(&format!(
                        "{clip:02} {}",
                        phrase.read().unwrap().name.read().unwrap()
                    ).as_str())?;
                    color = if track.sequence == Some(*clip) { Nord::PLAYING } else { COLOR_BG1 };
                }
            }
            add(&Background(color))
        })
    }
}

struct ArrangerViewHorizontal<'a, E: Engine>(
    &'a Arranger<E>
);

impl<'a> Content for ArrangerViewHorizontal<'a, Tui> {
    type Engine = Tui;
    fn content (&self) -> impl Widget<Engine = Tui> {
        let Arranger { tracks, focused, selected, scenes, .. } = self.0;
        let tracks = tracks.as_slice();
        Layers::new(|add|{
            add(&focused.then_some(Background(COLOR_BG0)))?;
            add(&Split::right(|add|{
                add(&TrackNameColumn(tracks, *selected))?;
                add(&TrackMonitorColumn(tracks))?;
                add(&TrackRecordColumn(tracks))?;
                add(&TrackOverdubColumn(tracks))?;
                add(&TrackEraseColumn(tracks))?;
                add(&TrackGainColumn(tracks))?;
                add(&TrackScenesColumn(tracks, scenes.as_slice(), *selected))?;
                Ok(())
            }))
        })
    }
}

struct TrackNameColumn<'a>(&'a [Sequencer<Tui>], ArrangerFocus);

impl<'a> Widget for TrackNameColumn<'a> {
    type Engine = Tui;
    fn layout (&self, area: [u16;2]) -> Perhaps<[u16;2]> {
        todo!()
    }
    fn render (&self, to: &mut TuiOutput) -> Usually<()> {
        todo!();
        //let Self(tracks, selected) = self;
        //let yellow = Some(Style::default().yellow().bold().not_dim());
        //let white  = Some(Style::default().white().bold().not_dim());
        //let area = to.area();
        //let area = [area.x(), area.y(), 3 + 5.max(track_name_max_len(tracks)) as u16, area.h()];
        //let offset = 0; // track scroll offset
        //for y in 0..area.h() {
            //if y == 0 {
                //to.blit(&"Mixer", area.x() + 1, area.y() + y, Some(DIM))?;
            //} else if y % 2 == 0 {
                //let index = (y as usize - 2) / 2 + offset;
                //if let Some(track) = tracks.get(index) {
                    //let selected = selected.track() == Some(index);
                    //let style = if selected { yellow } else { white };
                    //to.blit(&format!(" {index:>02} "), area.x(), area.y() + y, style)?;
                    //to.blit(&*track.name.read().unwrap(), area.x() + 4, area.y() + y, style)?;
                //}
            //}
        //}
        //Ok(Some(area))
    }
}

struct TrackMonitorColumn<'a>(&'a [Sequencer<Tui>]);

impl<'a> Widget for TrackMonitorColumn<'a> {
    type Engine = Tui;
    fn layout (&self, area: [u16;2]) -> Perhaps<[u16;2]> {
        todo!()
    }
    fn render (&self, to: &mut TuiOutput) -> Usually<()> {
        todo!();
        //let Self(tracks) = self;
        //let mut area = to.area();
        //let on  = Some(Style::default().not_dim().green().bold());
        //let off = Some(DIM);
        //area.x += 1;
        //for y in 0..area.h() {
            //if y == 0 {
                ////" MON ".blit(to.buffer, area.x, area.y + y, style2)?;
            //} else if y % 2 == 0 {
                //let index = (y as usize - 2) / 2;
                //if let Some(track) = tracks.get(index) {
                    //let style = if track.monitoring { on } else { off };
                    //to.blit(&" MON ", area.x(), area.y() + y, style)?;
                //} else {
                    //area.height = y;
                    //break
                //}
            //}
        //}
        //area.width = 4;
        //Ok(Some(area))
    }
}

struct TrackRecordColumn<'a>(&'a [Sequencer<Tui>]);

impl<'a> Widget for TrackRecordColumn<'a> {
    type Engine = Tui;
    fn layout (&self, area: [u16;2]) -> Perhaps<[u16;2]> {
        todo!()
    }
    fn render (&self, to: &mut TuiOutput) -> Usually<()> {
        todo!();
        //let Self(tracks) = self;
        //let mut area = to.area();
        //let on  = Some(Style::default().not_dim().red().bold());
        //let off = Some(Style::default().dim());
        //area.x += 1;
        //for y in 0..area.h() {
            //if y == 0 {
                ////" REC ".blit(to.buffer, area.x, area.y + y, style2)?;
            //} else if y % 2 == 0 {
                //let index = (y as usize - 2) / 2;
                //if let Some(track) = tracks.get(index) {
                    //let style = if track.recording { on } else { off };
                    //to.blit(&" REC ", area.x(), area.y() + y, style)?;
                //} else {
                    //area.height = y;
                    //break
                //}
            //}
        //}
        //area.width = 4;
        //Ok(Some(area))
    }
}

struct TrackOverdubColumn<'a>(&'a [Sequencer<Tui>]);

impl<'a> Widget for TrackOverdubColumn<'a> {
    type Engine = Tui;
    fn layout (&self, area: [u16;2]) -> Perhaps<[u16;2]> {
        todo!()
    }
    fn render (&self, to: &mut TuiOutput) -> Usually<()> {
        todo!();
        //let Self(tracks) = self;
        //let mut area = to.area();
        //let on  = Some(Style::default().not_dim().yellow().bold());
        //let off = Some(Style::default().dim());
        //area.x = area.x + 1;
        //for y in 0..area.h() {
            //if y == 0 {
                ////" OVR ".blit(to.buffer, area.x, area.y + y, style2)?;
            //} else if y % 2 == 0 {
                //let index = (y as usize - 2) / 2;
                //if let Some(track) = tracks.get(index) {
                    //to.blit(&" OVR ", area.x(), area.y() + y, if track.overdub {
                        //on
                    //} else {
                        //off
                    //})?;
                //} else {
                    //area.height = y;
                    //break
                //}
            //}
        //}
        //area.width = 4;
        //Ok(Some(area))
    }
}

struct TrackEraseColumn<'a>(&'a [Sequencer<Tui>]);

impl<'a> Widget for TrackEraseColumn<'a> {
    type Engine = Tui;
    fn layout (&self, area: [u16;2]) -> Perhaps<[u16;2]> {
        todo!()
    }
    fn render (&self, to: &mut TuiOutput) -> Usually<()> {
        todo!();
        //let Self(tracks) = self;
        //let mut area = to.area();
        //let off = Some(Style::default().dim());
        //area.x = area.x + 1;
        //for y in 0..area.h() {
            //if y == 0 {
                ////" DEL ".blit(to.buffer, area.x, area.y + y, style2)?;
            //} else if y % 2 == 0 {
                //let index = (y as usize - 2) / 2;
                //if let Some(_) = tracks.get(index) {
                    //to.blit(&" DEL ", area.x(), area.y() + y, off)?;
                //} else {
                    //area.height = y;
                    //break
                //}
            //}
        //}
        //area.width = 4;
        //Ok(Some(area))
    }
}

struct TrackGainColumn<'a>(&'a [Sequencer<Tui>]);

impl<'a> Widget for TrackGainColumn<'a> {
    type Engine = Tui;
    fn layout (&self, area: [u16;2]) -> Perhaps<[u16;2]> {
        todo!()
    }
    fn render (&self, to: &mut TuiOutput) -> Usually<()> {
        todo!();
        //let Self(tracks) = self;
        //let mut area = to.area();
        //let off = Some(Style::default().dim());
        //area.x = area.x() + 1;
        //for y in 0..area.h() {
            //if y == 0 {
                ////" GAIN ".blit(to.buffer, area.x, area.y + y, style2)?;
            //} else if y % 2 == 0 {
                //let index = (y as usize - 2) / 2;
                //if let Some(_) = tracks.get(index) {
                    //to.blit(&" +0.0 ", area.x(), area.y() + y, off)?;
                //} else {
                    //area.height = y;
                    //break
                //}
            //}
        //}
        //area.width = 7;
        //Ok(Some(area))
    }
}

struct TrackScenesColumn<'a>(&'a [Sequencer<Tui>], &'a [Scene], ArrangerFocus);

impl<'a> Widget for TrackScenesColumn<'a> {
    type Engine = Tui;
    fn layout (&self, area: [u16;2]) -> Perhaps<[u16;2]> {
        todo!()
    }
    fn render (&self, to: &mut TuiOutput) -> Usually<()> {
        let Self(tracks, scenes, selected) = self;
        let area = to.area();
        let mut x2 = 0;
        let [x, y, _, height] = area;
        for (scene_index, scene) in scenes.iter().enumerate() {
            let active_scene = selected.scene() == Some(scene_index);
            let sep = Some(if active_scene {
                Style::default().yellow().not_dim()
            } else {
                Style::default().dim()
            });
            for y in y+1..y+height {
                to.blit(&"│", x + x2, y, sep);
            }
            let name = scene.name.read().unwrap();
            let mut x3 = name.len() as u16;
            to.blit(&*name, x + x2, y, sep);
            for (i, clip) in scene.clips.iter().enumerate() {
                let active_track = selected.track() == Some(i);
                if let Some(clip) = clip {
                    let y2 = y + 2 + i as u16 * 2;
                    let label = match tracks[i].phrases.get(*clip) {
                        Some(phrase) => &format!("{}", phrase.read().unwrap().name.read().unwrap()),
                        None => "...."
                    };
                    to.blit(&label, x + x2, y2, Some(if active_track && active_scene {
                        Style::default().not_dim().yellow().bold()
                    } else {
                        Style::default().not_dim()
                    }));
                    x3 = x3.max(label.len() as u16)
                }
            }
            x2 = x2 + x3 + 1;
        }
        //Ok(Some([x, y, x2, height]))
        Ok(())
    }
}

/// Appears on first run (i.e. if state dir is missing).
pub struct ArrangerRenameModal<E: Engine> {
    _engine: std::marker::PhantomData<E>,
    done:   bool,
    target: ArrangerFocus,
    value:  String,
    result: Arc<RwLock<String>>,
    cursor: usize
}

impl<E: Engine> ArrangerRenameModal<E> {
    pub fn new (target: ArrangerFocus, value: &Arc<RwLock<String>>) -> Self {
        Self {
            _engine: Default::default(),
            done: false,
            target,
            value:  value.read().unwrap().clone(),
            cursor: value.read().unwrap().len(),
            result: value.clone(),
        }
    }
}

impl Widget for ArrangerRenameModal<Tui> {
    type Engine = Tui;
    fn layout (&self, area: [u16;2]) -> Perhaps<[u16;2]> {
        todo!()
    }
    fn render (&self, to: &mut TuiOutput) -> Usually<()> {
        let area = to.area();
        let y = area.y() + area.h() / 2;
        let bg_area = [1, y - 1, area.w() - 2, 3];
        to.fill_bg(bg_area, Nord::BG0);
        Lozenge(Style::default().bold().white().dim()).draw(to.with_rect(bg_area));
        let label = match self.target {
            ArrangerFocus::Mix => "Rename project:",
            ArrangerFocus::Track(_) => "Rename track:",
            ArrangerFocus::Scene(_) => "Rename scene:",
            ArrangerFocus::Clip(_, _) => "Rename clip:",
        };
        let style = Some(Style::default().not_bold().white().not_dim());
        to.blit(&label, area.x() + 3, y, style);
        let style = Some(Style::default().bold().white().not_dim());
        to.blit(&self.value, area.x() + 3 + label.len() as u16 + 1, y, style);
        let style = Some(Style::default().bold().white().not_dim().reversed());
        to.blit(&"▂", area.x() + 3 + label.len() as u16 + 1 + self.cursor as u16, y, style);
        //Ok(Some(area))
        Ok(())
    }
}

impl Handle<Tui> for ArrangerRenameModal<Tui> {
    fn handle (&mut self, from: &TuiInput) -> Perhaps<bool> {
        match from.event() {
            TuiEvent::Input(Event::Key(k)) => {
                match k.code {
                    KeyCode::Esc => {
                        self.exit();
                    },
                    KeyCode::Enter => {
                        *self.result.write().unwrap() = self.value.clone();
                        self.exit();
                    },
                    KeyCode::Left => {
                        self.cursor = self.cursor.saturating_sub(1);
                    },
                    KeyCode::Right => {
                        self.cursor = self.value.len().min(self.cursor + 1)
                    },
                    KeyCode::Backspace => {
                        let last = self.value.len().saturating_sub(1);
                        self.value = format!("{}{}",
                            &self.value[0..self.cursor.min(last)],
                            &self.value[self.cursor.min(last)..last]
                        );
                        self.cursor = self.cursor.saturating_sub(1)
                    }
                    KeyCode::Char(c) => {
                        self.value.insert(self.cursor, c);
                        self.cursor = self.value.len().min(self.cursor + 1)
                    },
                    _ => {}
                }
                Ok(Some(true))
            },
            _ => Ok(None),
        }
    }
}

impl<E: Engine + Send> Exit for ArrangerRenameModal<E> {
    fn exited (&self) -> bool {
        self.done
    }
    fn exit (&mut self) {
        self.done = true
    }
}

pub fn track_name_max_len <E: Engine> (tracks: &[Sequencer<E>]) -> usize {
    tracks.iter()
        .map(|s|s.name.read().unwrap().len())
        .fold(0, usize::max)
}

pub fn track_clip_name_lengths <E: Engine> (tracks: &[Sequencer<E>]) -> Vec<(usize, usize)> {
    let mut total = 0;
    let mut lengths: Vec<(usize, usize)> = tracks.iter().map(|track|{
        let len = 4 + track.phrases
            .iter()
            .fold(track.name.read().unwrap().len(), |len, phrase|{
                len.max(phrase.read().unwrap().name.read().unwrap().len())
            });
        total = total + len;
        (len, total - len)
    }).collect();
    lengths.push((0, total));
    lengths
}