use crate::*;

impl<T: Has<Selection>> HasSelection for T {}
pub trait HasSelection: Has<Selection> {
    fn selection (&self) -> &Selection { self.get() }
    fn selection_mut (&mut self) -> &mut Selection { self.get_mut() }
}

/// Represents the current user selection in the arranger
#[derive(PartialEq, Clone, Copy, Debug, Default)]
pub enum Selection {
    #[default]
    /// Nothing is selected
    Nothing,
    /// The whole mix is selected
    Mix,
    /// A MIDI input is selected.
    Input(usize),
    /// A MIDI output is selected.
    Output(usize),
    /// A scene is selected.
    #[cfg(feature = "scene")] Scene(usize),
    /// A track is selected.
    #[cfg(feature = "track")] Track(usize),
    /// A clip (track × scene) is selected.
    #[cfg(feature = "track")] TrackClip   { track: usize, scene:  usize },
    /// A track's MIDI input connection is selected.
    #[cfg(feature = "track")] TrackInput  { track: usize, port:   usize },
    /// A track's MIDI output connection is selected.
    #[cfg(feature = "track")] TrackOutput { track: usize, port:   usize },
    /// A track device slot is selected.
    #[cfg(feature = "track")] TrackDevice { track: usize, device: usize },
}

#[cfg(feature = "track")]
impl Selection {
    pub fn track (&self) -> Option<usize> {
        use Selection::*;
        if let Track(track)|TrackClip{track,..}|TrackInput{track,..}|TrackOutput{track,..}|TrackDevice{track,..} = self {
            Some(*track)
        } else {
            None
        }
    }
    pub fn select_track (&self, track_count: usize) -> Self {
        use Selection::*;
        match self {
            Mix => Track(0),
            Scene(_) => Mix,
            Track(t) => Track((t + 1) % track_count),
            TrackClip { track, .. } => Track(*track),
            _ => todo!(),
        }
    }
    pub fn select_track_next (&self, len: usize) -> Self {
        use Selection::*;
        match self {
            Mix => Track(0),
            Scene(s) => TrackClip { track: 0, scene: *s },
            Track(t) => if t + 1 < len { Track(t + 1) } else { Mix },
            TrackClip {track, scene} => if track + 1 < len { TrackClip { track: track + 1, scene: *scene } } else { Scene(*scene) },
            _ => todo!()
        }
    }
    pub fn select_track_prev (&self) -> Self {
        use Selection::*;
        match self {
            Mix => Mix,
            Scene(s) => Scene(*s),
            Track(0) => Mix,
            Track(t) => Track(t - 1),
            TrackClip { track: 0, scene } => Scene(*scene),
            TrackClip { track: t, scene } => TrackClip { track: t - 1, scene: *scene },
            _ => todo!()
        }
    }
}

#[cfg(feature = "scene")]
impl Selection {
    pub fn scene (&self) -> Option<usize> {
        use Selection::*;
        match self { Scene(scene) | TrackClip { scene, .. } => Some(*scene), _ => None }
    }
    pub fn select_scene (&self, scene_count: usize) -> Self {
        use Selection::*;
        match self {
            Mix | Track(_) => Scene(0),
            Scene(s) => Scene((s + 1) % scene_count),
            TrackClip { scene, .. } => Track(*scene),
            _ => todo!(),
        }
    }
    pub fn select_scene_next (&self, len: usize) -> Self {
        use Selection::*;
        match self {
            Mix => Scene(0),
            Track(t) => TrackClip { track: *t, scene: 0 },
            Scene(s) => if s + 1 < len { Scene(s + 1) } else { Mix },
            TrackClip { track, scene } => if scene + 1 < len { TrackClip { track: *track, scene: scene + 1 } } else { Track(*track) },
            _ => todo!()
        }
    }
    pub fn select_scene_prev (&self) -> Self {
        use Selection::*;
        match self {
            Mix | Scene(0) => Mix,
            Scene(s) => Scene(s - 1),
            Track(t) => Track(*t),
            TrackClip { track, scene: 0 } => Track(*track),
            TrackClip { track, scene } => TrackClip { track: *track, scene: scene - 1 },
            _ => todo!()
        }
    }
}

impl Selection {
    pub fn describe (
        &self,
        #[cfg(feature = "track")] tracks: &[Track],
        #[cfg(feature = "scene")] scenes: &[Scene],
    ) -> Arc<str> {
        use Selection::*;
        format!("{}", match self {
            Mix => "Everything".to_string(),
            #[cfg(feature = "scene")] Scene(s) =>
                scenes.get(*s).map(|scene|format!("S{s}: {}", &scene.name)).unwrap_or_else(||"S??".into()),
            #[cfg(feature = "track")] Track(t) =>
                tracks.get(*t).map(|track|format!("T{t}: {}", &track.name)).unwrap_or_else(||"T??".into()),
            TrackClip { track, scene } => match (tracks.get(*track), scenes.get(*scene)) {
                (Some(_), Some(s)) => match s.clip(*track) {
                    Some(clip) => format!("T{track} S{scene} C{}", &clip.read().unwrap().name),
                    None       => format!("T{track} S{scene}: Empty")
                },
                _ => format!("T{track} S{scene}: Empty"),
            },
            _ => todo!()
        }).into()
    }
}