use crate::*;

#[derive(PartialEq)]
/// 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_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 }
    }
}

/// Track focus methods
impl ArrangerFocus {
    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)
            }
        }
    }
}

/// Scene focus methods
impl ArrangerFocus {
    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))
            }
        }
    }
}