/// A trait for elements that can be selected.
///
/// Generally used to enable "toggle" or "active" behavior and styles on an element through the [`Selection`] status.
pub trait Selectable {
    /// Sets whether the element is selected.
    fn selected(self, selected: bool) -> Self;
}

/// Represents the selection status of an element.
#[derive(Debug, Default, PartialEq, Eq, Hash, Clone, Copy)]
pub enum Selection {
    /// The element is not selected.
    #[default]
    Unselected,
    /// The selection state of the element is indeterminate.
    Indeterminate,
    /// The element is selected.
    Selected,
}

impl Selection {
    /// Returns the inverse of the current selection status.
    ///
    /// Indeterminate states become selected if inverted.
    pub fn inverse(&self) -> Self {
        match self {
            Self::Unselected | Self::Indeterminate => Self::Selected,
            Self::Selected => Self::Unselected,
        }
    }
}

impl From<bool> for Selection {
    fn from(selected: bool) -> Self {
        if selected {
            Self::Selected
        } else {
            Self::Unselected
        }
    }
}

impl From<Option<bool>> for Selection {
    fn from(selected: Option<bool>) -> Self {
        match selected {
            Some(true) => Self::Selected,
            Some(false) => Self::Unselected,
            None => Self::Unselected,
        }
    }
}