use crate::*;

/// Various possible dialog modes.
#[derive(Debug, Clone, Default, PartialEq)]
pub enum Dialog {
    #[default] None,
    Help(usize),
    Menu(usize, MenuItems),
    Device(usize),
    Message(Arc<str>),
    Browse(BrowseTarget, Arc<Browse>),
    Options,
}

#[derive(Debug, Clone, Default, PartialEq)]
pub struct MenuItems(pub Arc<[MenuItem]>);

impl AsRef<Arc<[MenuItem]>> for MenuItems {
    fn as_ref (&self) -> &Arc<[MenuItem]> {
        &self.0
    }
}

#[derive(Clone)]
pub struct MenuItem(
    /// Label
    pub Arc<str>,
    /// Callback
    pub Arc<Box<dyn Fn(&mut App)->Usually<()> + Send + Sync>>
);

impl Default for MenuItem {
    fn default () -> Self { Self("".into(), Arc::new(Box::new(|_|Ok(())))) }
}

impl_debug!(MenuItem |self, w| { write!(w, "{}", &self.0) });

impl PartialEq for MenuItem {
    fn eq (&self, other: &Self) -> bool {
        self.0 == other.0
    }
}

impl Dialog {
    pub fn welcome () -> Self {
        Self::Menu(1, MenuItems([
            MenuItem("Resume session".into(),     Arc::new(Box::new(|_|Ok(())))),
            MenuItem("Create new session".into(), Arc::new(Box::new(|app|Ok({
                app.dialog = Dialog::None;
                app.mode = app.config.modes.clone().read().unwrap().get(":arranger").cloned().unwrap();
            })))),
            MenuItem("Load old session".into(),   Arc::new(Box::new(|_|Ok(())))),
        ].into()))
    }
    pub fn menu_next (&self) -> Self {
        match self {
            Self::Menu(index, items) => Self::Menu(wrap_inc(*index, items.0.len()), items.clone()),
            _ => Self::None
        }
    }
    pub fn menu_prev (&self) -> Self {
        match self {
            Self::Menu(index, items) => Self::Menu(wrap_dec(*index, items.0.len()), items.clone()),
            _ => Self::None
        }
    }
    pub fn menu_selected (&self) -> Option<usize> {
        if let Self::Menu(selected, _) = self { Some(*selected) } else { None }
    }
    pub fn device_kind (&self) -> Option<usize> {
        if let Self::Device(index) = self { Some(*index) } else { None }
    }
    pub fn device_kind_next (&self) -> Option<usize> {
        self.device_kind().map(|index|(index + 1) % device_kinds().len())
    }
    pub fn device_kind_prev (&self) -> Option<usize> {
        self.device_kind().map(|index|index.overflowing_sub(1).0.min(device_kinds().len().saturating_sub(1)))
    }
    pub fn message (&self) -> Option<&str> {
        todo!()
    }
    pub fn browser (&self) -> Option<&Arc<Browse>> {
        todo!()
    }
    pub fn browser_target (&self) -> Option<&BrowseTarget> {
        todo!()
    }
}