use crate::ifs::wl_seat::WlSeatGlobal;
use crate::tree::{Node, OutputNode};
use crate::utils::clonecell::CloneCell;
use std::ops::Deref;
use std::rc::Rc;

pub struct KbOwnerHolder {
    default: Rc<DefaultKbOwner>,
    owner: CloneCell<Rc<dyn KbOwner>>,
}

impl Default for KbOwnerHolder {
    fn default() -> Self {
        Self {
            default: Rc::new(DefaultKbOwner),
            owner: CloneCell::new(Rc::new(DefaultKbOwner)),
        }
    }
}

impl KbOwnerHolder {
    pub fn grab(&self, seat: &Rc<WlSeatGlobal>, node: Rc<dyn Node>) -> bool {
        self.owner.get().grab(seat, node)
    }

    pub fn ungrab(&self, seat: &Rc<WlSeatGlobal>) {
        self.owner.get().ungrab(seat)
    }

    pub fn set_kb_node(&self, seat: &Rc<WlSeatGlobal>, node: Rc<dyn Node>) {
        self.owner.get().set_kb_node(seat, node);
    }

    pub fn workspace_changed(&self, seat: &Rc<WlSeatGlobal>, output: &Rc<OutputNode>) {
        self.owner.get().workspace_changed(seat, output);
    }
}

struct DefaultKbOwner;

struct GrabKbOwner;

trait KbOwner {
    fn grab(&self, seat: &Rc<WlSeatGlobal>, node: Rc<dyn Node>) -> bool;
    fn ungrab(&self, seat: &Rc<WlSeatGlobal>);
    fn set_kb_node(&self, seat: &Rc<WlSeatGlobal>, node: Rc<dyn Node>);
    fn workspace_changed(&self, seat: &Rc<WlSeatGlobal>, output: &Rc<OutputNode>);
}

impl KbOwner for DefaultKbOwner {
    fn grab(&self, seat: &Rc<WlSeatGlobal>, node: Rc<dyn Node>) -> bool {
        self.set_kb_node(seat, node);
        seat.kb_owner.owner.set(Rc::new(GrabKbOwner));
        true
    }

    fn ungrab(&self, _seat: &Rc<WlSeatGlobal>) {
        // nothing
    }

    fn set_kb_node(&self, seat: &Rc<WlSeatGlobal>, node: Rc<dyn Node>) {
        let old = seat.keyboard_node.get();
        if old.id() == node.id() {
            return;
        }
        old.unfocus(seat);
        if old.seat_state().unfocus(seat) {
            old.active_changed(false);
        }

        if node.seat_state().focus(seat) {
            node.active_changed(true);
        }
        node.clone().focus(seat);
        seat.keyboard_node.set(node.clone());
    }

    fn workspace_changed(&self, seat: &Rc<WlSeatGlobal>, output: &Rc<OutputNode>) {
        let new_ws = match output.workspace.get() {
            Some(ws) => ws,
            _ => return,
        };
        let node = seat.keyboard_node.get();
        let ws = match node.get_workspace() {
            None => return,
            Some(ws) => ws,
        };
        let ws_output = ws.output.get();
        if ws_output.id != output.id {
            return;
        }
        for tl in seat.toplevel_focus_history.rev_iter() {
            if let Some(tl_ws) = tl.as_node().get_workspace() {
                if tl_ws.id == new_ws.id {
                    self.set_kb_node(seat, tl.deref().clone().into_node());
                    return;
                }
            }
        }
        self.set_kb_node(seat, seat.state.root.clone());
    }
}

impl KbOwner for GrabKbOwner {
    fn grab(&self, _seat: &Rc<WlSeatGlobal>, _node: Rc<dyn Node>) -> bool {
        false
    }

    fn ungrab(&self, seat: &Rc<WlSeatGlobal>) {
        seat.kb_owner.owner.set(seat.kb_owner.default.clone());
    }

    fn set_kb_node(&self, _seat: &Rc<WlSeatGlobal>, _node: Rc<dyn Node>) {
        // nothing
    }

    fn workspace_changed(&self, _seat: &Rc<WlSeatGlobal>, _output: &Rc<OutputNode>) {
        // nothing
    }
}