use std::marker::PhantomData;

use super::*;
use egui::*;

#[derive(Default)]
pub struct NodeFinder<NodeKind> {
    query: String,
    /// Reset every frame. When set, the node finder will be moved at that position
    pub position: Option<Pos2>,
    pub just_spawned: bool,
    _phantom: PhantomData<NodeKind>,
}

pub trait NodeKindIter {
    type Item;
    fn all_kinds<'a>() -> Box<dyn Iterator<Item=&'a Self::Item>>;
}

impl<NodeKind> NodeFinder<NodeKind> {
    pub fn new_at(pos: Pos2) -> Self {
        NodeFinder {
            position: Some(pos),
            just_spawned: true,
            _phantom: Default::default(),
            ..Default::default()
        }
    }

    /// Shows the node selector panel with a search bar. Returns whether a node
    /// archetype was selected and, in that case, the finder should be hidden on
    /// the next frame.
    pub fn show(&mut self, ui: &mut Ui, all_kinds: impl NodeKindIter<Item=NodeKind>) -> Option<NodeKind> {
        let background_color = color_from_hex("#3f3f3f").unwrap();
        let _titlebar_color = background_color.linear_multiply(0.8);
        let text_color = color_from_hex("#fefefe").unwrap();

        ui.visuals_mut().widgets.noninteractive.fg_stroke = Stroke::new(2.0, text_color);

        let frame = Frame::dark_canvas(ui.style())
            .fill(background_color)
            .margin(vec2(5.0, 5.0));

        // The archetype that will be returned.
        let mut submitted_archetype = None;
        frame.show(ui, |ui| {
            ui.vertical(|ui| {
                let resp = ui.text_edit_singleline(&mut self.query);
                if self.just_spawned {
                    resp.request_focus();
                    self.just_spawned = false;
                }

                let mut query_submit = resp.lost_focus() && ui.input().key_down(Key::Enter);

                Frame::default().margin(vec2(10.0, 10.0)).show(ui, |ui| {
                    for archetype in all_kinds.all_kinds() {
                        let archetype_name = archetype.type_label();
                        if archetype_name.contains(self.query.as_str()) {
                            if query_submit {
                                submitted_archetype = Some(archetype);
                                query_submit = false;
                            }
                            if ui.selectable_label(false, archetype_name).clicked() {
                                submitted_archetype = Some(archetype);
                            }
                        }
                    }
                });
            });
        });

        submitted_archetype
    }
}