use orbtk::prelude::*;

use std::collections::VecDeque;

#[derive(Debug)]
pub enum Event {
    Create(Entity),
    Delete(Entity),
}

#[derive(AsAny, Default)]
pub struct AppState {
    events: VecDeque<Event>,
    pub notes: Entity,
    count: u32,
}

impl AppState {
    fn append_note(&self, ctx: &mut Context, copy: String) {
	let id = ctx.entity;
	let bctx = &mut ctx.build_context();
	let text = TextBox::create().text(copy);

	let container = Stack::create()
	    .orientation(Orientation::Horizontal)
	    .vertical_alignment(Alignment::Start)
	    .child(text.build(bctx))
	    .build(bctx);

	let button = Button::create()
	    .horizontal_alignment(Alignment::End)
	    .text("Delete")
	    .on_click(move |ctxt, _| {
		ctxt.get_mut::<AppState>(id)
		    .events
		    .push_back(Event::Delete(container));

		true
	    })
	    .build(bctx);

	bctx.append_child(container, button);
	bctx.append_child(self.notes, container);
    }

    fn fetch_text(ctx: &mut Context, entity: Entity) -> Option<String> {
	let mut widget = ctx.get_widget(entity);

	let entry = widget.get_mut::<String16>("text");
	if entry.is_empty() {
	    return None;
	}

	let copy = entry.to_string();
	entry.clear();
	Some(copy)
    }

    pub fn send(&mut self, event: Event) {
	self.events.push_back(event);
    }
}

impl State for AppState {
    fn update(&mut self, _: &mut Registry, ctx: &mut Context) {
	if let Some(event) = self.events.pop_front() {
	    match event {
		// Create and append the note to the UI.
		Event::Create(entity) => {
		    if let Some(copy) = Self::fetch_text(ctx, entity) {
			self.append_note(ctx, copy);
			let count = self.count + 1;
			self.count = count;
			if count == 1 {
			    ctx.widget().set::<f64>("spacing", 12.0);
			}
		    }
		}

		// Delete the note of the given ID from the UI.
		Event::Delete(id) => {
		    ctx.remove_child_from(id, self.notes);
		    let count = self.count - 1;
		    self.count = count;
		    if count == 0 {
			ctx.widget().set::<f64>("spacing", 0.0);
		    }
		}
	    }
	}
    }
}