use quick_xml::events::{BytesStart, Event};

use crate::xml::*;
use anyhow::{anyhow, Result};
use quick_xml::name::ResolveResult;

pub const XMLNS: &'static str = "jabber:iq:roster";

#[derive(PartialEq, Eq, Debug)]
pub struct RosterQuery;

impl FromXml for RosterQuery {
    type P = impl Parser<Output = Result<Self>>;

    fn parse() -> Self::P {
        |(mut namespace, mut event): (ResolveResult<'static>, &'static Event<'static>)| -> Result<Self> {
            match event {
                Event::Start(_) => (),
                Event::Empty(_) => return Ok(RosterQuery),
                _ => return Err(anyhow!("Unexpected XML event: {event:?}")),
            }
            (namespace, event) = yield;
            match event {
                Event::End(_) => return Ok(RosterQuery),
                _ => return Err(anyhow!("Unexpected XML event: {event:?}")),
            }
        }
    }
}

impl FromXmlTag for RosterQuery {
    const NAME: &'static str = "query";
    const NS: &'static str = XMLNS;
}

impl ToXml for RosterQuery {
    fn serialize(&self, events: &mut Vec<Event<'static>>) {
        events.push(Event::Empty(BytesStart::new(format!(r#"query xmlns="{}""#, XMLNS))));
    }
}