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

use crate::prelude::*;
use crate::util::xml::*;

pub const XMLNS: &'static str = "urn:ietf:params:xml:ns:xmpp-session";

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

pub struct SessionParser(SessionParserInner);

enum SessionParserInner {
    Initial,
    InSession,
}

impl Parser for SessionParser {
    type Output = Result<Session>;

    fn consume<'a>(
        self: Self,
        namespace: quick_xml::name::ResolveResult,
        event: &quick_xml::events::Event<'a>,
    ) -> Continuation<Self, Self::Output> {
        match self.0 {
            SessionParserInner::Initial => match event {
                Event::Start(_) => {
                    Continuation::Continue(SessionParser(SessionParserInner::InSession))
                }
                Event::Empty(_) => Continuation::Final(Ok(Session)),
                _ => Continuation::Final(Err(ffail!("Unexpected XML event: {event:?}"))),
            },
            SessionParserInner::InSession => match event {
                Event::End(_) => Continuation::Final(Ok(Session)),
                _ => Continuation::Final(Err(ffail!("Unexpected XML event: {event:?}"))),
            },
        }
    }
}

impl FromXml for Session {
    type P = SessionParser;

    fn parse() -> Self::P {
        SessionParser(SessionParserInner::Initial)
    }
}

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

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