use quick_xml::events::attributes::Attribute;
use quick_xml::events::{BytesStart, Event};
use quick_xml::name::QName;
use quick_xml::{NsReader, Writer};
use tokio::io::{AsyncBufRead, AsyncWrite};

use super::skip_text;

use anyhow::{anyhow, Result};

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

pub struct StartTLS;
impl StartTLS {
    pub async fn parse(
        reader: &mut NsReader<impl AsyncBufRead + Unpin>,
        buf: &mut Vec<u8>,
    ) -> Result<StartTLS> {
        let incoming = skip_text!(reader, buf);
        if let Event::Empty(ref e) = incoming {
            if e.name().0 == b"starttls" {
                return Ok(StartTLS);
            }
        }
        Err(anyhow!("XML tag starttls expected, received: {incoming:?}"))
    }
}

pub struct ProceedTLS;
impl ProceedTLS {
    pub async fn write_xml(&self, writer: &mut Writer<impl AsyncWrite + Unpin>) -> Result<()> {
        let mut event = BytesStart::new("proceed");
        let attributes = [Attribute {
            key: QName(b"xmlns"),
            value: XMLNS.as_bytes().into(),
        }];
        event.extend_attributes(attributes.into_iter());
        writer.write_event_async(Event::Empty(event)).await?;
        Ok(())
    }
}