#![allow(unused_variables)]

use quick_xml::events::Event;
use quick_xml::name::ResolveResult;

use crate::xml::*;
use anyhow::{anyhow, Result};

pub const XMLNS: &'static str = "http://jabber.org/protocol/muc";

#[derive(PartialEq, Eq, Debug, Default)]
pub struct History {
    pub maxchars: Option<u32>,
    pub maxstanzas: Option<u32>,
    pub seconds: Option<u32>,
}

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

    fn parse() -> Self::P {
        |(namespace, event): (ResolveResult<'static>, &'static Event<'static>)| -> Result<Self> {
            let mut history = History::default();
            let (bytes, end) = match event {
                Event::Start(bytes) if bytes.name().0 == Self::NAME.as_bytes() => (bytes, false),
                Event::Empty(bytes) if bytes.name().0 == Self::NAME.as_bytes() => (bytes, true),
                _ => return Err(anyhow!("Unexpected XML event: {event:?}")),
            };
            for attr in bytes.attributes() {
                let attr = attr?;
                match attr.key.0 {
                    b"maxchars" => {
                        let s = std::str::from_utf8(&attr.value)?;
                        let a = s.parse()?;
                        history.maxchars = Some(a)
                    }
                    b"maxstanzas" => {
                        let s = std::str::from_utf8(&attr.value)?;
                        let a = s.parse()?;
                        history.maxstanzas = Some(a)
                    }
                    b"seconds" => {
                        let s = std::str::from_utf8(&attr.value)?;
                        let a = s.parse()?;
                        history.seconds = Some(a)
                    }
                    _ => {}
                }
            }
            if end {
                return Ok(history);
            }

            let (namespace, event) = yield;
            let Event::End(bytes) = event else {
                return Err(anyhow!("Unexpected XML event: {event:?}"));
            };
            Ok(history)
        }
    }
}

impl FromXmlTag for History {
    const NAME: &'static str = "history";

    const NS: &'static str = XMLNS;
}

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

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

    fn parse() -> Self::P {
        |(namespace, event): (ResolveResult<'static>, &'static Event<'static>)| -> Result<Self> {
            let bytes = match event {
                Event::Start(bytes) if bytes.name().0 == Self::NAME.as_bytes() => bytes,
                _ => return Err(anyhow!("Unexpected XML event: {event:?}")),
            };
            let (namespace, event) = yield;
            let Event::Text(bytes) = event else {
                return Err(anyhow!("Unexpected XML event: {event:?}"));
            };
            let s = std::str::from_utf8(bytes)?.to_string();
            let (namespace, event) = yield;
            let Event::End(bytes) = event else {
                return Err(anyhow!("Unexpected XML event: {event:?}"));
            };
            Ok(Password(s))
        }
    }
}

impl FromXmlTag for Password {
    const NAME: &'static str = "password";

    const NS: &'static str = XMLNS;
}

#[derive(PartialEq, Eq, Debug, Default)]
pub struct X {
    pub history: Option<History>,
    pub password: Option<Password>,
}

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

    fn parse() -> Self::P {
        |(namespace, event): (ResolveResult<'static>, &'static Event<'static>)| -> Result<Self> {
            let mut res = X::default();
            let (_, end) = match event {
                Event::Start(bytes) => (bytes, false),
                Event::Empty(bytes) => (bytes, true),
                _ => return Err(anyhow!("Unexpected XML event: {event:?}")),
            };
            if end {
                return Ok(res);
            }

            loop {
                let (namespace, event) = yield;
                let bytes = match event {
                    Event::Start(bytes) => bytes,
                    Event::Empty(bytes) => bytes,
                    Event::End(_) => break,
                    _ => return Err(anyhow!("Unexpected XML event: {event:?}")),
                };
                if bytes.name().0 == Password::NAME.as_bytes() {
                    let password = delegate_parsing!(Password, namespace, event)?;
                    res.password = Some(password);
                } else if bytes.name().0 == History::NAME.as_bytes() {
                    let history = delegate_parsing!(History, namespace, event)?;
                    res.history = Some(history);
                } else {
                    return Err(anyhow!("Unexpected XML event: {event:?}"));
                }
            }

            Ok(res)
        }
    }
}

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn test_history_success_empty() {
        let input = "<history/>";
        let res: History = parse(input).unwrap();
        let expected = History {
            maxchars: None,
            maxstanzas: None,
            seconds: None,
        };
        assert_eq!(res, expected);
    }

    #[test]
    fn test_history_success_empty_attrs() {
        let input = r#"<history maxchars="1" maxstanzas="2" seconds="4"/>"#;
        let res: History = parse(input).unwrap();
        let expected = History {
            maxchars: Some(1),
            maxstanzas: Some(2),
            seconds: Some(4),
        };
        assert_eq!(res, expected);
    }

    #[test]
    fn test_history_success_start_end() {
        let input = r#"<history></history>"#;
        let res: History = parse(input).unwrap();
        let expected = History {
            maxchars: None,
            maxstanzas: None,
            seconds: None,
        };
        assert_eq!(res, expected);
    }

    #[test]
    fn test_history_incorrect_empty() {
        let input = r#"<iq/>"#;
        parse::<History>(input).err().unwrap();
    }

    #[test]
    fn test_password_success() {
        let input = "<password>olala</password>";
        let res: Password = parse(input).unwrap();
        let expected = Password("olala".into());
        assert_eq!(res, expected);
    }

    #[test]
    fn test_password_incorrect() {
        let input = r#"<iq>asdsd</iq>"#;
        parse::<Password>(input).err().unwrap();
    }

    #[test]
    fn test_x_success_empty() {
        let input = "<x/>";
        let res: X = parse(input).unwrap();
        let expected = X {
            history: None,
            password: None,
        };
        assert_eq!(res, expected);
    }

    #[test]
    fn test_x_success_full() {
        let input = r#"<x><password>ololo</password><history maxchars="1"/></x>"#;
        let res: X = parse(input).unwrap();
        let expected = X {
            history: Some(History {
                maxchars: Some(1),
                maxstanzas: None,
                seconds: None,
            }),
            password: Some(Password("ololo".into())),
        };
        assert_eq!(res, expected);
    }
}