use quick_xml::events::attributes::Attribute;
use quick_xml::events::{BytesEnd, BytesStart, Event};
use quick_xml::name::{QName, ResolveResult};

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

use super::bind::Jid;

pub const XMLNS_INFO: &'static str = "http://jabber.org/protocol/disco#info";
pub const XMLNS_ITEM: &'static str = "http://jabber.org/protocol/disco#items";

#[derive(PartialEq, Eq, Debug)]
pub struct InfoQuery {
    pub node: Option<String>,
    pub identity: Vec<Identity>,
    pub feature: Vec<Feature>,
}

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

    fn parse() -> Self::P {
        |(mut namespace, mut event): (ResolveResult<'static>, &'static Event<'static>)| -> Result<Self> {
            let mut node = None;
            let mut identity = vec![];
            let mut feature = vec![];
            let (bytes, end) = match event {
                Event::Start(bytes) => (bytes, false),
                Event::Empty(bytes) => (bytes, true),
                _ => return Err(ffail!("Unexpected XML event: {event:?}")),
            };
            for attr in bytes.attributes() {
                let attr = attr?;
                match attr.key.0 {
                    b"node" => {
                        let s = std::str::from_utf8(&attr.value)?;
                        node = Some(s.to_owned())
                    }
                    _ => {}
                }
            }
            if end {
                return Ok(InfoQuery {
                    node,
                    identity,
                    feature,
                });
            }
            loop {
                (namespace, event) = yield;
                let bytes = match event {
                    Event::Start(bytes) => bytes,
                    Event::Empty(bytes) => bytes,
                    Event::End(_) => break,
                    _ => return Err(ffail!("Unexpected XML event: {event:?}")),
                };
                if bytes.name().0 == Identity::NAME.as_bytes() {
                    let res = delegate_parsing!(Identity, namespace, event)?;
                    identity.push(res);
                } else if bytes.name().0 == Feature::NAME.as_bytes() {
                    let res = delegate_parsing!(Feature, namespace, event)?;
                    feature.push(res);
                } else {
                    return Err(ffail!("Unexpected XML event: {event:?}"));
                }
            }
            return Ok(InfoQuery {
                node,
                identity,
                feature,
            });
        }
    }
}

impl FromXmlTag for InfoQuery {
    const NAME: &'static str = "query";

    const NS: &'static str = XMLNS_INFO;
}

impl ToXml for InfoQuery {
    fn serialize(&self, events: &mut Vec<Event<'static>>) {
        let mut bytes = BytesStart::new(format!(r#"query xmlns="{}""#, XMLNS_INFO));
        if let Some(node) = &self.node {
            bytes.push_attribute(Attribute {
                key: QName(b"node"),
                value: node.as_bytes().into(),
            });
        }
        let empty = self.feature.is_empty() && self.identity.is_empty();
        if empty {
            events.push(Event::Empty(bytes));
        } else {
            events.push(Event::Start(bytes));
        }

        for i in &self.identity {
            let mut bytes = BytesStart::new("identity");
            bytes.push_attribute(Attribute {
                key: QName(b"category"),
                value: i.category.as_bytes().into(),
            });
            if let Some(name) = &i.name {
                bytes.push_attribute(Attribute {
                    key: QName(b"name"),
                    value: name.as_bytes().into(),
                });
            }
            bytes.push_attribute(Attribute {
                key: QName(b"type"),
                value: i.r#type.as_bytes().into(),
            });
            events.push(Event::Empty(bytes));
        }

        for f in &self.feature {
            let mut bytes = BytesStart::new("feature");
            bytes.push_attribute(Attribute {
                key: QName(b"var"),
                value: f.var.as_bytes().into(),
            });
            events.push(Event::Empty(bytes));
        }

        if !empty {
            events.push(Event::End(BytesEnd::new("query")));
        }
    }
}

#[derive(PartialEq, Eq, Debug)]
pub struct Identity {
    pub category: String,
    pub name: Option<String>,
    pub r#type: String,
}

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

    fn parse() -> Self::P {
        |(mut namespace, mut event): (ResolveResult<'static>, &'static Event<'static>)| -> Result<Self> {
            let mut category = None;
            let mut name = None;
            let mut r#type = None;
            let (bytes, end) = match event {
                Event::Start(bytes) => (bytes, false),
                Event::Empty(bytes) => (bytes, true),
                _ => return Err(ffail!("Unexpected XML event: {event:?}")),
            };
            for attr in bytes.attributes() {
                let attr = attr?;
                match attr.key.0 {
                    b"category" => {
                        let s = std::str::from_utf8(&attr.value)?;
                        category = Some(s.to_owned())
                    }
                    b"name" => {
                        let s = std::str::from_utf8(&attr.value)?;
                        name = Some(s.to_owned())
                    }
                    b"type" => {
                        let s = std::str::from_utf8(&attr.value)?;
                        r#type = Some(s.to_owned())
                    }
                    _ => {}
                }
            }
            let Some(category) = category else {
                return Err(ffail!("No jid provided"));
            };
            let Some(r#type) = r#type else {
                return Err(ffail!("No type provided"));
            };
            let item = Identity { category, name, r#type };
            if end {
                return Ok(item);
            }

            (namespace, event) = yield;
            let Event::End(_) = event else {
                return Err(ffail!("Unexpected XML event: {event:?}"));
            };
            Ok(item)
        }
    }
}

impl FromXmlTag for Identity {
    const NAME: &'static str = "identity";

    const NS: &'static str = XMLNS_INFO;
}

#[derive(PartialEq, Eq, Debug)]
pub struct Feature {
    pub var: String,
}

impl Feature {
    pub fn new(s: &str) -> Feature {
        Feature { var: s.to_string() }
    }
}

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

    fn parse() -> Self::P {
        |(mut namespace, mut event): (ResolveResult<'static>, &'static Event<'static>)| -> Result<Self> {
            let mut var = None;
            let (bytes, end) = match event {
                Event::Start(bytes) => (bytes, false),
                Event::Empty(bytes) => (bytes, true),
                _ => return Err(ffail!("Unexpected XML event: {event:?}")),
            };
            for attr in bytes.attributes() {
                let attr = attr?;
                match attr.key.0 {
                    b"var" => {
                        let s = std::str::from_utf8(&attr.value)?;
                        var = Some(s.to_owned())
                    }
                    _ => {}
                }
            }
            let Some(var) = var else {
                return Err(ffail!("No jid provided"));
            };
            let item = Feature { var };
            if end {
                return Ok(item);
            }

            (namespace, event) = yield;
            let Event::End(_) = event else {
                return Err(ffail!("Unexpected XML event: {event:?}"));
            };
            Ok(item)
        }
    }
}

impl FromXmlTag for Feature {
    const NAME: &'static str = "feature";

    const NS: &'static str = XMLNS_INFO;
}

#[derive(PartialEq, Eq, Debug)]
pub struct ItemQuery {
    pub item: Vec<Item>,
}

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

    fn parse() -> Self::P {
        |(mut namespace, mut event): (ResolveResult<'static>, &'static Event<'static>)| -> Result<Self> {
            let mut item = vec![];
            let (_, end) = match event {
                Event::Start(bytes) => (bytes, false),
                Event::Empty(bytes) => (bytes, true),
                _ => return Err(ffail!("Unexpected XML event: {event:?}")),
            };
            if end {
                return Ok(ItemQuery { item });
            }
            loop {
                (namespace, event) = yield;
                let bytes = match event {
                    Event::Start(bytes) => bytes,
                    Event::Empty(bytes) => bytes,
                    Event::End(_) => break,
                    _ => return Err(ffail!("Unexpected XML event: {event:?}")),
                };
                if bytes.name().0 == Item::NAME.as_bytes() {
                    let res = delegate_parsing!(Item, namespace, event)?;
                    item.push(res);
                } else {
                    return Err(ffail!("Unexpected XML event: {event:?}"));
                }
            }
            Ok(ItemQuery { item })
        }
    }
}

impl FromXmlTag for ItemQuery {
    const NAME: &'static str = "query";

    const NS: &'static str = XMLNS_ITEM;
}

impl ToXml for ItemQuery {
    fn serialize(&self, events: &mut Vec<Event<'static>>) {
        let bytes = BytesStart::new(format!(r#"query xmlns="{}""#, XMLNS_ITEM));
        let empty = self.item.is_empty();
        if empty {
            events.push(Event::Empty(bytes));
        } else {
            events.push(Event::Start(bytes));
        }

        for f in &self.item {
            let mut bytes = BytesStart::new("item");
            bytes.push_attribute(Attribute {
                key: QName(b"jid"),
                value: f.jid.to_string().into_bytes().into(),
            });
            if let Some(name) = &f.name {
                bytes.push_attribute(Attribute {
                    key: QName(b"name"),
                    value: name.as_bytes().into(),
                });
            }
            if let Some(node) = &f.node {
                bytes.push_attribute(Attribute {
                    key: QName(b"node"),
                    value: node.as_bytes().into(),
                });
            }
            events.push(Event::Empty(bytes));
        }

        if !empty {
            events.push(Event::End(BytesEnd::new("query")));
        }
    }
}

#[derive(PartialEq, Eq, Debug)]
pub struct Item {
    pub jid: super::bind::Jid,
    pub name: Option<String>,
    pub node: Option<String>,
}

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

    fn parse() -> Self::P {
        |(_, mut event): (ResolveResult<'static>, &'static Event<'static>)| -> Result<Self> {
            let mut jid = None;
            let mut name = None;
            let mut node = None;
            let (bytes, end) = match event {
                Event::Start(bytes) => (bytes, false),
                Event::Empty(bytes) => (bytes, true),
                _ => return Err(ffail!("Unexpected XML event: {event:?}")),
            };
            for attr in bytes.attributes() {
                let attr = attr?;
                match attr.key.0 {
                    b"name" => {
                        let s = std::str::from_utf8(&attr.value)?;
                        name = Some(s.to_owned())
                    }
                    b"node" => {
                        let s = std::str::from_utf8(&attr.value)?;
                        node = Some(s.to_owned())
                    }
                    b"jid" => {
                        let s = std::str::from_utf8(&attr.value)?;
                        let s = Jid::from_string(s)?;
                        jid = Some(s)
                    }
                    _ => {}
                }
            }
            let Some(jid) = jid else {
                return Err(ffail!("No jid provided"));
            };
            let item = Item { jid, name, node };
            if end {
                return Ok(item);
            }

            (_, event) = yield;
            let Event::End(_) = event else {
                return Err(ffail!("Unexpected XML event: {event:?}"));
            };
            Ok(item)
        }
    }
}

impl FromXmlTag for Item {
    const NAME: &'static str = "item";

    const NS: &'static str = XMLNS_ITEM;
}