extern crate minidom;

use minidom::Element;

use error::Error;
use ns::{DISCO_INFO_NS, DATA_FORMS_NS};

use data_forms::{DataForm, DataFormType, parse_data_form};

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

#[derive(Debug)]
pub struct Identity {
    pub category: String, // TODO: use an enum here.
    pub type_: String, // TODO: use an enum here.
    pub xml_lang: String,
    pub name: Option<String>,
}

#[derive(Debug)]
pub struct Disco {
    pub node: Option<String>,
    pub identities: Vec<Identity>,
    pub features: Vec<Feature>,
    pub extensions: Vec<DataForm>,
}

pub fn parse_disco(root: &Element) -> Result<Disco, Error> {
    assert!(root.is("query", DISCO_INFO_NS));
    let mut identities: Vec<Identity> = vec!();
    let mut features: Vec<Feature> = vec!();
    let mut extensions: Vec<DataForm> = vec!();

    let node = root.attr("node")
                   .and_then(|node| node.parse().ok());

    for child in root.children() {
        if child.is("feature", DISCO_INFO_NS) {
            let feature = child.attr("var")
                               .ok_or(Error::ParseError("Feature must have a 'var' attribute."))?;
            features.push(Feature {
                var: feature.to_owned(),
            });
        } else if child.is("identity", DISCO_INFO_NS) {
            let category = child.attr("category")
                                .ok_or(Error::ParseError("Identity must have a 'category' attribute."))?;
            if category == "" {
                return Err(Error::ParseError("Identity must have a non-empty 'category' attribute."))
            }

            let type_ = child.attr("type")
                             .ok_or(Error::ParseError("Identity must have a 'type' attribute."))?;
            if type_ == "" {
                return Err(Error::ParseError("Identity must have a non-empty 'type' attribute."))
            }

            // TODO: this must check for the namespace of the attribute, but minidom doesn’t support that yet, see issue #2.
            let xml_lang = child.attr("lang").unwrap_or("");
            let name = child.attr("name")
                            .and_then(|node| node.parse().ok());
            identities.push(Identity {
                category: category.to_owned(),
                type_: type_.to_owned(),
                xml_lang: xml_lang.to_owned(),
                name: name,
            });
        } else if child.is("x", DATA_FORMS_NS) {
            let data_form = parse_data_form(child)?;
            match data_form.type_ {
                DataFormType::Result_ => (),
                _ => return Err(Error::ParseError("Data form must have a 'result' type in disco#info.")),
            }
            match data_form.form_type {
                Some(_) => extensions.push(data_form),
                None => return Err(Error::ParseError("Data form found without a FORM_TYPE.")),
            }
        } else {
            return Err(Error::ParseError("Unknown element in disco#info."));
        }
    }

    if identities.is_empty() {
        return Err(Error::ParseError("There must be at least one identity in disco#info."));
    }
    if features.is_empty() {
        return Err(Error::ParseError("There must be at least one feature in disco#info."));
    }
    if !features.contains(&Feature { var: DISCO_INFO_NS.to_owned() }) {
        return Err(Error::ParseError("disco#info feature not present in disco#info."));
    }

    return Ok(Disco {
        node: node,
        identities: identities,
        features: features,
        extensions: extensions
    });
}

#[cfg(test)]
mod tests {
    use minidom::Element;
    use error::Error;
    use disco;

    #[test]
    fn test_simple() {
        let elem: Element = "<query xmlns='http://jabber.org/protocol/disco#info'><identity category='client' type='pc'/><feature var='http://jabber.org/protocol/disco#info'/></query>".parse().unwrap();
        let query = disco::parse_disco(&elem).unwrap();
        assert!(query.node.is_none());
        assert_eq!(query.identities.len(), 1);
        assert_eq!(query.features.len(), 1);
        assert!(query.extensions.is_empty());
    }

    #[test]
    fn test_invalid() {
        let elem: Element = "<query xmlns='http://jabber.org/protocol/disco#info'><coucou/></query>".parse().unwrap();
        let error = disco::parse_disco(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "Unknown element in disco#info.");

        let elem: Element = "<query xmlns='http://jabber.org/protocol/disco#info'/>".parse().unwrap();
        let error = disco::parse_disco(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "There must be at least one identity in disco#info.");

        let elem: Element = "<query xmlns='http://jabber.org/protocol/disco#info'><identity/></query>".parse().unwrap();
        let error = disco::parse_disco(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "Identity must have a 'category' attribute.");

        let elem: Element = "<query xmlns='http://jabber.org/protocol/disco#info'><identity category=''/></query>".parse().unwrap();
        let error = disco::parse_disco(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "Identity must have a non-empty 'category' attribute.");

        let elem: Element = "<query xmlns='http://jabber.org/protocol/disco#info'><identity category='coucou'/></query>".parse().unwrap();
        let error = disco::parse_disco(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "Identity must have a 'type' attribute.");

        let elem: Element = "<query xmlns='http://jabber.org/protocol/disco#info'><identity category='coucou' type=''/></query>".parse().unwrap();
        let error = disco::parse_disco(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "Identity must have a non-empty 'type' attribute.");

        let elem: Element = "<query xmlns='http://jabber.org/protocol/disco#info'><feature/></query>".parse().unwrap();
        let error = disco::parse_disco(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "Feature must have a 'var' attribute.");

        let elem: Element = "<query xmlns='http://jabber.org/protocol/disco#info'><identity category='client' type='pc'/></query>".parse().unwrap();
        let error = disco::parse_disco(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "There must be at least one feature in disco#info.");

        let elem: Element = "<query xmlns='http://jabber.org/protocol/disco#info'><identity category='client' type='pc'/><feature var='http://jabber.org/protocol/disco#items'/></query>".parse().unwrap();
        let error = disco::parse_disco(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "disco#info feature not present in disco#info.");
    }
}