use minidom::Element;
use jid::Jid;

use error::Error;

use ns;

#[derive(Debug, Clone)]
pub enum StanzaId {
    StanzaId {
        id: String,
        by: Jid,
    },
    OriginId {
        id: String,
    },
}

pub fn parse_stanza_id(root: &Element) -> Result<StanzaId, Error> {
    let is_stanza_id = root.is("stanza-id", ns::SID);
    if !is_stanza_id && !root.is("origin-id", ns::SID) {
        return Err(Error::ParseError("This is not a stanza-id or origin-id element."));
    }
    for _ in root.children() {
        return Err(Error::ParseError("Unknown child in stanza-id or origin-id element."));
    }
    let id = match root.attr("id") {
        Some(id) => id.to_owned(),
        None => return Err(Error::ParseError("No 'id' attribute present in stanza-id or origin-id.")),
    };
    Ok(if is_stanza_id {
        let by = match root.attr("by") {
            Some(by) => by.parse().unwrap(),
            None => return Err(Error::ParseError("No 'by' attribute present in stanza-id.")),
        };
        StanzaId::StanzaId { id, by }
    } else {
        StanzaId::OriginId { id }
    })
}

pub fn serialise(stanza_id: &StanzaId) -> Element {
    match *stanza_id {
        StanzaId::StanzaId { ref id, ref by } => {
            Element::builder("stanza-id")
                    .ns(ns::SID)
                    .attr("id", id.clone())
                    .attr("by", String::from(by.clone()))
                    .build()
        },
        StanzaId::OriginId { ref id } => {
            Element::builder("origin-id")
                    .ns(ns::SID)
                    .attr("id", id.clone())
                    .build()
        },
    }
}

#[cfg(test)]
mod tests {
    use std::str::FromStr;

    use minidom::Element;
    use jid::Jid;
    use error::Error;
    use stanza_id;

    #[test]
    fn test_simple() {
        let elem: Element = "<stanza-id xmlns='urn:xmpp:sid:0' id='coucou' by='coucou@coucou'/>".parse().unwrap();
        let stanza_id = stanza_id::parse_stanza_id(&elem).unwrap();
        if let stanza_id::StanzaId::StanzaId { id, by } = stanza_id {
            assert_eq!(id, String::from("coucou"));
            assert_eq!(by, Jid::from_str("coucou@coucou").unwrap());
        } else {
            panic!();
        }

        let elem: Element = "<origin-id xmlns='urn:xmpp:sid:0' id='coucou'/>".parse().unwrap();
        let stanza_id = stanza_id::parse_stanza_id(&elem).unwrap();
        if let stanza_id::StanzaId::OriginId { id } = stanza_id {
            assert_eq!(id, String::from("coucou"));
        } else {
            panic!();
        }
    }

    #[test]
    fn test_invalid_child() {
        let elem: Element = "<stanza-id xmlns='urn:xmpp:sid:0'><coucou/></stanza-id>".parse().unwrap();
        let error = stanza_id::parse_stanza_id(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "Unknown child in stanza-id or origin-id element.");
    }

    #[test]
    fn test_invalid_id() {
        let elem: Element = "<stanza-id xmlns='urn:xmpp:sid:0'/>".parse().unwrap();
        let error = stanza_id::parse_stanza_id(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "No 'id' attribute present in stanza-id or origin-id.");
    }

    #[test]
    fn test_invalid_by() {
        let elem: Element = "<stanza-id xmlns='urn:xmpp:sid:0' id='coucou'/>".parse().unwrap();
        let error = stanza_id::parse_stanza_id(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "No 'by' attribute present in stanza-id.");
    }

    #[test]
    fn test_serialise() {
        let elem: Element = "<stanza-id xmlns='urn:xmpp:sid:0' id='coucou' by='coucou@coucou'/>".parse().unwrap();
        let stanza_id = stanza_id::StanzaId::StanzaId { id: String::from("coucou"), by: Jid::from_str("coucou@coucou").unwrap() };
        let elem2 = stanza_id::serialise(&stanza_id);
        assert_eq!(elem, elem2);
    }
}