// Copyright (c) 2017 Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

use std::convert::TryFrom;

use minidom::Element;

use error::Error;

use ns;

#[derive(Debug, Clone)]
pub struct ExplicitMessageEncryption {
    pub namespace: String,
    pub name: Option<String>,
}

impl<'a> TryFrom<&'a Element> for ExplicitMessageEncryption {
    type Error = Error;

    fn try_from(elem: &'a Element) -> Result<ExplicitMessageEncryption, Error> {
        if !elem.is("encryption", ns::EME) {
            return Err(Error::ParseError("This is not an encryption element."));
        }
        for _ in elem.children() {
            return Err(Error::ParseError("Unknown child in encryption element."));
        }
        let namespace = get_attr!(elem, "namespace", required);
        let name = get_attr!(elem, "name", optional);
        Ok(ExplicitMessageEncryption {
            namespace: namespace,
            name: name,
        })
    }
}

impl<'a> Into<Element> for &'a ExplicitMessageEncryption {
    fn into(self) -> Element {
        Element::builder("encryption")
                .ns(ns::EME)
                .attr("namespace", self.namespace.clone())
                .attr("name", self.name.clone())
                .build()
    }
}

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

    #[test]
    fn test_simple() {
        let elem: Element = "<encryption xmlns='urn:xmpp:eme:0' namespace='urn:xmpp:otr:0'/>".parse().unwrap();
        let encryption = ExplicitMessageEncryption::try_from(&elem).unwrap();
        assert_eq!(encryption.namespace, "urn:xmpp:otr:0");
        assert_eq!(encryption.name, None);

        let elem: Element = "<encryption xmlns='urn:xmpp:eme:0' namespace='some.unknown.mechanism' name='SuperMechanism'/>".parse().unwrap();
        let encryption = ExplicitMessageEncryption::try_from(&elem).unwrap();
        assert_eq!(encryption.namespace, "some.unknown.mechanism");
        assert_eq!(encryption.name, Some(String::from("SuperMechanism")));
    }

    #[test]
    fn test_unknown() {
        let elem: Element = "<replace xmlns='urn:xmpp:message-correct:0'/>".parse().unwrap();
        let error = ExplicitMessageEncryption::try_from(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "This is not an encryption element.");
    }

    #[test]
    fn test_invalid_child() {
        let elem: Element = "<encryption xmlns='urn:xmpp:eme:0'><coucou/></encryption>".parse().unwrap();
        let error = ExplicitMessageEncryption::try_from(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "Unknown child in encryption element.");
    }

    #[test]
    fn test_serialise() {
        let elem: Element = "<encryption xmlns='urn:xmpp:eme:0' namespace='coucou'/>".parse().unwrap();
        let eme = ExplicitMessageEncryption { namespace: String::from("coucou"), name: None };
        let elem2 = (&eme).into();
        assert_eq!(elem, elem2);
    }
}