// Copyright (c) 2017 Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
// Copyright (c) 2017 Maxime “pep” Buquet <pep+code@bouah.net>
//
// 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 minidom::IntoAttributeValue;

use jid::Jid;

use error::Error;

use ns;

use stanza_error::StanzaError;
use disco::Disco;
use ibb::IBB;
use jingle::Jingle;
use ping::Ping;

/// Lists every known payload of a `<iq/>`.
#[derive(Debug, Clone)]
pub enum IqPayload {
    Disco(Disco),
    IBB(IBB),
    Jingle(Jingle),
    Ping(Ping),
}

#[derive(Debug, Clone)]
pub enum IqPayloadType {
    XML(Element),
    Parsed(IqPayload),
}

#[derive(Debug, Clone)]
pub enum IqType {
    Get(IqPayloadType),
    Set(IqPayloadType),
    Result(Option<IqPayloadType>),
    Error(StanzaError),
}

impl IntoAttributeValue for IqType {
    fn into_attribute_value(self) -> Option<String> {
        Some(match self {
            IqType::Get(_) => "get",
            IqType::Set(_) => "set",
            IqType::Result(_) => "result",
            IqType::Error(_) => "error",
        }.to_owned())
    }
}

#[derive(Debug, Clone)]
pub struct Iq {
    pub from: Option<Jid>,
    pub to: Option<Jid>,
    pub id: Option<String>,
    pub payload: IqType,
}

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

    fn try_from(root: &'a Element) -> Result<Iq, Error> {
        if !root.is("iq", ns::JABBER_CLIENT) {
            return Err(Error::ParseError("This is not an iq element."));
        }
        let from = root.attr("from")
            .and_then(|value| value.parse().ok());
        let to = root.attr("to")
            .and_then(|value| value.parse().ok());
        let id = root.attr("id")
            .and_then(|value| value.parse().ok());
        let type_ = match root.attr("type") {
            Some(type_) => type_,
            None => return Err(Error::ParseError("Iq element requires a 'type' attribute.")),
        };

        let mut payload = None;
        let mut error_payload = None;
        for elem in root.children() {
            if payload.is_some() {
                return Err(Error::ParseError("Wrong number of children in iq element."));
            }
            if type_ == "error" {
                if elem.is("error", ns::JABBER_CLIENT) {
                    if error_payload.is_some() {
                        return Err(Error::ParseError("Wrong number of children in iq element."));
                    }
                    error_payload = Some(StanzaError::try_from(elem)?);
                } else if root.children().collect::<Vec<_>>().len() != 2 {
                    return Err(Error::ParseError("Wrong number of children in iq element."));
                }
            } else {
                let parsed_payload = if let Ok(disco) = Disco::try_from(elem) {
                    Some(IqPayload::Disco(disco))
                } else if let Ok(ibb) = IBB::try_from(elem) {
                    Some(IqPayload::IBB(ibb))
                } else if let Ok(jingle) = Jingle::try_from(elem) {
                    Some(IqPayload::Jingle(jingle))
                } else if let Ok(ping) = Ping::try_from(elem) {
                    Some(IqPayload::Ping(ping))
                } else {
                    None
                };

                payload = match parsed_payload {
                    Some(payload) => Some(IqPayloadType::Parsed(payload)),
                    None => Some(IqPayloadType::XML(elem.clone())),
                };
            }
        }

        let type_ = if type_ == "get" {
            if let Some(payload) = payload.clone() {
                IqType::Get(payload.clone())
            } else {
                return Err(Error::ParseError("Wrong number of children in iq element."));
            }
        } else if type_ == "set" {
            if let Some(payload) = payload.clone() {
                IqType::Set(payload.clone())
            } else {
                return Err(Error::ParseError("Wrong number of children in iq element."));
            }
        } else if type_ == "result" {
            if let Some(payload) = payload.clone() {
                IqType::Result(Some(payload.clone()))
            } else {
                IqType::Result(None)
            }
        } else if type_ == "error" {
            if let Some(payload) = error_payload.clone() {
                IqType::Error(payload.clone())
            } else {
                return Err(Error::ParseError("Wrong number of children in iq element."));
            }
        } else {
            panic!()
        };

        Ok(Iq {
            from: from,
            to: to,
            id: id,
            payload: type_,
        })
    }
}

impl<'a> Into<Element> for &'a IqPayload {
    fn into(self) -> Element {
        match *self {
            IqPayload::Disco(ref disco) => disco.into(),
            IqPayload::IBB(ref ibb) => ibb.into(),
            IqPayload::Jingle(ref jingle) => jingle.into(),
            IqPayload::Ping(ref ping) => ping.into(),
        }
    }
}

impl<'a> Into<Element> for &'a Iq {
    fn into(self) -> Element {
        let mut stanza = Element::builder("iq")
                                 .ns(ns::JABBER_CLIENT)
                                 .attr("from", self.from.clone().and_then(|value| Some(String::from(value))))
                                 .attr("to", self.to.clone().and_then(|value| Some(String::from(value))))
                                 .attr("id", self.id.clone())
                                 .attr("type", self.payload.clone())
                                 .build();
        let elem = match self.payload.clone() {
            IqType::Get(IqPayloadType::XML(elem))
          | IqType::Set(IqPayloadType::XML(elem))
          | IqType::Result(Some(IqPayloadType::XML(elem))) => elem,
            IqType::Error(error) => (&error).into(),
            IqType::Get(IqPayloadType::Parsed(payload))
          | IqType::Set(IqPayloadType::Parsed(payload))
          | IqType::Result(Some(IqPayloadType::Parsed(payload))) => (&payload).into(),
            IqType::Result(None) => return stanza,
        };
        stanza.append_child(elem);
        stanza
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use stanza_error::{ErrorType, DefinedCondition};

    #[test]
    fn test_require_type() {
        let elem: Element = "<iq xmlns='jabber:client'/>".parse().unwrap();
        let error = Iq::try_from(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "Iq element requires a 'type' attribute.");
    }

    #[test]
    fn test_get() {
        let elem: Element = "<iq xmlns='jabber:client' type='get'>
            <foo/>
        </iq>".parse().unwrap();
        let iq = Iq::try_from(&elem).unwrap();
        let query: Element = "<foo xmlns='jabber:client'/>".parse().unwrap();
        assert_eq!(iq.from, None);
        assert_eq!(iq.to, None);
        assert_eq!(iq.id, None);
        assert!(match iq.payload {
            IqType::Get(IqPayloadType::XML(element)) => element == query,
            _ => false
        });
    }

    #[test]
    fn test_set() {
        let elem: Element = "<iq xmlns='jabber:client' type='set'>
            <vCard xmlns='vcard-temp'/>
        </iq>".parse().unwrap();
        let iq = Iq::try_from(&elem).unwrap();
        let vcard: Element = "<vCard xmlns='vcard-temp'/>".parse().unwrap();
        assert_eq!(iq.from, None);
        assert_eq!(iq.to, None);
        assert_eq!(iq.id, None);
        assert!(match iq.payload {
            IqType::Set(IqPayloadType::XML(element)) => element == vcard,
            _ => false
        });
    }

    #[test]
    fn test_result_empty() {
        let elem: Element = "<iq xmlns='jabber:client' type='result'/>".parse().unwrap();
        let iq = Iq::try_from(&elem).unwrap();
        assert_eq!(iq.from, None);
        assert_eq!(iq.to, None);
        assert_eq!(iq.id, None);
        assert!(match iq.payload {
            IqType::Result(None) => true,
            _ => false,
        });
    }

    #[test]
    fn test_result() {
        let elem: Element = "<iq xmlns='jabber:client' type='result'>
            <query xmlns='http://jabber.org/protocol/disco#items'/>
        </iq>".parse().unwrap();
        let iq = Iq::try_from(&elem).unwrap();
        let query: Element = "<query xmlns='http://jabber.org/protocol/disco#items'/>".parse().unwrap();
        assert_eq!(iq.from, None);
        assert_eq!(iq.to, None);
        assert_eq!(iq.id, None);
        assert!(match iq.payload {
            IqType::Result(Some(IqPayloadType::XML(element))) => element == query,
            _ => false,
        });
    }

    #[test]
    fn test_error() {
        let elem: Element = "<iq xmlns='jabber:client' type='error'>
            <ping xmlns='urn:xmpp:ping'/>
            <error type='cancel'>
                <service-unavailable xmlns='urn:ietf:params:xml:ns:xmpp-stanzas'/>
            </error>
        </iq>".parse().unwrap();
        let iq = Iq::try_from(&elem).unwrap();
        assert_eq!(iq.from, None);
        assert_eq!(iq.to, None);
        assert_eq!(iq.id, None);
        match iq.payload {
            IqType::Error(error) => {
                assert_eq!(error.type_, ErrorType::Cancel);
                assert_eq!(error.by, None);
                assert_eq!(error.defined_condition, DefinedCondition::ServiceUnavailable);
                assert_eq!(error.texts.len(), 0);
                assert_eq!(error.other, None);
            },
            _ => panic!(),
        }
    }

    #[test]
    fn test_children_invalid() {
        let elem: Element = "<iq xmlns='jabber:client' type='error'></iq>".parse().unwrap();
        let error = Iq::try_from(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "Wrong number of children in iq element.");
    }

    #[test]
    fn test_serialise() {
        let elem: Element = "<iq xmlns='jabber:client' type='result'/>".parse().unwrap();
        let iq2 = Iq {
            from: None,
            to: None,
            id: None,
            payload: IqType::Result(None),
        };
        let elem2 = (&iq2).into();
        assert_eq!(elem, elem2);
    }

    #[test]
    fn test_disco() {
        let elem: Element = "<iq xmlns='jabber:client' type='get'><query xmlns='http://jabber.org/protocol/disco#info'/></iq>".parse().unwrap();
        let iq = Iq::try_from(&elem).unwrap();
        assert!(match iq.payload {
            IqType::Get(IqPayloadType::Parsed(IqPayload::Disco(Disco { .. }))) => true,
            _ => false,
        });
    }
}