// 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 std::str::FromStr;

use minidom::{Element, IntoAttributeValue};
use jid::Jid;

use error::Error;

use data_forms::DataForm;
use rsm::Set;
use forwarding::Forwarded;

use ns;

#[derive(Debug, Clone)]
pub struct Query {
    pub queryid: Option<String>,
    pub node: Option<String>,
    pub form: Option<DataForm>,
    pub set: Option<Set>,
}

#[derive(Debug, Clone)]
pub struct Result_ {
    pub queryid: String,
    pub id: String,
    pub forwarded: Forwarded,
}

#[derive(Debug, Clone)]
pub struct Fin {
    pub complete: bool,
    pub set: Set,
}

#[derive(Debug, Clone)]
pub enum DefaultPrefs {
    Always,
    Never,
    Roster,
}

impl FromStr for DefaultPrefs {
    type Err = Error;

    fn from_str(s: &str) -> Result<DefaultPrefs, Error> {
        Ok(match s {
            "always" => DefaultPrefs::Always,
            "never" => DefaultPrefs::Never,
            "roster" => DefaultPrefs::Roster,

            _ => return Err(Error::ParseError("Invalid 'default' attribute.")),
        })
    }
}

impl<'a> IntoAttributeValue for &'a DefaultPrefs {
    fn into_attribute_value(self) -> Option<String> {
        Some(String::from(match *self {
            DefaultPrefs::Always => "always",
            DefaultPrefs::Never => "never",
            DefaultPrefs::Roster => "roster",
        }))
    }
}

#[derive(Debug, Clone)]
pub struct Prefs {
    pub default_: DefaultPrefs,
    pub always: Vec<Jid>,
    pub never: Vec<Jid>,
}

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

    fn try_from(elem: &'a Element) -> Result<Query, Error> {
        if !elem.is("query", ns::MAM) {
            return Err(Error::ParseError("This is not a query element."));
        }
        let mut form = None;
        let mut set = None;
        for child in elem.children() {
            if child.is("x", ns::DATA_FORMS) {
                form = Some(DataForm::try_from(child)?);
            } else if child.is("set", ns::RSM) {
                set = Some(Set::try_from(child)?);
            } else {
                return Err(Error::ParseError("Unknown child in query element."));
            }
        }
        let queryid = get_attr!(elem, "queryid", optional);
        let node = get_attr!(elem, "node", optional);
        Ok(Query { queryid, node, form, set })
    }
}

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

    fn try_from(elem: &'a Element) -> Result<Result_, Error> {
        if !elem.is("result", ns::MAM) {
            return Err(Error::ParseError("This is not a result element."));
        }
        let mut forwarded = None;
        for child in elem.children() {
            if child.is("forwarded", ns::FORWARD) {
                forwarded = Some(Forwarded::try_from(child)?);
            } else {
                return Err(Error::ParseError("Unknown child in result element."));
            }
        }
        let forwarded = forwarded.ok_or(Error::ParseError("Mandatory forwarded element missing in result."))?;
        let queryid = get_attr!(elem, "queryid", required);
        let id = get_attr!(elem, "id", required);
        Ok(Result_ {
            queryid,
            id,
            forwarded,
        })
    }
}

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

    fn try_from(elem: &'a Element) -> Result<Fin, Error> {
        if !elem.is("fin", ns::MAM) {
            return Err(Error::ParseError("This is not a fin element."));
        }
        let mut set = None;
        for child in elem.children() {
            if child.is("set", ns::RSM) {
                set = Some(Set::try_from(child)?);
            } else {
                return Err(Error::ParseError("Unknown child in fin element."));
            }
        }
        let set = set.ok_or(Error::ParseError("Mandatory set element missing in fin."))?;
        let complete = match elem.attr("complete") {
            Some(complete) if complete == "true" => true,
            Some(complete) if complete == "false" => false,
            None => false,
            Some(_) => return Err(Error::ParseError("Invalid value for 'complete' attribute.")),
        };
        Ok(Fin { complete, set })
    }
}

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

    fn try_from(elem: &'a Element) -> Result<Prefs, Error> {
        if !elem.is("prefs", ns::MAM) {
            return Err(Error::ParseError("This is not a prefs element."));
        }
        let mut always = vec!();
        let mut never = vec!();
        for child in elem.children() {
            if child.is("always", ns::MAM) {
                for jid_elem in child.children() {
                    if !jid_elem.is("jid", ns::MAM) {
                        return Err(Error::ParseError("Invalid jid element in always."));
                    }
                    always.push(jid_elem.text().parse()?);
                }
            } else if child.is("never", ns::MAM) {
                for jid_elem in child.children() {
                    if !jid_elem.is("jid", ns::MAM) {
                        return Err(Error::ParseError("Invalid jid element in never."));
                    }
                    never.push(jid_elem.text().parse()?);
                }
            } else {
                return Err(Error::ParseError("Unknown child in prefs element."));
            }
        }
        let default_ = get_attr!(elem, "default", required);
        Ok(Prefs { default_, always, never })
    }
}

impl<'a> Into<Element> for &'a Query {
    fn into(self) -> Element {
        let mut elem = Element::builder("query")
                               .ns(ns::MAM)
                               .attr("queryid", self.queryid.clone())
                               .attr("node", self.node.clone())
                               .build();
        //if let Some(form) = self.form {
        //    elem.append_child((&form).into());
        //}
        if let Some(ref set) = self.set {
            elem.append_child(set.into());
        }
        elem
    }
}

impl<'a> Into<Element> for &'a Result_ {
    fn into(self) -> Element {
        let mut elem = Element::builder("result")
                               .ns(ns::MAM)
                               .attr("queryid", self.queryid.clone())
                               .attr("id", self.id.clone())
                               .build();
        elem.append_child((&self.forwarded).into());
        elem
    }
}

impl<'a> Into<Element> for &'a Fin {
    fn into(self) -> Element {
        let mut elem = Element::builder("fin")
                               .ns(ns::MAM)
                               .attr("complete", if self.complete { Some("true") } else { None })
                               .build();
        elem.append_child((&self.set).into());
        elem
    }
}

impl<'a> Into<Element> for &'a Prefs {
    fn into(self) -> Element {
        let mut elem = Element::builder("prefs")
                               .ns(ns::MAM)
                               .attr("default", &self.default_)
                               .build();
        if !self.always.is_empty() {
            let mut always = Element::builder("always")
                                     .ns(ns::RSM)
                                     .build();
            for jid in self.always.clone() {
                always.append_child(Element::builder("jid")
                                            .ns(ns::RSM)
                                            .append(String::from(jid))
                                            .build());
            }
            elem.append_child(always);
        }
        if !self.never.is_empty() {
            let mut never = Element::builder("never")
                                     .ns(ns::RSM)
                                     .build();
            for jid in self.never.clone() {
                never.append_child(Element::builder("jid")
                                            .ns(ns::RSM)
                                            .append(String::from(jid))
                                            .build());
            }
            elem.append_child(never);
        }
        elem
    }
}

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

    #[test]
    fn test_query() {
        let elem: Element = "<query xmlns='urn:xmpp:mam:2'/>".parse().unwrap();
        Query::try_from(&elem).unwrap();
    }

    #[test]
    fn test_result() {
        let elem: Element = r#"
<result xmlns='urn:xmpp:mam:2' queryid='f27' id='28482-98726-73623'>
  <forwarded xmlns='urn:xmpp:forward:0'>
    <delay xmlns='urn:xmpp:delay' stamp='2010-07-10T23:08:25Z'/>
    <message xmlns='jabber:client' from="witch@shakespeare.lit" to="macbeth@shakespeare.lit">
      <body>Hail to thee</body>
    </message>
  </forwarded>
</result>
"#.parse().unwrap();
        Result_::try_from(&elem).unwrap();
    }

    #[test]
    fn test_fin() {
        let elem: Element = r#"
<fin xmlns='urn:xmpp:mam:2'>
  <set xmlns='http://jabber.org/protocol/rsm'>
    <first index='0'>28482-98726-73623</first>
    <last>09af3-cc343-b409f</last>
  </set>
</fin>
"#.parse().unwrap();
        Fin::try_from(&elem).unwrap();
    }

    #[test]
    fn test_query_x() {
        let elem: Element = r#"
<query xmlns='urn:xmpp:mam:2'>
  <x xmlns='jabber:x:data' type='submit'>
    <field var='FORM_TYPE' type='hidden'>
      <value>urn:xmpp:mam:2</value>
    </field>
    <field var='with'>
      <value>juliet@capulet.lit</value>
    </field>
  </x>
</query>
"#.parse().unwrap();
        Query::try_from(&elem).unwrap();
    }

    #[test]
    fn test_query_x_set() {
        let elem: Element = r#"
<query xmlns='urn:xmpp:mam:2'>
  <x xmlns='jabber:x:data' type='submit'>
    <field var='FORM_TYPE' type='hidden'>
      <value>urn:xmpp:mam:2</value>
    </field>
    <field var='start'>
      <value>2010-08-07T00:00:00Z</value>
    </field>
  </x>
  <set xmlns='http://jabber.org/protocol/rsm'>
    <max>10</max>
  </set>
</query>
"#.parse().unwrap();
        Query::try_from(&elem).unwrap();
    }

    #[test]
    fn test_prefs_get() {
        let elem: Element = "<prefs xmlns='urn:xmpp:mam:2' default='always'/>".parse().unwrap();
        Prefs::try_from(&elem).unwrap();

        let elem: Element = r#"
<prefs xmlns='urn:xmpp:mam:2' default='roster'>
  <always/>
  <never/>
</prefs>
"#.parse().unwrap();
        Prefs::try_from(&elem).unwrap();
    }

    #[test]
    fn test_prefs_result() {
        let elem: Element = r#"
<prefs xmlns='urn:xmpp:mam:2' default='roster'>
  <always>
    <jid>romeo@montague.lit</jid>
  </always>
  <never>
    <jid>montague@montague.lit</jid>
  </never>
</prefs>
"#.parse().unwrap();
        Prefs::try_from(&elem).unwrap();
    }

    #[test]
    fn test_invalid_child() {
        let elem: Element = "<query xmlns='urn:xmpp:mam:2'><coucou/></query>".parse().unwrap();
        let error = Query::try_from(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "Unknown child in query element.");
    }

    #[test]
    fn test_serialise() {
        let elem: Element = "<query xmlns='urn:xmpp:mam:2'/>".parse().unwrap();
        let replace = Query { queryid: None, node: None, form: None, set: None };
        let elem2 = (&replace).into();
        assert_eq!(elem, elem2);
    }
}