// 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 enum ChatState {
    Active,
    Composing,
    Gone,
    Inactive,
    Paused,
}

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

    fn try_from(elem: &'a Element) -> Result<ChatState, Error> {
        for _ in elem.children() {
            return Err(Error::ParseError("Unknown child in chatstate element."));
        }
        if elem.is("active", ns::CHATSTATES) {
            Ok(ChatState::Active)
        } else if elem.is("composing", ns::CHATSTATES) {
            Ok(ChatState::Composing)
        } else if elem.is("gone", ns::CHATSTATES) {
            Ok(ChatState::Gone)
        } else if elem.is("inactive", ns::CHATSTATES) {
            Ok(ChatState::Inactive)
        } else if elem.is("paused", ns::CHATSTATES) {
            Ok(ChatState::Paused)
        } else {
            Err(Error::ParseError("This is not a chatstate element."))
        }
    }
}

impl<'a> Into<Element> for &'a ChatState {
    fn into(self) -> Element {
        Element::builder(match *self {
            ChatState::Active => "active",
            ChatState::Composing => "composing",
            ChatState::Gone => "gone",
            ChatState::Inactive => "inactive",
            ChatState::Paused => "paused",
        }).ns(ns::CHATSTATES)
          .build()
    }
}

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

    #[test]
    fn test_simple() {
        let elem: Element = "<active xmlns='http://jabber.org/protocol/chatstates'/>".parse().unwrap();
        ChatState::try_from(&elem).unwrap();
    }

    #[test]
    fn test_invalid() {
        let elem: Element = "<coucou xmlns='http://jabber.org/protocol/chatstates'/>".parse().unwrap();
        let error = ChatState::try_from(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "This is not a chatstate element.");
    }

    #[test]
    fn test_invalid_child() {
        let elem: Element = "<gone xmlns='http://jabber.org/protocol/chatstates'><coucou/></gone>".parse().unwrap();
        let error = ChatState::try_from(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "Unknown child in chatstate element.");
    }

    #[test]
    #[ignore]
    fn test_invalid_attribute() {
        let elem: Element = "<inactive xmlns='http://jabber.org/protocol/chatstates' coucou=''/>".parse().unwrap();
        let error = ChatState::try_from(&elem).unwrap_err();
        let message = match error {
            Error::ParseError(string) => string,
            _ => panic!(),
        };
        assert_eq!(message, "Unknown attribute in chatstate element.");
    }

    #[test]
    fn test_serialise() {
        let chatstate = ChatState::Active;
        let elem: Element = (&chatstate).into();
        assert!(elem.is("active", ns::CHATSTATES));
    }
}