use futures::{future, Future, Sink, Stream};
use std::convert::TryFrom;
use std::env::args;
use std::fs::{create_dir_all, File};
use std::io::{self, Write};
use std::process::exit;
use std::str::FromStr;
use tokio::runtime::current_thread::Runtime;
use tokio_xmpp::{Client, Packet};
use xmpp_parsers::{
    avatar::{Data as AvatarData, Metadata as AvatarMetadata},
    caps::{compute_disco, hash_caps, Caps},
    disco::{DiscoInfoQuery, DiscoInfoResult, Feature, Identity},
    hashes::Algo,
    iq::{Iq, IqType},
    message::Message,
    ns,
    presence::{Presence, Type as PresenceType},
    pubsub::{
        event::PubSubEvent,
        pubsub::{Items, PubSub},
        NodeName,
    },
    stanza_error::{StanzaError, ErrorType, DefinedCondition},
    Jid,
};

fn main() {
    let args: Vec<String> = args().collect();
    if args.len() != 3 {
        println!("Usage: {} <jid> <password>", args[0]);
        exit(1);
    }
    let jid = &args[1];
    let password = &args[2];

    // tokio_core context
    let mut rt = Runtime::new().unwrap();
    // Client instance
    let client = Client::new(jid, password).unwrap();

    // Make the two interfaces for sending and receiving independent
    // of each other so we can move one into a closure.
    let (sink, stream) = client.split();

    // Create outgoing pipe
    let (mut tx, rx) = futures::unsync::mpsc::unbounded();
    rt.spawn(
        rx.forward(
            sink.sink_map_err(|_| panic!("Pipe"))
        )
            .map(|(rx, mut sink)| {
                drop(rx);
                let _ = sink.close();
            })
            .map_err(|e| {
                panic!("Send error: {:?}", e);
            })
    );

    let disco_info = make_disco();

    // Main loop, processes events
    let mut wait_for_stream_end = false;
    let done = stream.for_each(move |event| {
        // Helper function to send an iq error.
        let mut send_error = |to, id, type_, condition, text: &str| {
            let error = StanzaError::new(type_, condition, "en", text);
            let iq = Iq::from_error(id, error)
                .with_to(to);
            tx.start_send(Packet::Stanza(iq.into())).unwrap();
        };

        if wait_for_stream_end {
            /* Do nothing */
        } else if event.is_online() {
            println!("Online!");

            let caps = get_disco_caps(&disco_info, "https://gitlab.com/xmpp-rs/tokio-xmpp");
            let presence = make_presence(caps);
            tx.start_send(Packet::Stanza(presence.into())).unwrap();
        } else if let Some(stanza) = event.into_stanza() {
            if stanza.is("iq", "jabber:client") {
                let iq = Iq::try_from(stanza).unwrap();
                if let IqType::Get(payload) = iq.payload {
                    if payload.is("query", ns::DISCO_INFO) {
                        let query = DiscoInfoQuery::try_from(payload);
                        match query {
                            Ok(query) => {
                                let mut disco = disco_info.clone();
                                disco.node = query.node;
                                let iq = Iq::from_result(iq.id, Some(disco))
                                    .with_to(iq.from.unwrap());
                                tx.start_send(Packet::Stanza(iq.into())).unwrap();
                            },
                            Err(err) => {
                                send_error(iq.from.unwrap(), iq.id, ErrorType::Modify, DefinedCondition::BadRequest, &format!("{}", err));
                            },
                        }
                    } else {
                        // We MUST answer unhandled get iqs with a service-unavailable error.
                        send_error(iq.from.unwrap(), iq.id, ErrorType::Cancel, DefinedCondition::ServiceUnavailable, "No handler defined for this kind of iq.");
                    }
                } else if let IqType::Result(Some(payload)) = iq.payload {
                    if payload.is("pubsub", ns::PUBSUB) {
                        let pubsub = PubSub::try_from(payload).unwrap();
                        let from =
                            iq.from.clone().unwrap_or(Jid::from_str(jid).unwrap());
                        handle_iq_result(pubsub, &from);
                    }
                } else if let IqType::Set(_) = iq.payload {
                    // We MUST answer unhandled set iqs with a service-unavailable error.
                    send_error(iq.from.unwrap(), iq.id, ErrorType::Cancel, DefinedCondition::ServiceUnavailable, "No handler defined for this kind of iq.");
                }
            } else if stanza.is("message", "jabber:client") {
                let message = Message::try_from(stanza).unwrap();
                let from = message.from.clone().unwrap();
                if let Some(body) = message.get_best_body(vec!["en"]) {
                    if body.1 .0 == "die" {
                        println!("Secret die command triggered by {}", from);
                        wait_for_stream_end = true;
                        tx.start_send(Packet::StreamEnd).unwrap();
                    }
                }
                for child in message.payloads {
                    if child.is("event", ns::PUBSUB_EVENT) {
                        let event = PubSubEvent::try_from(child).unwrap();
                        if let PubSubEvent::PublishedItems { node, items } = event {
                            if node.0 == ns::AVATAR_METADATA {
                                for item in items.into_iter() {
                                    let payload = item.payload.clone().unwrap();
                                    if payload.is("metadata", ns::AVATAR_METADATA) {
                                        // TODO: do something with these metadata.
                                        let _metadata = AvatarMetadata::try_from(payload).unwrap();
                                        println!(
                                            "{} has published an avatar, downloading...",
                                            from.clone()
                                        );
                                        let iq = download_avatar(from.clone());
                                        tx.start_send(Packet::Stanza(iq.into())).unwrap();
                                    }
                                }
                            }
                        }
                    }
                }
            } else if stanza.is("presence", "jabber:client") {
                // Nothing to do here.
            } else {
                panic!("Unknown stanza: {}", String::from(&stanza));
            }
        }

        future::ok(())
    });

    // Start polling `done`
    match rt.block_on(done) {
        Ok(_) => (),
        Err(e) => {
            println!("Fatal: {}", e);
            ()
        }
    }
}

fn make_disco() -> DiscoInfoResult {
    let identities = vec![Identity::new("client", "bot", "en", "tokio-xmpp")];
    let features = vec![
        Feature::new(ns::DISCO_INFO),
        Feature::new(format!("{}+notify", ns::AVATAR_METADATA)),
    ];
    DiscoInfoResult {
        node: None,
        identities,
        features,
        extensions: vec![],
    }
}

fn get_disco_caps(disco: &DiscoInfoResult, node: &str) -> Caps {
    let caps_data = compute_disco(disco);
    let hash = hash_caps(&caps_data, Algo::Sha_1).unwrap();
    Caps::new(node, hash)
}

// Construct a <presence/>
fn make_presence(caps: Caps) -> Presence {
    let mut presence = Presence::new(PresenceType::None)
        .with_priority(-1);
    presence.set_status("en", "Downloading avatars.");
    presence.add_payload(caps);
    presence
}

fn download_avatar(from: Jid) -> Iq {
    Iq::from_get("coucou", PubSub::Items(Items {
        max_items: None,
        node: NodeName(String::from(ns::AVATAR_DATA)),
        subid: None,
        items: Vec::new(),
    }))
    .with_to(from)
}

fn handle_iq_result(pubsub: PubSub, from: &Jid) {
    if let PubSub::Items(items) = pubsub {
        if items.node.0 == ns::AVATAR_DATA {
            for item in items.items {
                match (item.id.clone(), item.payload.clone()) {
                    (Some(id), Some(payload)) => {
                        let data = AvatarData::try_from(payload).unwrap();
                        save_avatar(from, id.0, &data.data).unwrap();
                    }
                    _ => {}
                }
            }
        }
    }
}

fn save_avatar(from: &Jid, id: String, data: &[u8]) -> io::Result<()> {
    let directory = format!("data/{}", from);
    let filename = format!("data/{}/{}", from, id);
    println!(
        "Saving avatar from {} to {}.",
        from, filename
    );
    create_dir_all(directory)?;
    let mut file = File::create(filename)?;
    file.write_all(data)
}