use rocket::Route;
use rocket_contrib::json::Json;
use serde_json::Value as JsonValue;

use crate::api::JsonResult;
use crate::auth::Headers;
use crate::db::DbConn;

use crate::CONFIG;

pub fn routes() -> Vec<Route> {
    routes![negotiate, websockets_err]
}

#[get("/hub")]
fn websockets_err() -> JsonResult {
    err!("'/notifications/hub' should be proxied to the websocket server or notifications won't work. Go to the README for more info.")
}

#[post("/hub/negotiate")]
fn negotiate(_headers: Headers, _conn: DbConn) -> JsonResult {
    use crate::crypto;
    use data_encoding::BASE64URL;

    let conn_id = BASE64URL.encode(&crypto::get_random(vec![0u8; 16]));
    let mut available_transports: Vec<JsonValue> = Vec::new();

    if CONFIG.websocket_enabled {
        available_transports.push(json!({"transport":"WebSockets", "transferFormats":["Text","Binary"]}));
    }

    // TODO: Implement transports
    // Rocket WS support: https://github.com/SergioBenitez/Rocket/issues/90
    // Rocket SSE support: https://github.com/SergioBenitez/Rocket/issues/33
    // {"transport":"ServerSentEvents", "transferFormats":["Text"]},
    // {"transport":"LongPolling", "transferFormats":["Text","Binary"]}
    Ok(Json(json!({
        "connectionId": conn_id,
        "availableTransports": available_transports
    })))
}

//
// Websockets server
//
use std::sync::Arc;
use std::thread;

use ws::{self, util::Token, Factory, Handler, Handshake, Message, Sender, WebSocket};

use chashmap::CHashMap;
use chrono::NaiveDateTime;
use serde_json::from_str;

use crate::db::models::{Cipher, Folder, User};

use rmpv::Value;

fn serialize(val: Value) -> Vec<u8> {
    use rmpv::encode::write_value;

    let mut buf = Vec::new();
    write_value(&mut buf, &val).expect("Error encoding MsgPack");

    // Add size bytes at the start
    // Extracted from BinaryMessageFormat.js
    let mut size: usize = buf.len();
    let mut len_buf: Vec<u8> = Vec::new();

    loop {
        let mut size_part = size & 0x7f;
        size >>= 7;

        if size > 0 {
            size_part |= 0x80;
        }

        len_buf.push(size_part as u8);

        if size == 0 {
            break;
        }
    }

    len_buf.append(&mut buf);
    len_buf
}

fn serialize_date(date: NaiveDateTime) -> Value {
    let seconds: i64 = date.timestamp();
    let nanos: i64 = date.timestamp_subsec_nanos() as i64;
    let timestamp = nanos << 34 | seconds;
    
    let bs = timestamp.to_be_bytes();

    // -1 is Timestamp
    // https://github.com/msgpack/msgpack/blob/master/spec.md#timestamp-extension-type
    Value::Ext(-1, bs.to_vec())
}

fn convert_option<T: Into<Value>>(option: Option<T>) -> Value {
    match option {
        Some(a) => a.into(),
        None => Value::Nil,
    }
}

// Server WebSocket handler
pub struct WSHandler {
    out: Sender,
    user_uuid: Option<String>,
    users: WebSocketUsers,
}

const RECORD_SEPARATOR: u8 = 0x1e;
const INITIAL_RESPONSE: [u8; 3] = [0x7b, 0x7d, RECORD_SEPARATOR]; // {, }, <RS>

#[derive(Deserialize)]
struct InitialMessage {
    protocol: String,
    version: i32,
}

const PING_MS: u64 = 15_000;
const PING: Token = Token(1);

impl Handler for WSHandler {
    fn on_open(&mut self, hs: Handshake) -> ws::Result<()> {
        // TODO: Improve this split
        let path = hs.request.resource();
        let mut query_split: Vec<_> = path.split('?').nth(1).unwrap().split('&').collect();
        query_split.sort();
        let access_token = &query_split[0][13..];
        let _id = &query_split[1][3..];

        // Validate the user
        use crate::auth;
        let claims = match auth::decode_login(access_token) {
            Ok(claims) => claims,
            Err(_) => return Err(ws::Error::new(ws::ErrorKind::Internal, "Invalid access token provided")),
        };

        // Assign the user to the handler
        let user_uuid = claims.sub;
        self.user_uuid = Some(user_uuid.clone());

        // Add the current Sender to the user list
        let handler_insert = self.out.clone();
        let handler_update = self.out.clone();

        self.users
            .map
            .upsert(user_uuid, || vec![handler_insert], |ref mut v| v.push(handler_update));

        // Schedule a ping to keep the connection alive
        self.out.timeout(PING_MS, PING)
    }

    fn on_message(&mut self, msg: Message) -> ws::Result<()> {
        info!("Server got message '{}'. ", msg);

        if let Message::Text(text) = msg.clone() {
            let json = &text[..text.len() - 1]; // Remove last char

            if let Ok(InitialMessage { protocol, version }) = from_str::<InitialMessage>(json) {
                if &protocol == "messagepack" && version == 1 {
                    return self.out.send(&INITIAL_RESPONSE[..]); // Respond to initial message
                }
            }
        }

        // If it's not the initial message, just echo the message
        self.out.send(msg)
    }

    fn on_timeout(&mut self, event: Token) -> ws::Result<()> {
        if event == PING {
            // send ping
            self.out.send(create_ping())?;

            // reschedule the timeout
            self.out.timeout(PING_MS, PING)
        } else {
            Err(ws::Error::new(
                ws::ErrorKind::Internal,
                "Invalid timeout token provided",
            ))
        }
    }
}

struct WSFactory {
    pub users: WebSocketUsers,
}

impl WSFactory {
    pub fn init() -> Self {
        WSFactory {
            users: WebSocketUsers {
                map: Arc::new(CHashMap::new()),
            },
        }
    }
}

impl Factory for WSFactory {
    type Handler = WSHandler;

    fn connection_made(&mut self, out: Sender) -> Self::Handler {
        WSHandler {
            out,
            user_uuid: None,
            users: self.users.clone(),
        }
    }

    fn connection_lost(&mut self, handler: Self::Handler) {
        // Remove handler
        if let Some(user_uuid) = &handler.user_uuid {
            if let Some(mut user_conn) = self.users.map.get_mut(user_uuid) {
                user_conn.remove_item(&handler.out);
            }
        }
    }
}

#[derive(Clone)]
pub struct WebSocketUsers {
    map: Arc<CHashMap<String, Vec<Sender>>>,
}

impl WebSocketUsers {
    fn send_update(&self, user_uuid: &String, data: &[u8]) -> ws::Result<()> {
        if let Some(user) = self.map.get(user_uuid) {
            for sender in user.iter() {
                sender.send(data)?;
            }
        }
        Ok(())
    }

    // NOTE: The last modified date needs to be updated before calling these methods
    #[allow(dead_code)]
    pub fn send_user_update(&self, ut: UpdateType, user: &User) {
        let data = create_update(
            vec![
                ("UserId".into(), user.uuid.clone().into()),
                ("Date".into(), serialize_date(user.updated_at)),
            ],
            ut,
        );

        self.send_update(&user.uuid.clone(), &data).ok();
    }

    pub fn send_folder_update(&self, ut: UpdateType, folder: &Folder) {
        let data = create_update(
            vec![
                ("Id".into(), folder.uuid.clone().into()),
                ("UserId".into(), folder.user_uuid.clone().into()),
                ("RevisionDate".into(), serialize_date(folder.updated_at)),
            ],
            ut,
        );

        self.send_update(&folder.user_uuid, &data).ok();
    }

    pub fn send_cipher_update(&self, ut: UpdateType, cipher: &Cipher, user_uuids: &[String]) {
        let user_uuid = convert_option(cipher.user_uuid.clone());
        let org_uuid = convert_option(cipher.organization_uuid.clone());

        let data = create_update(
            vec![
                ("Id".into(), cipher.uuid.clone().into()),
                ("UserId".into(), user_uuid),
                ("OrganizationId".into(), org_uuid),
                ("CollectionIds".into(), Value::Nil),
                ("RevisionDate".into(), serialize_date(cipher.updated_at)),
            ],
            ut,
        );

        for uuid in user_uuids {
            self.send_update(&uuid, &data).ok();
        }
    }
}

/* Message Structure
[
    1, // MessageType.Invocation
    {}, // Headers
    null, // InvocationId
    "ReceiveMessage", // Target
    [ // Arguments
        {
            "ContextId": "app_id",
            "Type": ut as i32,
            "Payload": {}
        }
    ]
]
*/
fn create_update(payload: Vec<(Value, Value)>, ut: UpdateType) -> Vec<u8> {
    use rmpv::Value as V;

    let value = V::Array(vec![
        1.into(),
        V::Array(vec![]),
        V::Nil,
        "ReceiveMessage".into(),
        V::Array(vec![V::Map(vec![
            ("ContextId".into(), "app_id".into()),
            ("Type".into(), (ut as i32).into()),
            ("Payload".into(), payload.into()),
        ])]),
    ]);

    serialize(value)
}

fn create_ping() -> Vec<u8> {
    serialize(Value::Array(vec![6.into()]))
}

#[allow(dead_code)]
pub enum UpdateType {
    CipherUpdate = 0,
    CipherCreate = 1,
    LoginDelete = 2,
    FolderDelete = 3,
    Ciphers = 4,

    Vault = 5,
    OrgKeys = 6,
    FolderCreate = 7,
    FolderUpdate = 8,
    CipherDelete = 9,
    SyncSettings = 10,

    LogOut = 11,
}

use rocket::State;
pub type Notify<'a> = State<'a, WebSocketUsers>;

pub fn start_notification_server() -> WebSocketUsers {
    let factory = WSFactory::init();
    let users = factory.users.clone();

    if CONFIG.websocket_enabled {
        thread::spawn(move || {
            WebSocket::new(factory).unwrap().listen(&CONFIG.websocket_url).unwrap();
        });
    }

    users
}