/* 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 dom::bindings::cell::DOMRefCell;
use dom::bindings::codegen::Bindings::WebSocketBinding;
use dom::bindings::codegen::Bindings::WebSocketBinding::WebSocketMethods;
use dom::bindings::codegen::Bindings::EventHandlerBinding::EventHandlerNonNull;
use dom::bindings::codegen::InheritTypes::EventTargetCast;
use dom::bindings::codegen::InheritTypes::EventCast;
use dom::bindings::error::{Error, Fallible};
use dom::bindings::error::Error::{InvalidAccess, Syntax};
use dom::bindings::global::{GlobalField, GlobalRef};
use dom::bindings::js::Root;
use dom::bindings::refcounted::Trusted;
use dom::bindings::str::USVString;
use dom::bindings::trace::JSTraceable;
use dom::bindings::utils::reflect_dom_object;
use dom::closeevent::CloseEvent;
use dom::event::{Event, EventBubbles, EventCancelable, EventHelpers};
use dom::eventtarget::{EventTarget, EventTargetHelpers, EventTargetTypeId};
use script_task::Runnable;
use script_task::ScriptMsg;
use std::cell::{Cell, RefCell};
use std::borrow::ToOwned;
use util::str::DOMString;
use util::task::spawn_named;

use hyper::header::Host;
use websocket::Message;
use websocket::ws::sender::Sender as Sender_Object;
use websocket::client::sender::Sender;
use websocket::client::receiver::Receiver;
use websocket::stream::WebSocketStream;
use websocket::client::request::Url;
use websocket::Client;
use websocket::header::Origin;
use websocket::result::WebSocketResult;
use websocket::ws::util::url::parse_url;

#[derive(JSTraceable, PartialEq, Copy, Clone)]
enum WebSocketRequestState {
    Connecting = 0,
    Open = 1,
    Closing = 2,
    Closed = 3,
}

no_jsmanaged_fields!(Sender<WebSocketStream>);

#[dom_struct]
pub struct WebSocket {
    eventtarget: EventTarget,
    url: Url,
    global: GlobalField,
    ready_state: Cell<WebSocketRequestState>,
    sender: RefCell<Option<Sender<WebSocketStream>>>,
    failed: Cell<bool>, //Flag to tell if websocket was closed due to failure
    full: Cell<bool>, //Flag to tell if websocket queue is full
    clean_close: Cell<bool>, //Flag to tell if the websocket closed cleanly (not due to full or fail)
    code: Cell<u16>, //Closing code
    reason: DOMRefCell<DOMString>, //Closing reason
    data: DOMRefCell<DOMString>, //Data from send - TODO: Remove after buffer is added.
}

/// *Establish a WebSocket Connection* as defined in RFC 6455.
fn establish_a_websocket_connection(url: (Host, String, bool), origin: String)
    -> WebSocketResult<(Sender<WebSocketStream>, Receiver<WebSocketStream>)> {
    let mut request = try!(Client::connect(url));
    request.headers.set(Origin(origin));

    let response = try!(request.send());
    try!(response.validate());

    Ok(response.begin().split())
}


impl WebSocket {
    pub fn new_inherited(global: GlobalRef, url: Url) -> WebSocket {
        WebSocket {
            eventtarget: EventTarget::new_inherited(EventTargetTypeId::WebSocket),
            url: url,
            global: GlobalField::from_rooted(&global),
            ready_state: Cell::new(WebSocketRequestState::Connecting),
            failed: Cell::new(false),
            sender: RefCell::new(None),
            full: Cell::new(false),
            clean_close: Cell::new(true),
            code: Cell::new(0),
            reason: DOMRefCell::new("".to_owned()),
            data: DOMRefCell::new("".to_owned()),
        }

    }

    pub fn new(global: GlobalRef,
               url: DOMString,
               protocols: Option<DOMString>)
               -> Fallible<Root<WebSocket>> {
        // Step 1.
        let parsed_url = try!(Url::parse(&url).map_err(|_| Error::Syntax));
        let url = try!(parse_url(&parsed_url).map_err(|_| Error::Syntax));

        // Step 2: Disallow https -> ws connections.
        // Step 3: Potentially block access to some ports.

        // Step 4.
        let protocols = protocols.as_slice();

        // Step 5.
        for (i, protocol) in protocols.iter().enumerate() {
            // https://tools.ietf.org/html/rfc6455#section-4.1
            // Handshake requirements, step 10
            if protocol.is_empty() {
                return Err(Syntax);
            }

            if protocols[i+1..].iter().any(|p| p == protocol) {
                return Err(Syntax);
            }

            if protocol.chars().any(|c| c < '\u{0021}' || c > '\u{007E}') {
                return Err(Syntax);
            }
        }

        // Step 6: Origin.

        // Step 7.
        let ws = reflect_dom_object(box WebSocket::new_inherited(global, parsed_url),
                                    global,
                                    WebSocketBinding::Wrap);
        let address = Trusted::new(global.get_cx(), ws.r(), global.script_chan());

        let origin = global.get_url().serialize();
        let sender = global.script_chan();
        spawn_named(format!("WebSocket connection to {}", ws.Url()), move || {
            // Step 8: Protocols.

            // Step 9.
            let channel = establish_a_websocket_connection(url, origin);
            let (temp_sender, _temp_receiver) = match channel {
                Ok(channel) => channel,
                Err(e) => {
                    debug!("Failed to establish a WebSocket connection: {:?}", e);
                    let task = box CloseTask {
                        addr: address,
                    };
                    sender.send(ScriptMsg::RunnableMsg(task)).unwrap();
                    return;
                }
            };

            let open_task = box ConnectionEstablishedTask {
                addr: address,
                sender: temp_sender,
            };
            sender.send(ScriptMsg::RunnableMsg(open_task)).unwrap();
        });

        // Step 7.
        Ok(ws)
    }

    pub fn Constructor(global: GlobalRef,
                       url: DOMString,
                       protocols: Option<DOMString>)
                       -> Fallible<Root<WebSocket>> {
        WebSocket::new(global, url, protocols)
    }
}

impl<'a> WebSocketMethods for &'a WebSocket {
    event_handler!(open, GetOnopen, SetOnopen);
    event_handler!(close, GetOnclose, SetOnclose);
    event_handler!(error, GetOnerror, SetOnerror);

    fn Url(self) -> DOMString {
        self.url.serialize()
    }

    fn ReadyState(self) -> u16 {
        self.ready_state.get() as u16
    }

    fn Send(self, data: Option<USVString>) -> Fallible<()> {
        match self.ready_state.get() {
            WebSocketRequestState::Connecting => {
                return Err(Error::InvalidState);
            },
            WebSocketRequestState::Open => (),
            WebSocketRequestState::Closing | WebSocketRequestState::Closed => {
                // TODO: Update bufferedAmount.
                return Ok(());
            }
        }

        /*TODO: This is not up to spec see http://html.spec.whatwg.org/multipage/comms.html search for
                "If argument is a string"
          TODO: Need to buffer data
          TODO: bufferedAmount attribute returns the size of the buffer in bytes -
                this is a required attribute defined in the websocket.webidl file
          TODO: The send function needs to flag when full by using the following
          self.full.set(true). This needs to be done when the buffer is full
        */
        let mut other_sender = self.sender.borrow_mut();
        let my_sender = other_sender.as_mut().unwrap();
        let _ = my_sender.send_message(Message::Text(data.unwrap().0));
        return Ok(())
    }

    fn Close(self, code: Option<u16>, reason: Option<USVString>) -> Fallible<()>{
        fn send_close(this: &WebSocket) {
            this.ready_state.set(WebSocketRequestState::Closing);

            let mut sender = this.sender.borrow_mut();
            //TODO: Also check if the buffer is full
            if let Some(sender) = sender.as_mut() {
                let _ = sender.send_message(Message::Close(None));
            }
        }


        if let Some(code) = code {
            //Check code is NOT 1000 NOR in the range of 3000-4999 (inclusive)
            if  code != 1000 && (code < 3000 || code > 4999) {
                return Err(Error::InvalidAccess);
            }
        }
        if let Some(ref reason) = reason {
            if reason.0.as_bytes().len() > 123 { //reason cannot be larger than 123 bytes
                return Err(Error::Syntax);
            }
        }

        match self.ready_state.get() {
            WebSocketRequestState::Closing | WebSocketRequestState::Closed  => {} //Do nothing
            WebSocketRequestState::Connecting => { //Connection is not yet established
                /*By setting the state to closing, the open function
                  will abort connecting the websocket*/
                self.failed.set(true);
                send_close(self);
                //Note: After sending the close message, the receive loop confirms a close message from the server and
                //      must fire a close event
            }
            WebSocketRequestState::Open => {
                //Closing handshake not started - still in open
                //Start the closing by setting the code and reason if they exist
                if let Some(code) = code {
                    self.code.set(code);
                }
                if let Some(reason) = reason {
                    *self.reason.borrow_mut() = reason.0;
                }
                send_close(self);
                //Note: After sending the close message, the receive loop confirms a close message from the server and
                //      must fire a close event
            }
        }
        Ok(()) //Return Ok
    }
}


/// Task queued when *the WebSocket connection is established*.
struct ConnectionEstablishedTask {
    addr: Trusted<WebSocket>,
    sender: Sender<WebSocketStream>,
}

impl Runnable for ConnectionEstablishedTask {
    fn handler(self: Box<Self>) {
        let ws = self.addr.root();

        *ws.r().sender.borrow_mut() = Some(self.sender);

        // Step 1: Protocols.

        // Step 2.
        ws.ready_state.set(WebSocketRequestState::Open);

        // Step 3: Extensions.
        // Step 4: Protocols.
        // Step 5: Cookies.

        // Step 6.
        let global = ws.global.root();
        let event = Event::new(global.r(), "open".to_owned(),
                               EventBubbles::DoesNotBubble,
                               EventCancelable::NotCancelable);
        event.fire(EventTargetCast::from_ref(ws.r()));
    }
}

struct CloseTask {
    addr: Trusted<WebSocket>,
}

impl Runnable for CloseTask {
    fn handler(self: Box<Self>) {
        let ws = self.addr.root();
        let ws = ws.r();
        let global = ws.global.root();
        ws.ready_state.set(WebSocketRequestState::Closed);
        //If failed or full, fire error event
        if ws.failed.get() || ws.full.get() {
            ws.failed.set(false);
            ws.full.set(false);
            //A Bad close
            ws.clean_close.set(false);
            let event = Event::new(global.r(),
                                   "error".to_owned(),
                                   EventBubbles::DoesNotBubble,
                                   EventCancelable::Cancelable);
            let target = EventTargetCast::from_ref(ws);
            event.r().fire(target);
        }
        let rsn = ws.reason.borrow();
        let rsn_clone = rsn.clone();
        /*In addition, we also have to fire a close even if error event fired
         https://html.spec.whatwg.org/multipage/#closeWebSocket
        */
        let close_event = CloseEvent::new(global.r(),
                                          "close".to_owned(),
                                          EventBubbles::DoesNotBubble,
                                          EventCancelable::NotCancelable,
                                          ws.clean_close.get(),
                                          ws.code.get(),
                                          rsn_clone);
        let target = EventTargetCast::from_ref(ws);
        let event = EventCast::from_ref(close_event.r());
        event.fire(target);
    }
}