/* 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::BlobBinding::BlobMethods;
use dom::bindings::codegen::Bindings::EventHandlerBinding::EventHandlerNonNull;
use dom::bindings::codegen::Bindings::WebSocketBinding;
use dom::bindings::codegen::Bindings::WebSocketBinding::{BinaryType, WebSocketMethods};
use dom::bindings::conversions::{ToJSValConvertible};
use dom::bindings::error::{Error, Fallible};
use dom::bindings::global::{GlobalField, GlobalRef};
use dom::bindings::inheritance::Castable;
use dom::bindings::js::Root;
use dom::bindings::refcounted::Trusted;
use dom::bindings::reflector::{Reflectable, reflect_dom_object};
use dom::bindings::str::USVString;
use dom::bindings::trace::JSTraceable;
use dom::blob::Blob;
use dom::closeevent::CloseEvent;
use dom::event::{Event, EventBubbles, EventCancelable};
use dom::eventtarget::EventTarget;
use dom::messageevent::MessageEvent;
use hyper::header::Host;
use js::jsapi::{JSAutoCompartment, JSAutoRequest, RootedValue};
use js::jsapi::{JS_GetArrayBufferData, JS_NewArrayBuffer};
use js::jsval::UndefinedValue;
use libc::{uint32_t, uint8_t};
use net_traits::hosts::replace_hosts;
use script_task::ScriptTaskEventCategory::WebSocketEvent;
use script_task::{CommonScriptMsg, Runnable};
use std::borrow::ToOwned;
use std::cell::Cell;
use std::sync::{Arc, Mutex};
use std::{ptr, slice};
use util::str::DOMString;
use util::task::spawn_named;
use websocket::client::receiver::Receiver;
use websocket::client::request::Url;
use websocket::client::sender::Sender;
use websocket::header::Origin;
use websocket::message::Type;
use websocket::result::WebSocketResult;
use websocket::stream::WebSocketStream;
use websocket::ws::receiver::Receiver as WSReceiver;
use websocket::ws::sender::Sender as Sender_Object;
use websocket::ws::util::url::parse_url;
use websocket::{Client, Message};

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

no_jsmanaged_fields!(Sender<WebSocketStream>);

#[derive(HeapSizeOf)]
enum MessageData {
    Text(String),
    Binary(Vec<u8>),
}

// list of blacklist ports according to
// http://mxr.mozilla.org/mozilla-central/source/netwerk/base/nsIOService.cpp#87
const BLOCKED_PORTS_LIST: &'static [u16] = &[
    1,    // tcpmux
    7,    // echo
    9,    // discard
    11,   // systat
    13,   // daytime
    15,   // netstat
    17,   // qotd
    19,   // chargen
    20,   // ftp-data
    21,   // ftp-cntl
    22,   // ssh
    23,   // telnet
    25,   // smtp
    37,   // time
    42,   // name
    43,   // nicname
    53,   // domain
    77,   // priv-rjs
    79,   // finger
    87,   // ttylink
    95,   // supdup
    101,  // hostriame
    102,  // iso-tsap
    103,  // gppitnp
    104,  // acr-nema
    109,  // pop2
    110,  // pop3
    111,  // sunrpc
    113,  // auth
    115,  // sftp
    117,  // uucp-path
    119,  // nntp
    123,  // NTP
    135,  // loc-srv / epmap
    139,  // netbios
    143,  // imap2
    179,  // BGP
    389,  // ldap
    465,  // smtp+ssl
    512,  // print / exec
    513,  // login
    514,  // shell
    515,  // printer
    526,  // tempo
    530,  // courier
    531,  // Chat
    532,  // netnews
    540,  // uucp
    556,  // remotefs
    563,  // nntp+ssl
    587,  //
    601,  //
    636,  // ldap+ssl
    993,  // imap+ssl
    995,  // pop3+ssl
    2049, // nfs
    4045, // lockd
    6000, // x11
];

#[dom_struct]
pub struct WebSocket {
    eventtarget: EventTarget,
    url: Url,
    global: GlobalField,
    ready_state: Cell<WebSocketRequestState>,
    buffered_amount: Cell<u32>,
    clearing_buffer: Cell<bool>, //Flag to tell if there is a running task to clear buffered_amount
    #[ignore_heap_size_of = "Defined in std"]
    sender: DOMRefCell<Option<Arc<Mutex<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<String>, //Closing reason
    binary_type: Cell<BinaryType>,
}

/// *Establish a WebSocket Connection* as defined in RFC 6455.
fn establish_a_websocket_connection(resource_url: &Url, net_url: (Host, String, bool),
                                    origin: String)
   -> WebSocketResult<(Sender<WebSocketStream>, Receiver<WebSocketStream>)> {
    // URL that we actually fetch from the network, after applying the replacements
    // specified in the hosts file.

    let host = Host {
        hostname: resource_url.serialize_host().unwrap(),
        port: resource_url.port_or_default()
    };

    let mut request = try!(Client::connect(net_url));
    request.headers.set(Origin(origin));
    request.headers.set(host);

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

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


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

    }

    fn new(global: GlobalRef, url: Url) -> Root<WebSocket> {
        reflect_dom_object(box WebSocket::new_inherited(global, url),
                           global, WebSocketBinding::Wrap)
    }

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

        // Step 2: Disallow https -> ws connections.

        // Step 3: Potentially block access to some ports.
        let port: u16 = resource_url.port_or_default().unwrap();

        if BLOCKED_PORTS_LIST.iter().any(|&p| p == port) {
            return Err(Error::Security);
        }

        // Step 4.
        let protocols: &[DOMString] = protocols
                                      .as_ref()
                                      .map_or(&[], |ref string| slice::ref_slice(string));

        // 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(Error::Syntax);
            }

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

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

        // Step 6: Origin.

        // Step 7.
        let ws = WebSocket::new(global, resource_url.clone());
        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(&resource_url, net_url, origin);
            let (ws_sender, mut receiver) = match channel {
                Ok(channel) => channel,
                Err(e) => {
                    debug!("Failed to establish a WebSocket connection: {:?}", e);
                    let task = box CloseTask {
                        addr: address,
                    };
                    sender.send(CommonScriptMsg::RunnableMsg(WebSocketEvent, task)).unwrap();
                    return;
                }
            };
            let ws_sender = Arc::new(Mutex::new(ws_sender));

            let open_task = box ConnectionEstablishedTask {
                addr: address.clone(),
                sender: ws_sender.clone(),
            };
            sender.send(CommonScriptMsg::RunnableMsg(WebSocketEvent, open_task)).unwrap();

            for message in receiver.incoming_messages() {
                let message: Message = match message {
                    Ok(m) => m,
                    Err(_) => break,
                };
                let message = match message.opcode {
                    Type::Text => MessageData::Text(String::from_utf8_lossy(&message.payload).into_owned()),
                    Type::Binary => MessageData::Binary(message.payload.into_owned()),
                    Type::Ping => {
                        let pong = Message::pong(message.payload);
                        ws_sender.lock().unwrap().send_message(&pong).unwrap();
                        continue;
                    },
                    Type::Pong => continue,
                    Type::Close => {
                        ws_sender.lock().unwrap().send_message(&message).unwrap();
                        let task = box CloseTask {
                            addr: address,
                        };
                        sender.send(CommonScriptMsg::RunnableMsg(WebSocketEvent, task)).unwrap();
                        break;
                    },
                };
                let message_task = box MessageReceivedTask {
                    address: address.clone(),
                    message: message,
                };
                sender.send(CommonScriptMsg::RunnableMsg(WebSocketEvent, message_task)).unwrap();
            }
        });

        // Step 7.
        Ok(ws)
    }

    // https://html.spec.whatwg.org/multipage/#dom-websocket-send
    fn send_impl(&self, data_byte_len: u64) -> Fallible<bool> {
        let return_after_buffer = match self.ready_state.get() {
            WebSocketRequestState::Connecting => {
                return Err(Error::InvalidState);
            },
            WebSocketRequestState::Open => false,
            WebSocketRequestState::Closing | WebSocketRequestState::Closed => true,
        };

        let global = self.global.root();
        let chan = global.r().script_chan();
        let address = Trusted::new(global.r().get_cx(), self, chan.clone());

        let new_buffer_amount = (self.buffered_amount.get() as u64) + data_byte_len;
        if new_buffer_amount > (u32::max_value() as u64) {
            self.buffered_amount.set(u32::max_value());
            self.full.set(true);

            let _ = self.Close(None, None);
            return Ok(false);

        }

        self.buffered_amount.set(new_buffer_amount as u32);

        if return_after_buffer {
            return Ok(false);
        }

        if !self.clearing_buffer.get() && self.ready_state.get() == WebSocketRequestState::Open {
            self.clearing_buffer.set(true);

            let task = box BufferedAmountTask {
                addr: address,
            };

            chan.send(CommonScriptMsg::RunnableMsg(WebSocketEvent, task)).unwrap();
        }

        Ok(true)
    }
}

impl WebSocketMethods for WebSocket {
    // https://html.spec.whatwg.org/multipage/#handler-websocket-onopen
    event_handler!(open, GetOnopen, SetOnopen);

    // https://html.spec.whatwg.org/multipage/#handler-websocket-onclose
    event_handler!(close, GetOnclose, SetOnclose);

    // https://html.spec.whatwg.org/multipage/#handler-websocket-onerror
    event_handler!(error, GetOnerror, SetOnerror);

    // https://html.spec.whatwg.org/multipage/#handler-websocket-onmessage
    event_handler!(message, GetOnmessage, SetOnmessage);

    // https://html.spec.whatwg.org/multipage/#dom-websocket-url
    fn Url(&self) -> DOMString {
        DOMString::from(self.url.serialize())
    }

    // https://html.spec.whatwg.org/multipage/#dom-websocket-readystate
    fn ReadyState(&self) -> u16 {
        self.ready_state.get() as u16
    }

    // https://html.spec.whatwg.org/multipage/#dom-websocket-bufferedamount
    fn BufferedAmount(&self) -> u32 {
        self.buffered_amount.get()
    }

    // https://html.spec.whatwg.org/multipage/#dom-websocket-binarytype
    fn BinaryType(&self) -> BinaryType {
        self.binary_type.get()
    }

    // https://html.spec.whatwg.org/multipage/#dom-websocket-binarytype
    fn SetBinaryType(&self, btype: BinaryType) {
        self.binary_type.set(btype)
    }

    // https://html.spec.whatwg.org/multipage/#dom-websocket-send
    fn Send(&self, data: USVString) -> Fallible<()> {

        let data_byte_len = data.0.as_bytes().len() as u64;
        let send_data = try!(self.send_impl(data_byte_len));

        if send_data {
            let mut other_sender = self.sender.borrow_mut();
            let my_sender = other_sender.as_mut().unwrap();
            let _ = my_sender.lock().unwrap().send_message(&Message::text(data.0));
        }

        Ok(())
    }

    // https://html.spec.whatwg.org/multipage/#dom-websocket-send
    fn Send_(&self, data: &Blob) -> Fallible<()> {

        /* As per https://html.spec.whatwg.org/multipage/#websocket
           the buffered amount needs to be clamped to u32, even though Blob.Size() is u64
           If the buffer limit is reached in the first place, there are likely other major problems
        */
        let data_byte_len = data.Size();
        let send_data = try!(self.send_impl(data_byte_len));

        if send_data {
            let mut other_sender = self.sender.borrow_mut();
            let my_sender = other_sender.as_mut().unwrap();
            let _ = my_sender.lock().unwrap().send_message(&Message::binary(data.clone_bytes()));
        }

        Ok(())
    }

    // https://html.spec.whatwg.org/multipage/#dom-websocket-close
    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 code: u16 = this.code.get();
                let reason = this.reason.borrow().clone();
                let _ = sender.lock().unwrap().send_message(&Message::close_because(code, reason));
            }
        }


        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: Arc<Mutex<Sender<WebSocketStream>>>,
}

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

        *ws.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(), DOMString::from("open"),
                               EventBubbles::DoesNotBubble,
                               EventCancelable::NotCancelable);
        event.fire(ws.upcast());
    }
}

struct BufferedAmountTask {
    addr: Trusted<WebSocket>,
}

impl Runnable for BufferedAmountTask {
    // See https://html.spec.whatwg.org/multipage/#dom-websocket-bufferedamount
    //
    // To be compliant with standards, we need to reset bufferedAmount only when the event loop
    // reaches step 1.  In our implementation, the bytes will already have been sent on a background
    // thread.
    fn handler(self: Box<Self>) {
        let ws = self.addr.root();

        ws.buffered_amount.set(0);
        ws.clearing_buffer.set(false);
    }
}

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(),
                                   DOMString::from("error"),
                                   EventBubbles::DoesNotBubble,
                                   EventCancelable::Cancelable);
            event.fire(ws.upcast());
        }
        let reason = ws.reason.borrow().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(),
                                          DOMString::from("close"),
                                          EventBubbles::DoesNotBubble,
                                          EventCancelable::NotCancelable,
                                          ws.clean_close.get(),
                                          ws.code.get(),
                                          DOMString::from(reason));
        close_event.upcast::<Event>().fire(ws.upcast());
    }
}

struct MessageReceivedTask {
    address: Trusted<WebSocket>,
    message: MessageData,
}

impl Runnable for MessageReceivedTask {
    #[allow(unsafe_code)]
    fn handler(self: Box<Self>) {
        let ws = self.address.root();
        debug!("MessageReceivedTask::handler({:p}): readyState={:?}", &*ws,
               ws.ready_state.get());

        // Step 1.
        if ws.ready_state.get() != WebSocketRequestState::Open {
            return;
        }

        // Step 2-5.
        let global = ws.global.root();
        // global.get_cx() returns a valid `JSContext` pointer, so this is safe.
        unsafe {
            let cx = global.r().get_cx();
            let _ar = JSAutoRequest::new(cx);
            let _ac = JSAutoCompartment::new(cx, ws.reflector().get_jsobject().get());
            let mut message = RootedValue::new(cx, UndefinedValue());
            match self.message {
                MessageData::Text(text) => text.to_jsval(cx, message.handle_mut()),
                MessageData::Binary(data) => {
                    match ws.binary_type.get() {
                        BinaryType::Blob => {
                            let blob = Blob::new(global.r(), Some(data), "");
                            blob.to_jsval(cx, message.handle_mut());
                        }
                        BinaryType::Arraybuffer => {
                            let len = data.len() as uint32_t;
                            let buf = JS_NewArrayBuffer(cx, len);
                            let buf_data: *mut uint8_t = JS_GetArrayBufferData(buf, ptr::null());
                            ptr::copy_nonoverlapping(data.as_ptr(), buf_data, len as usize);
                            buf.to_jsval(cx, message.handle_mut());
                        }

                    }
                },
            }
            MessageEvent::dispatch_jsval(ws.upcast(), global.r(), message.handle());
        }
    }
}