/* 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 https://mozilla.org/MPL/2.0/. */

use crate::connector::{create_tls_config, ALPN_H1};
use crate::cookie::Cookie;
use crate::fetch::methods::should_be_blocked_due_to_bad_port;
use crate::hosts::replace_host;
use crate::http_loader::HttpState;
use embedder_traits::resources::{self, Resource};
use headers::Host;
use http::header::{self, HeaderMap, HeaderName, HeaderValue};
use http::uri::Authority;
use ipc_channel::ipc::{IpcReceiver, IpcSender};
use ipc_channel::router::ROUTER;
use net_traits::request::{RequestBuilder, RequestMode};
use net_traits::{CookieSource, MessageData};
use net_traits::{WebSocketDomAction, WebSocketNetworkEvent};
use openssl::ssl::SslStream;
use servo_url::ServoUrl;
use std::fs;
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::Arc;
use std::thread;
use url::Url;
use ws::util::TcpStream;
use ws::{
    CloseCode, Factory, Handler, Handshake, Message, Request, Response as WsResponse, Sender,
    WebSocket,
};
use ws::{Error as WebSocketError, ErrorKind as WebSocketErrorKind, Result as WebSocketResult};

/// A client for connecting to a websocket server
#[derive(Clone)]
struct Client<'a> {
    origin: &'a str,
    host: &'a Host,
    protocols: &'a [String],
    http_state: &'a Arc<HttpState>,
    resource_url: &'a ServoUrl,
    event_sender: &'a IpcSender<WebSocketNetworkEvent>,
    protocol_in_use: Option<String>,
    certificate_path: Option<String>,
}

impl<'a> Factory for Client<'a> {
    type Handler = Self;

    fn connection_made(&mut self, _: Sender) -> Self::Handler {
        self.clone()
    }

    fn connection_lost(&mut self, _: Self::Handler) {
        let _ = self.event_sender.send(WebSocketNetworkEvent::Fail);
    }
}

impl<'a> Handler for Client<'a> {
    fn build_request(&mut self, url: &Url) -> WebSocketResult<Request> {
        let mut req = Request::from_url(url)?;
        req.headers_mut()
            .push(("Origin".to_string(), self.origin.as_bytes().to_owned()));
        req.headers_mut().push((
            "Host".to_string(),
            format!("{}", self.host).as_bytes().to_owned(),
        ));

        for protocol in self.protocols {
            req.add_protocol(protocol);
        }

        let mut cookie_jar = self.http_state.cookie_jar.write().unwrap();
        cookie_jar.remove_expired_cookies_for_url(self.resource_url);
        if let Some(cookie_list) = cookie_jar.cookies_for_url(self.resource_url, CookieSource::HTTP)
        {
            req.headers_mut()
                .push(("Cookie".into(), cookie_list.as_bytes().to_owned()))
        }

        Ok(req)
    }

    fn on_open(&mut self, shake: Handshake) -> WebSocketResult<()> {
        let mut headers = HeaderMap::new();
        for &(ref name, ref value) in shake.response.headers().iter() {
            let name = HeaderName::from_bytes(name.as_bytes()).unwrap();
            let value = HeaderValue::from_bytes(&value).unwrap();

            headers.insert(name, value);
        }

        let mut jar = self.http_state.cookie_jar.write().unwrap();
        // TODO(eijebong): Replace thise once typed headers settled on a cookie impl
        for cookie in headers.get_all(header::SET_COOKIE) {
            if let Ok(s) = std::str::from_utf8(cookie.as_bytes()) {
                if let Some(cookie) =
                    Cookie::from_cookie_string(s.into(), self.resource_url, CookieSource::HTTP)
                {
                    jar.push(cookie, self.resource_url, CookieSource::HTTP);
                }
            }
        }

        self.http_state
            .hsts_list
            .write()
            .unwrap()
            .update_hsts_list_from_response(self.resource_url, &headers);

        let _ = self
            .event_sender
            .send(WebSocketNetworkEvent::ConnectionEstablished {
                protocol_in_use: self.protocol_in_use.clone(),
            });
        Ok(())
    }

    fn on_message(&mut self, message: Message) -> WebSocketResult<()> {
        let message = match message {
            Message::Text(message) => MessageData::Text(message),
            Message::Binary(message) => MessageData::Binary(message),
        };
        let _ = self
            .event_sender
            .send(WebSocketNetworkEvent::MessageReceived(message));

        Ok(())
    }

    fn on_error(&mut self, err: WebSocketError) {
        debug!("Error in WebSocket communication: {:?}", err);
        let _ = self.event_sender.send(WebSocketNetworkEvent::Fail);
    }

    fn on_response(&mut self, res: &WsResponse) -> WebSocketResult<()> {
        let protocol_in_use = res.protocol()?;

        if let Some(protocol_name) = protocol_in_use {
            if !self.protocols.is_empty() && !self.protocols.iter().any(|p| protocol_name == (*p)) {
                let error = WebSocketError::new(
                    WebSocketErrorKind::Protocol,
                    "Protocol in Use not in client-supplied protocol list",
                );
                return Err(error);
            }
            self.protocol_in_use = Some(protocol_name.into());
        }
        Ok(())
    }

    fn on_close(&mut self, code: CloseCode, reason: &str) {
        debug!("Connection closing due to ({:?}) {}", code, reason);
        let _ = self.event_sender.send(WebSocketNetworkEvent::Close(
            Some(code.into()),
            reason.to_owned(),
        ));
    }

    fn upgrade_ssl_client(
        &mut self,
        stream: TcpStream,
        url: &Url,
    ) -> WebSocketResult<SslStream<TcpStream>> {
        let certs = match self.certificate_path {
            Some(ref path) => fs::read_to_string(path).expect("Couldn't not find certificate file"),
            None => resources::read_string(Resource::SSLCertificates),
        };

        let domain = self
            .resource_url
            .as_url()
            .domain()
            .ok_or(WebSocketError::new(
                WebSocketErrorKind::Protocol,
                format!("Unable to parse domain from {}. Needed for SSL.", url),
            ))?;
        let tls_config = create_tls_config(&certs, ALPN_H1);
        tls_config
            .build()
            .connect(domain, stream)
            .map_err(WebSocketError::from)
    }
}

pub fn init(
    req_builder: RequestBuilder,
    resource_event_sender: IpcSender<WebSocketNetworkEvent>,
    dom_action_receiver: IpcReceiver<WebSocketDomAction>,
    http_state: Arc<HttpState>,
    certificate_path: Option<String>,
) {
    thread::Builder::new()
        .name(format!("WebSocket connection to {}", req_builder.url))
        .spawn(move || {
            let mut req_builder = req_builder;
            let protocols = match req_builder.mode {
                RequestMode::WebSocket { protocols } => protocols,
                _ => panic!(
                    "Received a RequestBuilder with a non-websocket mode in websocket_loader"
                ),
            };

            // https://fetch.spec.whatwg.org/#websocket-opening-handshake
            // By standard, we should work with an http(s):// URL (req_url),
            // but as ws-rs expects to be called with a ws(s):// URL (net_url)
            // we upgrade ws to wss, so we don't have to convert http(s) back to ws(s).
            http_state
                .hsts_list
                .read()
                .unwrap()
                .apply_hsts_rules(&mut req_builder.url);

            let scheme = req_builder.url.scheme();
            let mut req_url = req_builder.url.clone();
            if scheme == "ws" {
                req_url.as_mut_url().set_scheme("http").unwrap();
            } else if scheme == "wss" {
                req_url.as_mut_url().set_scheme("https").unwrap();
            }

            if should_be_blocked_due_to_bad_port(&req_url) {
                debug!("Failed to establish a WebSocket connection: port blocked");
                let _ = resource_event_sender.send(WebSocketNetworkEvent::Fail);
                return;
            }

            let host = replace_host(req_builder.url.host_str().unwrap());
            let mut net_url = req_builder.url.clone().into_url();
            net_url.set_host(Some(&host)).unwrap();

            let host = Host::from(
                format!(
                    "{}{}",
                    req_builder.url.host_str().unwrap(),
                    req_builder
                        .url
                        .port_or_known_default()
                        .map(|v| format!(":{}", v))
                        .unwrap_or("".into())
                )
                .parse::<Authority>()
                .unwrap(),
            );

            let client = Client {
                origin: &req_builder.origin.ascii_serialization(),
                host: &host,
                protocols: &protocols,
                http_state: &http_state,
                resource_url: &req_builder.url,
                event_sender: &resource_event_sender,
                protocol_in_use: None,
                certificate_path,
            };
            let mut ws = WebSocket::new(client).unwrap();

            if let Err(e) = ws.connect(net_url) {
                debug!("Failed to establish a WebSocket connection: {:?}", e);
                return;
            };

            let ws_sender = ws.broadcaster();
            let initiated_close = Arc::new(AtomicBool::new(false));

            ROUTER.add_route(
                dom_action_receiver.to_opaque(),
                Box::new(move |message| {
                    let dom_action = message.to().expect("Ws dom_action message to deserialize");
                    match dom_action {
                        WebSocketDomAction::SendMessage(MessageData::Text(data)) => {
                            ws_sender.send(Message::text(data)).unwrap();
                        },
                        WebSocketDomAction::SendMessage(MessageData::Binary(data)) => {
                            ws_sender.send(Message::binary(data)).unwrap();
                        },
                        WebSocketDomAction::Close(code, reason) => {
                            if !initiated_close.fetch_or(true, Ordering::SeqCst) {
                                match code {
                                    Some(code) => ws_sender
                                        .close_with_reason(
                                            code.into(),
                                            reason.unwrap_or("".to_owned()),
                                        )
                                        .unwrap(),
                                    None => ws_sender.close(CloseCode::Status).unwrap(),
                                };
                            }
                        },
                    }
                }),
            );

            if let Err(e) = ws.run() {
                debug!("Failed to run WebSocket: {:?}", e);
                let _ = resource_event_sender.send(WebSocketNetworkEvent::Fail);
            };
        })
        .expect("Thread spawning failed");
}