/* 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::codegen::Bindings::WorkerBinding;
use dom::bindings::codegen::Bindings::WorkerBinding::WorkerMethods;
use dom::bindings::codegen::Bindings::EventHandlerBinding::EventHandlerNonNull;
use dom::bindings::codegen::InheritTypes::{EventCast, EventTargetCast};
use dom::bindings::error::{Fallible, ErrorResult};
use dom::bindings::error::Error::Syntax;
use dom::bindings::global::{GlobalRef, GlobalField};
use dom::bindings::js::{JSRef, Temporary};
use dom::bindings::refcounted::Trusted;
use dom::bindings::structuredclone::StructuredCloneData;
use dom::bindings::trace::JSTraceable;
use dom::bindings::utils::{Reflectable, reflect_dom_object};
use dom::window::WindowHelpers;
use dom::dedicatedworkerglobalscope::DedicatedWorkerGlobalScope;
use dom::errorevent::ErrorEvent;
use dom::event::{Event, EventBubbles, EventCancelable, EventHelpers};
use dom::eventtarget::{EventTarget, EventTargetHelpers, EventTargetTypeId};
use dom::messageevent::MessageEvent;
use script_task::{ScriptChan, ScriptMsg, Runnable};

use devtools_traits::{DevtoolsControlMsg, DevtoolsPageInfo};

use util::str::DOMString;

use js::jsapi::JSContext;
use js::jsval::{JSVal, UndefinedValue};
use url::UrlParser;

use std::borrow::ToOwned;
use std::sync::mpsc::{channel, Sender};

pub type TrustedWorkerAddress = Trusted<Worker>;

// https://html.spec.whatwg.org/multipage/workers.html#worker
#[dom_struct]
pub struct Worker {
    eventtarget: EventTarget,
    global: GlobalField,
    /// Sender to the Receiver associated with the DedicatedWorkerGlobalScope
    /// this Worker created.
    sender: Sender<(TrustedWorkerAddress, ScriptMsg)>,
}

impl Worker {
    fn new_inherited(global: GlobalRef, sender: Sender<(TrustedWorkerAddress, ScriptMsg)>) -> Worker {
        Worker {
            eventtarget: EventTarget::new_inherited(EventTargetTypeId::Worker),
            global: GlobalField::from_rooted(&global),
            sender: sender,
        }
    }

    pub fn new(global: GlobalRef, sender: Sender<(TrustedWorkerAddress, ScriptMsg)>) -> Temporary<Worker> {
        reflect_dom_object(box Worker::new_inherited(global, sender),
                           global,
                           WorkerBinding::Wrap)
    }

    // https://www.whatwg.org/html/#dom-worker
    pub fn Constructor(global: GlobalRef, script_url: DOMString) -> Fallible<Temporary<Worker>> {
        // Step 2-4.
        let worker_url = match UrlParser::new().base_url(&global.get_url())
                .parse(script_url.as_slice()) {
            Ok(url) => url,
            Err(_) => return Err(Syntax),
        };

        let resource_task = global.resource_task();

        let (sender, receiver) = channel();
        let worker = Worker::new(global, sender.clone()).root();
        let worker_ref = Trusted::new(global.get_cx(), worker.r(), global.script_chan());

        if let Some(ref chan) = global.devtools_chan() {
            let pipeline_id = global.pipeline();
            let (devtools_sender, _) = channel();
            let title = format!("Worker for {}", worker_url);
            let page_info = DevtoolsPageInfo {
                title: title,
                url: worker_url.clone(),
            };
            let worker_id = global.get_next_worker_id();
            chan.send(
                DevtoolsControlMsg::NewGlobal((pipeline_id, Some(worker_id)), devtools_sender.clone(), page_info)
            ).unwrap();
        }

        DedicatedWorkerGlobalScope::run_worker_scope(
            worker_url, global.pipeline(), global.devtools_chan(), worker_ref, resource_task, global.script_chan(),
            sender, receiver);

        Ok(Temporary::from_rooted(worker.r()))
    }

    pub fn handle_message(address: TrustedWorkerAddress,
                          data: StructuredCloneData) {
        let worker = address.to_temporary().root();

        let global = worker.r().global.root();
        let target: JSRef<EventTarget> = EventTargetCast::from_ref(worker.r());

        let message = data.read(global.r());
        MessageEvent::dispatch_jsval(target, global.r(), message);
    }

    pub fn dispatch_simple_error(address: TrustedWorkerAddress) {
        let worker = address.to_temporary().root();
        let global = worker.r().global.root();
        let target: JSRef<EventTarget> = EventTargetCast::from_ref(worker.r());

        let event = Event::new(global.r(),
                               "error".to_owned(),
                               EventBubbles::DoesNotBubble,
                               EventCancelable::NotCancelable).root();
        event.r().fire(target);
    }

    pub fn handle_error_message(address: TrustedWorkerAddress, message: DOMString,
                                filename: DOMString, lineno: u32, colno: u32) {
        let worker = address.to_temporary().root();
        let global = worker.r().global.root();
        let error = UndefinedValue();
        let target: JSRef<EventTarget> = EventTargetCast::from_ref(worker.r());
        let errorevent = ErrorEvent::new(global.r(), "error".to_owned(),
                                         EventBubbles::Bubbles, EventCancelable::Cancelable,
                                         message, filename, lineno, colno, error).root();
        let event: JSRef<Event> = EventCast::from_ref(errorevent.r());
        event.fire(target);
    }
}

impl<'a> WorkerMethods for JSRef<'a, Worker> {
    fn PostMessage(self, cx: *mut JSContext, message: JSVal) -> ErrorResult {
        let data = try!(StructuredCloneData::write(cx, message));
        let address = Trusted::new(cx, self, self.global.root().r().script_chan().clone());
        self.sender.send((address, ScriptMsg::DOMMessage(data))).unwrap();
        Ok(())
    }

    event_handler!(message, GetOnmessage, SetOnmessage);
}

pub struct WorkerMessageHandler {
    addr: TrustedWorkerAddress,
    data: StructuredCloneData,
}

impl WorkerMessageHandler {
    pub fn new(addr: TrustedWorkerAddress, data: StructuredCloneData) -> WorkerMessageHandler {
        WorkerMessageHandler {
            addr: addr,
            data: data,
        }
    }
}

impl Runnable for WorkerMessageHandler {
    fn handler(self: Box<WorkerMessageHandler>) {
        let this = *self;
        Worker::handle_message(this.addr, this.data);
    }
}

pub struct WorkerEventHandler {
    addr: TrustedWorkerAddress,
}

impl WorkerEventHandler {
    pub fn new(addr: TrustedWorkerAddress) -> WorkerEventHandler {
        WorkerEventHandler {
            addr: addr
        }
    }
}

impl Runnable for WorkerEventHandler {
    fn handler(self: Box<WorkerEventHandler>) {
        let this = *self;
        Worker::dispatch_simple_error(this.addr);
    }
}

pub struct WorkerErrorHandler {
    addr: TrustedWorkerAddress,
    msg: DOMString,
    file_name: DOMString,
    line_num: u32,
    col_num: u32,
}

impl WorkerErrorHandler {
    pub fn new(addr: TrustedWorkerAddress, msg: DOMString, file_name: DOMString, line_num: u32, col_num: u32) -> WorkerErrorHandler {
        WorkerErrorHandler {
            addr: addr,
            msg: msg,
            file_name: file_name,
            line_num: line_num,
            col_num: col_num,
        }
    }
}

impl Runnable for WorkerErrorHandler {
    fn handler(self: Box<WorkerErrorHandler>) {
        let this = *self;
        Worker::handle_error_message(this.addr, this.msg, this.file_name, this.line_num, this.col_num);
    }
}