/*
 * Copyright (C) 2013 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"
#include "WebEmbeddedWorkerImpl.h"

#include "ServiceWorkerGlobalScopeProxy.h"
#include "WebDataSourceImpl.h"
#include "WebFrameImpl.h"
#include "WebServiceWorkerContextClient.h"
#include "WebView.h"
#include "WebWorkerPermissionClientProxy.h"
#include "WorkerPermissionClient.h"
#include "core/dom/Document.h"
#include "core/loader/FrameLoadRequest.h"
#include "core/loader/SubstituteData.h"
#include "core/workers/WorkerClients.h"
#include "core/workers/WorkerLoaderProxy.h"
#include "core/workers/WorkerScriptLoader.h"
#include "core/workers/WorkerScriptLoaderClient.h"
#include "core/workers/WorkerThreadStartupData.h"
#include "modules/serviceworkers/ServiceWorkerThread.h"
#include "platform/NotImplemented.h"
#include "platform/SharedBuffer.h"
#include "wtf/Functional.h"

using namespace WebCore;

namespace blink {

// A thin wrapper for one-off script loading.
class WebEmbeddedWorkerImpl::Loader : public WorkerScriptLoaderClient {
public:
    static PassOwnPtr<Loader> create(ExecutionContext* loadingContext, const KURL& scriptURL, const Closure& callback)
    {
        return adoptPtr(new Loader(loadingContext, scriptURL, callback));
    }

    virtual ~Loader()
    {
        m_scriptLoader->setClient(0);
    }

    virtual void notifyFinished() OVERRIDE
    {
        m_callback();
    }

    void cancel()
    {
        m_scriptLoader->cancel();
    }

    bool failed() const { return m_scriptLoader->failed(); }
    const KURL& url() const { return m_scriptLoader->responseURL(); }
    String script() const { return m_scriptLoader->script(); }

private:
    Loader(ExecutionContext* loadingContext, const KURL& scriptURL, const Closure& callback)
        : m_scriptLoader(WorkerScriptLoader::create())
        , m_callback(callback)
    {
        m_scriptLoader->setTargetType(ResourceRequest::TargetIsServiceWorker);
        m_scriptLoader->loadAsynchronously(
            loadingContext, scriptURL, DenyCrossOriginRequests, this);
    }

    RefPtr<WorkerScriptLoader> m_scriptLoader;
    Closure m_callback;
};

class WebEmbeddedWorkerImpl::LoaderProxy : public WorkerLoaderProxy {
public:
    static PassOwnPtr<LoaderProxy> create(WebEmbeddedWorkerImpl& embeddedWorker)
    {
        return adoptPtr(new LoaderProxy(embeddedWorker));
    }

    virtual void postTaskToLoader(PassOwnPtr<ExecutionContextTask> task) OVERRIDE
    {
        m_embeddedWorker.m_loadingContext->postTask(task);
    }

    virtual bool postTaskForModeToWorkerGlobalScope(PassOwnPtr<ExecutionContextTask> task, const String& mode) OVERRIDE
    {
        if (m_embeddedWorker.m_askedToTerminate || !m_embeddedWorker.m_workerThread)
            return false;
        return m_embeddedWorker.m_workerThread->runLoop().postTaskForMode(task, mode);
    }

private:
    explicit LoaderProxy(WebEmbeddedWorkerImpl& embeddedWorker)
        : m_embeddedWorker(embeddedWorker)
    {
    }

    // Not owned, embedded worker owns this.
    WebEmbeddedWorkerImpl& m_embeddedWorker;
};

WebEmbeddedWorker* WebEmbeddedWorker::create(
    WebServiceWorkerContextClient* client,
    WebWorkerPermissionClientProxy* permissionClient)
{
    return new WebEmbeddedWorkerImpl(adoptPtr(client), adoptPtr(permissionClient));
}

WebEmbeddedWorkerImpl::WebEmbeddedWorkerImpl(
    PassOwnPtr<WebServiceWorkerContextClient> client,
    PassOwnPtr<WebWorkerPermissionClientProxy> permissionClient)
    : m_workerContextClient(client)
    , m_permissionClient(permissionClient)
    , m_askedToTerminate(false)
{
}

WebEmbeddedWorkerImpl::~WebEmbeddedWorkerImpl()
{
    ASSERT(m_webView);

    // Detach the client before closing the view to avoid getting called back.
    toWebFrameImpl(m_mainFrame)->setClient(0);

    m_webView->close();
    m_mainFrame->close();
}

void WebEmbeddedWorkerImpl::startWorkerContext(
    const WebEmbeddedWorkerStartData& data)
{
    ASSERT(!m_askedToTerminate);
    ASSERT(!m_mainScriptLoader);
    m_workerStartData = data;

    prepareShadowPageForLoader();

    m_mainScriptLoader = Loader::create(
        m_loadingContext.get(),
        data.scriptURL,
        bind(&WebEmbeddedWorkerImpl::onScriptLoaderFinished, this));
}

void WebEmbeddedWorkerImpl::terminateWorkerContext()
{
    if (m_askedToTerminate)
        return;
    m_askedToTerminate = true;
    if (m_mainScriptLoader)
        m_mainScriptLoader->cancel();
    if (m_workerThread)
        m_workerThread->stop();
}

void WebEmbeddedWorkerImpl::prepareShadowPageForLoader()
{
    // Create 'shadow page', which is never displayed and is used mainly to
    // provide a context for loading on the main thread.
    //
    // FIXME: This does mostly same as WebSharedWorkerImpl::initializeLoader.
    // This code, and probably most of the code in this class should be shared
    // with SharedWorker.
    ASSERT(!m_webView);
    m_webView = WebView::create(0);
    m_mainFrame = WebFrame::create(this);
    m_webView->setMainFrame(m_mainFrame);

    WebFrameImpl* webFrame = toWebFrameImpl(m_webView->mainFrame());

    // Construct substitute data source for the 'shadow page'. We only need it
    // to have same origin as the worker so the loading checks work correctly.
    CString content("");
    int length = static_cast<int>(content.length());
    RefPtr<SharedBuffer> buffer(SharedBuffer::create(content.data(), length));
    webFrame->frame()->loader().load(FrameLoadRequest(0, ResourceRequest(m_workerStartData.scriptURL), SubstituteData(buffer, "text/html", "UTF-8", KURL())));

    // This document context will be used as 'loading context' for the worker.
    m_loadingContext = webFrame->frame()->document();
}

void WebEmbeddedWorkerImpl::didCreateDataSource(WebFrame*, WebDataSource* ds)
{
    // Tell the loader to load the data into the 'shadow page' synchronously,
    // so we can grab the resulting Document right after load.
    static_cast<WebDataSourceImpl*>(ds)->setDeferMainResourceDataLoad(false);
}

void WebEmbeddedWorkerImpl::onScriptLoaderFinished()
{
    ASSERT(m_mainScriptLoader);

    if (m_mainScriptLoader->failed() || m_askedToTerminate) {
        m_workerContextClient->workerContextFailedToStart();
        m_mainScriptLoader.clear();
        return;
    }

    WorkerThreadStartMode startMode =
        (m_workerStartData.startMode == WebEmbeddedWorkerStartModePauseOnStart)
        ? PauseWorkerGlobalScopeOnStart : DontPauseWorkerGlobalScopeOnStart;

    OwnPtr<WorkerClients> workerClients = WorkerClients::create();
    providePermissionClientToWorker(workerClients.get(), m_permissionClient.release());

    OwnPtr<WorkerThreadStartupData> startupData =
        WorkerThreadStartupData::create(
            m_mainScriptLoader->url(),
            m_workerStartData.userAgent,
            m_mainScriptLoader->script(),
            startMode,
            // FIXME: fill appropriate CSP info and policy type.
            String(),
            ContentSecurityPolicy::Enforce,
            workerClients.release());

    m_mainScriptLoader.clear();

    m_workerGlobalScopeProxy = ServiceWorkerGlobalScopeProxy::create(*this, *m_loadingContext, m_workerContextClient.release());
    m_loaderProxy = LoaderProxy::create(*this);

    m_workerThread = ServiceWorkerThread::create(*m_loaderProxy, *m_workerGlobalScopeProxy, startupData.release());
    m_workerThread->start();
}

} // namespace blink