/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * The contents of this file are subject to the Netscape Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/NPL/
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is Netscape
 * Communications Corporation.  Portions created by Netscape are
 * Copyright (C) 1998 Netscape Communications Corporation. All
 * Rights Reserved.
 *
 * Contributor(s): 
 * Peter Van der Beken, peterv@netscape.com
 *    -- original author.
 *
 */

#include "nsSyncLoader.h"
#include "nsAppShellCIDs.h"
#include "nsIDocument.h"
#include "nsIDOMDocument.h"
#include "nsIDOMDOMImplementation.h"
#include "nsIDOMEventReceiver.h"
#include "nsIEventQueueService.h"
#include "nsIPrivateDOMImplementation.h"
#include "nsIScriptSecurityManager.h"
#include "nsLayoutCID.h"
#include "nsNetUtil.h"

static const char* kLoadAsData = "loadAsData";

static NS_DEFINE_CID(kIDOMDOMImplementationCID, NS_DOM_IMPLEMENTATION_CID);
static NS_DEFINE_CID(kEventQueueServiceCID, NS_EVENTQUEUESERVICE_CID);
static NS_DEFINE_CID(kAppShellServiceCID, NS_APPSHELL_SERVICE_CID);

/*
 * This class exists to prevent a circular reference between
 * the loaded document and the nsSyncloader instance. The
 * request owns the document. While the document is loading, 
 * the request is a load listener, held onto by the document.
 * The proxy class breaks the circularity by filling in as the
 * load listener and holding a weak reference to the request
 * object.
 */

class txLoadListenerProxy : public nsIDOMLoadListener {
public:
    txLoadListenerProxy(nsWeakPtr aParent);
    virtual ~txLoadListenerProxy();

    NS_DECL_ISUPPORTS

    // nsIDOMEventListener
    NS_IMETHOD HandleEvent(nsIDOMEvent* aEvent);

    // nsIDOMLoadListener
    NS_IMETHOD Load(nsIDOMEvent* aEvent);
    NS_IMETHOD Unload(nsIDOMEvent* aEvent);
    NS_IMETHOD Abort(nsIDOMEvent* aEvent);
    NS_IMETHOD Error(nsIDOMEvent* aEvent);

protected:
    nsWeakPtr  mParent;
};

txLoadListenerProxy::txLoadListenerProxy(nsWeakPtr aParent)
{
    NS_INIT_ISUPPORTS();
    mParent = aParent;
}

txLoadListenerProxy::~txLoadListenerProxy()
{
}

NS_IMPL_ISUPPORTS1(txLoadListenerProxy, nsIDOMLoadListener)

NS_IMETHODIMP
txLoadListenerProxy::HandleEvent(nsIDOMEvent* aEvent)
{
    nsCOMPtr<nsIDOMLoadListener> listener = do_QueryReferent(mParent);

    if (listener) {
        return listener->HandleEvent(aEvent);
    }

    return NS_OK;
}

NS_IMETHODIMP
txLoadListenerProxy::Load(nsIDOMEvent* aEvent)
{
    nsCOMPtr<nsIDOMLoadListener> listener = do_QueryReferent(mParent);

    if (listener) {
        return listener->Load(aEvent);
    }

    return NS_OK;
}

NS_IMETHODIMP
txLoadListenerProxy::Unload(nsIDOMEvent* aEvent)
{
    nsCOMPtr<nsIDOMLoadListener> listener = do_QueryReferent(mParent);

    if (listener) {
        return listener->Unload(aEvent);
    }

    return NS_OK;
}

NS_IMETHODIMP
txLoadListenerProxy::Abort(nsIDOMEvent* aEvent)
{
    nsCOMPtr<nsIDOMLoadListener> listener = do_QueryReferent(mParent);

    if (listener) {
        return listener->Abort(aEvent);
    }

    return NS_OK;
}

NS_IMETHODIMP
txLoadListenerProxy::Error(nsIDOMEvent* aEvent)
{
    nsCOMPtr<nsIDOMLoadListener> listener = do_QueryReferent(mParent);

    if (listener) {
        return listener->Error(aEvent);
    }

    return NS_OK;
}

nsSyncLoader::nsSyncLoader()
{
    NS_INIT_ISUPPORTS();
}

nsSyncLoader::~nsSyncLoader()
{
    if (mLoading && mChannel) {
        mChannel->Cancel(NS_BINDING_ABORTED);
    }
}

NS_IMPL_ISUPPORTS3(nsSyncLoader, nsISyncLoader, nsIDOMLoadListener, nsISupportsWeakReference)

NS_IMETHODIMP
nsSyncLoader::LoadDocument(nsIURI* documentURI, nsIDocument *aLoader, nsIDOMDocument **_retval)
{
    nsresult rv = NS_OK;

    nsCOMPtr<nsIURI> loaderURI;
    aLoader->GetDocumentURL(getter_AddRefs(loaderURI));

    nsCOMPtr<nsIScriptSecurityManager> securityManager = 
        do_GetService(NS_SCRIPTSECURITYMANAGER_CONTRACTID, &rv);
    NS_ENSURE_SUCCESS(rv, rv);

    rv = securityManager->CheckLoadURI(loaderURI, documentURI,
                                       nsIScriptSecurityManager::STANDARD);
    NS_ENSURE_SUCCESS(rv, rv);

    nsCOMPtr<nsILoadGroup> loadGroup;
    rv = aLoader->GetDocumentLoadGroup(getter_AddRefs(loadGroup));
    NS_ENSURE_SUCCESS(rv, rv);

    // Get and initialize a DOMImplementation
    nsCOMPtr<nsIDOMDOMImplementation> implementation = 
        do_CreateInstance(kIDOMDOMImplementationCID, &rv);
    NS_ENSURE_SUCCESS(rv, rv);

    nsCOMPtr<nsIPrivateDOMImplementation> privImplementation(do_QueryInterface(implementation, &rv));
    NS_ENSURE_SUCCESS(rv, rv);
    privImplementation->Init(documentURI);

    // Create an empty document from it
    nsString emptyStr;
    nsCOMPtr<nsIDOMDocument> DOMDocument;
    rv = implementation->CreateDocument(emptyStr, 
                                        emptyStr, 
                                        nsnull, 
                                        getter_AddRefs(DOMDocument));
    NS_ENSURE_SUCCESS(rv, rv);

    rv = NS_OpenURI(getter_AddRefs(mChannel), documentURI, nsnull, loadGroup);
    NS_ENSURE_SUCCESS(rv, rv);

    // Make sure we've been opened
    if (!mChannel) {
        return NS_ERROR_NOT_INITIALIZED;
    }

    // Tell the document to start loading
    nsCOMPtr<nsIDocument> document = do_QueryInterface(DOMDocument, &rv);
    NS_ENSURE_SUCCESS(rv, rv);

    nsCOMPtr<nsIEventQueueService> service = 
        do_GetService(NS_EVENTQUEUESERVICE_CONTRACTID, &rv);
    NS_ENSURE_SUCCESS(rv, rv);

    nsCOMPtr<nsIEventQueue> currentThreadQ;
    rv = service->PushThreadEventQueue(getter_AddRefs(currentThreadQ));
    NS_ENSURE_SUCCESS(rv, NS_ERROR_FAILURE);

    // Register as a load listener on the document
    nsCOMPtr<nsIDOMEventReceiver> target = do_QueryInterface(DOMDocument);
    txLoadListenerProxy* proxy;
    if (target) {
        nsWeakPtr requestWeak = getter_AddRefs(NS_GetWeakReference(NS_STATIC_CAST(nsIDOMLoadListener*, this)));
        proxy = new txLoadListenerProxy(requestWeak);
        if (!proxy) {
            service->PopThreadEventQueue(currentThreadQ);
            return NS_ERROR_OUT_OF_MEMORY;
        }

        // This will addref the proxy
        rv = target->AddEventListenerByIID(NS_STATIC_CAST(nsIDOMEventListener*, 
                                                          proxy), 
                                           NS_GET_IID(nsIDOMLoadListener));
        if (NS_FAILED(rv)) {
            service->PopThreadEventQueue(currentThreadQ);
            return rv;
        }
    }
    
    mLoadSuccess = PR_FALSE;

    nsCOMPtr<nsIStreamListener> listener;
    rv = document->StartDocumentLoad(kLoadAsData, mChannel, 
                                     loadGroup, nsnull, 
                                     getter_AddRefs(listener),
                                     PR_FALSE);

    if (NS_SUCCEEDED(rv)) {
        // Start reading from the channel
        rv = mChannel->AsyncOpen(listener, nsnull);

        if (NS_SUCCEEDED(rv)) {
            mLoading = PR_TRUE;

            // process events until we're finished.
            PLEvent *event;
            while (mLoading && NS_SUCCEEDED(rv)) {
                rv = currentThreadQ->WaitForEvent(&event);
                NS_ASSERTION(NS_SUCCEEDED(rv), ": currentThreadQ->WaitForEvent failed...\n");
                if (NS_SUCCEEDED(rv)) {
                    rv = currentThreadQ->HandleEvent(event);
                    NS_ASSERTION(NS_SUCCEEDED(rv), ": currentThreadQ->HandleEvent failed...\n");
                }
            }
        }
    }

    mChannel = 0;

    if (NS_FAILED(rv)) {
        service->PopThreadEventQueue(currentThreadQ);
        // This will release the proxy
        target->RemoveEventListenerByIID(NS_STATIC_CAST(nsIDOMEventListener*, 
                                                        proxy), 
                                         NS_GET_IID(nsIDOMLoadListener));
        return rv;
    }

    // This will release the proxy
    rv = target->RemoveEventListenerByIID(NS_STATIC_CAST(nsIDOMEventListener*, 
                                                         proxy), 
                                          NS_GET_IID(nsIDOMLoadListener));
    if (NS_FAILED(rv)) {
        return rv;
    }

    if (mLoadSuccess) {
        *_retval = DOMDocument;
        NS_ADDREF(*_retval);
    }

    rv = service->PopThreadEventQueue(currentThreadQ);

    return rv;
}

// nsIDOMEventListener
nsresult
nsSyncLoader::HandleEvent(nsIDOMEvent* aEvent)
{
    return NS_OK;
}

// nsIDOMLoadListener
nsresult
nsSyncLoader::Load(nsIDOMEvent* aEvent)
{
    if (mLoading) {
        mLoading = PR_FALSE;
        mLoadSuccess = PR_TRUE;
    }

    return NS_OK;
}

nsresult
nsSyncLoader::Unload(nsIDOMEvent* aEvent)
{
    return NS_OK;
}

nsresult
nsSyncLoader::Abort(nsIDOMEvent* aEvent)
{
    if (mLoading) {
        mLoading = PR_FALSE;
    }

    return NS_OK;
}

nsresult
nsSyncLoader::Error(nsIDOMEvent* aEvent)
{
    if (mLoading) {
        mLoading = PR_FALSE;
    }

    return NS_OK;
}