/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla 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/MPL/
 *
 * 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.
 *
 * The Initial Developer of the Original Code is
 * IBM Corporation.
 * Portions created by the Initial Developer are Copyright (C) 2005
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *  Brian Ryner <bryner@brianryner.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "nsStyleSheetService.h"
#include "nsIStyleSheet.h"
#include "nsICSSLoader.h"
#include "nsICSSStyleSheet.h"
#include "nsIURI.h"
#include "nsContentCID.h"
#include "nsCOMPtr.h"
#include "nsIServiceManager.h"
#include "nsICategoryManager.h"
#include "nsISupportsPrimitives.h"
#include "nsNetUtil.h"

static NS_DEFINE_CID(kCSSLoaderCID, NS_CSS_LOADER_CID);

nsStyleSheetService *nsStyleSheetService::gInstance = nsnull;

nsStyleSheetService::nsStyleSheetService()
{
  NS_ASSERTION(0 == AGENT_SHEET && 1 == USER_SHEET, "Invalid value for USER_SHEET or AGENT_SHEET");
  NS_ASSERTION(!gInstance, "Someone is using CreateInstance instead of GetService");
  gInstance = this;
}

nsStyleSheetService::~nsStyleSheetService()
{
  gInstance = nsnull;
}

NS_IMPL_ISUPPORTS1(nsStyleSheetService, nsIStyleSheetService)

void
nsStyleSheetService::RegisterFromEnumerator(nsICategoryManager  *aManager,
                                            const char          *aCategory,
                                            nsISimpleEnumerator *aEnumerator,
                                            PRUint32             aSheetType)
{
  if (!aEnumerator)
    return;

  PRBool hasMore;
  while (NS_SUCCEEDED(aEnumerator->HasMoreElements(&hasMore)) && hasMore) {
    nsCOMPtr<nsISupports> element;
    if (NS_FAILED(aEnumerator->GetNext(getter_AddRefs(element))))
      break;

    nsCOMPtr<nsISupportsCString> icStr = do_QueryInterface(element);
    NS_ASSERTION(icStr,
                 "category manager entries must be nsISupportsCStrings");

    nsCAutoString name;
    icStr->GetData(name);

    nsXPIDLCString spec;
    aManager->GetCategoryEntry(aCategory, name.get(), getter_Copies(spec));

    nsCOMPtr<nsIURI> uri;
    NS_NewURI(getter_AddRefs(uri), spec);
    if (uri)
      LoadAndRegisterSheet(uri, aSheetType);
  }
}

PRInt32
nsStyleSheetService::FindSheetByURI(const nsCOMArray<nsIStyleSheet> &sheets,
                                    nsIURI *sheetURI)
{
  for (PRInt32 i = sheets.Count() - 1; i >= 0; i-- ) {
    PRBool bEqual;
    nsCOMPtr<nsIURI> uri;
    if (NS_SUCCEEDED(sheets[i]->GetSheetURI(getter_AddRefs(uri)))
        && uri
        && NS_SUCCEEDED(uri->Equals(sheetURI, &bEqual))
        && bEqual) {
      return i;
    }
  }

  return -1;
}

nsresult
nsStyleSheetService::Init()
{
  // Enumerate all of the style sheet URIs registered in the category
  // manager and load them.

  nsCOMPtr<nsICategoryManager> catMan =
    do_GetService(NS_CATEGORYMANAGER_CONTRACTID);

  NS_ENSURE_TRUE(catMan, NS_ERROR_OUT_OF_MEMORY);

  nsCOMPtr<nsISimpleEnumerator> sheets;
  catMan->EnumerateCategory("agent-style-sheets", getter_AddRefs(sheets));
  RegisterFromEnumerator(catMan, "agent-style-sheets", sheets, AGENT_SHEET);

  catMan->EnumerateCategory("user-style-sheets", getter_AddRefs(sheets));
  RegisterFromEnumerator(catMan, "user-style-sheets", sheets, USER_SHEET);

  return NS_OK;
}

NS_IMETHODIMP
nsStyleSheetService::LoadAndRegisterSheet(nsIURI *aSheetURI,
                                          PRUint32 aSheetType)
{
  NS_ENSURE_ARG(aSheetType == AGENT_SHEET || aSheetType == USER_SHEET);

  nsCOMPtr<nsICSSLoader> loader = do_CreateInstance(kCSSLoaderCID);
  nsCOMPtr<nsICSSStyleSheet> sheet;
  nsresult rv = loader->LoadAgentSheet(aSheetURI, getter_AddRefs(sheet));
  NS_ENSURE_SUCCESS(rv, rv);

  mSheets[aSheetType].AppendObject(sheet);

  return NS_OK;
}

NS_IMETHODIMP
nsStyleSheetService::SheetRegistered(nsIURI *sheetURI,
                                     PRUint32 aSheetType, PRBool *_retval)
{
  NS_ENSURE_ARG(aSheetType == AGENT_SHEET || aSheetType == USER_SHEET);
  NS_ENSURE_ARG_POINTER(sheetURI);
  NS_PRECONDITION(_retval, "Null out param");

  *_retval = (FindSheetByURI(mSheets[aSheetType], sheetURI) >= 0);

  return NS_OK;
}

NS_IMETHODIMP
nsStyleSheetService::UnregisterSheet(nsIURI *sheetURI, PRUint32 aSheetType)
{
  NS_ENSURE_ARG(aSheetType == AGENT_SHEET || aSheetType == USER_SHEET);
  NS_ENSURE_ARG_POINTER(sheetURI);

  PRInt32 foundIndex = FindSheetByURI(mSheets[aSheetType], sheetURI);
  NS_ENSURE_TRUE(foundIndex >= 0, NS_ERROR_INVALID_ARG);
  mSheets[aSheetType].RemoveObjectAt(foundIndex);

  return NS_OK;
}