/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */

#ifndef nsFaviconService_h_
#define nsFaviconService_h_

#include "nsIFaviconService.h"
#include "mozIAsyncFavicons.h"

#include "nsCOMPtr.h"
#include "nsString.h"
#include "nsDataHashtable.h"
#include "nsServiceManagerUtils.h"
#include "nsTHashtable.h"
#include "nsToolkitCompsCID.h"
#include "nsURIHashKey.h"
#include "nsITimer.h"
#include "Database.h"
#include "mozilla/storage.h"

#include "AsyncFaviconHelpers.h"

// Favicons bigger than this size should not be saved to the db to avoid
// bloating it with large image blobs.
// This still allows us to accept a favicon even if we cannot optimize it.
#define MAX_FAVICON_SIZE 10240

// Most icons will be smaller than this rough estimate of the size of an
// uncompressed 16x16 RGBA image of the same dimensions.
#define MAX_ICON_FILESIZE(s) ((PRUint32) s*s*4)

// forward class definitions
class mozIStorageStatementCallback;

class UnassociatedIconHashKey : public nsURIHashKey
{
public:
  UnassociatedIconHashKey(const nsIURI* aURI)
  : nsURIHashKey(aURI)
  {
  }
  UnassociatedIconHashKey(const UnassociatedIconHashKey& aOther)
  : nsURIHashKey(aOther)
  {
    NS_NOTREACHED("Do not call me!");
  }
  mozilla::places::IconData iconData;
  PRTime created;
};

class nsFaviconService : public nsIFaviconService
                       , public mozIAsyncFavicons
                       , public nsITimerCallback
{
public:
  nsFaviconService();

  /**
   * Obtains the service's object.
   */
  static nsFaviconService* GetSingleton();

  /**
   * Initializes the service's object.  This should only be called once.
   */
  nsresult Init();

  static nsFaviconService* GetFaviconServiceIfAvailable() {
    return gFaviconService;
  }

  /**
   * Returns a cached pointer to the favicon service for consumers in the
   * places directory.
   */
  static nsFaviconService* GetFaviconService()
  {
    if (!gFaviconService) {
      nsCOMPtr<nsIFaviconService> serv =
        do_GetService(NS_FAVICONSERVICE_CONTRACTID);
      NS_ENSURE_TRUE(serv, nsnull);
      NS_ASSERTION(gFaviconService, "Should have static instance pointer now");
    }
    return gFaviconService;
  }

  // addition to API for strings to prevent excessive parsing of URIs
  nsresult GetFaviconLinkForIconString(const nsCString& aIcon, nsIURI** aOutput);
  void GetFaviconSpecForIconString(const nsCString& aIcon, nsACString& aOutput);

  nsresult OptimizeFaviconImage(const PRUint8* aData, PRUint32 aDataLen,
                                const nsACString& aMimeType,
                                nsACString& aNewData, nsACString& aNewMimeType);
  PRInt32 GetOptimizedIconDimension() { return mOptimizedIconDimension; }

  /**
   * Obtains the favicon data asynchronously.
   *
   * @param aFaviconURI
   *        The URI representing the favicon we are looking for.
   * @param aCallback
   *        The callback where results or errors will be dispatch to.  In the
   *        returned result, the favicon binary data will be at index 0, and the
   *        mime type will be at index 1.
   */
  nsresult GetFaviconDataAsync(nsIURI* aFaviconURI,
                               mozIStorageStatementCallback* aCallback);

  /**
   * Call to send out favicon changed notifications. Should only be called
   * when there is data loaded for the favicon.
   * @param aPageURI
   *        The URI of the page to notify about.
   * @param aFaviconURI
   *        The moz-anno:favicon URI of the icon.
   * @param aGUID
   *        The unique ID associated with the page.
   */
  void SendFaviconNotifications(nsIURI* aPageURI, nsIURI* aFaviconURI,
                                const nsACString& aGUID);

  NS_DECL_ISUPPORTS
  NS_DECL_NSIFAVICONSERVICE
  NS_DECL_MOZIASYNCFAVICONS
  NS_DECL_NSITIMERCALLBACK

private:
  ~nsFaviconService();

  nsRefPtr<mozilla::places::Database> mDB;

  nsCOMPtr<nsITimer> mExpireUnassociatedIconsTimer;

  static nsFaviconService* gFaviconService;

  /**
   * A cached URI for the default icon. We return this a lot, and don't want to
   * re-parse and normalize our unchanging string many times.  Important: do
   * not return this directly; use Clone() since callers may change the object
   * they get back. May be null, in which case it needs initialization.
   */
  nsCOMPtr<nsIURI> mDefaultIcon;

  // Set to true during favicons expiration, addition of new favicons won't be
  // allowed till expiration has finished since those should then be expired.
  bool mFaviconsExpirationRunning;

  // The target dimension, in pixels, for favicons we optimize.
  // If we find images that are as large or larger than an uncompressed RGBA
  // image of this size (mOptimizedIconDimension*mOptimizedIconDimension*4),
  // we will try to optimize it.
  PRInt32 mOptimizedIconDimension;

  PRUint32 mFailedFaviconSerial;
  nsDataHashtable<nsCStringHashKey, PRUint32> mFailedFavicons;

  // AsyncFetchAndSetIconForPage needs access to the icon cache
  friend class mozilla::places::AsyncFetchAndSetIconForPage;
  friend class mozilla::places::RemoveIconDataCacheEntry;
  nsTHashtable<UnassociatedIconHashKey> mUnassociatedIcons;

  // Caches the content of the default favicon if it's not already cached and
  // copies it into byteStr.
  nsresult GetDefaultFaviconData(nsCString& byteStr);

  // A string of bytes caching the default favicon's content.  Empty if not yet
  // cached.  Rather than accessing this directly, use GetDefaultFaviconData.
  nsCString mDefaultFaviconData;
};

#define FAVICON_ANNOTATION_NAME "favicon"

#endif // nsFaviconService_h_