// Copyright 2008, 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.

// This file defines a service that collects information about the user
// experience in order to help improve future versions of the app.

#ifndef CHROME_BROWSER_METRICS_SERVICE_H__
#define CHROME_BROWSER_METRICS_SERVICE_H__

#include <list>
#include <map>
#include <set>
#include <string>
#include <vector>

#include "base/basictypes.h"
#include "base/histogram.h"
#include "base/scoped_ptr.h"
#include "base/values.h"
#include "chrome/browser/metrics_log.h"
#include "chrome/browser/url_fetcher.h"
#include "chrome/common/notification_service.h"
#include "webkit/glue/webplugin.h"

class BookmarkBarModel;
class BookmarkBarNode;
class PrefService;
class Profile;
class TemplateURLModel;

// This is used to quickly log stats from plugin-related notifications in
// MetricsService::plugin_stats_buffer_.  The buffer's contents are transferred
// out when Local State is periodically saved.  The information is then
// reported to the UMA server on next launch.
struct PluginStats {
 public:
  PluginStats() : process_launches(0), process_crashes(0), instances(0) {}

  // The number of times that the given plugin process has been launched
  int process_launches;

  // The number of times that the given plugin process has crashed
  int process_crashes;

  // The number of instances of this plugin that have been created.
  // An instance is a DOM object rendered by this plugin during a page load.
  int instances;
};

class MetricsService : public NotificationObserver,
                       public URLFetcher::Delegate {
 public:
  MetricsService();
  virtual ~MetricsService();

  // At startup, prefs needs to be called with a list of all the pref names and
  // types we'll be using.
  static void RegisterPrefs(PrefService* local_state);

  // Sets and gets whether metrics recording is active.
  // SetRecording(false) also forces a persistent save of logging state (if
  // anything has been recorded, or transmitted).
  void SetRecording(bool enabled);
  bool IsRecording() const;

  // Enable/disable transmission of accumulated logs and crash reports (dumps).
  // Return value "true" indicates setting was definitively set as requested).
  // Return value of "false" indicates that the enable state is effectively
  // stuck in the other logical setting.
  // Google Update maintains the authoritative preference in the registry, so
  // the caller *might* not be able to actually change the setting.
  // It is always possible to set this to at least one value, which matches the
  // current value reported by querying Google Update.
  bool EnableReporting(bool enable);

  // Implementation of NotificationObserver
  virtual void Observe(NotificationType type,
                       const NotificationSource& source,
                       const NotificationDetails& details);

  // This should be called when the application is shutting down, to record
  // the fact that this was a clean shutdown in the stability metrics.
  void RecordCleanShutdown();

  // Invoked when we get a WM_SESSIONEND. This places a value in prefs that is
  // reset when RecordCompletedSessionEnd is invoked.
  void RecordStartOfSessionEnd();

  // This should be called when the application is shutting down. It records
  // that session end was successful.
  void RecordCompletedSessionEnd();

  // Saves in the preferences if the crash report registration was successful.
  // This count is eventually send via UMA logs.
  void RecordBreakpadRegistration(bool success);

  // Saves in the preferences if the browser is running under a debugger.
  // This count is eventually send via UMA logs.
  void RecordBreakpadHasDebugger(bool has_debugger);

  // Callback to let us knew that the plugin list is warmed up.
  void OnGetPluginListTaskComplete();

  // Save any unsent logs into a persistent store in a pref.  We always do this
  // at shutdown, but we can do it as we reduce the list as well.
  void StoreUnsentLogs();

 private:
  // The MetricsService has a lifecycle that is stored as a state.
  // See metrics_service.cc for description of this lifecycle.
  enum State {
    INITIALIZED,            // Constructor was called.
    PLUGIN_LIST_REQUESTED,  // Waiting for DLL list to be loaded.
    PLUGIN_LIST_ARRIVED,    // Waiting for timer to send initial log.
    INITIAL_LOG_READY,      // Initial log generated, and waiting for reply.
    SEND_OLD_INITIAL_LOGS,  // Sending unsent logs from previous session.
    SENDING_OLD_LOGS,       // Sending unsent logs from previous session.
    SENDING_CURRENT_LOGS,   // Sending standard current logs as they acrue.
  };

  // Maintain a map of histogram names to the sample stats we've sent.
  typedef std::map<std::string, Histogram::SampleSet> LoggedSampleMap;

  class GetPluginListTask;
  class GetPluginListTaskComplete;

  // Set up client ID, session ID, etc.
  void InitializeMetricsState();
  // Generates a new client ID to use to identify self to metrics server.
  static std::string GenerateClientID();
  // Schedule the next save of LocalState information.  This is called
  // automatically by the task that performs each save to schedule the next one.
  void ScheduleNextStateSave();
  // Save the LocalState information immediately. This should not be called by
  // anybody other than the scheduler to avoid doing too many writes. When you
  // make a change, call ScheduleNextStateSave() instead.
  void SaveLocalState();

  // Called to start recording user experience metrics.
  void StartRecording();
  // Called to stop recording user experience metrics.  The caller takes
  // ownership of the resulting MetricsLog object via the log parameter,
  // or passes in NULL to indicate that the log should simply be deleted.
  void StopRecording(MetricsLog** log);
  void ListenerRegistration(bool start_listening);
  // Adds or Removes (depending on the value of is_add) the given observer
  // to the given notification type for all sources.
  static void AddOrRemoveObserver(NotificationObserver* observer,
                                  NotificationType type,
                                  bool is_add);

  // Deletes pending_log_ and current_log_, and pushes their text into the
  // appropriate unsent_log vectors.
  void PushPendingLogsToUnsentLists();

  // Start timer for next log transmission.
  void StartLogTransmissionTimer();
  // Do not call TryToStartTransmission() directly.
  // Use StartLogTransmissionTimer() to schedule a call.
  void TryToStartTransmission();
  // Internal function to collect process memory information.
  void CollectMemoryDetails();
  // Check to see if there is a log that needs to be, or is being, transmitted.
  bool pending_log() const {
    return pending_log_ || !pending_log_text_.empty();
  }
  // Check to see if there are any unsent logs from previous sessions.
  bool unsent_logs() const {
    return !unsent_initial_logs_.empty() || !unsent_ongoing_logs_.empty();
  }
  // Record stats, client ID, Session ID, etc. in a special "first" log.
  void PrepareInitialLog();
  // Pull copies of unsent logs from prefs into instance variables.
  void RecallUnsentLogs();
  // Convert pending_log_ to XML in pending_log_text_ for transmission.
  void PreparePendingLogText();
  // Convert pending_log_ to XML, compress it, and prepare to pass to server.
  void PreparePendingLogForTransmission();
  // Discard pending_log_, and clear pending_log_text_. Called after processing
  // of this log is complete.
  void DiscardPendingLog();
  // Compress the report log in input using bzip2, store the result in output.
  bool Bzip2Compress(const std::string& input, std::string* output);
  // Implementation of URLFetcher::Delegate. Called after transmission
  // completes (either successfully or with failure).
  virtual void OnURLFetchComplete(const URLFetcher* source,
                                  const GURL& url,
                                  const URLRequestStatus& status,
                                  int response_code,
                                  const ResponseCookies& cookies,
                                  const std::string& data);

  // Called by OnURLFetchComplete to handle the case when the server returned
  // a response code not equal to 200.
  void HandleBadResponseCode();

  // Called by OnURLFetchComplete with data as the argument
  // parses the xml returned by the server in the call to OnURLFetchComplete
  // and extracts settings for subsequent frequency and content of log posts.
  void GetSettingsFromResponseData(const std::string& data);

  // This is a helper function for GetSettingsFromResponseData which iterates
  // through the xml tree at the level of the <config> node.
  void GetSettingsFromConfigNode(xmlNodePtr config_node);

  // Records a window-related notification.
  void LogWindowChange(NotificationType type,
                       const NotificationSource& source,
                       const NotificationDetails& details);

  // Reads, increments and then sets the specified integer preference.
  void IncrementPrefValue(const wchar_t* path);

  // Records a renderer process crash.
  void LogRendererCrash();

  // Records a renderer process hang.
  void LogRendererHang();

  // Records the desktop security status of a renderer in the sandbox at
  // creation time.
  void LogRendererInSandbox(bool on_sandbox_desktop);

  // Set the value in preferences for for the number of bookmarks and folders
  // in node. The pref key for the number of bookmarks in num_bookmarks_key and
  // the pref key for number of folders in num_folders_key.
  void LogBookmarks(BookmarkBarNode* node,
                    const wchar_t* num_bookmarks_key,
                    const wchar_t* num_folders_key);

  // Sets preferences for the for the number of bookmarks in model.
  void LogBookmarks(BookmarkBarModel* model);

  // Records a plugin-related notification.  These are recorded to an in-object
  // buffer because these notifications are sent on page load, and we don't
  // want to slow that down.
  void LogPluginChange(NotificationType type,
                       const NotificationSource& source,
                       const NotificationDetails& details);

  // Logs keywords specific metrics. Keyword metrics are recorded in the
  // profile specific metrics.
  void LogKeywords(const TemplateURLModel* url_model);

  // Saves plugin-related updates from the in-object buffer to Local State
  // for retrieval next time we send a Profile log (generally next launch).
  void RecordPluginChanges(PrefService* pref);

  // Records state that should be periodically saved, like uptime and
  // buffered plugin stability statistics.
  void RecordCurrentState(PrefService* pref);

  // Record complete list of histograms.  Called when we close a log.
  void RecordCurrentHistograms();
  // Record a specific histogram.
  void RecordHistogram(const Histogram& histogram);

  // Logs the initiation of a page load
  void LogLoadStarted();

  // Records a page load notification.
  void LogLoadComplete(NotificationType type,
                       const NotificationSource& source,
                       const NotificationDetails& details);

  // Adds a profile metric with the specified key/value pair.
  void AddProfileMetric(Profile* profile, const std::wstring& key,
                        int value);

  // Checks whether a notification can be logged.
  bool CanLogNotification(NotificationType type,
                          const NotificationSource& source,
                          const NotificationDetails& details);

  // Sets the value of the specified path in prefs and schedules a save.
  void RecordBooleanPrefValue(const wchar_t* path, bool value);

  bool recording_;
  bool reporting_;  // if false, metrics logs are discarded rather than sent

  // The progession of states made by the browser are recorded in the following
  // state.
  State state_;

  // A log that we are currently transmiting, or about to try to transmit.
  MetricsLog* pending_log_;
  // An alternate form of pending_log_.  We persistently save this text version
  // into prefs if we can't transmit it.  As a result, sometimes all we have is
  // the text version (recalled from a previous session).
  std::string pending_log_text_;
  // The outstanding transmission appears as a URL Fetch operation.
  scoped_ptr<URLFetcher> current_fetch_;
  // The log that we are still appending to.
  MetricsLog* current_log_;
  // The identifier that's sent to the server with the log reports.
  std::string client_id_;
  // A number that identifies the how many times the app has been launched.
  int session_id_;

  // When logs were not sent during a previous session they are queued to be
  // sent instead of currently accumulating logs.  We give preference to sending
  // our inital log first, then unsent intial logs, then unsent ongoing logs.
  // Unsent logs are gathered at shutdown, and save in a persistent pref, one
  // log in each string in the following arrays.
  // Note that the vector has the oldest logs listed first (early in the
  // vector), and we'll discard old logs if we have gathered too many logs.
  std::vector<std::string> unsent_initial_logs_;
  std::vector<std::string> unsent_ongoing_logs_;

  // Maps NavigationControllers (corresponding to tabs) or Browser
  // (corresponding to Windows) to a unique integer that we will use to identify
  // it. |next_window_id_| is used to track which IDs we have used so far.
  typedef std::map<uintptr_t, int> WindowMap;
  WindowMap window_map_;
  int next_window_id_;

  // Buffer of plugin notifications for quick access.  See PluginStats
  // documentation above for more details.
  std::map<std::wstring, PluginStats> plugin_stats_buffer_;

  ScopedRunnableMethodFactory<MetricsService> log_sender_factory_;
  ScopedRunnableMethodFactory<MetricsService> state_saver_factory_;

  // Dictionary containing all the profile specific metrics. This is set
  // at creation time from the prefs.
  scoped_ptr<DictionaryValue> profile_dictionary_;

  // For histograms, record what we've already logged (as a sample for each
  // histogram) so that we can send only the delta with the next log.
  MetricsService::LoggedSampleMap logged_samples_;

  // The interval between consecutive log transmissions (to avoid hogging the
  // outbound network link).  This is usually also the duration for which we
  // build up a log, but if other unsent-logs from previous sessions exist, we
  // quickly transmit those unsent logs while we continue to build a log.
  TimeDelta interlog_duration_;

  // The maximum number of events which get transmitted in the log.  This is
  // provided by the UMA server in the server response data.
  int event_limit_;

  // The types of data that are to be included in the log.  These are called
  // "collectors" in the server response data.
  std::set<std::string> collectors_;

  // Indicate that a timer for sending the next log has already been queued,
  // or that a URLFetch (i.e., log transmission) is in progress.
  bool timer_pending_;

  DISALLOW_EVIL_CONSTRUCTORS(MetricsService);
};

#endif  // CHROME_BROWSER_METRICS_SERVICE_H__