// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// 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 BookmarkModel;
class BookmarkNode;
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();

  // Sets whether the user permits uploading.  The argument of this function
  // should match the checkbox in Options.
  void SetUserPermitsUpload(bool enabled);

  // Start/stop the metrics recording and uploading machine.  These should be
  // used on startup and when the user clicks the checkbox in the prefs.
  // StartRecordingOnly starts the metrics recording but not reporting, for use
  // in tests only.
  void Start();
  void StartRecordingOnly();
  void Stop();

  // 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);

  // 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;

  // 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 recording_active() 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.
  void SetReporting(bool enabled);
  bool reporting_active() const;

  // If in_idle is true, sets idle_since_last_transmission to true.
  // If in_idle is false and idle_since_last_transmission_ is true, sets
  // idle_since_last_transmission to false and starts the timer (provided
  // starting the timer is permitted).
  void HandleIdleSinceLastTransmission(bool in_idle);

  // 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.
  // Constructs a new, empty current_log_.
  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.  Called when Chrome shuts down.
  void PushPendingLogsToUnsentLists();

  // Save the pending_log_text_ persistently in a pref for transmission when we
  // next run.  Note that IF this text is "too large," we just dicard it.
  void PushPendingLogTextToUnsentOngoingLogs();

  // Start timer for next log transmission.
  void StartLogTransmissionTimer();
  // Do not call TryToStartTransmission() directly.
  // Use StartLogTransmissionTimer() to schedule a call.
  void TryToStartTransmission();

  // Takes whatever log should be uploaded next (according to the state_)
  // and makes it the pending log.  If pending_log_ is not NULL,
  // MakePendingLog does nothing and returns.
  void MakePendingLog();

  // Determines from state_ and permissions set out by the server and by
  // the user whether the pending_log_ should be sent or discarded.  Called by
  // TryToStartTransmission.
  bool TransmissionPermitted() const;

  // 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.
  // Upon return, current_fetch_ should be reset with its upload data set to
  // a compressed copy of the pending log.
  void PrepareFetchWithPendingLog();

  // 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();

  // Class to hold all attributes that gets inherited by children in the UMA
  // response data xml tree.  This is to make it convenient in the
  // recursive function that does the tree traversal to pass all such
  // data in the recursive call.  If you want to add more such attributes,
  // add them to this class.
  class InheritedProperties {
    public:
    InheritedProperties() : salt(123123), denominator(1000000) {}
    int salt, denominator;
    // Notice salt and denominator are inherited from parent nodes, but
    // not probability; the default value of probability is 1.

    // When a new node is reached it might have fields which overwrite inherited
    // properties for that node (and its children).  Call this method to
    // overwrite those settings.
    void OverwriteWhereNeeded(xmlNodePtr node);
  };

  // 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 <chrome_config> node.
  void GetSettingsFromChromeConfigNode(xmlNodePtr chrome_config_node);

  // GetSettingsFromUploadNode handles iteration over the children of the
  // <upload> child of the <chrome_config> node.  It calls the recursive
  // function GetSettingsFromUploadNodeRecursive which does the actual
  // tree traversal.
  void GetSettingsFromUploadNode(xmlNodePtr upload_node);
  void GetSettingsFromUploadNodeRecursive(xmlNodePtr node,
      InheritedProperties props,
      std::string path_prefix,
      bool uploadOn);

  // NodeProbabilityTest gets called at every node in the tree traversal
  // performed by GetSettingsFromUploadNodeRecursive.  It determines from
  // the inherited attributes (salt, denominator) and the probability
  // assiciated with the node whether that node and its contents should
  // contribute to the upload.
  bool NodeProbabilityTest(xmlNodePtr node, InheritedProperties props) const;
  bool ProbabilityTest(double probability, int salt, int denominator) const;

  // 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(BookmarkNode* 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(BookmarkModel* 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 into the current log.
  // 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);

  // Indicate whether recording and reporting are currently happening.
  // These should not be set directly, but by calling SetRecording and
  // SetReporting.
  bool recording_active_;
  bool reporting_active_;

  // Coincides with the check box in options window that lets the user control
  // whether to upload.
  bool user_permits_upload_;

  // The variable server_permits_upload_ is set true when the response
  // data forbids uploading.  This should coinside with the "die roll"
  // with probability in the upload tag of the response data came out
  // affirmative.
  bool server_permits_upload_;

  // 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_;

  // Whether the MetricsService object has received any notifications since
  // the last time a transmission was sent.
  bool idle_since_last_transmission_;

  // 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.
  base::TimeDelta interlog_duration_;

  // The maximum number of events which get transmitted in a log.  This defaults
  // to a constant and otherwise is provided by the UMA server in the server
  // response data.
  int log_event_limit_;

  // The types of data that are to be included in the logs and histograms
  // according to the UMA response data.
  std::set<std::string> logs_to_upload_;
  std::set<std::string> logs_to_omit_;
  std::set<std::string> histograms_to_upload_;
  std::set<std::string> histograms_to_omit_;

  // Indicate that a timer for sending the next log has already been queued.
  bool timer_pending_;

  DISALLOW_EVIL_CONSTRUCTORS(MetricsService);
};

#endif  // CHROME_BROWSER_METRICS_SERVICE_H__