// Copyright (c) 2012 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.

#ifndef CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_ACTIVITY_LOG_H_
#define CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_ACTIVITY_LOG_H_

#include <map>
#include <string>
#include <vector>

#include "base/callback.h"
#include "base/memory/singleton.h"
#include "base/observer_list_threadsafe.h"
#include "base/synchronization/lock.h"
#include "base/threading/thread.h"
#include "chrome/browser/extensions/activity_log/activity_actions.h"
#include "chrome/browser/extensions/activity_log/activity_database.h"
#include "chrome/browser/extensions/activity_log/activity_log_policy.h"
#include "chrome/browser/extensions/install_observer.h"
#include "chrome/browser/extensions/install_tracker.h"
#include "chrome/browser/extensions/tab_helper.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/common/extensions/dom_action_types.h"
#include "components/browser_context_keyed_service/browser_context_dependency_manager.h"
#include "components/browser_context_keyed_service/browser_context_keyed_service.h"
#include "components/browser_context_keyed_service/browser_context_keyed_service_factory.h"
#include "extensions/browser/event_router.h"

class Profile;
using content::BrowserThread;

namespace content {
class BrowserContext;
}

namespace user_prefs {
class PrefRegistrySyncable;
}

namespace extensions {
class Extension;
class ActivityLogPolicy;

// A utility for tracing interesting activity for each extension.
// It writes to an ActivityDatabase on a separate thread to record the activity.
class ActivityLog : public BrowserContextKeyedService,
                    public EventRouter::EventDispatchObserver,
                    public TabHelper::ScriptExecutionObserver,
                    public InstallObserver {
 public:
  // Observers can listen for activity events. There is probably only one
  // observer: the activityLogPrivate API.
  class Observer {
   public:
    virtual void OnExtensionActivity(scoped_refptr<Action> activity) = 0;
  };

  // ActivityLog is a singleton, so don't instantiate it with the constructor;
  // use GetInstance instead.
  static ActivityLog* GetInstance(content::BrowserContext* context);

  // Add/remove observer: the activityLogPrivate API only listens when the
  // ActivityLog extension is registered for an event.
  void AddObserver(Observer* observer);
  void RemoveObserver(Observer* observer);

  // Logs an extension action: passes it to any installed policy to be logged
  // to the database, to any observers, and logs to the console if in testing
  // mode.
  void LogAction(scoped_refptr<Action> action);

  // Gets all actions that match the specified fields. URLs are treated like
  // prefixes; other fields are exact matches. Empty strings are not matched to
  // anything. For daysAgo, today is 0, yesterday is 1, etc.; a negative number
  // of days is treated as a missing parameter.
  void GetFilteredActions(
      const std::string& extension_id,
      const Action::ActionType type,
      const std::string& api_name,
      const std::string& page_url,
      const std::string& arg_url,
      const int days_ago,
      const base::Callback
          <void(scoped_ptr<std::vector<scoped_refptr<Action> > >)>& callback);

  // Extension::InstallObserver
  // We keep track of whether the whitelisted extension is installed; if it is,
  // we want to recompute whether to have logging enabled.
  virtual void OnExtensionInstalled(const Extension* extension) OVERRIDE {}
  virtual void OnExtensionLoaded(const Extension* extension) OVERRIDE;
  virtual void OnExtensionUnloaded(const Extension* extension) OVERRIDE;
  virtual void OnExtensionUninstalled(const Extension* extension) OVERRIDE;
  // We also have to list the following from InstallObserver.
  virtual void OnBeginExtensionInstall(
      const ExtensionInstallParams& params) OVERRIDE {}
  virtual void OnDownloadProgress(const std::string& extension_id,
                                  int percent_downloaded) OVERRIDE {}
  virtual void OnInstallFailure(const std::string& extension_id) OVERRIDE {}
  virtual void OnAppsReordered() OVERRIDE {}
  virtual void OnAppInstalledToAppList(
      const std::string& extension_id) OVERRIDE {}
  virtual void OnShutdown() OVERRIDE {}

  // EventRouter::EventDispatchObserver
  virtual void OnWillDispatchEvent(scoped_ptr<EventDispatchInfo> details)
      OVERRIDE;

  // BrowserContextKeyedService
  virtual void Shutdown() OVERRIDE;

  static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);

  // Clean up URLs from the activity log database.
  // If restrict_urls is empty then all URLs in the activity log database are
  // removed, otherwise only those in restrict_urls are removed.
  void RemoveURLs(const std::vector<GURL>& restrict_urls);
  void RemoveURLs(const std::set<GURL>& restrict_urls);
  void RemoveURL(const GURL& url);

  // Deletes the database associated with the policy that's currently in use.
  void DeleteDatabase();

 private:
  friend class ActivityLogFactory;
  friend class ActivityLogTest;
  friend class RenderViewActivityLogTest;

  explicit ActivityLog(Profile* profile);
  virtual ~ActivityLog();

  // Specifies if the Watchdog app is active (installed & enabled).
  // If so, we need to log to the database and stream to the API.
  bool IsWatchdogAppActive();
  // If we're in a browser test, we need to pretend that the watchdog app is
  // active.
  void SetWatchdogAppActive(bool active);

  // Specifies if we need to record actions to the db. If so, we need to log to
  // the database. This is true if the Watchdog app is active *or* the
  // --enable-extension-activity-logging flag is set.
  bool IsDatabaseEnabled();

  // Delayed initialization of Install Tracker which waits until after the
  // ExtensionSystem/ExtensionService are done with their own setup.
  void InitInstallTracker();

  // TabHelper::ScriptExecutionObserver implementation.
  // Fires when a ContentScript is executed.
  virtual void OnScriptsExecuted(
      const content::WebContents* web_contents,
      const ExecutingScriptsMap& extension_ids,
      int32 page_id,
      const GURL& on_url) OVERRIDE;

  // At the moment, ActivityLog will use only one policy for summarization.
  // These methods are used to choose and set the most appropriate policy.
  // Changing policies at runtime is not recommended, and likely only should be
  // done for unit tests.
  void ChooseDatabasePolicy();
  void SetDatabasePolicy(ActivityLogPolicy::PolicyType policy_type);

  typedef ObserverListThreadSafe<Observer> ObserverList;
  scoped_refptr<ObserverList> observers_;

  // Policy objects are owned by the ActivityLog, but cannot be scoped_ptrs
  // since they may need to do some cleanup work on the database thread.
  // Calling policy->Close() will free the object; see the comments on the
  // ActivityDatabase class for full details.

  // The database policy object takes care of recording & looking up data:
  // data summarization, compression, and logging. There should only be a
  // database_policy_ if the Watchdog app is installed or flag is set.
  ActivityLogDatabasePolicy* database_policy_;
  ActivityLogPolicy::PolicyType database_policy_type_;

  // The UMA policy is used for recording statistics about extension behavior.
  // This policy is always in use, except for Incognito profiles.
  ActivityLogPolicy* uma_policy_;

  Profile* profile_;
  bool db_enabled_;  // Whether logging to disk is currently enabled.
  // testing_mode_ controls which policy is selected.
  // * By default, we choose a policy that doesn't log most arguments to avoid
  // saving too much data. We also elide some arguments for privacy reasons.
  // * In testing mode, we choose a policy that logs all arguments.
  // testing_mode_ also causes us to print to the console.
  bool testing_mode_;
  // We need the DB, FILE, and IO threads to write to the database.
  // In some cases (tests), these threads might not exist, so we avoid
  // dispatching anything to the policies/database to prevent things from
  // exploding.
  bool has_threads_;

  // Used to track whether the whitelisted extension is installed. If it's
  // added or removed, enabled_ may change.
  InstallTracker* tracker_;

  // Set if the watchdog app is installed and enabled. Maintained by
  // kWatchdogExtensionActive pref variable. Since there are multiple valid
  // extension IDs, this needs to be an int to count how many are installed.
  int watchdog_apps_active_;

  FRIEND_TEST_ALL_PREFIXES(ActivityLogApiTest, TriggerEvent);
  FRIEND_TEST_ALL_PREFIXES(ActivityLogEnabledTest, AppAndCommandLine);
  FRIEND_TEST_ALL_PREFIXES(ActivityLogEnabledTest, CommandLineSwitch);
  FRIEND_TEST_ALL_PREFIXES(ActivityLogEnabledTest, NoSwitch);
  FRIEND_TEST_ALL_PREFIXES(ActivityLogEnabledTest, PrefSwitch);
  FRIEND_TEST_ALL_PREFIXES(ActivityLogEnabledTest, WatchdogSwitch);
  DISALLOW_COPY_AND_ASSIGN(ActivityLog);
};

// Each profile has different extensions, so we keep a different database for
// each profile.
class ActivityLogFactory : public BrowserContextKeyedServiceFactory {
 public:
  static ActivityLog* GetForBrowserContext(content::BrowserContext* context) {
    return static_cast<ActivityLog*>(
        GetInstance()->GetServiceForBrowserContext(context, true));
  }

  static ActivityLogFactory* GetInstance();

 private:
  friend struct DefaultSingletonTraits<ActivityLogFactory>;
  ActivityLogFactory();
  virtual ~ActivityLogFactory();

  virtual BrowserContextKeyedService* BuildServiceInstanceFor(
      content::BrowserContext* profile) const OVERRIDE;

  virtual content::BrowserContext* GetBrowserContextToUse(
      content::BrowserContext* context) const OVERRIDE;

  DISALLOW_COPY_AND_ASSIGN(ActivityLogFactory);
};


}  // namespace extensions

#endif  // CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_ACTIVITY_LOG_H_