// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CHROME_BROWSER_EXTENSIONS_EXTENSION_MANAGEMENT_H_
#define CHROME_BROWSER_EXTENSIONS_EXTENSION_MANAGEMENT_H_

#include <memory>
#include <string>
#include <vector>

#include "base/containers/flat_map.h"
#include "base/feature_list.h"
#include "base/memory/raw_ptr.h"
#include "base/no_destructor.h"
#include "base/observer_list.h"
#include "base/values.h"
#include "chrome/browser/profiles/profile_keyed_service_factory.h"
#include "components/keyed_service/core/keyed_service.h"
#include "components/prefs/pref_change_registrar.h"
#include "extensions/browser/extension_management_client.h"
#include "extensions/browser/forced_extensions/install_stage_tracker.h"
#include "extensions/browser/managed_installation_mode.h"
#include "extensions/browser/management_policy.h"
#include "extensions/buildflags/buildflags.h"
#include "extensions/common/extension_id.h"
#include "extensions/common/manifest.h"
#include "third_party/abseil-cpp/absl/container/flat_hash_set.h"

static_assert(BUILDFLAG(ENABLE_EXTENSIONS_CORE));

class GURL;
class PrefService;
class Profile;

namespace content {
class BrowserContext;
}  // namespace content

namespace extensions {

enum class ManagedToolbarPinMode;

#if BUILDFLAG(IS_WIN) || BUILDFLAG(IS_MAC)
BASE_DECLARE_FEATURE(
    kDisableForceInstalledExtensionsInLowTrustEnviromentWhenGreylisted);
#endif

namespace internal {

struct IndividualSettings;
struct GlobalSettings;

}  // namespace internal

class APIPermissionSet;
class CWSInfoServiceInterface;
class Extension;
class PermissionSet;

// Tracks the management policies that affect extensions and provides interfaces
// for observing and obtaining the global settings for all extensions, as well
// as per-extension settings.
class ExtensionManagement : public KeyedService,
                            public ExtensionManagementClient {
 public:
  // Observer class for extension management settings changes.
  class Observer {
   public:
    virtual ~Observer() = default;

    // Called when the extension management settings change.
    virtual void OnExtensionManagementSettingsChanged() = 0;
  };

  explicit ExtensionManagement(Profile* profile);

  ExtensionManagement(const ExtensionManagement&) = delete;
  ExtensionManagement& operator=(const ExtensionManagement&) = delete;

  ~ExtensionManagement() override;

  // KeyedService implementations:
  void Shutdown() override;

  // ExtensionManagementClient implementations:
  bool UpdatesFromWebstore(const Extension& extension) override;
  bool IsInstallationExplicitlyAllowed(const ExtensionId& id) override;
  bool IsForceInstalledInLowTrustEnvironment(
      const Extension& extension) override;
  const URLPatternSet& GetPolicyBlockedHosts(
      const Extension* extension) override;
  const URLPatternSet& GetPolicyAllowedHosts(
      const Extension* extension) override;
  bool UsesDefaultPolicyHostRestrictions(const Extension* extension) override;
  bool BlocklistedByDefault() const override;
  GURL GetEffectiveUpdateURL(const Extension& extension) override;
  bool IsAllowedManifestType(Manifest::Type manifest_type,
                             const std::string& extension_id) const override;
  ManagedInstallationMode GetInstallationMode(
      const Extension* extension) override;
  ManagedInstallationMode GetInstallationMode(
      const ExtensionId& extension_id,
      const std::string& update_url) override;
  bool IsInstallationExplicitlyBlocked(const ExtensionId& id) override;
  const std::string BlockedInstallMessage(const ExtensionId& id) override;
  bool IsPermissionSetAllowed(const Extension* extension,
                              const PermissionSet& perms) override;
  bool IsPermissionSetAllowed(const ExtensionId& extension_id,
                              const std::string& update_url,
                              const PermissionSet& perms) override;

  void AddObserver(Observer* observer);
  void RemoveObserver(Observer* observer);

  // Get the list of ManagementPolicy::Provider controlled by extension
  // management policy settings.
  const std::vector<std::unique_ptr<ManagementPolicy::Provider>>& GetProviders()
      const;

  // Returns the force install list, in format specified by
  // ExternalPolicyLoader::AddExtension().
  base::DictValue GetForceInstallList() const;

  // Like GetForceInstallList(), but returns recommended install list instead.
  base::DictValue GetRecommendedInstallList() const;

  // Returns `true` if there is at least one extension with
  // `INSTALLATION_ALLOWED` as installation mode. This excludes force installed
  // extensions.
  bool HasAllowlistedExtension();

  // Returns if an extension with `id` is force installed and the update URL is
  // overridden by policy.
  bool IsUpdateUrlOverridden(const ExtensionId& id);

  // Returns true if an extension download should be allowed to proceed.
  bool IsOffstoreInstallAllowed(const GURL& url,
                                const GURL& referrer_url) const;

  bool IsAllowedByUnpublishedAvailabilityPolicy(const Extension* extension);

  // Returns false if the extension is loaded as unpacked and the developer mode
  // is OFF.
  bool IsAllowedByUnpackedDeveloperModePolicy(const Extension& extension);

  // Returns true if a greylisted extension is force-installed in a low-trust
  // environment. Only applies to Windows and MacOS.
  bool IsGreylistedForceInstalledInLowTrustEnvironment(
      const ExtensionId& extension_id);

  // Returns true if an off-store extension is force-installed in low trust
  // environments. Only trusted environments like domain-joined devices or
  // cloud-managed user profiles are allowed to force-install off-store
  // extensions. All other devices and users may still install policy extensions
  // but they must be hosted within the web store. See https://b/283274398.
  bool ShouldBlockForceInstalledOffstoreExtension(const Extension& extension);

  // Returns the list of blocked API permissions for `extension`.
  APIPermissionSet GetBlockedAPIPermissions(const Extension* extension);

  // Returns the list of blocked API permissions for an extension with id
  // `extension_id` and updated with `update_url`.
  APIPermissionSet GetBlockedAPIPermissions(const ExtensionId& extension_id,
                                            const std::string& update_url);

  // Returns the list of hosts blocked by policy for Default scope. This can be
  // overridden by an individual scope which is queried via
  // GetPolicyBlockedHosts.
  const URLPatternSet& GetDefaultPolicyBlockedHosts() const;

  // Returns the hosts exempted by policy from PolicyBlockedHosts for
  // the default scope. This can be overridden by an individual scope which is
  // queries via GetPolicyAllowedHosts. This should only be used to
  // initialize a new renderer.
  const URLPatternSet& GetDefaultPolicyAllowedHosts() const;

  // Returns blocked permission set for `extension`.
  std::unique_ptr<const PermissionSet> GetBlockedPermissions(
      const Extension* extension);

  // Returns true if `extension` meets the minimum required version set for it.
  // If there is no such requirement set for it, returns true as well.
  // If false is returned and `required_version` is not null, the minimum
  // required version is returned.
  bool CheckMinimumVersion(const Extension* extension,
                           std::string* required_version);

  // Returns the list of extensions with "force_pinned" mode for the
  // "toolbar_pin" setting. This only considers policies that are loaded (e.g.
  // aren't deferred).
  ExtensionIdSet GetForcePinnedList() const;

  // Returns if an extension with `id` can navigate to file URLs.
  bool IsFileUrlNavigationAllowed(const ExtensionId& id);

  // Returns the toolbar pin mode for `extension_id`.
  extensions::ManagedToolbarPinMode GetToolbarPinMode(
      const ExtensionId& extension_id);

 private:
  using SettingsIdMap =
      base::flat_map<ExtensionId,
                     std::unique_ptr<internal::IndividualSettings>>;
  using SettingsUpdateUrlMap =
      base::flat_map<std::string,
                     std::unique_ptr<internal::IndividualSettings>>;
  friend class ExtensionManagementServiceTest;

  // Load all extension management preferences from `pref_service`, and
  // refresh the settings.
  void Refresh();

  // Tries to parse the individual setting in `settings_by_id_` for
  // `extension_id`. Returns true if it succeeds, otherwise returns false and
  // removes the entry from `settings_by_id_`.
  bool ParseById(const std::string& extension_id,
                 const base::DictValue& subdict);

  // Returns the individual settings for `extension_id` if it exists, otherwise
  // returns nullptr. This method will also lazy load the settings if they're
  // not loaded yet.
  internal::IndividualSettings* GetSettingsForId(
      const std::string& extension_id);

  // Loads the deferred settings information for `extension_id`.
  void LoadDeferredExtensionSetting(const std::string& extension_id);

  // Loads preference with name `pref_name` and expected type `expected_type`.
  // If `force_managed` is true, only loading from the managed preference store
  // is allowed. Returns NULL if the preference is not present, not allowed to
  // be loaded from or has the wrong type.
  const base::Value* LoadPreference(const char* pref_name,
                                    bool force_managed,
                                    base::Value::Type expected_type) const;

  // Loads the dictionary preference with name `pref_name` - see
  // `LoadPreference` for more details.
  const base::DictValue* LoadDictPreference(const char* pref_name,
                                            bool force_managed) const;

  // Loads the list preference with name `pref_name` - see `LoadPreference` for
  // more details.
  const base::ListValue* LoadListPreference(const char* pref_name,
                                            bool force_managed) const;

  void OnExtensionPrefChanged();
  void NotifyExtensionManagementPrefChanged();

  // Reports install creation stage to InstallStageTracker for the extensions.
  // `forced_stage` is reported for the extensions which have installation mode
  // as INSTALLATION_FORCED, and `other_stage` is reported for all other
  // installation modes.
  void ReportExtensionManagementInstallCreationStage(
      InstallStageTracker::InstallCreationStage forced_stage,
      InstallStageTracker::InstallCreationStage other_stage);

  // Helper to return an extension install list, in format specified by
  // ExternalPolicyLoader::AddExtension().
  base::DictValue GetInstallListByMode(
      ManagedInstallationMode installation_mode) const;

  // Helper to update `extension_dict` for forced installs.
  void UpdateForcedExtensions(const base::DictValue* extension_dict);

  // Helper function to access `settings_by_id_` with `id` as key.
  // Adds a new IndividualSettings entry to `settings_by_id_` if none exists for
  // `id` yet.
  internal::IndividualSettings* AccessById(const ExtensionId& id);

  // Similar to AccessById(), but access `settings_by_update_url_` instead.
  internal::IndividualSettings* AccessByUpdateUrl(
      const std::string& update_url);

  // A map containing all IndividualSettings applied to an individual extension
  // identified by extension ID. The extension ID is used as index key of the
  // map.
  SettingsIdMap settings_by_id_;

  // A set of extension IDs whose parsing of settings and insertion into
  // `settings_by_id_` has been deferred until needed. We keep track of this to
  // avoid scanning the prefs repeatedly for entries that don't have a setting.
  absl::flat_hash_set<std::string> deferred_ids_;

  // Similar to `settings_by_id_`, but contains the settings for a group of
  // extensions with same update URL. The update url itself is used as index
  // key for the map.
  SettingsUpdateUrlMap settings_by_update_url_;

  // The default IndividualSettings.
  // For extension settings applied to an individual extension (identified by
  // extension ID) or a group of extension (with specified extension update
  // URL), all unspecified part will take value from `default_settings_`.
  // For all other extensions, all settings from `default_settings_` will be
  // enforced.
  std::unique_ptr<internal::IndividualSettings> default_settings_;

  // Extension settings applicable to all extensions.
  std::unique_ptr<internal::GlobalSettings> global_settings_;

  const raw_ptr<Profile> profile_ = nullptr;
  raw_ptr<PrefService> pref_service_ = nullptr;
  bool is_signin_profile_ = false;

  // TODO(crbug.com/484371187): Investigate if reentrancy can be removed.
  base::ObserverList<
      Observer,
      /*check_empty=*/true,
      base::ObserverListReentrancyPolicy::kAllowReentrancyUntriaged>::Unchecked
      observer_list_;
  PrefChangeRegistrar pref_change_registrar_;
  std::vector<std::unique_ptr<ManagementPolicy::Provider>> providers_;

  // Unowned pointer to the CWSInfoService keyed-service instance for this
  // profile. The service provides information about CWS publish status for
  // extensions.
  raw_ptr<CWSInfoServiceInterface> cws_info_service_ = nullptr;
};

class ExtensionManagementFactory : public ProfileKeyedServiceFactory {
 public:
  ExtensionManagementFactory(const ExtensionManagementFactory&) = delete;
  ExtensionManagementFactory& operator=(const ExtensionManagementFactory&) =
      delete;

  static ExtensionManagement* GetForBrowserContext(
      content::BrowserContext* context);
  static ExtensionManagementFactory* GetInstance();

 private:
  friend base::NoDestructor<ExtensionManagementFactory>;

  ExtensionManagementFactory();
  ~ExtensionManagementFactory() override;

  // BrowserContextKeyedServiceExtensionManagementFactory:
  std::unique_ptr<KeyedService> BuildServiceInstanceForBrowserContext(
      content::BrowserContext* context) const override;
};

}  // namespace extensions

#endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_MANAGEMENT_H_