// Copyright 2018 Google LLC. All Rights Reserved. This file and proprietary
// source code may only be used and distributed under the Widevine License
// Agreement.

#ifndef CDM_BASE_WV_CONTENT_DECRYPTION_MODULE_H_
#define CDM_BASE_WV_CONTENT_DECRYPTION_MODULE_H_

#include <time.h>

#include <map>
#include <memory>
#include <mutex>

#include "utils/RefBase.h"

#include "cdm_identifier.h"
#include "disallow_copy_and_assign.h"
#include "file_store.h"
#include "timer.h"
#include "wv_cdm_types.h"
#include "wv_metrics.pb.h"

namespace wvcdm {

class CdmClientPropertySet;
class CdmEngine;
class WvCdmEventListener;

class WvMetricsSnapshot {
 public:
  WvMetricsSnapshot(const CdmIdentifier& identifier,
                    drm_metrics::WvCdmMetrics&& metrics, ::time_t ts);

  // Acts as a constructor, but uses the current time.
  static WvMetricsSnapshot MakeSnapshot(const CdmIdentifier& identifier,
                                        drm_metrics::WvCdmMetrics&& metrics);

  WvMetricsSnapshot() = default;
  WvMetricsSnapshot(const WvMetricsSnapshot&) = default;
  WvMetricsSnapshot(WvMetricsSnapshot&&) = default;
  WvMetricsSnapshot& operator=(const WvMetricsSnapshot&) = default;
  WvMetricsSnapshot& operator=(WvMetricsSnapshot&&) = default;

  const CdmIdentifier& cdm_id() const { return cdm_id_; }
  const drm_metrics::WvCdmMetrics& metrics() const { return metrics_; }
  ::time_t timestamp() const { return timestamp_; }
  std::string GetFormattedTimestamp() const;

 private:
  CdmIdentifier cdm_id_;
  drm_metrics::WvCdmMetrics metrics_;
  ::time_t timestamp_ = 0;
};

class WvMetricsSnapshotQueue
    : public android::LightRefBase<WvMetricsSnapshotQueue> {
 public:
  WvMetricsSnapshotQueue();
  explicit WvMetricsSnapshotQueue(size_t capacity) : capacity_(capacity) {}

  size_t capacity() const { return capacity_; }
  size_t size() const { return snapshots_.size(); }

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

  void PushMetrics(WvMetricsSnapshot&& snapshot);
  void PushMetrics(const WvMetricsSnapshot& snapshot);

  bool GetAll(std::vector<WvMetricsSnapshot>* snapshots) const;

  void Clear();

 private:
  void ReFit();

  const size_t capacity_;
  mutable std::mutex mutex_;
  std::deque<WvMetricsSnapshot> snapshots_;
};

class WvContentDecryptionModule : public android::RefBase, public TimerHandler {
 public:
  WvContentDecryptionModule();
  explicit WvContentDecryptionModule(WvMetricsSnapshotQueue* metrics_queue);
  virtual ~WvContentDecryptionModule();

  // Static methods
  static bool IsSupported(const std::string& init_data_type);
  static bool IsCenc(const std::string& init_data_type);
  static bool IsWebm(const std::string& init_data_type);
  static bool IsHls(const std::string& init_data_type);
  static bool IsAudio(const std::string& init_data_type);

  // Session related methods
  virtual CdmResponseType OpenSession(const CdmKeySystem& key_system,
                                      CdmClientPropertySet* property_set,
                                      const CdmIdentifier& identifier,
                                      WvCdmEventListener* event_listener,
                                      CdmSessionId* session_id);
  virtual CdmResponseType CloseSession(const CdmSessionId& session_id);
  virtual bool IsOpenSession(const CdmSessionId& session_id);

  // Construct a valid license request.
  virtual CdmResponseType GenerateKeyRequest(
      const CdmSessionId& session_id, const CdmKeySetId& key_set_id,
      const std::string& init_data_type, const CdmInitData& init_data,
      const CdmLicenseType license_type, CdmAppParameterMap& app_parameters,
      CdmClientPropertySet* property_set, const CdmIdentifier& identifier,
      CdmKeyRequest* key_request);

  // Accept license response and extract key info.
  virtual CdmResponseType AddKey(const CdmSessionId& session_id,
                                 const CdmKeyResponse& key_data,
                                 CdmKeySetId* key_set_id);

  // Setup keys for offline usage which were retrived in an earlier key request
  virtual CdmResponseType RestoreKey(const CdmSessionId& session_id,
                                     const CdmKeySetId& key_set_id);

  // Cancel session
  virtual CdmResponseType RemoveKeys(const CdmSessionId& session_id);

  // Query system information
  virtual CdmResponseType QueryStatus(RequestedSecurityLevel security_level,
                                      const std::string& key,
                                      std::string* value);
  // Query session information
  virtual CdmResponseType QuerySessionStatus(const CdmSessionId& session_id,
                                             CdmQueryMap* key_info);

  // Query license information
  virtual CdmResponseType QueryKeyStatus(const CdmSessionId& session_id,
                                         CdmQueryMap* key_info);

  // Query device CSR information for Provisioning 4.0
  virtual CdmResponseType QueryDeviceSignedCsrPayload(
      const std::string& challenge, const std::string& device_info,
      std::string* value);

  // Query OEMCrypto session ID
  virtual CdmResponseType QueryOemCryptoSessionId(
      const CdmSessionId& session_id, CdmQueryMap* response);

  // Query security level support
  static bool IsSecurityLevelSupported(CdmSecurityLevel level);

  // Provisioning related methods
  virtual CdmResponseType GetProvisioningRequest(
      CdmCertificateType cert_type, const std::string& cert_authority,
      const CdmIdentifier& identifier, const std::string& service_certificate,
      RequestedSecurityLevel requested_security_level,
      CdmProvisioningRequest* request, std::string* default_url);

  virtual CdmResponseType HandleProvisioningResponse(
      const CdmIdentifier& identifier, const CdmProvisioningResponse& response,
      RequestedSecurityLevel requested_security_level, std::string* cert,
      std::string* wrapped_key);

  virtual CdmResponseType Unprovision(CdmSecurityLevel level,
                                      const CdmIdentifier& identifier);

  virtual bool IsProvisioned(CdmSecurityLevel level, const std::string& origin,
                             const std::string& spoid, bool atsc_mode_enabled);

  // Secure stop related methods
  virtual CdmResponseType GetUsageInfo(const std::string& app_id,
                                       const CdmIdentifier& identifier,
                                       CdmUsageReportList* usage_reports);
  virtual CdmResponseType GetUsageInfo(const std::string& app_id,
                                       const CdmSecureStopId& ssid,
                                       const CdmIdentifier& identifier,
                                       CdmUsageReport* usage_report);
  virtual CdmResponseType RemoveAllUsageInfo(const std::string& app_id,
                                             const CdmIdentifier& identifier);
  virtual CdmResponseType RemoveUsageInfo(
      const std::string& app_id, const CdmIdentifier& identifier,
      const CdmSecureStopId& secure_stop_id);
  virtual CdmResponseType ReleaseUsageInfo(const CdmKeyResponse& message,
                                           const CdmIdentifier& identifier);

  virtual CdmResponseType GetSecureStopIds(const std::string& app_id,
                                           const CdmIdentifier& identifier,
                                           std::vector<CdmSecureStopId>* ssids);

  // Accept encrypted buffer and decrypt data.
  // Decryption parameters that need to be specified are
  // is_encrypted, is_secure, key_id, encrypt_buffer, encrypt_length,
  // iv, block_offset, decrypt_buffer, decrypt_buffer_length,
  // decrypt_buffer_offset and subsample_flags
  virtual CdmResponseType Decrypt(const CdmSessionId& session_id,
                                  bool validate_key_id,
                                  const CdmDecryptionParameters& parameters);

  // Accept encrypted sample and decrypt data.
  virtual CdmResponseType DecryptV16(
      const CdmSessionId& session_id, bool validate_key_id,
      const CdmDecryptionParametersV16& parameters);

  virtual void NotifyResolution(const CdmSessionId& session_id, uint32_t width,
                                uint32_t height);

  // Validate a passed-in service certificate
  virtual bool IsValidServiceCertificate(const std::string& certificate);

  // Fill the |metrics| parameter with the engine metrics data for the
  // CdmEngine associated with the given CdmIdentifier.
  // If the CdmEngine instance does not exist, this will return an error.
  virtual CdmResponseType GetCurrentMetrics(const CdmIdentifier& identifier,
                                            drm_metrics::WvCdmMetrics* metrics);

  // Fill the |snapshots| parameter wrapped engine metrics for all CdmEngine
  // instances that currently enabled (actively decrypting or performing
  // other engine-level operations).
  // Current metrics snapshots contain the engine identifier, metrics data
  // and time (roughly current time).
  // |full_list_returned| will indicate whether all existing enginers were
  // able to report their metrics successfully.
  virtual CdmResponseType GetAllCurrentMetricsSnapshots(
      std::vector<WvMetricsSnapshot>* snapshots, bool* full_list_returned);

  // Fill the |snapshots| parameter wrapped engine metrics for several of
  // the most recently closed CdmEngine instances.
  // Saved metrics snapshots contain the engine identifier, metrics data
  // and time of closing.
  // The same engine identifier may appear multiple times in the list (
  // depending on how the app utilizes the MediaDrm plugin).
  virtual CdmResponseType GetAllSavedMetricsSnapshots(
      std::vector<WvMetricsSnapshot>* snapshots);

  // Closes the CdmEngine and sessions associated with the given CdmIdentifier.
  virtual CdmResponseType CloseCdm(const CdmIdentifier& identifier);

  // When positive, the keybox will be ignored at initialization and force the
  // device to request a keybox OTA reprovisioning.
  virtual CdmResponseType SetDebugIgnoreKeyboxCount(uint32_t count);

  virtual CdmResponseType SetDecryptHash(const std::string& hash_data,
                                         CdmSessionId* session_id);
  virtual CdmResponseType GetDecryptHashError(const CdmSessionId& session_id,
                                              std::string* hash_error_string);

  // Return the list of key_set_ids stored on the current (origin-specific)
  // file system.
  virtual CdmResponseType ListStoredLicenses(
      CdmSecurityLevel security_level, const CdmIdentifier& identifier,
      std::vector<CdmKeySetId>* key_set_ids);

  // Retrieve offline license state using key_set_id.
  virtual CdmResponseType GetOfflineLicenseState(
      const CdmKeySetId& key_set_id, CdmSecurityLevel security_level,
      const CdmIdentifier& identifier, CdmOfflineLicenseState* licenseState);

  // Remove offline license using key_set_id.
  virtual CdmResponseType RemoveOfflineLicense(const CdmKeySetId& key_set_id,
                                               CdmSecurityLevel security_level,
                                               const CdmIdentifier& identifier);

  virtual CdmResponseType SetPlaybackId(const CdmSessionId& session_id,
                                        const std::string& playback_id);

  virtual CdmResponseType GetSessionUserId(const CdmSessionId& session_id,
                                           uint32_t* user_id);

  virtual CdmResponseType StoreAtscLicense(
      const CdmIdentifier& identifier, RequestedSecurityLevel security_level,
      const CdmKeySetId& key_set_id,
      const std::string& serialized_license_data);
  virtual bool SetDefaultOtaKeyboxFallbackDurationRules();
  virtual bool SetFastOtaKeyboxFallbackDurationRules();

  // Generic crypto API.
  virtual CdmResponseType GenericEncrypt(const CdmSessionId& session_id,
                                         const KeyId& key_id,
                                         const std::string& input,
                                         const std::string& iv,
                                         CdmEncryptionAlgorithm algorithm,
                                         std::string* output);

  virtual CdmResponseType GenericDecrypt(const CdmSessionId& session_id,
                                         const KeyId& key_id,
                                         const std::string& input,
                                         const std::string& iv,
                                         CdmEncryptionAlgorithm algorithm,
                                         std::string* output);

  virtual CdmResponseType GenericSign(const CdmSessionId& session_id,
                                      const KeyId& key_id,
                                      const std::string& input,
                                      CdmSigningAlgorithm algorithm,
                                      std::string* signature);

  virtual CdmResponseType GenericVerify(const CdmSessionId& session_id,
                                        const KeyId& key_id,
                                        const std::string& input,
                                        CdmSigningAlgorithm algorithm,
                                        const std::string& signature);

 private:
  struct CdmInfo {
    CdmInfo();

    wvutil::FileSystem file_system;
    std::unique_ptr<CdmEngine> cdm_engine;
  };

  // Finds the CdmEngine instance for the given identifier, creating one if
  // needed.
  CdmEngine* EnsureCdmForIdentifier(const CdmIdentifier& identifier);
  // Finds the CdmEngine instance for the given session id, returning nullptr
  // if not found.
  CdmEngine* GetCdmForSessionId(const std::string& session_id);

  // Close all of the open CdmEngine instances. This is used when ready to close
  // the WvContentDecryptionModule instance.
  void CloseAllCdms();

  uint32_t GenerateSessionSharingId();

  // Timer related methods to drive policy decisions
  void EnableTimer();
  void DisableTimer();
  // Call this method only if invoked from a thread other than the timer thread.
  // Otherwise this might result in deadlock.
  void DisableTimerAndWaitForExit();
  void OnTimerEvent();

  // Fill the |metrics| parameter with the metrics data for the CdmEngine
  // associated with the given |identifier|. If the CdmEngine instance does
  // not exist, this will return an error.
  // This methods assumes that |metrics| is not null and that the |cdms_lock_|
  // has already been acquired.
  CdmResponseType GetCurrentMetricsInternal(const CdmIdentifier& identifier,
                                            drm_metrics::WvCdmMetrics* metrics);
  void SaveMetrics(const CdmIdentifier& identifier,
                   drm_metrics::WvCdmMetrics&& metrics);

  static std::mutex session_sharing_id_generation_lock_;
  std::mutex timer_lock_;
  Timer timer_;

  // instance variables
  // This manages the lifetime of the CDM instances.
  std::map<CdmIdentifier, CdmInfo> cdms_;
  // This contains weak pointers to the CDM instances contained in |cdms_|.
  std::map<std::string, CdmEngine*> cdm_by_session_id_;
  // Lock for accessing either |cdms_| or |cdm_by_session_id_|.
  // This lock should be acquired for any of the following:
  // 1) Getting a CDM instance from |cdms_| or |cdm_by_session_id_|
  //    - Hold lock while searching, release lock once pointer is acquired
  // 2) Iterating over |cdms_| or |cdm_by_session_id_|
  //    - Hold lock for the entire duration of iterating over CDMs
  //    - DO NOT release the lock until all operations are complete
  //    - This MUST be done regardless of whether |cdms_| or
  //      |cdm_by_session_id_| is being modified
  // 3) Creating a new CDM instance with |cdms_|
  //    - Hold lock when creating AND initializing the CDM
  //    - Release once CDM is fully initialized
  // 4) Linking a session to a CDM with |cdm_by_session_id_|
  //    - Hold lock when mapping a session ID to a CDM, release once set
  // 5) Unlinking a session from a CDM with |cdm_by_session_id_|
  //    - Hold lock when erasing, release once erased.
  std::mutex cdms_lock_;

  // Contains a finite list of histories of different CDM engine instances.
  // When a CDM engine is closed, its metrics will be saved.
  // Only used if not null.
  WvMetricsSnapshotQueue* saved_metrics_snapshots_ = nullptr;

  CORE_DISALLOW_COPY_AND_ASSIGN(WvContentDecryptionModule);
};
}  // namespace wvcdm
#endif  // CDM_BASE_WV_CONTENT_DECRYPTION_MODULE_H_