// Copyright 2013 Google Inc. All Rights Reserved.

#ifndef CDM_BASE_POLICY_ENGINE_H_
#define CDM_BASE_POLICY_ENGINE_H_

#include <string>

#include "license_protocol.pb.h"
#include "wv_cdm_types.h"

namespace wvcdm {

// This acts as an oracle that basically says "Yes(true) you may still decrypt
// or no(false) you may not decrypt this data anymore."
class PolicyEngine {
 public:
  PolicyEngine();
  ~PolicyEngine();

  // |current_time| is used to check if license has to be renewed or expired.
  void OnTimerEvent(int64_t current_time, bool event_occurred, CdmEventType& event);

  // SetLicense is used in handling the initial license response. It stores
  // an exact copy of the policy information stored in the license.
  // The license state transitions to kLicenseStateCanPlay if the license
  // permits playback.
  void SetLicense(const video_widevine_server::sdk::License& license);

  // UpdateLicense is used in handling a license response for a renewal request.
  // The response may only contain any policy fields that have changed. In this
  // case an exact copy is not what we want to happen. We also will receive an
  // updated license_start_time from the server. The license will transition to
  // kLicenseStateCanPlay if the license permits playback.
  void UpdateLicense(const video_widevine_server::sdk::License& license);

  const video_widevine_server::sdk::LicenseIdentification& license_id() {
    return license_id_;
  }

 private:
  typedef enum {
    kLicenseStateInitial,
    kLicenseStateCanPlay,
    kLicenseStateCannotPlay,
    kLicenseStateNeedRenewal,
    kLicenseStateWaitingLicenseUpdate,
    kLicenseStateExpired
  } LicenseState;

  bool IsLicenseDurationExpired(int64_t current_time);
  bool IsRenewalDelayExpired(int64_t current_time);
  bool IsRenewalRecoveryDurationExpired(int64_t current_time);
  bool IsRenewalRetryIntervalExpired(int64_t current_time);

  void UpdateRenewalRequest(int64_t current_time);

  LicenseState license_state_;

  // This is the current policy information for this license. This gets updated
  // as license renewals occur.
  video_widevine_server::sdk::License::Policy policy_;

  // This is the license id field from server response. This data gets passed
  // back to the server in each renewal request. When we get a renewal response
  // from the license server we will get an updated id field.
  video_widevine_server::sdk::LicenseIdentification license_id_;

  // This is the license start time that gets sent from the server in each
  // license request or renewal.
  int64_t license_start_time_;

  // This is used as a reference point for policy management. This value
  // represents an offset from license_start_time_. This is used to calculate
  // the time where renewal retries should occur.
  int64_t next_renewal_time_;
  int64_t policy_max_duration_seconds_;

  CORE_DISALLOW_COPY_AND_ASSIGN(PolicyEngine);
};
}  // wvcdm

#endif  // CDM_BASE_POLICY_ENGINE_H_