// Copyright 2014 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.

#include "media/blink/cdm_session_adapter.h"

#include <utility>

#include "base/bind.h"
#include "base/logging.h"
#include "base/metrics/histogram.h"
#include "base/stl_util.h"
#include "base/threading/thread_task_runner_handle.h"
#include "base/trace_event/trace_event.h"
#include "media/base/cdm_factory.h"
#include "media/base/cdm_key_information.h"
#include "media/base/cdm_promise.h"
#include "media/base/key_systems.h"
#include "media/blink/webcontentdecryptionmodule_impl.h"
#include "media/blink/webcontentdecryptionmodulesession_impl.h"
#include "url/gurl.h"

namespace media {

namespace {
const char kMediaEME[] = "Media.EME.";
const char kDot[] = ".";
const char kTimeToCreateCdmUMAName[] = "CreateCdmTime";
}  // namespace

CdmSessionAdapter::CdmSessionAdapter()
    : trace_id_(0), weak_ptr_factory_(this) {}

CdmSessionAdapter::~CdmSessionAdapter() {}

void CdmSessionAdapter::CreateCdm(
    CdmFactory* cdm_factory,
    const std::string& key_system,
    const GURL& security_origin,
    const CdmConfig& cdm_config,
    std::unique_ptr<blink::WebContentDecryptionModuleResult> result) {
  TRACE_EVENT_ASYNC_BEGIN0("media", "CdmSessionAdapter::CreateCdm",
                           ++trace_id_);

  base::TimeTicks start_time = base::TimeTicks::Now();

  // Note: WebContentDecryptionModuleImpl::Create() calls this method without
  // holding a reference to the CdmSessionAdapter. Bind OnCdmCreated() with
  // |this| instead of |weak_this| to prevent |this| from being destructed.
  base::WeakPtr<CdmSessionAdapter> weak_this = weak_ptr_factory_.GetWeakPtr();

  DCHECK(!cdm_created_result_);
  cdm_created_result_ = std::move(result);

  cdm_factory->Create(
      key_system, security_origin, cdm_config,
      base::Bind(&CdmSessionAdapter::OnSessionMessage, weak_this),
      base::Bind(&CdmSessionAdapter::OnSessionClosed, weak_this),
      base::Bind(&CdmSessionAdapter::OnSessionKeysChange, weak_this),
      base::Bind(&CdmSessionAdapter::OnSessionExpirationUpdate, weak_this),
      base::Bind(&CdmSessionAdapter::OnCdmCreated, this, key_system,
                 start_time));
}

void CdmSessionAdapter::SetServerCertificate(
    const std::vector<uint8_t>& certificate,
    std::unique_ptr<SimpleCdmPromise> promise) {
  cdm_->SetServerCertificate(certificate, std::move(promise));
}

WebContentDecryptionModuleSessionImpl* CdmSessionAdapter::CreateSession() {
  return new WebContentDecryptionModuleSessionImpl(this);
}

bool CdmSessionAdapter::RegisterSession(
    const std::string& session_id,
    base::WeakPtr<WebContentDecryptionModuleSessionImpl> session) {
  // If this session ID is already registered, don't register it again.
  if (base::ContainsKey(sessions_, session_id))
    return false;

  sessions_[session_id] = session;
  return true;
}

void CdmSessionAdapter::UnregisterSession(const std::string& session_id) {
  DCHECK(base::ContainsKey(sessions_, session_id));
  sessions_.erase(session_id);
}

void CdmSessionAdapter::InitializeNewSession(
    EmeInitDataType init_data_type,
    const std::vector<uint8_t>& init_data,
    MediaKeys::SessionType session_type,
    std::unique_ptr<NewSessionCdmPromise> promise) {
  cdm_->CreateSessionAndGenerateRequest(session_type, init_data_type, init_data,
                                        std::move(promise));
}

void CdmSessionAdapter::LoadSession(
    MediaKeys::SessionType session_type,
    const std::string& session_id,
    std::unique_ptr<NewSessionCdmPromise> promise) {
  cdm_->LoadSession(session_type, session_id, std::move(promise));
}

void CdmSessionAdapter::UpdateSession(
    const std::string& session_id,
    const std::vector<uint8_t>& response,
    std::unique_ptr<SimpleCdmPromise> promise) {
  cdm_->UpdateSession(session_id, response, std::move(promise));
}

void CdmSessionAdapter::CloseSession(
    const std::string& session_id,
    std::unique_ptr<SimpleCdmPromise> promise) {
  cdm_->CloseSession(session_id, std::move(promise));
}

void CdmSessionAdapter::RemoveSession(
    const std::string& session_id,
    std::unique_ptr<SimpleCdmPromise> promise) {
  cdm_->RemoveSession(session_id, std::move(promise));
}

scoped_refptr<MediaKeys> CdmSessionAdapter::GetCdm() {
  return cdm_;
}

const std::string& CdmSessionAdapter::GetKeySystem() const {
  return key_system_;
}

const std::string& CdmSessionAdapter::GetKeySystemUMAPrefix() const {
  DCHECK(!key_system_uma_prefix_.empty());
  return key_system_uma_prefix_;
}

void CdmSessionAdapter::OnCdmCreated(const std::string& key_system,
                                     base::TimeTicks start_time,
                                     const scoped_refptr<MediaKeys>& cdm,
                                     const std::string& error_message) {
  DVLOG(2) << __func__ << ": "
           << (cdm ? "success" : "failure (" + error_message + ")");
  DCHECK(!cdm_);

  TRACE_EVENT_ASYNC_END2("media", "CdmSessionAdapter::CreateCdm", trace_id_,
                         "success", (cdm ? "true" : "false"), "error_message",
                         error_message);

  if (!cdm) {
    cdm_created_result_->completeWithError(
        blink::WebContentDecryptionModuleExceptionNotSupportedError, 0,
        blink::WebString::fromUTF8(error_message));
    cdm_created_result_.reset();
    return;
  }

  key_system_ = key_system;
  key_system_uma_prefix_ =
      kMediaEME + GetKeySystemNameForUMA(key_system) + kDot;

  // Only report time for successful CDM creation.
  ReportTimeToCreateCdmUMA(base::TimeTicks::Now() - start_time);

  cdm_ = cdm;

  cdm_created_result_->completeWithContentDecryptionModule(
      new WebContentDecryptionModuleImpl(this));
  cdm_created_result_.reset();
}

void CdmSessionAdapter::OnSessionMessage(const std::string& session_id,
                                         MediaKeys::MessageType message_type,
                                         const std::vector<uint8_t>& message) {
  WebContentDecryptionModuleSessionImpl* session = GetSession(session_id);
  DLOG_IF(WARNING, !session) << __func__ << " for unknown session "
                             << session_id;
  if (session)
    session->OnSessionMessage(message_type, message);
}

void CdmSessionAdapter::OnSessionKeysChange(const std::string& session_id,
                                            bool has_additional_usable_key,
                                            CdmKeysInfo keys_info) {
  WebContentDecryptionModuleSessionImpl* session = GetSession(session_id);
  DLOG_IF(WARNING, !session) << __func__ << " for unknown session "
                             << session_id;
  if (session)
    session->OnSessionKeysChange(has_additional_usable_key,
                                 std::move(keys_info));
}

void CdmSessionAdapter::OnSessionExpirationUpdate(
    const std::string& session_id,
    const base::Time& new_expiry_time) {
  WebContentDecryptionModuleSessionImpl* session = GetSession(session_id);
  DLOG_IF(WARNING, !session) << __func__ << " for unknown session "
                             << session_id;
  if (session)
    session->OnSessionExpirationUpdate(new_expiry_time);
}

void CdmSessionAdapter::OnSessionClosed(const std::string& session_id) {
  WebContentDecryptionModuleSessionImpl* session = GetSession(session_id);
  DLOG_IF(WARNING, !session) << __func__ << " for unknown session "
                             << session_id;
  if (session)
    session->OnSessionClosed();
}

WebContentDecryptionModuleSessionImpl* CdmSessionAdapter::GetSession(
    const std::string& session_id) {
  // Since session objects may get garbage collected, it is possible that there
  // are events coming back from the CDM and the session has been unregistered.
  // We can not tell if the CDM is firing events at sessions that never existed.
  SessionMap::iterator session = sessions_.find(session_id);
  return (session != sessions_.end()) ? session->second.get() : NULL;
}

void CdmSessionAdapter::ReportTimeToCreateCdmUMA(base::TimeDelta time) const {
  // Note: This leaks memory, which is expected behavior.
  base::HistogramBase* histogram = base::Histogram::FactoryTimeGet(
      GetKeySystemUMAPrefix() + kTimeToCreateCdmUMAName,
      base::TimeDelta::FromMilliseconds(1), base::TimeDelta::FromSeconds(10),
      50, base::HistogramBase::kUmaTargetedHistogramFlag);

  histogram->AddTime(time);
}

}  // namespace media