/*
 * Copyright 2015, Mozilla Foundation and contributors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "ClearKeyPersistence.h"

#include <assert.h>
#include <stdint.h>

#include <sstream>

#include "ClearKeySessionManager.h"
#include "ClearKeyStorage.h"
#include "ClearKeyUtils.h"
#include "RefCounted.h"

using namespace cdm;

using std::function;
using std::string;
using std::stringstream;
using std::vector;

void ClearKeyPersistence::ReadAllRecordsFromIndex(
    function<void()>&& aOnComplete) {
  // Clear what we think the index file contains, we're about to read it again.
  mPersistentSessionIds.clear();

  // Hold a reference to the persistence manager, so it isn't released before
  // we try and use it.
  RefPtr<ClearKeyPersistence> self(this);
  function<void(const uint8_t*, uint32_t)> onIndexSuccess =
      [self, aOnComplete](const uint8_t* data, uint32_t size) {
        CK_LOGD("ClearKeyPersistence: Loaded index file!");
        const char* charData = (const char*)data;

        stringstream ss(string(charData, charData + size));
        string name;
        while (getline(ss, name)) {
          if (ClearKeyUtils::IsValidSessionId(name.data(), name.size())) {
            self->mPersistentSessionIds.insert(atoi(name.c_str()));
          }
        }

        self->mPersistentKeyState = PersistentKeyState::LOADED;
        aOnComplete();
      };

  function<void()> onIndexFailed = [self, aOnComplete]() {
    CK_LOGD(
        "ClearKeyPersistence: Failed to load index file (it might not exist");
    self->mPersistentKeyState = PersistentKeyState::LOADED;
    aOnComplete();
  };

  string filename = "index";
  ReadData(mHost, filename, std::move(onIndexSuccess),
           std::move(onIndexFailed));
}

void ClearKeyPersistence::WriteIndex() {
  function<void()> onIndexSuccess = []() {
    CK_LOGD("ClearKeyPersistence: Wrote index file");
  };

  function<void()> onIndexFail = []() {
    CK_LOGD("ClearKeyPersistence: Failed to write index file (this is bad)");
  };

  stringstream ss;

  for (const uint32_t& sessionId : mPersistentSessionIds) {
    ss << sessionId;
    ss << '\n';
  }

  string dataString = ss.str();
  uint8_t* dataArray = (uint8_t*)dataString.data();
  vector<uint8_t> data(dataArray, dataArray + dataString.size());

  string filename = "index";
  WriteData(mHost, filename, data, std::move(onIndexSuccess),
            std::move(onIndexFail));
}

ClearKeyPersistence::ClearKeyPersistence(Host_11* aHost) : mHost(aHost) {}

void ClearKeyPersistence::EnsureInitialized(bool aPersistentStateAllowed,
                                            function<void()>&& aOnInitialized) {
  if (aPersistentStateAllowed &&
      mPersistentKeyState == PersistentKeyState::UNINITIALIZED) {
    mPersistentKeyState = LOADING;
    ReadAllRecordsFromIndex(std::move(aOnInitialized));
  } else {
    mPersistentKeyState = PersistentKeyState::LOADED;
    aOnInitialized();
  }
}

bool ClearKeyPersistence::IsLoaded() const {
  return mPersistentKeyState == PersistentKeyState::LOADED;
}

string ClearKeyPersistence::GetNewSessionId(SessionType aSessionType) {
  static uint32_t sNextSessionId = 1;

  // Ensure we don't re-use a session id that was persisted.
  while (Contains(mPersistentSessionIds, sNextSessionId)) {
    sNextSessionId++;
  }

  string sessionId;
  stringstream ss;
  ss << sNextSessionId;
  ss >> sessionId;

  if (aSessionType == SessionType::kPersistentLicense) {
    mPersistentSessionIds.insert(sNextSessionId);

    // Save the updated index file.
    WriteIndex();
  }

  sNextSessionId++;

  return sessionId;
}

bool ClearKeyPersistence::IsPersistentSessionId(const string& aSessionId) {
  return Contains(mPersistentSessionIds, atoi(aSessionId.c_str()));
}

void ClearKeyPersistence::PersistentSessionRemoved(string& aSessionId) {
  mPersistentSessionIds.erase(atoi(aSessionId.c_str()));

  // Update the index file.
  WriteIndex();
}