#include "PersistentTmStore.h"

#include <mission/memory/SdCardMountedIF.h>
#include <mission/tmtc/DirectTmSinkIF.h>

#include <algorithm>
#include <cinttypes>
#include <filesystem>
#include <fstream>
#include <utility>

#include "eive/definitions.h"
#include "fsfw/ipc/CommandMessage.h"
#include "fsfw/ipc/QueueFactory.h"
#include "fsfw/tmstorage/TmStoreMessage.h"
#include "mission/persistentTmStoreDefs.h"

using namespace returnvalue;

static constexpr bool DEBUG_DUMPS = false;

PersistentTmStore::PersistentTmStore(PersistentTmStoreArgs args)
    : SystemObject(args.objectId),
      tmStore(args.tmStore),
      baseDir(args.baseDir),
      baseName(std::move(args.baseName)),
      sdcMan(args.sdcMan) {
  tcQueue = QueueFactory::instance()->createMessageQueue();
  calcDiffSeconds(args.intervalUnit, args.intervalCount);
}

ReturnValue_t PersistentTmStore::cancelDump() {
  state = State::IDLE;
  return returnvalue::OK;
}

ReturnValue_t PersistentTmStore::buildDumpSet(uint32_t fromUnixSeconds, uint32_t upToUnixSeconds) {
  using namespace std::filesystem;
  std::error_code e;
  dumpParams.orderedDumpFilestamps.clear();
  for (auto const& fileOrDir : directory_iterator(basePath)) {
    if (not fileOrDir.is_regular_file(e)) {
      continue;
    }
    dumpParams.fileSize = std::filesystem::file_size(fileOrDir.path(), e);
    if (e) {
      sif::error << "PersistentTmStore: Could not retrieve file size: " << e.message() << std::endl;
      continue;
    }

    // File empty or can't even read CCSDS header.
    if (dumpParams.fileSize <= 6) {
      continue;
    }
    if (dumpParams.fileSize > fileBuf.size()) {
      sif::error << "PersistentTmStore: File too large, is deleted" << std::endl;
      triggerEvent(persTmStore::FILE_TOO_LARGE, dumpParams.fileSize, fileBuf.size());
      std::filesystem::remove(fileOrDir.path(), e);
      continue;
    }
    const path& file = fileOrDir.path();
    struct tm fileTime {};
    if (pathToTime(file, fileTime) != returnvalue::OK) {
      sif::error << "Time extraction for file " << file << "failed" << std::endl;
      continue;
    }
    auto fileEpoch = static_cast<uint32_t>(timegm(&fileTime));
    if ((fileEpoch > dumpParams.fromUnixTime) and
        (fileEpoch + rolloverDiffSeconds <= dumpParams.untilUnixTime)) {
      std::ifstream ifile(file, std::ios::binary);
      if (ifile.bad()) {
        sif::error << "PersistentTmStore: File is bad" << std::endl;
        // TODO: Consider deleting file here?
        continue;
      }

      if (DEBUG_DUMPS) {
        sif::debug << "Inserting file " << fileOrDir.path() << std::endl;
      }
      DumpIndex dumpIndex;
      dumpIndex.epoch = fileEpoch;
      // Multiple files for the same time are supported via a special suffix. We simply count the
      // number of copies and later try to dump the same number of files with the additional
      // suffixes
      auto iter = dumpParams.orderedDumpFilestamps.find(dumpIndex);
      if (iter != dumpParams.orderedDumpFilestamps.end()) {
        dumpIndex.epoch = iter->epoch;
        dumpIndex.additionalFiles = iter->additionalFiles + 1;
        dumpParams.orderedDumpFilestamps.erase(dumpIndex);
      } else {
        dumpIndex.additionalFiles = 0;
      }
      dumpParams.orderedDumpFilestamps.emplace(dumpIndex);
    }
  }
  return returnvalue::OK;
}

std::optional<uint8_t> PersistentTmStore::extractSuffix(const std::string& pathStr) {
  std::string numberStr;
  // Find the position of the dot at the end of the file path
  size_t dotPos = pathStr.find_last_of('.');
  if ((dotPos < pathStr.length()) and not std::isdigit(pathStr[dotPos + 1])) {
    return std::nullopt;
  }
  // Extract the substring after the dot
  numberStr = pathStr.substr(dotPos + 1);
  std::optional<uint8_t> number;
  try {
    number = std::stoi(numberStr);
    if (number.value() > std::numeric_limits<uint8_t>::max()) {
      return std::nullopt;
    }

  } catch (std::invalid_argument& exception) {
    sif::error << "PersistentTmStore::extractSuffix: Exception " << exception.what()
               << ", invald input string: " << numberStr << std::endl;
  }
  return number;
}

ReturnValue_t PersistentTmStore::assignAndOrCreateMostRecentFile() {
  if (not activeFile.has_value()) {
    return createMostRecentFile(std::nullopt);
  }
  return returnvalue::OK;
}

ReturnValue_t PersistentTmStore::handleCommandQueue(StorageManagerIF& ipcStore,
                                                    Command_t& execCmd) {
  CommandMessage cmdMessage;
  ReturnValue_t result = tcQueue->receiveMessage(&cmdMessage);
  if (result != returnvalue::OK) {
    return result;
  }
  if (cmdMessage.getMessageType() == messagetypes::TM_STORE) {
    Command_t cmd = cmdMessage.getCommand();
    if (cmd == TmStoreMessage::DELETE_STORE_CONTENT_TIME) {
      Clock::getClock_timeval(&currentTv);
      store_address_t storeId = TmStoreMessage::getStoreId(&cmdMessage);
      auto accessor = ipcStore.getData(storeId);
      uint32_t deleteUpToUnixSeconds = 0;
      size_t size = accessor.second.size();
      SerializeAdapter::deSerialize(&deleteUpToUnixSeconds, accessor.second.data(), &size,
                                    SerializeIF::Endianness::NETWORK);
      execCmd = cmd;
      deleteUpTo(deleteUpToUnixSeconds);
    } else if (cmd == TmStoreMessage::DOWNLINK_STORE_CONTENT_TIME) {
      Clock::getClock_timeval(&currentTv);
      store_address_t storeId = TmStoreMessage::getStoreId(&cmdMessage);
      auto accessor = ipcStore.getData(storeId);
      if (accessor.second.size() < 8) {
        return returnvalue::FAILED;
      }
      uint32_t dumpFromUnixSeconds = 0;
      uint32_t dumpUntilUnixSeconds = 0;
      size_t size = 8;
      SerializeAdapter::deSerialize(&dumpFromUnixSeconds, accessor.second.data(), &size,
                                    SerializeIF::Endianness::NETWORK);
      SerializeAdapter::deSerialize(&dumpUntilUnixSeconds, accessor.second.data() + 4, &size,
                                    SerializeIF::Endianness::NETWORK);
      result = startDumpFromUpTo(dumpFromUnixSeconds, dumpUntilUnixSeconds);
      if (result == BUSY_DUMPING) {
        triggerEvent(persTmStore::BUSY_DUMPING_EVENT);
      } else {
        execCmd = cmd;
      }
    }
  }
  return result;
}

ReturnValue_t PersistentTmStore::startDumpFrom(uint32_t fromUnixSeconds) {
  return startDumpFromUpTo(fromUnixSeconds, currentTv.tv_sec);
}

ReturnValue_t PersistentTmStore::storePacket(PusTmReader& reader) {
  using namespace std::filesystem;
  if (baseDirUninitialized) {
    updateBaseDir();
  }
  Clock::getClock_timeval(&currentTv);
  // It is assumed here that the filesystem is usable.
  if (not activeFile.has_value()) {
    ReturnValue_t result = assignAndOrCreateMostRecentFile();
    if (result != returnvalue::OK) {
      return result;
    }
  }

  bool createNewFile = false;
  std::optional<uint8_t> suffix = std::nullopt;
  std::error_code e;
  size_t fileSize = file_size(activeFile.value(), e);
  if (e) {
    sif::error << "PersistentTmStore: Could not retrieve file size, "
                  "error "
               << e.message() << std::endl;
    return returnvalue::FAILED;
  }
  if (currentTv.tv_sec > activeFileTv.tv_sec + static_cast<int>(rolloverDiffSeconds)) {
    createNewFile = true;
    currentSameSecNumber = 0;
  } else if (fileSize + reader.getFullPacketLen() > fileBuf.size()) {
    createNewFile = true;
    if (currentSameSecNumber >= MAX_FILES_IN_ONE_SECOND) {
      currentSameSecNumber = 0;
    }
    if (currentTv.tv_sec == activeFileTv.tv_sec) {
      suffix = currentSameSecNumber++;
    } else {
      currentSameSecNumber = 0;
    }
  }
  if (createNewFile) {
    createMostRecentFile(suffix);
  }

  // Rollover conditions were handled, write to file now
  std::ofstream of(activeFile.value(), std::ios::app | std::ios::binary);
  of.write(reinterpret_cast<const char*>(reader.getFullData()),
           static_cast<std::streamsize>(reader.getFullPacketLen()));
  return returnvalue::OK;
}

MessageQueueId_t PersistentTmStore::getCommandQueue() const { return tcQueue->getId(); }

void PersistentTmStore::calcDiffSeconds(RolloverInterval intervalUnit, uint32_t intervalCount) {
  if (intervalUnit == RolloverInterval::MINUTELY) {
    rolloverDiffSeconds = 60 * intervalCount;
  } else if (intervalUnit == RolloverInterval::HOURLY) {
    rolloverDiffSeconds = 60 * 60 * intervalCount;
  } else if (intervalUnit == RolloverInterval::DAILY) {
    rolloverDiffSeconds = 60 * 60 * 24 * intervalCount;
  }
}

bool PersistentTmStore::updateBaseDir() {
  using namespace std::filesystem;
  const char* currentPrefix = sdcMan.getCurrentMountPrefix();
  if (currentPrefix == nullptr) {
    return false;
  }
  basePath = path(currentPrefix) / baseDir / baseName;
  std::error_code e;
  if (not exists(basePath, e)) {
    create_directories(basePath);
  }
  // Each file will have the base name as a prefix again
  path preparedFullFilePath = basePath / baseName;
  basePathSize = preparedFullFilePath.string().length();
  std::memcpy(filePathBuf.data(), preparedFullFilePath.c_str(), basePathSize);
  filePathBuf[basePathSize] = '_';
  basePathSize += 1;
  baseDirUninitialized = false;
  return true;
}

void PersistentTmStore::deleteUpTo(uint32_t unixSeconds) {
  using namespace std::filesystem;
  for (auto const& file : directory_iterator(basePath)) {
    if (file.is_directory() or (activeFile.has_value() and (activeFile.value() == file.path()))) {
      continue;
    }
    // Convert file time to the UNIX epoch
    struct tm fileTime {};
    if (pathToTime(file.path(), fileTime) != returnvalue::OK) {
      sif::error << "Time extraction for " << file << " failed" << std::endl;
      continue;
    }
    time_t fileEpoch = timegm(&fileTime);
    if (fileEpoch + rolloverDiffSeconds < unixSeconds) {
      std::error_code e;
      std::filesystem::remove(file.path(), e);
    }
  }
}

ReturnValue_t PersistentTmStore::startDumpFromUpTo(uint32_t fromUnixSeconds,
                                                   uint32_t upToUnixSeconds) {
  using namespace std::filesystem;
  if (state == State::DUMPING) {
    return returnvalue::FAILED;
  }
  auto dirIter = directory_iterator(basePath);
  // Directory empty case.
  if (dirIter == directory_iterator()) {
    return returnvalue::FAILED;
  }
  dumpParams.fromUnixTime = fromUnixSeconds;
  dumpParams.untilUnixTime = upToUnixSeconds;
  buildDumpSet(fromUnixSeconds, upToUnixSeconds);
  // No files in time window found.
  if (dumpParams.orderedDumpFilestamps.empty()) {
    return DUMP_DONE;
  }
  dumpParams.dumpIter = dumpParams.orderedDumpFilestamps.begin();
  dumpParams.currentSameFileIdx = std::nullopt;
  state = State::DUMPING;
  return loadNextDumpFile();
}

ReturnValue_t PersistentTmStore::loadNextDumpFile() {
  using namespace std::filesystem;
  dumpParams.currentSize = 0;
  std::error_code e;
  // Handle iteration, which does not necessarily have to increment the set iterator
  // if there are multiple files for a given timestamp.
  auto handleIteration = [&](DumpIndex& dumpIndex) {
    if (dumpIndex.additionalFiles > 0) {
      if (not dumpParams.currentSameFileIdx.has_value()) {
        // Initialize the file index and stay on same file
        dumpParams.currentSameFileIdx = 0;
        return;
      } else if (dumpParams.currentSameFileIdx.value() < dumpIndex.additionalFiles - 1) {
        dumpParams.currentSameFileIdx = dumpParams.currentSameFileIdx.value() + 1;
        return;
      }
    }
    // File will change, reset this field for correct state-keeping.
    dumpParams.currentSameFileIdx = std::nullopt;
    // Increment iterator for next cycle.
    dumpParams.dumpIter++;
  };
  while (dumpParams.dumpIter != dumpParams.orderedDumpFilestamps.end()) {
    DumpIndex dumpIndex = *dumpParams.dumpIter;
    timeval tv{};
    tv.tv_sec = dumpIndex.epoch;
    size_t fullPathLength = 0;
    createFileName(tv, dumpParams.currentSameFileIdx, fullPathLength);
    dumpParams.currentFile =
        path(std::string(reinterpret_cast<const char*>(filePathBuf.data()), fullPathLength));
    if (DEBUG_DUMPS) {
      sif::debug << baseName << " dump: Loading " << dumpParams.currentFile << std::endl;
    }
    dumpParams.fileSize = std::filesystem::file_size(dumpParams.currentFile, e);
    if (e) {
      // TODO: Event?
      sif::error << "PersistentTmStore: Could not load next dump file: " << e.message()
                 << std::endl;
      handleIteration(dumpIndex);
      continue;
    }
    std::ifstream ifile(dumpParams.currentFile, std::ios::binary);
    if (ifile.bad()) {
      sif::error << "PersistentTmStore: File is bad. Loading next file" << std::endl;
      handleIteration(dumpIndex);
      continue;
    }
    ifile.read(reinterpret_cast<char*>(fileBuf.data()),
               static_cast<std::streamsize>(dumpParams.fileSize));
    // Next file is loaded, exit the loop.
    handleIteration(dumpIndex);
    return returnvalue::OK;
  }
  // Directory iterator was consumed and we are done.
  state = State::IDLE;
  return DUMP_DONE;
}

ReturnValue_t PersistentTmStore::getNextDumpPacket(PusTmReader& reader, bool& fileHasSwapped) {
  if (state == State::IDLE or dumpParams.pendingPacketDump) {
    return returnvalue::FAILED;
  }
  fileHasSwapped = false;
  reader.setReadOnlyData(fileBuf.data() + dumpParams.currentSize,
                         fileBuf.size() - dumpParams.currentSize);
  // CRC check to fully ensure this is a valid TM
  ReturnValue_t result = reader.parseDataWithCrcCheck();
  if (result != returnvalue::OK) {
    sif::error << "PersistentTmStore: Parsing of PUS TM failed with code " << result << std::endl;
    triggerEvent(persTmStore::POSSIBLE_FILE_CORRUPTION, result, dumpParams.currentFileUnixStamp);
    // Delete the file and load next. Could use better algorithm to partially
    // restore the file dump, but for now do not trust the file.
    std::error_code e;
    std::filesystem::remove(dumpParams.currentFile.c_str(), e);
    if (dumpParams.currentFile == activeFile) {
      activeFile == std::nullopt;
      assignAndOrCreateMostRecentFile();
    }
    fileHasSwapped = true;
    return loadNextDumpFile();
  }
  dumpParams.pendingPacketDump = true;
  return returnvalue::OK;
}

ReturnValue_t PersistentTmStore::confirmDump(const PusTmReader& reader, bool& fileHasSwapped) {
  dumpParams.pendingPacketDump = false;
  dumpParams.currentSize += reader.getFullPacketLen();
  if (dumpParams.currentSize >= dumpParams.fileSize) {
    fileHasSwapped = true;
    return loadNextDumpFile();
  }
  fileHasSwapped = false;
  return returnvalue::OK;
}

ReturnValue_t PersistentTmStore::pathToTime(const std::filesystem::path& path, struct tm& time) {
  auto pathStr = path.string();
  size_t splitChar = pathStr.find('_');
  auto timeOnlyStr = pathStr.substr(splitChar + 1);
  if (nullptr == strptime(timeOnlyStr.c_str(), config::FILE_DATE_FORMAT, &time)) {
    return returnvalue::FAILED;
  }
  return returnvalue::OK;
}

ReturnValue_t PersistentTmStore::createMostRecentFile(std::optional<uint8_t> suffix) {
  using namespace std::filesystem;
  size_t currentIdx;
  createFileName(currentTv, suffix, currentIdx);
  path newPath(std::string(reinterpret_cast<const char*>(filePathBuf.data()), currentIdx));
  std::ofstream of(newPath, std::ios::binary);
  activeFile = newPath;
  activeFileTv = currentTv;
  return returnvalue::OK;
}

ReturnValue_t PersistentTmStore::initializeTmStore() {
  Clock::getClock_timeval(&currentTv);
  updateBaseDir();
  // Reset active file, base directory might have changed.
  activeFile = std::nullopt;
  return assignAndOrCreateMostRecentFile();
}

PersistentTmStore::State PersistentTmStore::getState() const { return state; }

void PersistentTmStore::getStartAndEndTimeCurrentOrLastDump(uint32_t& startTime,
                                                            uint32_t& endTime) const {
  startTime = dumpParams.fromUnixTime;
  endTime = dumpParams.untilUnixTime;
}

ReturnValue_t PersistentTmStore::createFileName(timeval& tv, std::optional<uint8_t> suffix,
                                                size_t& fullPathLength) {
  unsigned currentIdx = basePathSize;
  time_t epoch = tv.tv_sec;
  struct tm* time = gmtime(&epoch);
  size_t writtenBytes = strftime(reinterpret_cast<char*>(filePathBuf.data() + currentIdx),
                                 filePathBuf.size(), config::FILE_DATE_FORMAT, time);
  if (writtenBytes == 0) {
    sif::error << "PersistentTmStore::createMostRecentFile: Could not create file timestamp"
               << std::endl;
    return returnvalue::FAILED;
  }
  currentIdx += writtenBytes;
  char* res = strcpy(reinterpret_cast<char*>(filePathBuf.data() + currentIdx), ".bin");
  if (res == nullptr) {
    return returnvalue::FAILED;
  }
  currentIdx += 4;
  if (suffix.has_value()) {
    std::string fullSuffix = "." + std::to_string(suffix.value());
    res = strcpy(reinterpret_cast<char*>(filePathBuf.data() + currentIdx), fullSuffix.c_str());
    if (res == nullptr) {
      return returnvalue::FAILED;
    }
    currentIdx += fullSuffix.size();
  }
  fullPathLength = currentIdx;
  return returnvalue::OK;
}