#include "SdCardManager.h"

#include <fsfw/ipc/MutexGuard.h>
#include <fsfw/timemanager/Countdown.h>
#include <unistd.h>

#include <cstring>
#include <filesystem>
#include <fstream>
#include <memory>

#include "OBSWConfig.h"
#include "bsp_q7s/memory/scratchApi.h"
#include "eive/definitions.h"
#include "eive/objects.h"
#include "fsfw/ipc/MutexFactory.h"
#include "fsfw/serviceinterface/ServiceInterface.h"
#include "linux/utility/utility.h"

SdCardManager* SdCardManager::INSTANCE = nullptr;

SdCardManager::SdCardManager() : SystemObject(objects::SDC_MANAGER), cmdExecutor(256) {
  sdLock = MutexFactory::instance()->createMutex();
  prefLock = MutexFactory::instance()->createMutex();
  defaultLock = MutexFactory::instance()->createMutex();

  MutexGuard mg(prefLock, LOCK_TYPE, OTHER_TIMEOUT, LOCK_CTX);
  if (mg.getLockResult() != returnvalue::OK) {
    sif::error << "SdCardManager::SdCardManager: Mutex lock failed" << std::endl;
  }
  uint8_t prefSdRaw = 0;
  ReturnValue_t result = scratch::readNumber(scratch::PREFERED_SDC_KEY, prefSdRaw);

  if (result != returnvalue::OK) {
    if (result == scratch::KEY_NOT_FOUND) {
      sif::warning << "CoreController::sdCardInit: "
                      "Preferred SD card not set. Setting to 0"
                   << std::endl;
      setPreferredSdCard(sd::SdCard::SLOT_0);
      scratch::writeNumber(scratch::PREFERED_SDC_KEY, static_cast<uint8_t>(sd::SdCard::SLOT_0));
      prefSdRaw = sd::SdCard::SLOT_0;

    } else {
      // Should not happen.
      // TODO: Maybe trigger event?
      sif::error << "SdCardManager::SdCardManager: Reading preferred SD card from scratch"
                    "buffer failed"
                 << std::endl;
      prefSdRaw = sd::SdCard::SLOT_0;
    }
  }
  sdInfo.pref = static_cast<sd::SdCard>(prefSdRaw);
}

SdCardManager::~SdCardManager() {}

void SdCardManager::create() {
  if (INSTANCE == nullptr) {
    INSTANCE = new SdCardManager();
  }
}

SdCardManager* SdCardManager::instance() {
  SdCardManager::create();
  return SdCardManager::INSTANCE;
}

ReturnValue_t SdCardManager::switchOnSdCard(sd::SdCard sdCard, bool doMountSdCard,
                                            SdStatePair* statusPair) {
  ReturnValue_t result = returnvalue::OK;
  if (doMountSdCard) {
    if (not blocking) {
      sif::warning << "SdCardManager::switchOnSdCard: Two-step command but manager is"
                      " not configured for blocking operation. "
                      "Forcing blocking mode.."
                   << std::endl;
      blocking = true;
    }
  }
  std::unique_ptr<SdStatePair> sdStatusPtr;
  if (statusPair == nullptr) {
    sdStatusPtr = std::make_unique<SdStatePair>();
    statusPair = sdStatusPtr.get();
    result = getSdCardsStatus(*statusPair);
    if (result != returnvalue::OK) {
      return result;
    }
  }

  // Not allowed, this function turns on one SD card
  if (sdCard == sd::SdCard::BOTH) {
    sif::warning << "SdCardManager::switchOffSdCard: API does not allow sd::SdStatus::BOTH"
                 << std::endl;
    return returnvalue::FAILED;
  }

  sd::SdState currentState;
  if (sdCard == sd::SdCard::SLOT_0) {
    currentState = statusPair->first;
  } else if (sdCard == sd::SdCard::SLOT_1) {
    currentState = statusPair->second;
  } else {
    // Should not happen
    currentState = sd::SdState::OFF;
  }

  if (currentState == sd::SdState::ON) {
    if (not doMountSdCard) {
      return ALREADY_ON;
    } else {
      return mountSdCard(sdCard);
    }
  } else if (currentState == sd::SdState::MOUNTED) {
    result = ALREADY_MOUNTED;
  } else if (currentState == sd::SdState::OFF) {
    result = setSdCardState(sdCard, true);
  } else {
    result = returnvalue::FAILED;
  }

  if (result != returnvalue::OK or not doMountSdCard) {
    return result;
  }

  return mountSdCard(sdCard);
}

ReturnValue_t SdCardManager::switchOffSdCard(sd::SdCard sdCard, bool doUnmountSdCard,
                                             SdStatePair* statusPair) {
  std::pair<sd::SdState, sd::SdState> active;
  ReturnValue_t result = getSdCardsStatus(active);
  if (result != returnvalue::OK) {
    return result;
  }
  if (doUnmountSdCard) {
    if (not blocking) {
      sif::warning << "SdCardManager::switchOffSdCard: Two-step command but manager is"
                      " not configured for blocking operation. Forcing blocking mode.."
                   << std::endl;
      blocking = true;
    }
  }
  // Not allowed, this function turns off one SD card
  if (sdCard == sd::SdCard::BOTH) {
    sif::warning << "SdCardManager::switchOffSdCard: API does not allow sd::SdStatus::BOTH"
                 << std::endl;
    return returnvalue::FAILED;
  }
  if (sdCard == sd::SdCard::SLOT_0) {
    if (active.first == sd::SdState::OFF) {
      return ALREADY_OFF;
    }
  } else if (sdCard == sd::SdCard::SLOT_1) {
    if (active.second == sd::SdState::OFF) {
      return ALREADY_OFF;
    }
  }

  if (doUnmountSdCard) {
    result = unmountSdCard(sdCard);
    if (result != returnvalue::OK) {
      return result;
    }
  }

  return setSdCardState(sdCard, false);
}

ReturnValue_t SdCardManager::setSdCardState(sd::SdCard sdCard, bool on) {
  using namespace std;
  if (cmdExecutor.getCurrentState() == CommandExecutor::States::PENDING) {
    return CommandExecutor::COMMAND_PENDING;
  }
  string sdstring = "";
  string statestring = "";
  if (sdCard == sd::SdCard::SLOT_0) {
    sdstring = "0";
  } else if (sdCard == sd::SdCard::SLOT_1) {
    sdstring = "1";
  }
  if (on) {
    currentOp = Operations::SWITCHING_ON;
    statestring = "on";
  } else {
    currentOp = Operations::SWITCHING_OFF;
    statestring = "off";
  }
  ostringstream command;
  command << "q7hw sd set " << sdstring << " " << statestring;
  cmdExecutor.load(command.str(), blocking, printCmdOutput);
  ReturnValue_t result = cmdExecutor.execute();
  if (blocking and result != returnvalue::OK) {
    utility::handleSystemError(cmdExecutor.getLastError(), "SdCardManager::setSdCardState");
  }
  return result;
}

ReturnValue_t SdCardManager::getSdCardsStatus(SdStatePair& sdStates) {
  MutexGuard mg(sdLock, LOCK_TYPE, SD_LOCK_TIMEOUT, LOCK_CTX);
  sdStates = this->sdStates;
  return returnvalue::OK;
}

ReturnValue_t SdCardManager::mountSdCard(sd::SdCard sdCard) {
  using namespace std;
  if (cmdExecutor.getCurrentState() == CommandExecutor::States::PENDING) {
    return CommandExecutor::COMMAND_PENDING;
  }
  if (sdCard == sd::SdCard::BOTH) {
    sif::warning << "SdCardManager::mountSdCard: API does not allow sd::SdStatus::BOTH"
                 << std::endl;
    return returnvalue::FAILED;
  }
  string mountDev;
  string mountPoint;
  if (sdCard == sd::SdCard::SLOT_0) {
    mountDev = SD_0_DEV_NAME;
    mountPoint = config::SD_0_MOUNT_POINT;
  } else if (sdCard == sd::SdCard::SLOT_1) {
    mountDev = SD_1_DEV_NAME;
    mountPoint = config::SD_1_MOUNT_POINT;
  }
  std::error_code e;
  if (not filesystem::exists(mountDev, e)) {
    sif::warning << "SdCardManager::mountSdCard: Device file does not exists. Make sure to"
                    " turn on the SD card"
                 << std::endl;
    return MOUNT_ERROR;
  }

  if (not blocking) {
    currentOp = Operations::MOUNTING;
  }
  string sdMountCommand = "mount " + mountDev + " " + mountPoint;
  cmdExecutor.load(sdMountCommand, blocking, printCmdOutput);
  ReturnValue_t result = cmdExecutor.execute();
  if (blocking and result != returnvalue::OK) {
    utility::handleSystemError(cmdExecutor.getLastError(), "SdCardManager::mountSdCard");
  }
  return result;
}

ReturnValue_t SdCardManager::unmountSdCard(sd::SdCard sdCard) {
  if (cmdExecutor.getCurrentState() == CommandExecutor::States::PENDING) {
    return CommandExecutor::COMMAND_PENDING;
  }
  using namespace std;
  if (sdCard == sd::SdCard::BOTH) {
    sif::warning << "SdCardManager::unmountSdCard: API does not allow sd::SdStatus::BOTH"
                 << std::endl;
    return returnvalue::FAILED;
  }
  string mountPoint;
  if (sdCard == sd::SdCard::SLOT_0) {
    mountPoint = config::SD_0_MOUNT_POINT;
  } else if (sdCard == sd::SdCard::SLOT_1) {
    mountPoint = config::SD_1_MOUNT_POINT;
  }
  std::error_code e;
  if (not filesystem::exists(mountPoint, e)) {
    sif::error << "SdCardManager::unmountSdCard: Default mount point " << mountPoint
               << "does not exist" << std::endl;
    return UNMOUNT_ERROR;
  }
  if (filesystem::is_empty(mountPoint)) {
    // The mount point will always exist, but if it is empty, that is strong hint that
    // the SD card was not mounted properly. Still proceed with operation.
    sif::warning << "SdCardManager::unmountSdCard: Mount point is empty!" << std::endl;
  }
  string sdUnmountCommand = "umount " + mountPoint;
  if (not blocking) {
    currentOp = Operations::UNMOUNTING;
  }
  cmdExecutor.load(sdUnmountCommand, blocking, printCmdOutput);
  ReturnValue_t result = cmdExecutor.execute();
  if (blocking and result != returnvalue::OK) {
    utility::handleSystemError(cmdExecutor.getLastError(), "SdCardManager::unmountSdCard");
  }
  return result;
}

ReturnValue_t SdCardManager::sanitizeState(SdStatePair* statusPair, sd::SdCard prefSdCard) {
  std::unique_ptr<SdStatePair> sdStatusPtr;
  ReturnValue_t result = returnvalue::OK;
  // Enforce blocking operation for now. Be careful to reset it when returning prematurely!
  bool resetNonBlockingState = false;
  if (not this->blocking) {
    blocking = true;
    resetNonBlockingState = true;
  }
  if (statusPair == nullptr) {
    return returnvalue::FAILED;
  }
  getSdCardsStatus(*statusPair);

  if (statusPair->first == sd::SdState::ON) {
    result = mountSdCard(prefSdCard);
  }

  result = switchOnSdCard(prefSdCard, true, statusPair);
  if (resetNonBlockingState) {
    blocking = false;
  }
  return result;
}

void SdCardManager::resetState() {
  cmdExecutor.reset();
  currentOp = Operations::IDLE;
}

ReturnValue_t SdCardManager::updateSdStatePair() {
  using namespace std;

  MutexGuard mg(sdLock, LOCK_TYPE, SD_LOCK_TIMEOUT, LOCK_CTX);
  std::error_code e;
  if (not filesystem::exists(SD_STATE_FILE, e)) {
    return STATUS_FILE_NEXISTS;
  }

  // Now the file should exist in any case. Still check whether it exists.
  fstream sdStatus(SD_STATE_FILE);
  if (not sdStatus.good()) {
    return STATUS_FILE_NEXISTS;
  }
  string line;
  uint8_t idx = 0;
  sd::SdCard currentSd = sd::SdCard::SLOT_0;
  // Process status file line by line
  while (std::getline(sdStatus, line)) {
    processSdStatusLine(line, idx, currentSd);
  }
  if (sdStates.first != sd::SdState::MOUNTED && sdStates.second != sd::SdState::MOUNTED) {
    sdCardActive = false;
  }
  return returnvalue::OK;
}

void SdCardManager::processSdStatusLine(std::string& line, uint8_t& idx, sd::SdCard& currentSd) {
  using namespace std;
  istringstream iss(line);
  string word;
  bool slotLine = false;
  bool mountLine = false;
  while (iss >> word) {
    if (word == "Slot") {
      slotLine = true;
    }
    if (word == "Mounted") {
      mountLine = true;
    }

    if (slotLine) {
      if (word == "1:") {
        currentSd = sd::SdCard::SLOT_1;
      }

      if (word == "on") {
        if (currentSd == sd::SdCard::SLOT_0) {
          sdStates.first = sd::SdState::ON;
        } else {
          sdStates.second = sd::SdState::ON;
        }
      } else if (word == "off") {
        if (currentSd == sd::SdCard::SLOT_0) {
          sdStates.first = sd::SdState::OFF;
        } else {
          sdStates.second = sd::SdState::OFF;
        }
      }
    }

    if (mountLine) {
      if (currentSd == sd::SdCard::SLOT_0) {
        sdStates.first = sd::SdState::MOUNTED;
      } else {
        sdStates.second = sd::SdState::MOUNTED;
      }
    }

    if (idx > 5) {
      sif::warning << "SdCardManager::sdCardActive: /tmp/sd_status.txt has more than 6 "
                      "lines and might be invalid!"
                   << std::endl;
    }
  }
  idx++;
}

std::optional<sd::SdCard> SdCardManager::getPreferredSdCard() const {
  MutexGuard mg(prefLock, LOCK_TYPE, OTHER_TIMEOUT, LOCK_CTX);
  auto res = mg.getLockResult();
  if (res != returnvalue::OK) {
    sif::error << "SdCardManager::getPreferredSdCard: Lock error" << std::endl;
  }
  return sdInfo.pref;
}

ReturnValue_t SdCardManager::setPreferredSdCard(sd::SdCard sdCard) {
  MutexGuard mg(prefLock, LOCK_TYPE, OTHER_TIMEOUT, LOCK_CTX);
  if (sdCard == sd::SdCard::BOTH) {
    return returnvalue::FAILED;
  }
  sdInfo.pref = sdCard;
  return scratch::writeNumber(scratch::PREFERED_SDC_KEY, static_cast<uint8_t>(sdCard));
}

ReturnValue_t SdCardManager::updateSdCardStateFile() {
  if (cmdExecutor.getCurrentState() == CommandExecutor::States::PENDING) {
    return CommandExecutor::COMMAND_PENDING;
  }
  MutexGuard mg(sdLock, LOCK_TYPE, SD_LOCK_TIMEOUT, LOCK_CTX);
  // Use q7hw utility and pipe the command output into the state file
  std::string updateCmd = "q7hw sd info all > " + std::string(SD_STATE_FILE);
  cmdExecutor.load(updateCmd, true, printCmdOutput);
  ReturnValue_t result = cmdExecutor.execute();
  if (blocking and result != returnvalue::OK) {
    utility::handleSystemError(cmdExecutor.getLastError(), "SdCardManager::mountSdCard");
  }
  return result;
}

const char* SdCardManager::getCurrentMountPrefix() const {
  MutexGuard mg(defaultLock, LOCK_TYPE, OTHER_TIMEOUT, LOCK_CTX);
  if (currentPrefix.has_value()) {
    return currentPrefix.value().c_str();
  }
  return nullptr;
}

SdCardManager::OpStatus SdCardManager::checkCurrentOp(Operations& currentOp) {
  CommandExecutor::States state = cmdExecutor.getCurrentState();
  if (state == CommandExecutor::States::IDLE or state == CommandExecutor::States::COMMAND_LOADED) {
    return OpStatus::IDLE;
  }
  currentOp = this->currentOp;
  bool bytesRead = false;

#if OBSW_ENABLE_TIMERS == 1
  Countdown timer(1000);
#endif
  while (true) {
    ReturnValue_t result = cmdExecutor.check(bytesRead);
    // This timer can prevent deadlocks due to missconfigurations
#if OBSW_ENABLE_TIMERS == 1
    if (timer.hasTimedOut()) {
      sif::error << "SdCardManager::checkCurrentOp: Timeout!" << std::endl;
      return OpStatus::FAIL;
    }
#endif
    switch (result) {
      case (CommandExecutor::BYTES_READ): {
        continue;
      }
      case (CommandExecutor::EXECUTION_FINISHED): {
        return OpStatus::SUCCESS;
      }
      case (returnvalue::OK): {
        return OpStatus::ONGOING;
      }
      case (returnvalue::FAILED): {
        return OpStatus::FAIL;
      }
      default: {
        sif::warning << "SdCardManager::checkCurrentOp: Unhandled case" << std::endl;
      }
    }
  }
}

void SdCardManager::setBlocking(bool blocking) { this->blocking = blocking; }

void SdCardManager::setPrintCommandOutput(bool print) { this->printCmdOutput = print; }

bool SdCardManager::isSdCardUsable(std::optional<sd::SdCard> sdCard) {
  {
    MutexGuard mg(defaultLock, LOCK_TYPE, OTHER_TIMEOUT, LOCK_CTX);
    if (markedUnusable) {
      return false;
    }
  }

  MutexGuard mg(sdLock, LOCK_TYPE, SD_LOCK_TIMEOUT, LOCK_CTX);
  if (not sdCard) {
    if (sdStates.first == sd::MOUNTED or sdStates.second == sd::MOUNTED) {
      return true;
    }
    return false;
  }
  if (sdCard == sd::SLOT_0) {
    if (sdStates.first == sd::MOUNTED) {
      return true;
    } else {
      return false;
    }
  }
  if (sdCard == sd::SLOT_1) {
    if (sdStates.second == sd::MOUNTED) {
      return true;
    } else {
      return false;
    }
  }
  if (sdCard == sd::BOTH) {
    if (sdStates.first == sd::MOUNTED && sdStates.second == sd::MOUNTED) {
      return true;
    }
  }
  return false;
}

ReturnValue_t SdCardManager::isSdCardMountedReadOnly(sd::SdCard sdcard, bool& readOnly) {
  std::ostringstream command;
  if (sdcard == sd::SdCard::SLOT_0) {
    command << "grep -q '" << config::SD_0_MOUNT_POINT << " ext4 rw,' /proc/mounts";
  } else if (sdcard == sd::SdCard::SLOT_1) {
    command << "grep -q '" << config::SD_1_MOUNT_POINT << " ext4 rw,' /proc/mounts";
  } else {
    return returnvalue::FAILED;
  }
  ReturnValue_t result = cmdExecutor.load(command.str(), true, false);
  if (result != returnvalue::OK) {
    return result;
  }
  result = cmdExecutor.execute();
  if (result == returnvalue::OK) {
    readOnly = false;
    return result;
  }
  readOnly = true;
  return returnvalue::OK;
}

ReturnValue_t SdCardManager::remountReadWrite(sd::SdCard sdcard) {
  std::ostringstream command;
  if (sdcard == sd::SdCard::SLOT_0) {
    command << "mount -o remount,rw " << SD_0_DEV_NAME << " " << config::SD_0_MOUNT_POINT;
  } else {
    command << "mount -o remount,rw " << SD_1_DEV_NAME << " " << config::SD_1_MOUNT_POINT;
  }
  ReturnValue_t result = cmdExecutor.load(command.str(), true, false);
  if (result != returnvalue::OK) {
    return result;
  }
  return cmdExecutor.execute();
}

ReturnValue_t SdCardManager::performFsck(sd::SdCard sdcard, bool printOutput, int& linuxError) {
  std::ostringstream command;
  if (sdcard == sd::SdCard::SLOT_0) {
    command << "fsck -y " << SD_0_DEV_NAME;
  } else {
    command << "fsck -y " << SD_1_DEV_NAME;
  }
  ReturnValue_t result = cmdExecutor.load(command.str(), true, printOutput);
  if (result != returnvalue::OK) {
    return result;
  }
  result = cmdExecutor.execute();
  if (result != returnvalue::OK) {
    linuxError = cmdExecutor.getLastError();
  }
  return result;
}

void SdCardManager::setActiveSdCard(sd::SdCard sdCard) {
  MutexGuard mg(defaultLock, LOCK_TYPE, OTHER_TIMEOUT, LOCK_CTX);
  sdInfo.active = sdCard;
  if (sdInfo.active == sd::SdCard::SLOT_0) {
    currentPrefix = config::SD_0_MOUNT_POINT;
  } else {
    currentPrefix = config::SD_1_MOUNT_POINT;
  }
}

std::optional<sd::SdCard> SdCardManager::getActiveSdCard() const {
  MutexGuard mg(defaultLock, LOCK_TYPE, OTHER_TIMEOUT, LOCK_CTX);
  if (markedUnusable) {
    return std::nullopt;
  }
  return sdInfo.active;
}

void SdCardManager::markUnusable() {
  MutexGuard mg(defaultLock, LOCK_TYPE, OTHER_TIMEOUT, LOCK_CTX);
  markedUnusable = true;
}