#include "SourceHandler.h"

#include <etl/crc32.h>

#include <array>

#include "fsfw/filesystem/HasFileSystemIF.h"

using namespace returnvalue;

cfdp::SourceHandler::SourceHandler(SourceHandlerParams params, FsfwParams fsfwParams)
    : transactionParams(params.maxFilePathSize),
      sourceParams(std::move(params)),
      fsfwParams(fsfwParams) {}

void cfdp::SourceHandler::fsmNacked() {
  if (step == TransactionStep::IDLE) {
    step = TransactionStep::TRANSACTION_START;
  }
  if (step == TransactionStep::TRANSACTION_START) {
    // TODO: Use put request information to start the transaction
    step = TransactionStep::CRC_PROCEDURE;
  }
  if (step == TransactionStep::CRC_PROCEDURE) {
    ReturnValue_t result = checksumGeneration();
    if (result != OK) {
      // TODO: Some error handling
    }
  }
  if (step == TransactionStep::SENDING_METADATA) {
    // TODO: Prepare and send metadata PDU
  }
  if (step == TransactionStep::SENDING_FILE_DATA) {
    // TODO: Prepare and send file data PDUs
  }
  if (step == TransactionStep::SENDING_EOF) {
    // TODO: Send EOF PDU
  }
  if (step == TransactionStep::WAIT_FOR_FINISH) {
    // TODO: In case this is a request with closure, wait for finish.
  }
  if (step == TransactionStep::NOTICE_OF_COMPLETION) {
    // TODO: Notice of completion
  }
}
void cfdp::SourceHandler::stateMachine() {
  if (state == cfdp::CfdpState::IDLE) {
    return;
  }
  if (state == cfdp::CfdpState::BUSY_CLASS_1_NACKED) {
    return fsmNacked();
  }
}

ReturnValue_t cfdp::SourceHandler::checksumGeneration() {
  std::array<uint8_t, 1024> buf{};
  etl::crc32 crcCalc;
  uint64_t currentOffset = 0;
  FileOpParams params(transactionParams.destName.data(), transactionParams.fileSize.value());
  while (currentOffset < transactionParams.fileSize.value()) {
    uint64_t readLen;
    if (currentOffset + buf.size() > transactionParams.fileSize.value()) {
      readLen = transactionParams.fileSize.value() - currentOffset;
    } else {
      readLen = buf.size();
    }
    if (readLen > 0) {
      params.offset = currentOffset;
      params.size = readLen;
      auto result = sourceParams.user.vfs.readFromFile(params, buf.data(), buf.size());
      if (result != OK) {
        // TODO: I think this is a case for a filestore rejection, but it might sense to print
        //       a warning or trigger an event because this should generally not happen
        return FAILED;
      }
      crcCalc.add(buf.begin(), buf.begin() + readLen);
    }
    currentOffset += readLen;
  }

  transactionParams.crc = crcCalc.value();
  return OK;
}

ReturnValue_t cfdp::SourceHandler::putRequest() { return 0; }