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/*******************************************************************************
* Copyright (C) 2019 Maxim Integrated Products, Inc., All Rights Reserved.
*
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* OTHER DEALINGS IN THE SOFTWARE.
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* Products, Inc. Branding Policy.
*
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#include <stddef.h>
#include <algorithm>
#include <MaximInterfaceCore/Error.hpp>
#include "DS28C40.hpp"

namespace MaximInterfaceDevices {

using namespace Core;
using std::copy;

static const int readMemoryTimeMs = 2;
static const int writeMemoryTimeMs = 150;
static const int writeStateTimeMs = 15;
static const int generateEccKeyPairTimeMs = 500;
static const int generateEcdsaSignatureTimeMs = 50;
static const int computeTimeMs = 4;
static const int verifyEcdsaTimeMs = 160;
static const int trngGenerationTimeMs = 50;
static const int trngOnDemandCheckTimeMs = 50;

static const uint_least8_t computeAndReadPageAuthenticationCmd = 0xA5;
static const uint_least8_t readRngCmd = 0xD2;

const int DS28C40::publicKeyAxPage;
const int DS28C40::publicKeyAyPage;
const int DS28C40::publicKeyBxPage;
const int DS28C40::publicKeyByPage;
const int DS28C40::authorityPublicKeyAxPage;
const int DS28C40::authorityPublicKeyAyPage;
const int DS28C40::authorityPublicKeyBxPage;
const int DS28C40::authorityPublicKeyByPage;
const int DS28C40::privateKeyAPage;
const int DS28C40::privateKeyBPage;
const int DS28C40::secretAPage;
const int DS28C40::secretBPage;
const int DS28C40::romOptionsPage;
const int DS28C40::gpioControlPage;
const int DS28C40::publicKeySxPage;
const int DS28C40::publicKeySyPage;

const int DS28C40::memoryPages;
const int DS28C40::protectionBlocks;

error_code DS28C40::writeMemory(int pageNum, Page::const_span page) {
  if (pageNum < 0 || pageNum >= memoryPages) {
    return make_error_code(InvalidParameterError);
  }

  uint_least8_t request[2 + Page::size];
  request[0] = 0x96;
  request[1] = pageNum;
  copy(page.begin(), page.end(), request + 2);
  return runCommand(request, writeMemoryTimeMs);
}

error_code DS28C40::readMemory(int pageNum, Page::span page) {
  if (pageNum < 0 || pageNum >= memoryPages) {
    return make_error_code(InvalidParameterError);
  }

  uint_least8_t buffer[1 + Page::size];
  buffer[0] = 0x44;
  buffer[1] = pageNum;
  span<uint_least8_t> response(buffer);
  const error_code result =
      runCommand(make_span(buffer, 2), readMemoryTimeMs, response);
  if (!result) {
    copy(response.begin(), response.end(), page.begin());
  }
  return result;
}

error_code
DS28C40::encryptedReadMemory(int pageNum, KeySecret secret,
                             EncryptionChallenge::span encryptionChallenge,
                             Page::span encryptedPage) {
  if (pageNum < 0 || pageNum >= memoryPages) {
    return make_error_code(InvalidParameterError);
  }

  const size_t requestSize = 3;
  const size_t responseSize = 1 + EncryptionChallenge::size + Page::size;
  uint_least8_t buffer[MaximInterfaceCore_MAX(requestSize, responseSize)];
  buffer[0] = 0x4B;
  buffer[1] = pageNum;
  buffer[2] = secret;
  span<uint_least8_t> response(buffer, responseSize);
  const error_code result =
      runCommand(make_span(buffer, requestSize),
                 readMemoryTimeMs + computeTimeMs, response);
  if (!result) {
    span<uint_least8_t>::const_iterator begin = response.begin();
    span<uint_least8_t>::const_iterator end =
        begin + encryptionChallenge.size();
    copy(begin, end, encryptionChallenge.begin());
    begin = end;
    end = begin + encryptedPage.size();
    copy(begin, end, encryptedPage.begin());
  }
  return result;
}

error_code DS28C40::readBlockProtection(int blockNumber,
                                        Optional<KeySecret> & keySecret,
                                        BlockProtection & protection) {
  if (blockNumber < 0 || blockNumber >= protectionBlocks) {
    return make_error_code(InvalidParameterError);
  }

  const size_t requestSize = 2;
  const size_t responseSize = 3;
  uint_least8_t buffer[MaximInterfaceCore_MAX(requestSize, responseSize)];
  buffer[0] = 0xAA;
  buffer[1] = blockNumber;
  span<uint_least8_t> response(buffer, responseSize);
  const error_code result =
      runCommand(make_span(buffer, requestSize), readMemoryTimeMs, response);
  if (result) {
    return result;
  }
  if ((response[0] & 0x3F) != blockNumber) {
    return make_error_code(InvalidResponseError);
  }
  switch (response[0] >> 6) {
  case 0:
    keySecret = none;
    break;
  case 1:
    keySecret = KeySecretA;
    break;
  case 2:
    keySecret = KeySecretB;
    break;
  default:
    return make_error_code(InvalidResponseError);
  }
  if ((response[1] & 0x20) != 0) {
    return make_error_code(InvalidResponseError);
  }
  protection = response[1];
  return error_code();
}

error_code DS28C40::setBlockProtection(int blockNum, KeySecret keySecret,
                                       const BlockProtection & protection) {
  if (blockNum < 0 || blockNum >= protectionBlocks || keySecret == KeySecretS) {
    return make_error_code(InvalidParameterError);
  }

  const uint_least8_t request[] = {
      0xC3,
      static_cast<uint_least8_t>((keySecret == KeySecretB ? 0x80 : 0x40) |
                                 blockNum),
      static_cast<uint_least8_t>(protection.to_ulong())};
  return runCommand(request, writeStateTimeMs);
}

error_code
DS28C40::computeAndReadPageAuthentication(int pageNum, KeySecret key,
                                          Page::const_span challenge,
                                          Ecc256::Signature::span signature) {
  if (pageNum < 0 || pageNum >= memoryPages || key == KeySecretS) {
    return make_error_code(InvalidParameterError);
  }

  const size_t requestSize = 3 + Page::size;
  const size_t responseSize = 1 + 2 * Ecc256::Scalar::size;
  uint_least8_t buffer[MaximInterfaceCore_MAX(requestSize, responseSize)];
  buffer[0] = computeAndReadPageAuthenticationCmd;
  buffer[1] = pageNum;
  buffer[2] = key + 3;
  copy(challenge.begin(), challenge.end(), buffer + 3);
  span<uint_least8_t> response(buffer, responseSize);
  const error_code result = runCommand(make_span(buffer, requestSize),
                                       generateEcdsaSignatureTimeMs, response);
  if (!result) {
    span<uint_least8_t>::const_iterator begin = response.begin();
    span<uint_least8_t>::const_iterator end = begin + signature.s.size();
    copy(begin, end, signature.s.begin());
    begin = end;
    end = begin + signature.r.size();
    copy(begin, end, signature.r.begin());
  }
  return result;
}

error_code DS28C40::computeAndReadPageAuthentication(int pageNum,
                                                     KeySecret secret,
                                                     Page::const_span challenge,
                                                     Page::span hmac) {
  if (pageNum < 0 || pageNum >= memoryPages) {
    return make_error_code(InvalidParameterError);
  }

  const size_t requestSize = 3 + Page::size;
  const size_t responseSize = 1 + Page::size;
  uint_least8_t buffer[MaximInterfaceCore_MAX(requestSize, responseSize)];
  buffer[0] = computeAndReadPageAuthenticationCmd;
  buffer[1] = pageNum;
  buffer[2] = secret;
  copy(challenge.begin(), challenge.end(), buffer + 3);
  span<uint_least8_t> response(buffer, responseSize);
  const error_code result =
      runCommand(make_span(buffer, requestSize), computeTimeMs, response);
  if (!result) {
    copy(response.begin(), response.end(), hmac.begin());
  }
  return result;
}

error_code DS28C40::computeMultiblockHash(bool firstBlock, bool lastBlock,
                                          span<const uint_least8_t> data) {
  const span<const uint_least8_t>::index_type maxDataSize = 64;

  if (data.size() < 1 || data.size() > maxDataSize) {
    return make_error_code(InvalidParameterError);
  }

  uint_least8_t buffer[2 + maxDataSize];
  buffer[0] = 0x33;
  buffer[1] = 0;
  if (firstBlock) {
    buffer[1] |= 0x40;
  }
  if (lastBlock) {
    buffer[1] |= 0x80;
  }
  copy(data.begin(), data.end(), buffer + 2);
  return runCommand(make_span(buffer, 2 + data.size()), computeTimeMs);
}

error_code DS28C40::verifyEcdsaSignature(
    KeySecret key, bool authorityKey, GpioState gpioState,
    Ecc256::Signature::const_span signature, span<const uint_least8_t> data) {
  return verifyEcdsaSignature(key, authorityKey, DataInput, gpioState,
                              signature, data);
}

error_code DS28C40::verifyEcdsaSignature(
    KeySecret key, bool authorityKey, GpioState gpioState,
    Ecc256::Signature::const_span signature, Page::const_span hash) {
  return verifyEcdsaSignature(key, authorityKey, HashInput, gpioState,
                              signature, hash);
}

error_code
DS28C40::verifyEcdsaSignature(KeySecret key, bool authorityKey,
                              GpioState gpioState,
                              Ecc256::Signature::const_span signature) {
  return verifyEcdsaSignature(key, authorityKey, THASH, gpioState, signature,
                              span<const uint_least8_t>());
}

error_code DS28C40::verifyEcdsaSignature(
    KeySecret key, bool authorityKey, HashType hashType, GpioState gpioState,
    Ecc256::Signature::const_span signature, span<const uint_least8_t> buffer) {
  const span<const uint_least8_t>::index_type maxBufferSize = 61;

  if (buffer.size() > maxBufferSize) {
    return make_error_code(InvalidParameterError);
  }

  uint_least8_t request[2 + 2 * Ecc256::Scalar::size + maxBufferSize];
  uint_least8_t * requestIt = request;
  *requestIt++ = 0x59;
  switch (key) {
  case KeySecretA:
    if (authorityKey) {
      *requestIt = 2;
    } else {
      *requestIt = 0;
    }
    break;
  case KeySecretB:
    if (authorityKey) {
      *requestIt = 3;
    } else {
      *requestIt = 1;
    }
    break;
  case KeySecretS:
    if (!authorityKey) {
      *requestIt = 4;
      break;
    }
    // else: Go to default case.
  default:
    return make_error_code(InvalidParameterError);
  }
  *requestIt |= hashType << 3;
  if (gpioState != Unchanged) {
    *requestIt |= 0x40;
  }
  if (gpioState == Conducting) {
    *requestIt |= 0x20;
  }
  requestIt = copy(signature.r.begin(), signature.r.end(), ++requestIt);
  requestIt = copy(signature.s.begin(), signature.s.end(), requestIt);
  requestIt = copy(buffer.begin(), buffer.end(), requestIt);
  return runCommand(make_span(request, requestIt),
                    verifyEcdsaTimeMs +
                        (hashType == DataInput ? computeTimeMs : 0));
}

error_code DS28C40::authenticateEcdsaPublicKey(
    KeySecret key, Ecc256::Signature::const_span cert,
    span<const uint_least8_t> certCustomization) {
  return authenticateEcdsaPublicKey(key, true, cert, certCustomization, NULL);
}

error_code DS28C40::authenticateEcdsaPublicKey(
    KeySecret key, bool authWrites, Ecc256::Signature::const_span cert,
    span<const uint_least8_t> certCustomization,
    span<const uint_least8_t> ecdhCustomization) {
  return authenticateEcdsaPublicKey(key, authWrites, cert, certCustomization,
                                    &ecdhCustomization);
}

error_code DS28C40::authenticateEcdsaPublicKey(
    KeySecret key, bool authWrites, Ecc256::Signature::const_span cert,
    span<const uint_least8_t> certCustomization,
    const span<const uint_least8_t> * ecdhCustomization) {
  const span<const uint_least8_t>::index_type minCustomizationSize = 1;
  const span<const uint_least8_t>::index_type maxCertCustomizationSize = 32;
  const span<const uint_least8_t>::index_type maxEcdhCustomizationSize = 48;
  const span<const uint_least8_t>::index_type maxTotalCustomizationSize = 60;

  if (!(certCustomization.size() >= minCustomizationSize &&
        certCustomization.size() <= maxCertCustomizationSize &&
        (!ecdhCustomization ||
         (ecdhCustomization->size() >= minCustomizationSize &&
          ecdhCustomization->size() <= maxEcdhCustomizationSize &&
          certCustomization.size() + ecdhCustomization->size() <=
              maxTotalCustomizationSize)))) {
    return make_error_code(InvalidParameterError);
  }

  if (key == KeySecretS) {
    return make_error_code(InvalidParameterError);
  }

  uint_least8_t
      request[2 + 2 * Ecc256::Scalar::size + maxTotalCustomizationSize];
  uint_least8_t * requestIt = request;
  *requestIt++ = 0xA8;
  *requestIt++ = static_cast<uint_least8_t>(
      ((certCustomization.size() - 1) << 3) | (key << 2) |
      ((ecdhCustomization != NULL) << 1) | (authWrites << 0));
  requestIt = copy(cert.r.begin(), cert.r.end(), requestIt);
  requestIt = copy(cert.s.begin(), cert.s.end(), requestIt);
  requestIt =
      copy(certCustomization.begin(), certCustomization.end(), requestIt);
  int delay = verifyEcdsaTimeMs;
  if (ecdhCustomization) {
    const span<const uint_least8_t>::index_type certCustomizationPaddingSize =
        maxCertCustomizationSize - certCustomization.size();
    std::fill_n(requestIt, certCustomizationPaddingSize, 0);
    requestIt += certCustomizationPaddingSize;
    requestIt =
        copy(ecdhCustomization->begin(), ecdhCustomization->end(), requestIt);
    delay += verifyEcdsaTimeMs;
  }
  return runCommand(make_span(request, requestIt), delay);
}

error_code DS28C40::authenticatedEcdsaWriteMemory(
    int pageNum, bool useKeyS, Page::const_span newPageData,
    Ecc256::Signature::const_span signature) {
  return authenticatedEcdsaWriteMemory(pageNum, useKeyS, newPageData, signature,
                                       NULL);
}

error_code DS28C40::authenticatedEcdsaWriteMemory(
    int pageNum, bool useKeyS, Page::const_span newPageData,
    Ecc256::Signature::const_span signature,
    EncryptionChallenge::const_span challenge) {
  return authenticatedEcdsaWriteMemory(pageNum, useKeyS, newPageData, signature,
                                       &challenge);
}

error_code DS28C40::authenticatedEcdsaWriteMemory(
    int pageNum, bool useKeyS, Page::const_span newPageData,
    Ecc256::Signature::const_span signature,
    const EncryptionChallenge::const_span * challenge) {
  if (pageNum < 0 || pageNum >= memoryPages) {
    return make_error_code(InvalidParameterError);
  }

  uint_least8_t request[2 + Page::size + 2 * Ecc256::Scalar::size +
                        EncryptionChallenge::size];
  uint_least8_t * requestIt = request;
  *requestIt++ = 0x89;
  *requestIt = pageNum;
  if (useKeyS) {
    *requestIt |= 0x80;
  }
  requestIt = copy(newPageData.begin(), newPageData.end(), ++requestIt);
  requestIt = copy(signature.r.begin(), signature.r.end(), requestIt);
  requestIt = copy(signature.s.begin(), signature.s.end(), requestIt);
  int delay = verifyEcdsaTimeMs + writeMemoryTimeMs;
  if (challenge) {
    requestIt = copy(challenge->begin(), challenge->end(), requestIt);
    delay += computeTimeMs;
  }
  return runCommand(make_span(request, requestIt), delay);
}

error_code DS28C40::authenticatedSha256WriteMemory(int pageNum, bool useSecretS,
                                                   Page::const_span newPageData,
                                                   Page::const_span hmac) {
  return authenticatedSha256WriteMemory(pageNum, useSecretS, newPageData, hmac,
                                        NULL);
}

error_code DS28C40::authenticatedSha256WriteMemory(
    int pageNum, bool useSecretS, Page::const_span newPageData,
    Page::const_span hmac, EncryptionChallenge::const_span challenge) {
  return authenticatedSha256WriteMemory(pageNum, useSecretS, newPageData, hmac,
                                        &challenge);
}

error_code DS28C40::authenticatedSha256WriteMemory(
    int pageNum, bool useSecretS, Page::const_span newPageData,
    Page::const_span hmac, const EncryptionChallenge::const_span * challenge) {
  if (pageNum < 0 || pageNum >= memoryPages) {
    return make_error_code(InvalidParameterError);
  }

  uint_least8_t request[3 + 2 * Page::size + EncryptionChallenge::size];
  uint_least8_t * requestIt = request;
  *requestIt++ = 0x99;
  *requestIt++ = pageNum;
  *requestIt++ = useSecretS ? 2 : 0;
  requestIt = copy(newPageData.begin(), newPageData.end(), requestIt);
  requestIt = copy(hmac.begin(), hmac.end(), requestIt);
  int delay = writeMemoryTimeMs + computeTimeMs;
  if (challenge) {
    requestIt = copy(challenge->begin(), challenge->end(), requestIt);
    delay += computeTimeMs;
  }
  return runCommand(make_span(request, requestIt), delay);
}

error_code
DS28C40::computeAndWriteSha256Secret(int pageNum, KeySecret masterSecret,
                                     KeySecret destinationSecret,
                                     Page::const_span partialSecret) {
  if (pageNum < 0 || pageNum >= memoryPages) {
    return make_error_code(InvalidParameterError);
  }

  uint_least8_t request[3 + Page::size];
  request[0] = 0x3C;
  request[1] = pageNum;
  request[2] = (destinationSecret << 2) | masterSecret;
  copy(partialSecret.begin(), partialSecret.end(), request + 3);
  return runCommand(request, writeMemoryTimeMs + computeTimeMs);
}

error_code DS28C40::generateEcc256KeyPair(KeySecret key) {
  if (key == KeySecretS) {
    return make_error_code(InvalidParameterError);
  }

  const uint_least8_t request[] = {0xCB, key == KeySecretB};
  return runCommand(request, generateEccKeyPairTimeMs);
}

error_code DS28C40::readRng(span<uint_least8_t> data) {
  const span<uint_least8_t>::index_type maxDataSize = 64;
  if ((data.size() < 1) || (data.size() > maxDataSize)) {
    return make_error_code(InvalidParameterError);
  }

  uint_least8_t buffer[1 + maxDataSize];
  buffer[0] = readRngCmd;
  buffer[1] = static_cast<uint_least8_t>(data.size() - 1);
  span<uint_least8_t> response(buffer, 1 + data.size());
  const error_code result =
      runCommand(make_span(buffer, 2), trngGenerationTimeMs, response);
  if (!result) {
    copy(response.begin(), response.end(), data.begin());
  }
  return result;
}

error_code DS28C40::entropyHealthTest() {
  const uint_least8_t request[] = {readRngCmd, 0x80};
  return runCommand(request, trngOnDemandCheckTimeMs);
}

error_code DS28C40::runCommand(span<const uint_least8_t> request, int delayTime,
                               span<uint_least8_t> & response) {
  const span<const uint_least8_t>::index_type responseInputSize =
      response.size();
  error_code result = doRunCommand(request, delayTime, response);
  if (result) {
    return result;
  }
  if (response.empty()) {
    return make_error_code(InvalidResponseError);
  }
  // Parse command result byte.
  switch (response[0]) {
  case 0xAA:
    // Success response.
    if (response.size() != responseInputSize) {
      result = make_error_code(InvalidResponseError);
    }
    break;

  case 0x00:
    result = make_error_code(AuthenticationError);
    break;

  default:
    result.assign(response[0], errorCategory());
    break;
  }
  response = response.subspan(1);
  return result;
}

error_code DS28C40::runCommand(span<const uint_least8_t> request,
                               int delayTime) {
  uint_least8_t buffer;
  span<uint_least8_t> response(&buffer, 1);
  return runCommand(request, delayTime, response);
}

const error_category & DS28C40::errorCategory() {
  static class : public error_category {
  public:
    virtual const char * name() const { return "DS28C40"; }

    virtual std::string message(int condition) const {
      switch (condition) {
      case InvalidOperationError:
        return "Invalid Operation Error";

      case InvalidParameterError:
        return "Invalid Parameter Error";

      case InvalidSequenceError:
        return "Invalid Sequence Error";

      case AuthenticationError:
        return "Authentication Error";

      case InternalError:
        return "Internal Error";

      case DeviceDisabledError:
        return "Device Disabled Error";

      case InvalidResponseError:
        return "Invalid Response Error";
      }
      return defaultErrorMessage(condition);
    }
  } instance;
  return instance;
}

error_code computeMultiblockHash(DS28C40 & device,
                                 span<const uint_least8_t> data) {
  error_code result;
  span<const uint_least8_t>::index_type dataIdx = 0;
  while (dataIdx < data.size() && !result) {
    const span<const uint_least8_t>::index_type remainingSize =
        data.size() - dataIdx;
    const span<const uint_least8_t>::index_type chunkSize =
        std::min<span<const uint_least8_t>::index_type>(remainingSize, 64);
    result =
        device.computeMultiblockHash(dataIdx == 0, remainingSize == chunkSize,
                                     data.subspan(dataIdx, chunkSize));
    dataIdx += chunkSize;
  }
  return result;
}

error_code readRomIdAndManId(DS28C40 & device, RomId::span romId,
                             ManId::span manId) {
  DS28C40::Page::array page;
  error_code result = device.readMemory(DS28C40::romOptionsPage, page);
  if (!result) {
    const DS28C40::RomOptions romOptions(page);
    copy(romOptions.romId(), romId);
    copy(romOptions.manId(), manId);
  }
  return result;
}

static void setAnonymous(RomId::span romId) {
  std::fill(romId.begin(), romId.end(), 0xFF);
}

DS28C40::PageAuthenticationData &
DS28C40::PageAuthenticationData::setAnonymousRomId() {
  setAnonymous(romId());
  return *this;
}

DS28C40::ComputeSecretData::ComputeSecretData() : data() {
  setPageNum(0);
  setManId(ManId::array());
}

DS28C40::ComputeSecretData &
DS28C40::ComputeSecretData::setManId(ManId::const_span manId) {
  ManId::array validatedManId;
  copy(manId, make_span(validatedManId));
  validatedManId[1] |= 0x80;
  data.setManId(validatedManId);
  return *this;
}

DS28C40::DecryptionHmacData & DS28C40::DecryptionHmacData::setAnonymousRomId() {
  setAnonymous(romId());
  return *this;
}

} // namespace MaximInterfaceDevices