text: // Copyright (c) 2019, The Monero Project
  //
  // All rights reserved.
  //
  // Redistribution and use in source and binary forms, with or without modification, are
  // permitted provided that the following conditions are met:
  //
  // 1. Redistributions of source code must retain the above copyright notice, this list of
  //    conditions and the following disclaimer.
  //
  // 2. Redistributions in binary form must reproduce the above copyright notice, this list
  //    of conditions and the following disclaimer in the documentation and/or other
  //    materials provided with the distribution.
  //
  // 3. Neither the name of the copyright holder nor the names of its contributors may be
  //    used to endorse or promote products derived from this software without specific
  //    prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
  // EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
  // THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  // STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
  // THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  #include "message_store.h"
  #include <boost/archive/portable_binary_oarchive.hpp>
  #include <boost/archive/portable_binary_iarchive.hpp>
  #include <boost/format.hpp>
  #include <boost/algorithm/string.hpp>
  #include <fstream>
  #include <sstream>
  #include "wallet_errors.h"
  #include "serialization/binary_utils.h"
  #include "common/base58.h"
  #include "common/util.h"
  #include "common/file.h"
  #include "epee/string_tools.h"
  
  
  #undef ITALO_DEFAULT_LOG_CATEGORY
  #define ITALO_DEFAULT_LOG_CATEGORY "wallet.mms"
  
  namespace mms
  {
  
  message_store::message_store()
  {
    m_active = false;
    m_auto_send = false;
    m_next_message_id = 1;
    m_num_authorized_signers = 0;
    m_num_required_signers = 0;
    m_nettype = cryptonote::network_type::UNDEFINED;
    m_run = true;
  }
  
  namespace
  {
    // MMS options handling mirrors what "wallet2" is doing for its options, on-demand init and all
    // It's not very clean to initialize Bitmessage-specific options here, but going one level further
    // down still into "message_transporter" for that is a little bit too much
    struct options
    {
      const command_line::arg_descriptor<std::string> bitmessage_address = {"bitmessage-address", mms::message_store::tr("Use PyBitmessage instance at URL <arg>"), "http://localhost:8442/"};
      const command_line::arg_descriptor<std::string> bitmessage_login = {"bitmessage-login", mms::message_store::tr("Specify <arg> as username:password for PyBitmessage API"), "username:password"};
    };
  }
  
  void message_store::init_options(boost::program_options::options_description& desc_params)
  {
    const options opts{};
    command_line::add_arg(desc_params, opts.bitmessage_address);
    command_line::add_arg(desc_params, opts.bitmessage_login);
  }
  
  void message_store::init(const multisig_wallet_state &state, const std::string &own_label,
                           const std::string &own_transport_address, uint32_t num_authorized_signers, uint32_t num_required_signers)
  {
    m_num_authorized_signers = num_authorized_signers;
    m_num_required_signers = num_required_signers;
    m_signers.clear();
    m_messages.clear();
    m_next_message_id = 1;
  
    // The vector "m_signers" gets here once the required number of elements, one for each authorized signer,
    // and is never changed again. The rest of the code relies on "size(m_signers) == m_num_authorized_signers"
    // without further checks.
    authorized_signer signer;
    for (uint32_t i = 0; i < m_num_authorized_signers; ++i)
    {
      signer.me = signer.index == 0;    // Strict convention: The very first signer is fixed as / must be "me"
      m_signers.push_back(signer);
      signer.index++;
    }
  
    set_signer(state, 0, own_label, own_transport_address, state.address);
  
    m_nettype = state.nettype;
    set_active(true);
    m_filename = state.mms_file;
    save(state);
  }
  
  void message_store::set_options(const boost::program_options::variables_map& vm)
  {
    const options opts{};
    std::string bitmessage_address = command_line::get_arg(vm, opts.bitmessage_address);
    epee::wipeable_string bitmessage_login = command_line::get_arg(vm, opts.bitmessage_login);
    set_options(bitmessage_address, bitmessage_login);
  }
  
  void message_store::set_options(const std::string &bitmessage_address, const epee::wipeable_string &bitmessage_login)
  {
    m_transporter.set_options(bitmessage_address, bitmessage_login);
  }
  
  void message_store::set_signer(const multisig_wallet_state &state,
                                 uint32_t index,
                                 const std::optional<std::string> &label,
                                 const std::optional<std::string> &transport_address,
                                 const std::optional<cryptonote::account_public_address> monero_address)
  {
    THROW_WALLET_EXCEPTION_IF(index >= m_num_authorized_signers, tools::error::wallet_internal_error, "Invalid signer index " + std::to_string(index));
    authorized_signer &m = m_signers[index];
    if (label)
    {
      m.label = *label;
    }
    if (transport_address)
    {
      m.transport_address = *transport_address;
    }
    if (monero_address)
    {
      m.monero_address_known = true;
      m.monero_address = *monero_address;
    }
    // Save to minimize the chance to loose that info (at least while in beta)
    save(state);
  }
  
  const authorized_signer &message_store::get_signer(uint32_t index) const
  {
    THROW_WALLET_EXCEPTION_IF(index >= m_num_authorized_signers, tools::error::wallet_internal_error, "Invalid signer index " + std::to_string(index));
    return m_signers[index];
  }
  
  bool message_store::signer_config_complete() const
  {
    for (uint32_t i = 0; i < m_num_authorized_signers; ++i)
    {
      const authorized_signer &m = m_signers[i];
      if (m.label.empty() || m.transport_address.empty() || !m.monero_address_known)
      {
        return false;
      }
    }
    return true;
  }
  
  // Check if all signers have a label set (as it's a requirement for starting auto-config
  // by the "manager")
  bool message_store::signer_labels_complete() const
  {
    for (uint32_t i = 0; i < m_num_authorized_signers; ++i)
    {
      const authorized_signer &m = m_signers[i];
      if (m.label.empty())
      {
        return false;
      }
    }
    return true;
  }
  
  void message_store::get_signer_config(std::string &signer_config)
  {
    std::stringstream oss;
    boost::archive::portable_binary_oarchive ar(oss);
    ar << m_signers;
    signer_config = oss.str();
  }
  
  void message_store::unpack_signer_config(const multisig_wallet_state &state, const std::string &signer_config,
                                           std::vector<authorized_signer> &signers)
  {
    try
    {
      std::stringstream iss;
      iss << signer_config;
      boost::archive::portable_binary_iarchive ar(iss);
      ar >> signers;
    }
    catch (...)
    {
      THROW_WALLET_EXCEPTION_IF(true, tools::error::wallet_internal_error, "Invalid structure of signer config");
    }
    uint32_t num_signers = (uint32_t)signers.size();
    THROW_WALLET_EXCEPTION_IF(num_signers != m_num_authorized_signers, tools::error::wallet_internal_error, "Wrong number of signers in config: " + std::to_string(num_signers));
  }
  
  void message_store::process_signer_config(const multisig_wallet_state &state, const std::string &signer_config)
  {
    // The signers in "signer_config" and the resident wallet signers are matched not by label, but
    // by Monero address, and ALL labels will be set from "signer_config", even the "me" label.
    // In the auto-config process as implemented now the auto-config manager is responsible for defining
    // the labels, and right at the end of the process ALL wallets use the SAME labels. The idea behind this
    // is preventing problems like duplicate labels and confusion (Bob choosing a label "IamAliceHonest").
    // (Of course signers are free to re-define any labels they don't like AFTER auto-config.)
    //
    // Usually this method will be called with only the "me" signer defined in the wallet, and may
    // produce unexpected behaviour if that wallet contains additional signers that have nothing to do with
    // those arriving in "signer_config".
    std::vector<authorized_signer> signers;
    unpack_signer_config(state, signer_config, signers);
    
    uint32_t new_index = 1;
    for (uint32_t i = 0; i < m_num_authorized_signers; ++i)
    {
      const authorized_signer &m = signers[i];
      uint32_t index;
      uint32_t take_index;
      bool found = get_signer_index_by_monero_address(m.monero_address, index);
      if (found)
      {
        // Redefine existing (probably "me", under usual circumstances)
        take_index = index;
      }
      else
      {
        // Add new; neglect that we may erroneously overwrite already defined signers
        // (but protect "me")
        take_index = new_index;
        if ((new_index + 1) < m_num_authorized_signers)
        {
          new_index++;
        }
      }
      authorized_signer &modify = m_signers[take_index];
      modify.label = m.label;  // ALWAYS set label, see comments above
      if (!modify.me)
      {
        modify.transport_address = m.transport_address;
        modify.monero_address_known = m.monero_address_known;
        if (m.monero_address_known)
        {
          modify.monero_address = m.monero_address;
        }
      }
    }
    save(state);
  }
  
  void message_store::start_auto_config(const multisig_wallet_state &state)
  {
    for (uint32_t i = 0; i < m_num_authorized_signers; ++i)
    {
      authorized_signer &m = m_signers[i];
      if (!m.me)
      {
        setup_signer_for_auto_config(i, create_auto_config_token(), true);
      }
      m.auto_config_running = true;
    }
    save(state);
  }
  
  // Check auto-config token string and convert to standardized form;
  // Try to make it as foolproof as possible, with built-in tolerance to make up for
  // errors in transmission that still leave the token recognizable.
  bool message_store::check_auto_config_token(const std::string &raw_token,
                                              std::string &adjusted_token) const
  {
    std::string prefix(AUTO_CONFIG_TOKEN_PREFIX);
    uint32_t num_hex_digits = (AUTO_CONFIG_TOKEN_BYTES + 1) * 2;
    uint32_t full_length = num_hex_digits + prefix.length();
    uint32_t raw_length = raw_token.length();
    std::string hex_digits;
  
    if (raw_length == full_length)
    {
      // Prefix must be there; accept it in any casing
      std::string raw_prefix(raw_token.substr(0, 3));
      boost::algorithm::to_lower(raw_prefix);
      if (raw_prefix != prefix)
      {
        return false;
      }
      hex_digits = raw_token.substr(3);
    }
    else if (raw_length == num_hex_digits)
    {
      // Accept the token without the prefix if it's otherwise ok
      hex_digits = raw_token;
    }
    else
    {
      return false;
    }
  
    // Convert to strict lowercase and correct any common misspellings
    boost::algorithm::to_lower(hex_digits);
    std::replace(hex_digits.begin(), hex_digits.end(), 'o', '0');
    std::replace(hex_digits.begin(), hex_digits.end(), 'i', '1');
    std::replace(hex_digits.begin(), hex_digits.end(), 'l', '1');
  
    // Now it must be correct hex with correct checksum, no further tolerance possible
    std::string token_bytes;
    if (!epee::string_tools::parse_hexstr_to_binbuff(hex_digits, token_bytes))
    {
      return false;
    }
    const crypto::hash &hash = crypto::cn_fast_hash(token_bytes.data(), token_bytes.size() - 1);
    if (token_bytes[AUTO_CONFIG_TOKEN_BYTES] != hash.data[0])
    {
      return false;
    }
    adjusted_token = prefix + hex_digits;
    return true;
  }
  
  // Create a new auto-config token with prefix, random 8-hex digits plus 2 checksum digits
  std::string message_store::create_auto_config_token()
  {
    unsigned char random[AUTO_CONFIG_TOKEN_BYTES];
    crypto::rand(AUTO_CONFIG_TOKEN_BYTES, random);
    std::string token_bytes;
    token_bytes.append((char *)random, AUTO_CONFIG_TOKEN_BYTES);
  
    // Add a checksum because technically ANY four bytes are a valid token, and without a checksum we would send
    // auto-config messages "to nowhere" after the slightest typo without knowing it
    const crypto::hash &hash = crypto::cn_fast_hash(token_bytes.data(), token_bytes.size());
    token_bytes += hash.data[0];
    std::string prefix(AUTO_CONFIG_TOKEN_PREFIX);
    return prefix + italomq::to_hex(token_bytes);
  }
  
  // Add a message for sending "me" address data to the auto-config transport address
  // that can be derived from the token and activate auto-config
  size_t message_store::add_auto_config_data_message(const multisig_wallet_state &state,
                                                     const std::string &auto_config_token)
  {
    authorized_signer &me = m_signers[0];
    me.auto_config_token = auto_config_token;
    setup_signer_for_auto_config(0, auto_config_token, false);
    me.auto_config_running = true;
  
    auto_config_data data;
    data.label = me.label;
    data.transport_address = me.transport_address;
    data.monero_address = me.monero_address;
  
    std::stringstream oss;
    boost::archive::portable_binary_oarchive ar(oss);
    ar << data;
  
    return add_message(state, 0, message_type::auto_config_data, message_direction::out, oss.str());
  }
  
  // Process a single message with auto-config data, destined for "message.signer_index"
  void message_store::process_auto_config_data_message(uint32_t id)
  {
    // "auto_config_data" contains the label that the auto-config data sender uses for "me", but that's
    // more for completeness' sake, and right now it's not used. In general, the auto-config manager
    // decides/defines the labels, and right after completing auto-config ALL wallets use the SAME labels.
  
    const message &m = get_message_ref_by_id(id);
  
    auto_config_data data;
    try
    {
      std::stringstream iss;
      iss << m.content;
      boost::archive::portable_binary_iarchive ar(iss);
      ar >> data;
    }
    catch (...)
    {
      THROW_WALLET_EXCEPTION_IF(true, tools::error::wallet_internal_error, "Invalid structure of auto config data");
    }
  
    authorized_signer &signer = m_signers[m.signer_index];
    // "signer.label" does NOT change, see comment above
    signer.transport_address = data.transport_address;
    signer.monero_address_known = true;
    signer.monero_address = data.monero_address;
    signer.auto_config_running = false;
  }
  
  void message_store::stop_auto_config()
  {
    for (uint32_t i = 0; i < m_num_authorized_signers; ++i)
    {
      authorized_signer &m = m_signers[i];
      if (!m.auto_config_transport_address.empty())
      {
        // Try to delete the chan that was used for auto-config
        m_transporter.delete_transport_address(m.auto_config_transport_address);
      }
      m.auto_config_token.clear();
      m.auto_config_public_key = crypto::null_pkey;
      m.auto_config_secret_key = crypto::null_skey;
      m.auto_config_transport_address.clear();
      m.auto_config_running = false;
    }  
  }
  
  void message_store::setup_signer_for_auto_config(uint32_t index, const std::string token, bool receiving)
  {
    // It may be a little strange to hash the textual hex digits of the auto config token into
    // 32 bytes and turn that into a Monero public/secret key pair, instead of doing something
    // much less complicated like directly using the underlying random 40 bits as key for a
    // symmetric cipher, but everything is there already for encrypting and decrypting messages
    // with such key pairs, and furthermore it would be trivial to use tokens with a different
    // number of bytes.
    //
    // In the wallet of the auto-config manager each signer except "me" gets set its own
    // auto-config parameters. In the wallet of somebody using the token to send auto-config
    // data the auto-config parameters are stored in the "me" signer and taken from there
    // to send that data.
    THROW_WALLET_EXCEPTION_IF(index >= m_num_authorized_signers, tools::error::wallet_internal_error, "Invalid signer index " + std::to_string(index));
    authorized_signer &m = m_signers[index];
    m.auto_config_token = token;
    crypto::hash_to_scalar(token.data(), token.size(), m.auto_config_secret_key);
    crypto::secret_key_to_public_key(m.auto_config_secret_key, m.auto_config_public_key);
    m.auto_config_transport_address = m_transporter.derive_transport_address(m.auto_config_token);
  }
  
  bool message_store::get_signer_index_by_monero_address(const cryptonote::account_public_address &monero_address, uint32_t &index) const
  {
    for (uint32_t i = 0; i < m_num_authorized_signers; ++i)
    {
      const authorized_signer &m = m_signers[i];
      if (m.monero_address == monero_address)
      {
        index = m.index;
        return true;
      }
    }
    MWARNING("No authorized signer with Monero address " << account_address_to_string(monero_address));
    return false;
  }
  
  bool message_store::get_signer_index_by_label(const std::string label, uint32_t &index) const
  {
    for (uint32_t i = 0; i < m_num_authorized_signers; ++i)
    {
      const authorized_signer &m = m_signers[i];
      if (m.label == label)
      {
        index = m.index;
        return true;
      }
    }
    MWARNING("No authorized signer with label " << label);
    return false;
  }
  
  void message_store::process_wallet_created_data(const multisig_wallet_state &state, message_type type, const std::string &content)
  {
    switch(type)
    {
    case message_type::key_set:
      // Result of a "prepare_multisig" command in the wallet
      // Send the key set to all other signers
    case message_type::additional_key_set:
      // Result of a "make_multisig" command or a "exchange_multisig_keys" in the wallet in case of M/N multisig
      // Send the additional key set to all other signers
    case message_type::multisig_sync_data:
      // Result of a "export_multisig_info" command in the wallet
      // Send the sync data to all other signers
      for (uint32_t i = 1; i < m_num_authorized_signers; ++i)
      {
        add_message(state, i, type, message_direction::out, content);
      }
      break;
  
    case message_type::partially_signed_tx:
      // Result of a "transfer" command in the wallet, or a "sign_multisig" command
      // that did not yet result in the minimum number of signatures required
      // Create a message "from me to me" as a container for the tx data
      if (m_num_required_signers == 1)
      {
        // Probably rare, but possible: The 1 signature is already enough, correct the type
        // Easier to correct here than asking all callers to detect this rare special case
        type = message_type::fully_signed_tx;
      }
      add_message(state, 0, type, message_direction::in, content);
      break;
  
    case message_type::fully_signed_tx:
      add_message(state, 0, type, message_direction::in, content);
      break;
  
    default:
      THROW_WALLET_EXCEPTION(tools::error::wallet_internal_error, "Illegal message type " + std::to_string((uint32_t)type));
      break;
    }
  }
  
  size_t message_store::add_message(const multisig_wallet_state &state,
                                    uint32_t signer_index, message_type type, message_direction direction,
                                    const std::string &content)
  {
    message m;
    m.id = m_next_message_id++;
    m.type = type;
    m.direction = direction;
    m.content = content;
    m.created = (uint64_t)time(NULL);
    m.modified = m.created;
    m.sent = 0;
    m.signer_index = signer_index;
    if (direction == message_direction::out)
    {
      m.state = message_state::ready_to_send;
    }
    else
    {
      m.state = message_state::waiting;
    };
    m.wallet_height = (uint32_t)state.num_transfer_details;
    if (m.type == message_type::additional_key_set)
    {
      m.round = state.multisig_rounds_passed;
    }
    else
    {
      m.round = 0;
    }
    m.signature_count = 0;  // Future expansion for signature counting when signing txs
    m.hash = crypto::null_hash;
    m_messages.push_back(m);
  
    // Save for every new message right away (at least while in beta)
    save(state);
  
    MINFO(boost::format("Added %s message %s for signer %s of type %s")
            % message_direction_to_string(direction) % m.id % signer_index % message_type_to_string(type));
    return m_messages.size() - 1;
  }
  
  // Get the index of the message with id "id", return false if not found
  bool message_store::get_message_index_by_id(uint32_t id, size_t &index) const
  {
    for (size_t i = 0; i < m_messages.size(); ++i)
    {
      if (m_messages[i].id == id)
      {
        index = i;
        return true;
      }
    }
    MWARNING("No message found with an id of " << id);
    return false;
  }
  
  // Get the index of the message with id "id" that must exist
  size_t message_store::get_message_index_by_id(uint32_t id) const
  {
    size_t index;
    bool found = get_message_index_by_id(id, index);
    THROW_WALLET_EXCEPTION_IF(!found, tools::error::wallet_internal_error, "Invalid message id " + std::to_string(id));
    return index;
  }
  
  // Get the modifiable message with id "id" that must exist; private/internal use!
  message& message_store::get_message_ref_by_id(uint32_t id)
  {
    return m_messages[get_message_index_by_id(id)];
  }
  
  // Get the message with id "id", return false if not found
  // This version of the method allows to check whether id is valid without triggering an error
  bool message_store::get_message_by_id(uint32_t id, message &m) const
  {
    size_t index;
    bool found = get_message_index_by_id(id, index);
    if (found)
    {
      m = m_messages[index];
    }
    return found;
  }
  
  // Get the message with id "id" that must exist
  message message_store::get_message_by_id(uint32_t id) const
  {
    message m;
    bool found = get_message_by_id(id, m);
    THROW_WALLET_EXCEPTION_IF(!found, tools::error::wallet_internal_error, "Invalid message id " + std::to_string(id));
    return m;
  }
  
  bool message_store::any_message_of_type(message_type type, message_direction direction) const
  {
    for (size_t i = 0; i < m_messages.size(); ++i)
    {
      if ((m_messages[i].type == type) && (m_messages[i].direction == direction))
      {
        return true;
      }
    }
    return false;
  }
  
  bool message_store::any_message_with_hash(const crypto::hash &hash) const
  {
    for (size_t i = 0; i < m_messages.size(); ++i)
    {
      if (m_messages[i].hash == hash)
      {
        return true;
      }
    }
    return false;
  }
  
  // Count the ids in the vector that are set i.e. not 0, while ignoring index 0
  // Mostly used to check whether we have a message for each authorized signer except me,
  // with the signer index used as index into 'ids'; the element at index 0, for me,
  // is ignored, to make constant subtractions of 1 for indices when filling the
  // vector unnecessary
  size_t message_store::get_other_signers_id_count(const std::vector<uint32_t> &ids) const
  {
    size_t count = 0;
    for (size_t i = 1 /* and not 0 */; i < ids.size(); ++i)
    {
      if (ids[i] != 0)
      {
        count++;
      }
    }
    return count;
  }
  
  // Is in every element of vector 'ids' (except at index 0) a message id i.e. not 0?
  bool message_store::message_ids_complete(const std::vector<uint32_t> &ids) const
  {
    return get_other_signers_id_count(ids) == (ids.size() - 1);
  }
  
  void message_store::delete_message(uint32_t id)
  {
    delete_transport_message(id);
    size_t index = get_message_index_by_id(id);
    m_messages.erase(m_messages.begin() + index);
  }
  
  void message_store::delete_all_messages()
  {
    for (size_t i = 0; i < m_messages.size(); ++i)
    {
      delete_transport_message(m_messages[i].id);
    }
    m_messages.clear();
  }
  
  // Make a message text, which is "attacker controlled data", reasonably safe to display
  // This is mostly geared towards the safe display of notes sent by "mms note" with a "mms show" command
  void message_store::get_sanitized_message_text(const message &m, std::string &sanitized_text) const
  {
    sanitized_text.clear();
  
    // Restrict the size to fend of DOS-style attacks with heaps of data
    size_t length = std::min(m.content.length(), (size_t)1000);
  
    for (size_t i = 0; i < length; ++i)
    {
      char c = m.content[i];
      if ((int)c < 32)
      {
        // Strip out any controls, especially ESC for getting rid of potentially dangerous
        // ANSI escape sequences that a console window might interpret
        c = ' ';
      }
      else if ((c == '<') || (c == '>'))
      {
        // Make XML or HTML impossible that e.g. might contain scripts that Qt might execute
        // when displayed in the GUI wallet
        c = ' ';
      }
      sanitized_text += c;
    }
  }
  
  void message_store::write_to_file(const multisig_wallet_state &state, const fs::path &filename)
  {
    std::stringstream oss;
    boost::archive::portable_binary_oarchive ar(oss);
    ar << *this;
    std::string buf = oss.str();
  
    crypto::chacha_key key;
    crypto::generate_chacha_key(&state.view_secret_key, sizeof(crypto::secret_key), key, 1);
  
    file_data write_file_data{};
    write_file_data.magic_string = "MMS";
    write_file_data.file_version = 0;
    write_file_data.iv = crypto::rand<crypto::chacha_iv>();
    std::string encrypted_data;
    encrypted_data.resize(buf.size());
    crypto::chacha20(buf.data(), buf.size(), key, write_file_data.iv, &encrypted_data[0]);
    write_file_data.encrypted_data = encrypted_data;
  
    std::stringstream file_oss;
    boost::archive::portable_binary_oarchive file_ar(file_oss);
    file_ar << write_file_data;
  
    bool success = tools::dump_file(filename, file_oss.str());
    THROW_WALLET_EXCEPTION_IF(!success, tools::error::file_save_error, filename);
  }
  
  void message_store::read_from_file(const multisig_wallet_state &state, const fs::path &filename)
  {
    if (std::error_code ec; !fs::exists(filename, ec))
    {
      // Simply do nothing if the file is not there; allows e.g. easy recovery
      // from problems with the MMS by deleting the file
      MINFO("No message store file found: " << filename);
      return;
    }
  
    std::string buf;
    bool success = tools::slurp_file(filename, buf);
    THROW_WALLET_EXCEPTION_IF(!success, tools::error::file_read_error, filename);
  
    file_data read_file_data;
    try
    {
      std::stringstream iss;
      iss << buf;
      boost::archive::portable_binary_iarchive ar(iss);
      ar >> read_file_data;
    }
    catch (const std::exception &e)
    {
      MERROR("MMS file " << filename << " has bad structure <iv,encrypted_data>: " << e.what());
      THROW_WALLET_EXCEPTION_IF(true, tools::error::file_read_error, filename);
    }
  
    crypto::chacha_key key;
    crypto::generate_chacha_key(&state.view_secret_key, sizeof(crypto::secret_key), key, 1);
    std::string decrypted_data;
    decrypted_data.resize(read_file_data.encrypted_data.size());
    crypto::chacha20(read_file_data.encrypted_data.data(), read_file_data.encrypted_data.size(), key, read_file_data.iv, &decrypted_data[0]);
  
    try
    {
      std::stringstream iss;
      iss << decrypted_data;
      boost::archive::portable_binary_iarchive ar(iss);
      ar >> *this;
    }
    catch (const std::exception &e)
    {
      MERROR("MMS file " << filename << " has bad structure: " << e.what());
      THROW_WALLET_EXCEPTION_IF(true, tools::error::file_read_error, filename);
    }
  
    m_filename = filename;
  }
  
  // Save to the same file this message store was loaded from
  // Called after changes deemed "important", to make it less probable to lose messages in case of
  // a crash; a better and long-term solution would of course be to use LMDB ...
  void message_store::save(const multisig_wallet_state &state)
  {
    if (!m_filename.empty())
    {
      write_to_file(state, m_filename);
    }
  }
  
  bool message_store::get_processable_messages(const multisig_wallet_state &state,
                                               bool force_sync, std::vector<processing_data> &data_list, std::string &wait_reason)
  {
    uint32_t wallet_height = (uint32_t)state.num_transfer_details;
    data_list.clear();
    wait_reason.clear();
    // In all scans over all messages looking for complete sets (1 message for each signer),
    // if there are duplicates, the OLDEST of them is taken. This may not play a role with
    // any of the current message types, but may with future ones, and it's probably a good
    // idea to have a clear and somewhat defensive strategy.
  
    std::vector<uint32_t> auto_config_messages(m_num_authorized_signers, 0);
    bool any_auto_config = false;
  
    for (size_t i = 0; i < m_messages.size(); ++i)
    {
      message &m = m_messages[i];
      if ((m.type == message_type::auto_config_data) && (m.state == message_state::waiting))
      {
        if (auto_config_messages[m.signer_index] == 0)
        {
          auto_config_messages[m.signer_index] = m.id;
          any_auto_config = true;
        }
        // else duplicate auto config data, ignore
      }
    }
  
    if (any_auto_config)
    {
      bool auto_config_complete = message_ids_complete(auto_config_messages);
      if (auto_config_complete)
      {
        processing_data data;
        data.processing = message_processing::process_auto_config_data;
        data.message_ids = auto_config_messages;
        data.message_ids.erase(data.message_ids.begin());
        data_list.push_back(data);
        return true;
      }
      else
      {
        wait_reason = tr("Auto-config cannot proceed because auto config data from other signers is not complete");
        return false;
        // With ANY auto config data present but not complete refuse to check for any
        // other processing. Manually delete those messages to abort such an auto config
        // phase if needed.
      }
    }
  
    // Any signer config that arrived will be processed right away, regardless of other things that may wait
    for (size_t i = 0; i < m_messages.size(); ++i)
    {
      message &m = m_messages[i];
      if ((m.type == message_type::signer_config) && (m.state == message_state::waiting))
      {
        processing_data data;
        data.processing = message_processing::process_signer_config;
        data.message_ids.push_back(m.id);
        data_list.push_back(data);
        return true;
      }
    }
  
    // ALL of the following processings depend on the signer info being complete
    if (!signer_config_complete())
    {
      wait_reason = tr("The signer config is not complete.");
      return false;
    }
  
    if (!state.multisig)
    {
      
      if (!any_message_of_type(message_type::key_set, message_direction::out))
      {
        // With the own key set not yet ready we must do "prepare_multisig" first;
        // Key sets from other signers may be here already, but if we process them now
        // the wallet will go multisig too early: we can't produce our own key set any more!
        processing_data data;
        data.processing = message_processing::prepare_multisig;
        data_list.push_back(data);
        return true;
      }
  
      // Ids of key set messages per signer index, to check completeness
      // Naturally, does not care about the order of the messages and is trivial to secure against
      // key sets that were received more than once
      // With full M/N multisig now possible consider only key sets of the right round, i.e.
      // with not yet multisig the only possible round 0
      std::vector<uint32_t> key_set_messages(m_num_authorized_signers, 0);
  
      for (size_t i = 0; i < m_messages.size(); ++i)
      {
        message &m = m_messages[i];
        if ((m.type == message_type::key_set) && (m.state == message_state::waiting)
            && (m.round == 0))
        {
          if (key_set_messages[m.signer_index] == 0)
          {
            key_set_messages[m.signer_index] = m.id;
          }
          // else duplicate key set, ignore
        }
      }
  
      bool key_sets_complete = message_ids_complete(key_set_messages);
      if (key_sets_complete)
      {
        // Nothing else can be ready to process earlier than this, ignore everything else and give back
        processing_data data;
        data.processing = message_processing::make_multisig;
        data.message_ids = key_set_messages;
        data.message_ids.erase(data.message_ids.begin());
        data_list.push_back(data);
        return true;
      }
      else
      {
        wait_reason = tr("Wallet can't go multisig because key sets from other signers are missing or not complete.");
        return false;
      }
    }
  
    if (state.multisig && !state.multisig_is_ready)
    {
      // In the case of M/N multisig the call 'wallet2::multisig' returns already true
      // after "make_multisig" but with calls to "exchange_multisig_keys" still needed, and
      // sets the parameter 'ready' to false to document this particular "in-between" state.
      // So what may be possible here, with all necessary messages present, is a call to
      // "exchange_multisig_keys".
      // Consider only messages belonging to the next round to do, which has the number
      // "state.multisig_rounds_passed".
      std::vector<uint32_t> additional_key_set_messages(m_num_authorized_signers, 0);
  
      for (size_t i = 0; i < m_messages.size(); ++i)
      {
        message &m = m_messages[i];
        if ((m.type == message_type::additional_key_set) && (m.state == message_state::waiting)
           && (m.round == state.multisig_rounds_passed))
        {
          if (additional_key_set_messages[m.signer_index] == 0)
          {
            additional_key_set_messages[m.signer_index] = m.id;
          }
          // else duplicate key set, ignore
        }
      }
  
      bool key_sets_complete = message_ids_complete(additional_key_set_messages);
      if (key_sets_complete)
      {
        processing_data data;
        data.processing = message_processing::exchange_multisig_keys;
        data.message_ids = additional_key_set_messages;
        data.message_ids.erase(data.message_ids.begin());
        data_list.push_back(data);
        return true;
      }
      else
      {
        wait_reason = tr("Wallet can't start another key exchange round because key sets from other signers are missing or not complete.");
        return false;
      }
    }
  
    // Properly exchanging multisig sync data is easiest and most transparent
    // for the user if a wallet sends its own data first and processes any received
    // sync data afterwards so that's the order that the MMS enforces here.
    // (Technically, it seems to work also the other way round.)
    //
    // To check whether a NEW round of syncing is necessary the MMS works with a
    // "wallet state": new state means new syncing needed.
    //
    // The MMS monitors the "wallet state" by recording "wallet heights" as
    // numbers of transfers present in a wallet at the time of message creation. While
    // not watertight, this quite simple scheme should already suffice to trigger
    // and orchestrate a sensible exchange of sync data.
    if (state.has_multisig_partial_key_images || force_sync)
    {
      // Sync is necessary and not yet completed: Processing of transactions
      // will only be possible again once properly synced
      // Check first whether we generated already OUR sync info; take note of
      // any processable sync info from other signers on the way in case we need it
      bool own_sync_data_created = false;
      std::vector<uint32_t> sync_messages(m_num_authorized_signers, 0);
      for (size_t i = 0; i < m_messages.size(); ++i)
      {
        message &m = m_messages[i];
        if ((m.type == message_type::multisig_sync_data) && (force_sync || (m.wallet_height == wallet_height)))
        // It's data for the same "round" of syncing, on the same "wallet height", therefore relevant
        // With "force_sync" take ANY waiting sync data, maybe it will work out
        {
          if (m.direction == message_direction::out)
          {
            own_sync_data_created = true;
            // Ignore whether sent already or not, and assume as complete if several other signers there
          }
          else if ((m.direction == message_direction::in) && (m.state == message_state::waiting))
          {
            if (sync_messages[m.signer_index] == 0)
            {
              sync_messages[m.signer_index] = m.id;
            }
            // else duplicate sync message, ignore
          }
        }
      }
      if (!own_sync_data_created)
      {
        // As explained above, creating sync data BEFORE processing such data from
        // other signers reliably works, so insist on that here
        processing_data data;
        data.processing = message_processing::create_sync_data;
        data_list.push_back(data);
        return true;
      }
      uint32_t id_count = (uint32_t)get_other_signers_id_count(sync_messages);
      // Do we have sync data from ALL other signers?
      bool all_sync_data = id_count == (m_num_authorized_signers - 1);
      // Do we have just ENOUGH sync data to have a minimal viable sync set?
      // In cases like 2/3 multisig we don't need messages from ALL other signers, only
      // from enough of them i.e. num_required_signers minus 1 messages
      bool enough_sync_data = id_count >= (m_num_required_signers - 1);
      bool sync = false;
      wait_reason = tr("Syncing not done because multisig sync data from other signers are missing or not complete.");
      if (all_sync_data)
      {
        sync = true;
      }
      else if (enough_sync_data)
      {
        if (force_sync)
        {
          sync = true;
        }
        else
        {
          // Don't sync, but give a hint how this minimal set COULD be synced if really wanted
          wait_reason += (boost::format("\nUse \"mms next sync\" if you want to sync with just %s out of %s authorized signers and transact just with them")
                                       % (m_num_required_signers - 1) % (m_num_authorized_signers - 1)).str();
        }
      }
      if (sync)
      {
        processing_data data;
        data.processing = message_processing::process_sync_data;
        for (size_t i = 0; i < sync_messages.size(); ++i)
        {
          uint32_t id = sync_messages[i];
          if (id != 0)
          {
            data.message_ids.push_back(id);
          }
        }
        data_list.push_back(data);
        return true;
      }
      else
      {
        // We can't proceed to any transactions until we have synced; "wait_reason" already set above
        return false;
      }
    }
  
    bool waiting_found = false;
    bool note_found = false;
    bool sync_data_found = false;
    for (size_t i = 0; i < m_messages.size(); ++i)
    {
      message &m = m_messages[i];
      if (m.state == message_state::waiting)
      {
        waiting_found = true;
        switch (m.type)
        {
        case message_type::fully_signed_tx:
        {
          // We can either submit it ourselves, or send it to any other signer for submission
          processing_data data;
          data.processing = message_processing::submit_tx;
          data.message_ids.push_back(m.id);
          data_list.push_back(data);
  
          data.processing = message_processing::send_tx;
          for (uint32_t j = 1; j < m_num_authorized_signers; ++j)
          {
            data.receiving_signer_index = j;
            data_list.push_back(data);
          }
          return true;
        }
  
        case message_type::partially_signed_tx:
        {
          if (m.signer_index == 0)
          {
            // We started this ourselves, or signed it but with still signatures missing:
            // We can send it to any other signer for signing / further signing
            // In principle it does not make sense to send it back to somebody who
            // already signed, but the MMS does not / not yet keep track of that,
            // because that would be somewhat complicated.
            processing_data data;
            data.processing = message_processing::send_tx;
            data.message_ids.push_back(m.id);
            for (uint32_t j = 1; j < m_num_authorized_signers; ++j)
            {
              data.receiving_signer_index = j;
              data_list.push_back(data);
            }
            return true;
          }
          else
          {
            // Somebody else sent this to us: We can sign it
            // It would be possible to just pass it on, but that's not directly supported here
            processing_data data;
            data.processing = message_processing::sign_tx;
            data.message_ids.push_back(m.id);
            data_list.push_back(data);
            return true;
          }
        }
  
        case message_type::note:
          note_found = true;
          break;
  
        case message_type::multisig_sync_data:
          sync_data_found = true;
          break;
  
        default:
          break;
        }
      }
    }
    if (waiting_found)
    {
      wait_reason = tr("There are waiting messages, but nothing is ready to process under normal circumstances");
      if (sync_data_found)
      {
        wait_reason += tr("\nUse \"mms next sync\" if you want to force processing of the waiting sync data");
      }
      if (note_found)
      {
        wait_reason += tr("\nUse \"mms note\" to display the waiting notes");
      }
    }
    else
    {
      wait_reason = tr("There are no messages waiting to be processed.");
    }
  
    return false;
  }
  
  void message_store::set_messages_processed(const processing_data &data)
  {
    for (size_t i = 0; i < data.message_ids.size(); ++i)
    {
      set_message_processed_or_sent(data.message_ids[i]);
    }
  }
  
  void message_store::set_message_processed_or_sent(uint32_t id)
  {
    message &m = get_message_ref_by_id(id);
    if (m.state == message_state::waiting)
    {
      // So far a fairly cautious and conservative strategy: Only delete from Bitmessage
      // when fully processed (and e.g. not already after reception and writing into
      // the message store file)
      delete_transport_message(id);
      m.state = message_state::processed;
    }
    else if (m.state == message_state::ready_to_send)
    {
      m.state = message_state::sent;
    }
    m.modified = (uint64_t)time(NULL);
  }
  
  void message_store::encrypt(crypto::public_key public_key, const std::string &plaintext,
                              std::string &ciphertext, crypto::public_key &encryption_public_key, crypto::chacha_iv &iv)
  {
    crypto::secret_key encryption_secret_key;
    crypto::generate_keys(encryption_public_key, encryption_secret_key);
  
    crypto::key_derivation derivation;
    bool success = crypto::generate_key_derivation(public_key, encryption_secret_key, derivation);
    THROW_WALLET_EXCEPTION_IF(!success, tools::error::wallet_internal_error, "Failed to generate key derivation for message encryption");
  
    crypto::chacha_key chacha_key;
    crypto::generate_chacha_key(&derivation, sizeof(derivation), chacha_key, 1);
    iv = crypto::rand<crypto::chacha_iv>();
    ciphertext.resize(plaintext.size());
    crypto::chacha20(plaintext.data(), plaintext.size(), chacha_key, iv, &ciphertext[0]);
  }
  
  void message_store::decrypt(const std::string &ciphertext, const crypto::public_key &encryption_public_key, const crypto::chacha_iv &iv,
                              const crypto::secret_key &view_secret_key, std::string &plaintext)
  {
    crypto::key_derivation derivation;
    bool success = crypto::generate_key_derivation(encryption_public_key, view_secret_key, derivation);
    THROW_WALLET_EXCEPTION_IF(!success, tools::error::wallet_internal_error, "Failed to generate key derivation for message decryption");
    crypto::chacha_key chacha_key;
    crypto::generate_chacha_key(&derivation, sizeof(derivation), chacha_key, 1);
    plaintext.resize(ciphertext.size());
    crypto::chacha20(ciphertext.data(), ciphertext.size(), chacha_key, iv, &plaintext[0]);
  }
  
  void message_store::send_message(const multisig_wallet_state &state, uint32_t id)
  {
    message &m = get_message_ref_by_id(id);
    const authorized_signer &me = m_signers[0];
    const authorized_signer &receiver = m_signers[m.signer_index];
    transport_message dm{};
    crypto::public_key public_key;
  
    dm.timestamp = (uint64_t)time(NULL);
    dm.subject = "MMS V0 " + tools::get_human_readable_timestamp(dm.timestamp);
    dm.source_transport_address = me.transport_address;
    dm.source_monero_address = me.monero_address;
    if (m.type == message_type::auto_config_data)
    {
      // Encrypt with the public key derived from the auto-config token, and send to the
      // transport address likewise derived from that token
      public_key = me.auto_config_public_key;
      dm.destination_transport_address = me.auto_config_transport_address;
      // The destination Monero address is not yet known
      memset(&dm.destination_monero_address, 0, sizeof(cryptonote::account_public_address));
    }
    else
    {
      // Encrypt with the receiver's view public key
      public_key = receiver.monero_address.m_view_public_key;
      const authorized_signer &receiver = m_signers[m.signer_index];
      dm.destination_monero_address = receiver.monero_address;
      dm.destination_transport_address = receiver.transport_address;
    }
    encrypt(public_key, m.content, dm.content, dm.encryption_public_key, dm.iv);
    dm.type = (uint32_t)m.type;
    dm.hash = crypto::cn_fast_hash(dm.content.data(), dm.content.size());
    dm.round = m.round;
  
    crypto::generate_signature(dm.hash, me.monero_address.m_view_public_key, state.view_secret_key, dm.signature);
  
    m_transporter.send_message(dm);
  
    m.state=message_state::sent;
    m.sent= (uint64_t)time(NULL);
  }
  
  bool message_store::check_for_messages(const multisig_wallet_state &state, std::vector<message> &messages)
  {
    m_run.store(true, std::memory_order_relaxed);
    const authorized_signer &me = m_signers[0];
    std::vector<std::string> destinations;
    destinations.push_back(me.transport_address);
    for (uint32_t i = 1; i < m_num_authorized_signers; ++i)
    {
      const authorized_signer &m = m_signers[i];
      if (m.auto_config_running)
      {
        destinations.push_back(m.auto_config_transport_address);
      }
    }
    std::vector<transport_message> transport_messages;
    bool r = m_transporter.receive_messages(destinations, transport_messages);
    if (!m_run.load(std::memory_order_relaxed))
    {
      // Stop was called, don't waste time processing the messages
      // (but once started processing them, don't react to stop request anymore, avoid receiving them "partially)"
      return false;
    }
  
    bool new_messages = false;
    for (size_t i = 0; i < transport_messages.size(); ++i)
    {
      transport_message &rm = transport_messages[i];
      if (any_message_with_hash(rm.hash))
      {
        // Already seen, do not take again
      }
      else
      {
        uint32_t sender_index;
        bool take = false;
        message_type type = static_cast<message_type>(rm.type);
        crypto::secret_key decrypt_key = state.view_secret_key;
        if (type == message_type::auto_config_data)
        {
          // Find out which signer sent it by checking which auto config transport address
          // the message was sent to
          for (uint32_t i = 1; i < m_num_authorized_signers; ++i)
          {
            const authorized_signer &m = m_signers[i];
            if (m.auto_config_transport_address == rm.destination_transport_address)
            {
              take = true;
              sender_index = i;
              decrypt_key = m.auto_config_secret_key;
              break;
            }
          }
        }
        else if (type == message_type::signer_config)
        {
          // Typically we can't check yet whether we know the sender, so take from any
          // and pretend it's from "me" because we might have nothing else yet
          take = true;
          sender_index = 0;
        }
        else
        {
          // Only accept from senders that are known as signer here, otherwise just ignore
          take = get_signer_index_by_monero_address(rm.source_monero_address, sender_index);
        }
        if (take && (type != message_type::auto_config_data))
        {
          // If the destination address is known, check it as well; this additional filter
          // allows using the same transport address for multiple signers
          take = rm.destination_monero_address == me.monero_address;
        }
        if (take)
        {
          crypto::hash actual_hash = crypto::cn_fast_hash(rm.content.data(), rm.content.size());
          THROW_WALLET_EXCEPTION_IF(actual_hash != rm.hash, tools::error::wallet_internal_error, "Message hash mismatch");
  
          bool signature_valid = crypto::check_signature(actual_hash, rm.source_monero_address.m_view_public_key, rm.signature);
          THROW_WALLET_EXCEPTION_IF(!signature_valid, tools::error::wallet_internal_error, "Message signature not valid");
  
          std::string plaintext;
          decrypt(rm.content, rm.encryption_public_key, rm.iv, decrypt_key, plaintext);
          size_t index = add_message(state, sender_index, (message_type)rm.type, message_direction::in, plaintext);
          message &m = m_messages[index];
          m.hash = rm.hash;
          m.transport_id = rm.transport_id;
          m.sent = rm.timestamp;
          m.round = rm.round;
          m.signature_count = rm.signature_count;
          messages.push_back(m);
          new_messages = true;
        }
      }
    }
    return new_messages;
  }
  
  void message_store::delete_transport_message(uint32_t id)
  {
    const message &m = get_message_by_id(id);
    if (!m.transport_id.empty())
    {
      m_transporter.delete_message(m.transport_id);
    }
  }
  
  std::string message_store::account_address_to_string(const cryptonote::account_public_address &account_address) const
  {
    return get_account_address_as_str(m_nettype, false, account_address);
  }
  
  const char* message_store::message_type_to_string(message_type type)
  {
    switch (type)
    {
    case message_type::key_set:
      return tr("key set");
    case message_type::additional_key_set:
      return tr("additional key set");
    case message_type::multisig_sync_data:
      return tr("multisig sync data");
    case message_type::partially_signed_tx:
      return tr("partially signed tx");
    case message_type::fully_signed_tx:
      return tr("fully signed tx");
    case message_type::note:
      return tr("note");
    case message_type::signer_config:
      return tr("signer config");
    case message_type::auto_config_data:
      return tr("auto-config data");
    default:
      return tr("unknown message type");
    }
  }
  
  const char* message_store::message_direction_to_string(message_direction direction)
  {
    switch (direction)
    {
    case message_direction::in:
      return tr("in");
    case message_direction::out:
      return tr("out");
    default:
      return tr("unknown message direction");
    }
  }
  
  const char* message_store::message_state_to_string(message_state state)
  {
    switch (state)
    {
    case message_state::ready_to_send:
      return tr("ready to send");
    case message_state::sent:
      return tr("sent");
    case message_state::waiting:
      return tr("waiting");
    case message_state::processed:
      return tr("processed");
    case message_state::cancelled:
      return tr("cancelled");
    default:
      return tr("unknown message state");
    }
  }
  
  // Convert a signer to string suitable for a column in a list, with 'max_width'
  // Format: label: transport_address
  std::string message_store::signer_to_string(const authorized_signer &signer, uint32_t max_width)
  {
    std::string s = "";
    s.reserve(max_width);
    uint32_t avail = max_width;
    uint32_t label_len = signer.label.length();
    if (label_len > avail)
    {
      s.append(signer.label.substr(0, avail - 2));
      s.append("..");
      return s;
    }
    s.append(signer.label);
    avail -= label_len;
    uint32_t transport_addr_len = signer.transport_address.length();
    if ((transport_addr_len > 0) && (avail > 10))
    {
      s.append(": ");
      avail -= 2;
      if (transport_addr_len <= avail)
      {
        s.append(signer.transport_address);
      }
      else
      {
        s.append(signer.transport_address.substr(0, avail-2));
        s.append("..");
      }
    }
    return s;
  }
  
  }
  