/*
 * This file is part of PowerDNS or dnsdist.
 * Copyright -- PowerDNS.COM B.V. and its contributors
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * In addition, for the avoidance of any doubt, permission is granted to
 * link this program with OpenSSL and to (re)distribute the binaries
 * produced as the result of such linking.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTAPILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
#pragma once
#include "boost/algorithm/string/join.hpp"
#include "pdns/arguments.hh"

#include "pdns/dnsbackend.hh"
#include "pdns/lua-auth4.hh"

class Lua2BackendAPIv2 : public DNSBackend, AuthLua4
{
private:
  typedef std::function<void()> init_call_t;
  typedef std::function<void()> deinit_call_t;

  typedef std::vector<std::pair<string, string>> lookup_context_t;

  typedef std::vector<std::pair<int, std::vector<std::pair<string, boost::variant<bool, int, DNSName, string, QType>>>>> lookup_result_t;
  typedef std::function<lookup_result_t(const QType& qtype, const DNSName& qname, domainid_t domain_id, const lookup_context_t& ctx)> lookup_call_t;

  typedef boost::variant<bool, lookup_result_t> list_result_t;
  typedef std::function<list_result_t(const DNSName& qname, domainid_t domain_id)> list_call_t;

  typedef vector<pair<string, boost::variant<bool, long, string, vector<string>>>> domaininfo_result_t;
  typedef boost::variant<bool, domaininfo_result_t> get_domaininfo_result_t;
  typedef vector<pair<DNSName, domaininfo_result_t>> get_all_domains_result_t;
  typedef std::function<get_domaininfo_result_t(const DNSName& domain)> get_domaininfo_call_t;
  typedef std::function<get_all_domains_result_t()> get_all_domains_call_t;

  typedef vector<pair<int, string>> domain_metadata_result_t;
  typedef boost::variant<bool, domain_metadata_result_t> get_domain_metadata_result_t;
  typedef boost::variant<bool, vector<pair<string, domain_metadata_result_t>>> get_all_domain_metadata_result_t;
  typedef std::function<get_domain_metadata_result_t(const DNSName& domain, const string& kind)> get_domain_metadata_call_t;
  typedef std::function<get_all_domain_metadata_result_t(const DNSName& domain)> get_all_domain_metadata_call_t;

  typedef vector<pair<string, boost::variant<bool, int, string>>> keydata_result_t;
  typedef boost::variant<bool, vector<pair<int, keydata_result_t>>> get_domain_keys_result_t;
  typedef std::function<get_domain_keys_result_t(const DNSName& domain)> get_domain_keys_call_t;

  typedef std::vector<std::pair<string, boost::variant<string, DNSName>>> before_and_after_names_result_t;
  typedef boost::variant<bool, before_and_after_names_result_t> get_before_and_after_names_absolute_result_t;
  typedef std::function<get_before_and_after_names_absolute_result_t(domainid_t id, const DNSName& qname)> get_before_and_after_names_absolute_call_t;

  typedef std::function<void(domainid_t, long)> set_notified_call_t;

  typedef std::function<string(const string& cmd)> direct_backend_cmd_call_t;

public:
  Lua2BackendAPIv2(const string& suffix)
  {
    d_include_path = ::arg()["lua-global-include-dir"];
    setArgPrefix("lua2" + suffix);
    d_debug_log = mustDo("query-logging");
    prepareContext();
    loadFile(getArg("filename"));
  }

  ~Lua2BackendAPIv2() override;

#define logCall(func, var)                                                                               \
  {                                                                                                      \
    if (d_debug_log) {                                                                                   \
      g_log << Logger::Debug << "[" << getPrefix() << "] Calling " << func << "(" << var << ")" << endl; \
    }                                                                                                    \
  }
#define logResult(var)                                                \
  {                                                                   \
    if (d_debug_log) {                                                \
      g_log << Logger::Debug << "[" << getPrefix() << "] Got result " \
            << "'" << var << "'" << endl;                             \
    }                                                                 \
  }

  void postPrepareContext() override
  {
    AuthLua4::postPrepareContext();
  }

  void postLoad() override
  {
    f_lookup = d_lw->readVariable<boost::optional<lookup_call_t>>("dns_lookup").get_value_or(0);
    f_list = d_lw->readVariable<boost::optional<list_call_t>>("dns_list").get_value_or(0);
    f_get_all_domains = d_lw->readVariable<boost::optional<get_all_domains_call_t>>("dns_get_all_domains").get_value_or(0);
    f_get_domaininfo = d_lw->readVariable<boost::optional<get_domaininfo_call_t>>("dns_get_domaininfo").get_value_or(0);
    f_get_domain_metadata = d_lw->readVariable<boost::optional<get_domain_metadata_call_t>>("dns_get_domain_metadata").get_value_or(0);
    f_get_all_domain_metadata = d_lw->readVariable<boost::optional<get_all_domain_metadata_call_t>>("dns_get_all_domain_metadata").get_value_or(0);
    f_get_domain_keys = d_lw->readVariable<boost::optional<get_domain_keys_call_t>>("dns_get_domain_keys").get_value_or(0);
    f_get_before_and_after_names_absolute = d_lw->readVariable<boost::optional<get_before_and_after_names_absolute_call_t>>("dns_get_before_and_after_names_absolute").get_value_or(0);
    f_set_notified = d_lw->readVariable<boost::optional<set_notified_call_t>>("dns_set_notified").get_value_or(0);

    auto init = d_lw->readVariable<boost::optional<init_call_t>>("dns_init").get_value_or(0);
    if (init)
      init();

    f_deinit = d_lw->readVariable<boost::optional<deinit_call_t>>("dns_deinit").get_value_or(0);

    if (f_lookup == nullptr)
      throw PDNSException("dns_lookup missing");

    /* see if dnssec support is wanted */
    d_dnssec = d_lw->readVariable<boost::optional<bool>>("dns_dnssec").get_value_or(false);
    if (d_dnssec) {
      if (f_get_domain_metadata == nullptr)
        throw PDNSException("dns_dnssec is true but dns_get_domain_metadata is missing");
      if (f_get_before_and_after_names_absolute == nullptr)
        throw PDNSException("dns_dnssec is true but dns_get_before_and_after_names_absolute is missing");
      /* domain keys is not strictly speaking necessary for dnssec backend */
      if (f_get_domain_keys == nullptr)
        g_log << Logger::Warning << "dns_get_domain_keys missing - cannot do live signing" << endl;
    }
  }

  unsigned int getCapabilities() override
  {
    unsigned int caps = CAP_DIRECT | CAP_LIST;
    if (d_dnssec) {
      caps |= CAP_DNSSEC;
    }
    return caps;
  }

  void parseLookup(const lookup_result_t& result)
  {
    for (const auto& row : result) {
      DNSResourceRecord rec;
      for (const auto& item : row.second) {
        if (item.first == "type") {
          if (item.second.which() == 1)
            rec.qtype = QType(boost::get<int>(item.second));
          else if (item.second.which() == 3)
            rec.qtype = boost::get<string>(item.second);
          else if (item.second.which() == 4)
            rec.qtype = boost::get<QType>(item.second);
          else
            throw PDNSException("Unsupported value for type");
        }
        else if (item.first == "name") {
          if (item.second.which() == 3)
            rec.qname = DNSName(boost::get<string>(item.second));
          else if (item.second.which() == 2)
            rec.qname = boost::get<DNSName>(item.second);
          else
            throw PDNSException("Unsupported value for name");
        }
        else if (item.first == "domain_id")
          rec.domain_id = boost::get<int>(item.second);
        else if (item.first == "auth")
          rec.auth = boost::get<bool>(item.second);
        else if (item.first == "last_modified")
          rec.last_modified = static_cast<time_t>(boost::get<int>(item.second));
        else if (item.first == "ttl")
          rec.ttl = boost::get<int>(item.second);
        else if (item.first == "content")
          rec.setContent(boost::get<string>(item.second));
        else if (item.first == "scopeMask")
          rec.scopeMask = boost::get<int>(item.second);
        else
          g_log << Logger::Warning << "Unsupported key '" << item.first << "' in lookup or list result" << endl;
      }
      logResult(rec.qname << " IN " << rec.qtype.toString() << " " << rec.ttl << " " << rec.getZoneRepresentation());
      d_result.push_back(rec);
    }
    if (d_result.empty() && d_debug_log)
      g_log << Logger::Debug << "[" << getPrefix() << "] Got empty result" << endl;
  }

  bool list(const ZoneName& target, domainid_t domain_id, bool /* include_disabled */ = false) override
  {
    if (f_list == nullptr) {
      g_log << Logger::Error << "[" << getPrefix() << "] dns_list missing - cannot do AXFR" << endl;
      return false;
    }

    if (d_result.size() != 0)
      throw PDNSException("list attempted while another was running");

    logCall("list", "target=" << target << ",domain_id=" << domain_id);
    list_result_t result = f_list(target.operator const DNSName&(), domain_id);

    if (result.which() == 0)
      return false;

    parseLookup(boost::get<lookup_result_t>(result));

    return true;
  }

  void lookup(const QType& qtype, const DNSName& qname, domainid_t domain_id, DNSPacket* p = nullptr) override
  {
    if (d_result.size() != 0)
      throw PDNSException("lookup attempted while another was running");

    lookup_context_t ctx;
    if (p != NULL) {
      ctx.emplace_back(lookup_context_t::value_type{"source_address", p->getInnerRemote().toString()});
      ctx.emplace_back(lookup_context_t::value_type{"real_source_address", p->getRealRemote().toString()});
    }

    logCall("lookup", "qtype=" << qtype.toString() << ",qname=" << qname << ",domain_id=" << domain_id);
    lookup_result_t result = f_lookup(qtype, qname, domain_id, ctx);
    parseLookup(result);
  }

  bool get(DNSResourceRecord& rr) override
  {
    if (d_result.size() == 0)
      return false;
    rr = std::move(d_result.front());
    d_result.pop_front();
    return true;
  }

  string directBackendCmd(const string& querystr) override
  {
    string::size_type pos = querystr.find_first_of(" \t");
    string cmd = querystr;
    string par = "";
    if (pos != string::npos) {
      cmd = querystr.substr(0, pos);
      par = querystr.substr(pos + 1);
    }
    direct_backend_cmd_call_t f = d_lw->readVariable<boost::optional<direct_backend_cmd_call_t>>(cmd).get_value_or(0);
    if (f == nullptr) {
      return cmd + "not found";
    }
    logCall(cmd, "parameter=" << par);
    return f(par);
  }

  void setNotified(domainid_t id, uint32_t serial) override
  {
    if (f_set_notified == NULL)
      return;
    logCall("dns_set_notified", "id=" << id << ",serial=" << serial);
    f_set_notified(id, serial);
  }

  void parseDomainInfo(const domaininfo_result_t& row, DomainInfo& di)
  {
    di.id = UnknownDomainID;
    for (const auto& item : row) {
      if (item.first == "account")
        di.account = boost::get<string>(item.second);
      else if (item.first == "last_check")
        di.last_check = static_cast<time_t>(boost::get<long>(item.second));
      else if (item.first == "masters")
        for (const auto& primary : boost::get<vector<string>>(item.second))
          di.primaries.push_back(ComboAddress(primary, 53));
      else if (item.first == "id")
        di.id = static_cast<domainid_t>(boost::get<long>(item.second));
      else if (item.first == "notified_serial")
        di.notified_serial = static_cast<unsigned int>(boost::get<long>(item.second));
      else if (item.first == "serial")
        di.serial = static_cast<unsigned int>(boost::get<long>(item.second));
      else if (item.first == "kind")
        di.kind = DomainInfo::stringToKind(boost::get<string>(item.second));
      else
        g_log << Logger::Warning << "Unsupported key '" << item.first << "' in domaininfo result" << endl;
    }
    di.backend = this;
    logResult("zone=" << di.zone << ",serial=" << di.serial << ",kind=" << di.getKindString());
  }

  bool getDomainInfo(const ZoneName& domain, DomainInfo& di, bool /* getSerial */ = true) override
  {
    if (f_get_domaininfo == nullptr) {
      // use getAuth instead... but getAuth wraps getSOA which will call
      // getDomainInfo if this is a domain variant, so protect against this
      // would-be infinite recursion.
      if (domain.hasVariant()) {
        g_log << Logger::Info << "Unable to return domain information for '" << domain.toLogString() << "' due to unimplemented dns_get_domaininfo" << endl;
        return false;
      }
      SOAData sd;
      if (!getAuth(domain, &sd))
        return false;

      di.id = sd.domain_id;
      di.zone = domain;
      di.backend = this;
      di.serial = sd.serial;
      return true;
    }

    logCall("get_domaininfo", "domain=" << domain);
    get_domaininfo_result_t result = f_get_domaininfo(domain.operator const DNSName&());

    if (result.which() == 0)
      return false;

    di.zone = domain;
    parseDomainInfo(boost::get<domaininfo_result_t>(result), di);

    return true;
  }

  void getAllDomains(vector<DomainInfo>* domains, bool /* getSerial */, bool /* include_disabled */) override
  {
    if (f_get_all_domains == nullptr)
      return;

    logCall("get_all_domains", "");
    for (const auto& row : f_get_all_domains()) {
      DomainInfo di;
      di.zone = ZoneName(row.first);
      logResult(di.zone);
      parseDomainInfo(row.second, di);
      domains->push_back(di);
    }
  }

  bool getAllDomainMetadata(const ZoneName& name, std::map<std::string, std::vector<std::string>>& meta) override
  {
    if (f_get_all_domain_metadata == nullptr)
      return false;

    logCall("get_all_domain_metadata", "name=" << name);
    get_all_domain_metadata_result_t result = f_get_all_domain_metadata(name.operator const DNSName&());
    if (result.which() == 0)
      return false;

    for (const auto& row : boost::get<vector<pair<string, domain_metadata_result_t>>>(result)) {
      meta[row.first].clear();
      for (const auto& item : row.second)
        meta[row.first].push_back(item.second);
      logResult("kind=" << row.first << ",value=" << boost::algorithm::join(meta[row.first], ", "));
    }

    return true;
  }

  bool getDomainMetadata(const ZoneName& name, const std::string& kind, std::vector<std::string>& meta) override
  {
    if (f_get_domain_metadata == nullptr)
      return false;

    logCall("get_domain_metadata", "name=" << name << ",kind=" << kind);
    get_domain_metadata_result_t result = f_get_domain_metadata(name.operator const DNSName&(), kind);
    if (result.which() == 0)
      return false;

    meta.clear();
    for (const auto& item : boost::get<domain_metadata_result_t>(result))
      meta.push_back(item.second);

    logResult("value=" << boost::algorithm::join(meta, ", "));
    return true;
  }

  bool getDomainKeys(const ZoneName& name, std::vector<DNSBackend::KeyData>& keys) override
  {
    if (f_get_domain_keys == nullptr)
      return false;

    logCall("get_domain_keys", "name=" << name);
    get_domain_keys_result_t result = f_get_domain_keys(name.operator const DNSName&());

    if (result.which() == 0)
      return false;

    for (const auto& row : boost::get<vector<pair<int, keydata_result_t>>>(result)) {
      DNSBackend::KeyData key;
      key.published = true;
      for (const auto& item : row.second) {
        if (item.first == "content")
          key.content = boost::get<string>(item.second);
        else if (item.first == "id")
          key.id = static_cast<unsigned int>(boost::get<int>(item.second));
        else if (item.first == "flags")
          key.flags = static_cast<unsigned int>(boost::get<int>(item.second));
        else if (item.first == "active")
          key.active = boost::get<bool>(item.second);
        else if (item.first == "published")
          key.published = boost::get<bool>(item.second);
        else
          g_log << Logger::Warning << "[" << getPrefix() << "] Unsupported key '" << item.first << "' in keydata result" << endl;
      }
      logResult("id=" << key.id << ",flags=" << key.flags << ",active=" << (key.active ? "true" : "false") << ",published=" << (key.published ? "true" : "false"));
      keys.emplace_back(std::move(key));
    }

    return true;
  }

  bool getBeforeAndAfterNamesAbsolute(domainid_t id, const DNSName& qname, DNSName& unhashed, DNSName& before, DNSName& after) override
  {
    if (f_get_before_and_after_names_absolute == nullptr)
      return false;

    logCall("get_before_and_after_names_absolute", "id=<<" << id << ",qname=" << qname);
    get_before_and_after_names_absolute_result_t result = f_get_before_and_after_names_absolute(id, qname);

    if (result.which() == 0)
      return false;

    before_and_after_names_result_t row = boost::get<before_and_after_names_result_t>(result);
    if (row.size() != 3) {
      g_log << Logger::Error << "Invalid result from dns_get_before_and_after_names_absolute, expected array with 3 items, got " << row.size() << "item(s)" << endl;
      return false;
    }
    for (const auto& item : row) {
      DNSName value;
      if (item.second.which() == 0)
        value = DNSName(boost::get<string>(item.second));
      else
        value = DNSName(boost::get<DNSName>(item.second));
      if (item.first == "unhashed")
        unhashed = value;
      else if (item.first == "before")
        before = value;
      else if (item.first == "after")
        after = value;
      else {
        g_log << Logger::Error << "Invalid result from dns_get_before_and_after_names_absolute, unexpected key " << item.first << endl;
        return false;
      }
    }

    logResult("unhashed=" << unhashed << ",before=" << before << ",after=" << after);
    return true;
  }

private:
  std::list<DNSResourceRecord> d_result;
  bool d_debug_log{false};
  bool d_dnssec{false};

  lookup_call_t f_lookup;
  list_call_t f_list;

  get_domaininfo_call_t f_get_domaininfo;
  get_all_domains_call_t f_get_all_domains;

  get_domain_metadata_call_t f_get_domain_metadata;
  get_all_domain_metadata_call_t f_get_all_domain_metadata;

  get_domain_keys_call_t f_get_domain_keys;

  get_before_and_after_names_absolute_call_t f_get_before_and_after_names_absolute;

  set_notified_call_t f_set_notified;

  deinit_call_t f_deinit;
};