#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <cinttypes>

#include "recursor_cache.hh"
#include "misc.hh"
#include <iostream>
#include "dnsrecords.hh"
#include "arguments.hh"
#include "syncres.hh"
#include "recursor_cache.hh"
#include "cachecleaner.hh"
#include "namespaces.hh"

unsigned int MemRecursorCache::size() const
{
  return (unsigned int)d_cache.size();
}

size_t MemRecursorCache::ecsIndexSize() const
{
  return d_ecsIndex.size();
}

// this function is too slow to poll!
unsigned int MemRecursorCache::bytes() const
{
  unsigned int ret=0;

  for(const auto& i : d_cache) {
    ret+=sizeof(struct CacheEntry);
    ret+=(unsigned int)i.d_qname.toString().length();
    for(const auto& record : i.d_records)
      ret+= sizeof(record); // XXX WRONG we don't know the stored size!
  }
  return ret;
}

int32_t MemRecursorCache::handleHit(MemRecursorCache::OrderedTagIterator_t& entry, const DNSName& qname, const ComboAddress& who, vector<DNSRecord>* res, vector<std::shared_ptr<RRSIGRecordContent>>* signatures, std::vector<std::shared_ptr<DNSRecord>>* authorityRecs, bool* variable, vState* state, bool* wasAuth)
{
  int32_t ttd = entry->d_ttd;

  if(variable && !entry->d_netmask.empty()) {
    *variable = true;
  }

  // cerr<<"Looking at "<<entry->d_records.size()<<" records for this name"<<endl;
  if (res) {
    res->reserve(res->size() + entry->d_records.size());

    for(const auto& k : entry->d_records) {
      DNSRecord dr;
      dr.d_name = qname;
      dr.d_type = entry->d_qtype;
      dr.d_class = QClass::IN;
      dr.d_content = k;
      dr.d_ttl = static_cast<uint32_t>(entry->d_ttd);
      dr.d_place = DNSResourceRecord::ANSWER;
      res->push_back(std::move(dr));
    }
  }

  if(signatures) { // if you do an ANY lookup you are hosed XXXX
    *signatures = entry->d_signatures;
  }

  if(authorityRecs) {
    *authorityRecs = entry->d_authorityRecs;
  }

  if (state) {
    *state = entry->d_state;
  }

  if (wasAuth) {
    *wasAuth = entry->d_auth;
  }

  moveCacheItemToBack<SequencedTag>(d_cache, entry);

  return ttd;
}

MemRecursorCache::cache_t::const_iterator MemRecursorCache::getEntryUsingECSIndex(time_t now, const DNSName &qname, uint16_t qtype, bool requireAuth, const ComboAddress& who)
{
  auto ecsIndexKey = tie(qname, qtype);
  auto ecsIndex = d_ecsIndex.find(ecsIndexKey);
  if (ecsIndex != d_ecsIndex.end() && !ecsIndex->isEmpty()) {
    /* we have netmask-specific entries, let's see if we match one */
    while (true) {
      const Netmask best = ecsIndex->lookupBestMatch(who);
      if (best.empty()) {
        /* we have nothing more specific for you */
        break;
      }
      auto key = boost::make_tuple(qname, qtype, best);
      auto entry = d_cache.find(key);
      if (entry == d_cache.end()) {
        /* ecsIndex is not up-to-date */
        ecsIndex->removeNetmask(best);
        if (ecsIndex->isEmpty()) {
          d_ecsIndex.erase(ecsIndex);
          break;
        }
        continue;
      }

      if (entry->d_ttd > now) {
        if (!requireAuth || entry->d_auth) {
          return entry;
        }
        /* we need auth data and the best match is not authoritative */
        return d_cache.end();
      }
      else {
        /* this netmask-specific entry has expired */
        moveCacheItemToFront<SequencedTag>(d_cache, entry);
        ecsIndex->removeNetmask(best);
        if (ecsIndex->isEmpty()) {
          d_ecsIndex.erase(ecsIndex);
          break;
        }
      }
    }
  }

  /* we have nothing specific, let's see if we have a generic one */
  auto key = boost::make_tuple(qname, qtype, Netmask());
  auto entry = d_cache.find(key);
  if (entry != d_cache.end()) {
    if (entry->d_ttd > now) {
      if (!requireAuth || entry->d_auth) {
        return entry;
      }
    }
    else {
      moveCacheItemToFront<SequencedTag>(d_cache, entry);
    }
  }

  /* nothing for you, sorry */
  return d_cache.end();
}

// returns -1 for no hits
std::pair<MemRecursorCache::NameOnlyHashedTagIterator_t, MemRecursorCache::NameOnlyHashedTagIterator_t> MemRecursorCache::getEntries(const DNSName &qname, const QType& qt)
{
  //  cerr<<"looking up "<< qname<<"|"+qt.getName()<<"\n";
  if(!d_cachecachevalid || d_cachedqname!= qname) {
    //    cerr<<"had cache cache miss"<<endl;
    d_cachedqname = qname;
    const auto& idx = d_cache.get<NameOnlyHashedTag>();
    d_cachecache = idx.equal_range(qname);
    d_cachecachevalid = true;
  }
  //  else cerr<<"had cache cache hit!"<<endl;

  return d_cachecache;
}

bool MemRecursorCache::entryMatches(MemRecursorCache::OrderedTagIterator_t& entry, uint16_t qt, bool requireAuth, const ComboAddress& who)
{
  if (requireAuth && !entry->d_auth)
    return false;

  return ((entry->d_qtype == qt || qt == QType::ANY ||
           (qt == QType::ADDR && (entry->d_qtype == QType::A || entry->d_qtype == QType::AAAA)))
          && (entry->d_netmask.empty() || entry->d_netmask.match(who)));
}

// returns -1 for no hits
int32_t MemRecursorCache::get(time_t now, const DNSName &qname, const QType& qt, bool requireAuth, vector<DNSRecord>* res, const ComboAddress& who, vector<std::shared_ptr<RRSIGRecordContent>>* signatures, std::vector<std::shared_ptr<DNSRecord>>* authorityRecs, bool* variable, vState* state, bool* wasAuth)
{
  time_t ttd=0;
  //  cerr<<"looking up "<< qname<<"|"+qt.getName()<<"\n";
  if(res) {
    res->clear();
  }

  const uint16_t qtype = qt.getCode();
  /* If we don't have any netmask-specific entries at all, let's just skip this
     to be able to use the nice d_cachecache hack. */
  if (qtype != QType::ANY && !d_ecsIndex.empty()) {
    if (qtype == QType::ADDR) {
      int32_t ret = -1;

      auto entryA = getEntryUsingECSIndex(now, qname, QType::A, requireAuth, who);
      if (entryA != d_cache.end()) {
        ret = handleHit(entryA, qname, who, res, signatures, authorityRecs, variable, state, wasAuth);
      }
      auto entryAAAA = getEntryUsingECSIndex(now, qname, QType::AAAA, requireAuth, who);
      if (entryAAAA != d_cache.end()) {
        int32_t ttdAAAA = handleHit(entryAAAA, qname, who, res, signatures, authorityRecs, variable, state, wasAuth);
        if (ret > 0) {
          ret = std::min(ret, ttdAAAA);
        } else {
          ret = ttdAAAA;
        }
      }
      return ret > 0 ? static_cast<int32_t>(ret-now) : ret;
    }
    else {
      auto entry = getEntryUsingECSIndex(now, qname, qtype, requireAuth, who);
      if (entry != d_cache.end()) {
        return static_cast<int32_t>(handleHit(entry, qname, who, res, signatures, authorityRecs, variable, state, wasAuth) - now);
      }
      return -1;
    }
  }

  auto entries = getEntries(qname, qt);

  if(entries.first!=entries.second) {
    for(auto i=entries.first; i != entries.second; ++i) {

      auto firstIndexIterator = d_cache.project<OrderedTag>(i);
      if (i->d_ttd <= now) {
        moveCacheItemToFront<SequencedTag>(d_cache, firstIndexIterator);
        continue;
      }

      if (!entryMatches(firstIndexIterator, qtype, requireAuth, who))
        continue;

      ttd = handleHit(firstIndexIterator, qname, who, res, signatures, authorityRecs, variable, state, wasAuth);

      if(qt.getCode()!=QType::ANY && qt.getCode()!=QType::ADDR) // normally if we have a hit, we are done
        break;
    }

    // cerr<<"time left : "<<ttd - now<<", "<< (res ? res->size() : 0) <<"\n";
    return static_cast<int32_t>(ttd-now);
  }
  return -1;
}

void MemRecursorCache::replace(time_t now, const DNSName &qname, const QType& qt, const vector<DNSRecord>& content, const vector<shared_ptr<RRSIGRecordContent>>& signatures, const std::vector<std::shared_ptr<DNSRecord>>& authorityRecs, bool auth, boost::optional<Netmask> ednsmask, vState state)
{
  d_cachecachevalid = false;
  //  cerr<<"Replacing "<<qname<<" for "<< (ednsmask ? ednsmask->toString() : "everyone") << endl;
  auto key = boost::make_tuple(qname, qt.getCode(), ednsmask ? *ednsmask : Netmask());
  bool isNew = false;
  cache_t::iterator stored = d_cache.find(key);
  if (stored == d_cache.end()) {
    stored = d_cache.insert(CacheEntry(key, auth)).first;
    isNew = true;
  }

  /* if we are inserting a new entry or updating an expired one (in which case the
     ECS index might have been removed but the entry still exists because it has not
     been garbage collected yet) we might need to update the ECS index.
     Otherwise it should already be indexed and we don't need to update it.
  */
  if (isNew || stored->d_ttd <= now) {
    /* don't bother building an ecsIndex if we don't have any netmask-specific entries */
    if (ednsmask && !ednsmask->empty()) {
      auto ecsIndexKey = boost::make_tuple(qname, qt.getCode());
      auto ecsIndex = d_ecsIndex.find(ecsIndexKey);
      if (ecsIndex == d_ecsIndex.end()) {
        ecsIndex = d_ecsIndex.insert(ECSIndexEntry(qname, qt.getCode())).first;
      }
      ecsIndex->addMask(*ednsmask);
    }
  }

  time_t maxTTD=std::numeric_limits<time_t>::max();
  CacheEntry ce=*stored; // this is a COPY
  ce.d_qtype=qt.getCode();
  ce.d_signatures=signatures;
  ce.d_authorityRecs=authorityRecs;
  ce.d_state=state;
  
  //  cerr<<"asked to store "<< (qname.empty() ? "EMPTY" : qname.toString()) <<"|"+qt.getName()<<" -> '";
  //  cerr<<(content.empty() ? string("EMPTY CONTENT")  : content.begin()->d_content->getZoneRepresentation())<<"', auth="<<auth<<", ce.auth="<<ce.d_auth;
  //  cerr<<", ednsmask: "  <<  (ednsmask ? ednsmask->toString() : "none") <<endl;

  if(!auth && ce.d_auth) {  // unauth data came in, we have some auth data, but is it fresh?
    if(ce.d_ttd > now) { // we still have valid data, ignore unauth data
      //      cerr<<"\tStill hold valid auth data, and the new data is unauth, return\n";
      return;
    }
    else {
      ce.d_auth = false;  // new data won't be auth
    }
  }

  // refuse any attempt to *raise* the TTL of auth NS records, as it would make it possible
  // for an auth to keep a "ghost" zone alive forever, even after the delegation is gone from
  // the parent
  // BUT make sure that we CAN refresh the root
  if(ce.d_auth && auth && qt.getCode()==QType::NS && !isNew && !qname.isRoot()) {
    //    cerr<<"\tLimiting TTL of auth->auth NS set replace to "<<ce.d_ttd<<endl;
    maxTTD = ce.d_ttd;
  }

  if(auth) {
    ce.d_auth = true;
  }

  ce.d_records.clear();
  ce.d_records.reserve(content.size());

  for(const auto i : content) {
    /* Yes, we have altered the d_ttl value by adding time(nullptr) to it
       prior to calling this function, so the TTL actually holds a TTD. */
    ce.d_ttd=min(maxTTD, static_cast<time_t>(i.d_ttl));   // XXX this does weird things if TTLs differ in the set
    //    cerr<<"To store: "<<i.d_content->getZoneRepresentation()<<" with ttl/ttd "<<i.d_ttl<<", capped at: "<<maxTTD<<endl;
    ce.d_records.push_back(i.d_content);
  }

  if (!isNew) {
    moveCacheItemToBack<SequencedTag>(d_cache, stored);
  }
  d_cache.replace(stored, ce);
}

int MemRecursorCache::doWipeCache(const DNSName& name, bool sub, uint16_t qtype)
{
  int count=0;
  d_cachecachevalid=false;

  if(!sub) {
    auto& idx = d_cache.get<NameOnlyHashedTag>();
    auto range = idx.equal_range(name);
    for(auto& i=range.first; i != range.second; ) {
      if (qtype == 0xffff || i->d_qtype == qtype) {
        count++;
        idx.erase(i++);
      }
      else {
        ++i;
      }
    }
    if (qtype == 0xffff) {
      auto& ecsIdx = d_ecsIndex.get<OrderedTag>();
      auto ecsIndexRange = ecsIdx.equal_range(name);
      for(auto i = ecsIndexRange.first; i != ecsIndexRange.second; ) {
        ecsIdx.erase(i++);
      }
    }
    else {
      auto& ecsIdx = d_ecsIndex.get<HashedTag>();
      auto ecsIndexRange = ecsIdx.equal_range(tie(name, qtype));
      for(auto i = ecsIndexRange.first; i != ecsIndexRange.second; ) {
        ecsIdx.erase(i++);
      }
    }
  }
  else {
    auto& idx = d_cache.get<OrderedTag>();
    auto& ecsIdx = d_ecsIndex.get<OrderedTag>();

    for(auto iter = idx.lower_bound(name); iter != idx.end(); ) {
      if(!iter->d_qname.isPartOf(name))
	break;
      if(iter->d_qtype == qtype || qtype == 0xffff) {
	count++;
	idx.erase(iter++);
      }
      else 
	iter++;
    }
    for(auto iter = ecsIdx.lower_bound(name); iter != ecsIdx.end(); ) {
      if(!iter->d_qname.isPartOf(name))
	break;
      if(iter->d_qtype == qtype || qtype == 0xffff) {
	ecsIdx.erase(iter++);
      }
      else {
	iter++;
      }
    }
  }
  return count;
}

bool MemRecursorCache::doAgeCache(time_t now, const DNSName& name, uint16_t qtype, uint32_t newTTL)
{
  cache_t::iterator iter = d_cache.find(tie(name, qtype));
  if(iter == d_cache.end()) {
    return false;
  }

  CacheEntry ce = *iter;
  if(ce.d_ttd < now)
    return false;  // would be dead anyhow

  uint32_t maxTTL = static_cast<uint32_t>(ce.d_ttd - now);
  if(maxTTL > newTTL) {
    d_cachecachevalid=false;

    time_t newTTD = now + newTTL;


    if(ce.d_ttd > newTTD) // do never renew expired or older TTLs
      ce.d_ttd = newTTD;
  

    d_cache.replace(iter, ce);
    return true;
  }
  return false;
}

bool MemRecursorCache::updateValidationStatus(time_t now, const DNSName &qname, const QType& qt, const ComboAddress& who, bool requireAuth, vState newState, boost::optional<time_t> capTTD)
{
  bool updated = false;
  uint16_t qtype = qt.getCode();
  if (qtype != QType::ANY && qtype != QType::ADDR && !d_ecsIndex.empty()) {
    auto entry = getEntryUsingECSIndex(now, qname, qtype, requireAuth, who);
    if (entry == d_cache.end()) {
      return false;
    }

    entry->d_state = newState;
    if (capTTD) {
      entry->d_ttd = std::min(entry->d_ttd, *capTTD);
    }
    return true;
  }

  auto entries = getEntries(qname, qt);

  for(auto i = entries.first; i != entries.second; ++i) {
    auto firstIndexIterator = d_cache.project<OrderedTag>(i);

    if (!entryMatches(firstIndexIterator, qtype, requireAuth, who))
      continue;

    i->d_state = newState;
    if (capTTD) {
      i->d_ttd = std::min(i->d_ttd, *capTTD);
    }
    updated = true;

    if(qtype != QType::ANY && qtype != QType::ADDR) // normally if we have a hit, we are done
      break;
  }

  return updated;
}

uint64_t MemRecursorCache::doDump(int fd)
{
  auto fp = std::unique_ptr<FILE, int(*)(FILE*)>(fdopen(dup(fd), "w"), fclose);
  if(!fp) { // dup probably failed
    return 0;
  }
  fprintf(fp.get(), "; main record cache dump from thread follows\n;\n");
  const auto& sidx=d_cache.get<SequencedTag>();

  uint64_t count=0;
  time_t now=time(0);
  for(const auto i : sidx) {
    for(const auto j : i.d_records) {
      count++;
      try {
        fprintf(fp.get(), "%s %" PRId64 " IN %s %s ; (%s) auth=%i %s\n", i.d_qname.toString().c_str(), static_cast<int64_t>(i.d_ttd - now), DNSRecordContent::NumberToType(i.d_qtype).c_str(), j->getZoneRepresentation().c_str(), vStates[i.d_state], i.d_auth, i.d_netmask.empty() ? "" : i.d_netmask.toString().c_str());
      }
      catch(...) {
        fprintf(fp.get(), "; error printing '%s'\n", i.d_qname.empty() ? "EMPTY" : i.d_qname.toString().c_str());
      }
    }
    for(const auto &sig : i.d_signatures) {
      count++;
      try {
        fprintf(fp.get(), "%s %" PRId64 " IN RRSIG %s ; %s\n", i.d_qname.toString().c_str(), static_cast<int64_t>(i.d_ttd - now), sig->getZoneRepresentation().c_str(), i.d_netmask.empty() ? "" : i.d_netmask.toString().c_str());
      }
      catch(...) {
        fprintf(fp.get(), "; error printing '%s'\n", i.d_qname.empty() ? "EMPTY" : i.d_qname.toString().c_str());
      }
    }
  }
  return count;
}

void MemRecursorCache::doPrune(unsigned int keep)
{
  d_cachecachevalid=false;

  pruneCollection<SequencedTag>(*this, d_cache, keep);
}

