////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2017 ArangoDB GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
///     http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Simon Gräter
////////////////////////////////////////////////////////////////////////////////

#include "UpgradeTasks.h"
#include "Agency/AgencyComm.h"
#include "Basics/Common.h"
#include "Basics/Exceptions.h"
#include "Basics/FileUtils.h"
#include "Basics/StringUtils.h"
#include "Basics/VelocyPackHelper.h"
#include "Basics/files.h"
#include "Cluster/ClusterComm.h"
#include "Cluster/ClusterFeature.h"
#include "Cluster/ClusterInfo.h"
#include "Cluster/ServerState.h"
#include "GeneralServer/AuthenticationFeature.h"
#include "Logger/Logger.h"
#include "MMFiles/MMFilesEngine.h"
#include "RocksDBEngine/RocksDBCommon.h"
#include "RocksDBEngine/RocksDBIndex.h"
#include "StorageEngine/EngineSelectorFeature.h"
#include "StorageEngine/PhysicalCollection.h"
#include "Transaction/StandaloneContext.h"
#include "Utils/OperationOptions.h"
#include "Utils/SingleCollectionTransaction.h"
#include "VocBase/LogicalCollection.h"
#include "VocBase/Methods/Collections.h"
#include "VocBase/Methods/Indexes.h"
#include "VocBase/vocbase.h"

#include <velocypack/Builder.h>
#include <velocypack/Collection.h>
#include <velocypack/Iterator.h>
#include <velocypack/velocypack-aliases.h>

using namespace arangodb;
using namespace arangodb::methods;
using application_features::ApplicationServer;
using basics::VelocyPackHelper;

// Note: this entire file should run with superuser rights

namespace {

/// create a collection if it does not exists.
bool createSystemCollection(TRI_vocbase_t* vocbase, std::string const& name) {
  auto res =
      methods::Collections::lookup(vocbase, name,
                                   [](std::shared_ptr<LogicalCollection> const&) -> void {});

  if (res.is(TRI_ERROR_ARANGO_DATA_SOURCE_NOT_FOUND)) {
    uint32_t defaultReplFactor = 1;
    ClusterFeature* cl =
        ApplicationServer::getFeature<ClusterFeature>("Cluster");

    if (cl != nullptr) {
      defaultReplFactor = cl->systemReplicationFactor();
    }

    VPackBuilder bb;

    bb.openObject();
    bb.add("isSystem", VPackSlice::trueSlice());
    bb.add("waitForSync", VPackSlice::falseSlice());
    bb.add("journalSize", VPackValue(1024 * 1024));
    bb.add("replicationFactor", VPackValue(defaultReplFactor));

    if (name != "_graphs") {
      bb.add("distributeShardsLike", VPackValue("_graphs"));
    }

    bb.close();
    res = Collections::create(vocbase, name, TRI_COL_TYPE_DOCUMENT, bb.slice(),
                              /*waitsForSyncReplication*/ false,
                              /*enforceReplicationFactor*/ true,
                              [](std::shared_ptr<LogicalCollection> const&) -> void {});
  }

  // if the system collection exists by now, then some other thread
  // has just created it between the lookup and the create
  if (res.fail() && !res.is(TRI_ERROR_ARANGO_DUPLICATE_NAME)) {
    THROW_ARANGO_EXCEPTION(res);
  }

  return true;
}

/// create an index if it does not exist
bool createIndex(TRI_vocbase_t* vocbase, std::string const& name, Index::IndexType type,
                 std::vector<std::string> const& fields, bool unique, bool sparse) {
  VPackBuilder output;
  Result res1, res2;

  res1 = methods::Collections::lookup(
      vocbase, name, [&](std::shared_ptr<LogicalCollection> const& coll) -> void {
        TRI_ASSERT(coll);
        res2 = methods::Indexes::createIndex(coll.get(), type, fields, unique, sparse);
      });

  if (res1.fail() || res2.fail()) {
    THROW_ARANGO_EXCEPTION(res1.fail() ? res1 : res2);
  }

  return true;
}

arangodb::Result recreateGeoIndex(TRI_vocbase_t& vocbase,
                                  arangodb::LogicalCollection& collection,
                                  arangodb::RocksDBIndex* oldIndex) {
  arangodb::Result res;
  TRI_idx_iid_t iid = oldIndex->id();

  VPackBuilder oldDesc;
  oldIndex->toVelocyPack(oldDesc, Index::makeFlags());
  VPackBuilder overw;

  overw.openObject();
  overw.add(arangodb::StaticStrings::IndexType,
            arangodb::velocypack::Value(
                arangodb::Index::oldtypeName(Index::TRI_IDX_TYPE_GEO_INDEX)));
  overw.close();

  VPackBuilder newDesc = VPackCollection::merge(oldDesc.slice(), overw.slice(), false);
  bool dropped = collection.dropIndex(iid);

  if (!dropped) {
    res.reset(TRI_ERROR_INTERNAL);

    return res;
  }

  bool created = false;
  auto newIndex =
      collection.getPhysical()->createIndex(newDesc.slice(), /*restore*/ true, created);

  if (!created) {
    res.reset(TRI_ERROR_INTERNAL);
  }

  TRI_ASSERT(newIndex->id() == iid);  // will break cluster otherwise
  TRI_ASSERT(newIndex->type() == Index::TRI_IDX_TYPE_GEO_INDEX);

  return res;
}
}  // namespace

bool UpgradeTasks::upgradeGeoIndexes(TRI_vocbase_t& vocbase,
                                     arangodb::velocypack::Slice const& slice) {
  if (EngineSelectorFeature::engineName() != "rocksdb") {
    LOG_TOPIC(DEBUG, Logger::STARTUP) << "No need to upgrade geo indexes!";
    return true;
  }

  auto collections = vocbase.collections(false);

  for (auto collection : collections) {
    auto indexes = collection->getIndexes();
    for (auto index : indexes) {
      RocksDBIndex* rIndex = static_cast<RocksDBIndex*>(index.get());
      if (index->type() == Index::TRI_IDX_TYPE_GEO1_INDEX ||
          index->type() == Index::TRI_IDX_TYPE_GEO2_INDEX) {
        LOG_TOPIC(INFO, Logger::STARTUP)
            << "Upgrading legacy geo index '" << rIndex->id() << "'";

        auto res = ::recreateGeoIndex(vocbase, *collection, rIndex);

        if (res.fail()) {
          LOG_TOPIC(ERR, Logger::STARTUP)
              << "Error upgrading geo indexes " << res.errorMessage();
          return false;
        }
      }
    }
  }

  return true;
}

bool UpgradeTasks::setupGraphs(TRI_vocbase_t& vocbase,
                               arangodb::velocypack::Slice const& slice) {
  return ::createSystemCollection(&vocbase, "_graphs");
}

bool UpgradeTasks::setupUsers(TRI_vocbase_t& vocbase,
                              arangodb::velocypack::Slice const& slice) {
  return ::createSystemCollection(&vocbase, "_users");
}

bool UpgradeTasks::createUsersIndex(TRI_vocbase_t& vocbase,
                                    arangodb::velocypack::Slice const& slice) {
  TRI_ASSERT(vocbase.isSystem());

  return ::createIndex(&vocbase, "_users", Index::TRI_IDX_TYPE_HASH_INDEX, {"user"},
                       /*unique*/ true,
                       /*sparse*/ true);
}

bool UpgradeTasks::addDefaultUserOther(TRI_vocbase_t& vocbase,
                                       arangodb::velocypack::Slice const& params) {
  TRI_ASSERT(!vocbase.isSystem());
  TRI_ASSERT(params.isObject());

  VPackSlice users = params.get("users");

  if (users.isNone()) {
    return true;  // exit, no users were specified
  } else if (!users.isArray()) {
    LOG_TOPIC(ERR, Logger::STARTUP) << "addDefaultUserOther: users is invalid";
    return false;
  }
  auth::UserManager* um = AuthenticationFeature::instance()->userManager();
  if (um == nullptr) {
    return true;  // server does not support users
  }

  for (VPackSlice slice : VPackArrayIterator(users)) {
    std::string user =
        VelocyPackHelper::getStringValue(slice, "username", StaticStrings::Empty);
    if (user.empty()) {
      continue;
    }
    std::string passwd = VelocyPackHelper::getStringValue(slice, "passwd", "");
    bool active = VelocyPackHelper::getBooleanValue(slice, "active", true);
    VPackSlice extra = slice.get("extra");
    Result res = um->storeUser(false, user, passwd, active, VPackSlice::noneSlice());
    if (res.fail() && !res.is(TRI_ERROR_USER_DUPLICATE)) {
      LOG_TOPIC(WARN, Logger::STARTUP) << "could not add database user " << user << ": " << res.errorMessage();
    } else if (extra.isObject() && !extra.isEmptyObject()) {
      um->updateUser(user, [&](auth::User& user) {
        user.setUserData(VPackBuilder(extra));
        return TRI_ERROR_NO_ERROR;
      });
    }
  
    res = um->updateUser(user, [&](auth::User& entry) {
      entry.grantDatabase(vocbase.name(), auth::Level::RW);
      entry.grantCollection(vocbase.name(), "*", auth::Level::RW);
      return TRI_ERROR_NO_ERROR;
    });
    if (res.fail()) {
      LOG_TOPIC(WARN, Logger::STARTUP) << "could not set permissions for new user " << user << ": " << res.errorMessage();
    }
  }
  return true;
}

bool UpgradeTasks::updateUserModels(TRI_vocbase_t& vocbase,
                                    arangodb::velocypack::Slice const& slice) {
  TRI_ASSERT(vocbase.isSystem());
  // TODO isn't this done on the fly ?
  return true;
}

bool UpgradeTasks::createModules(TRI_vocbase_t& vocbase,
                                 arangodb::velocypack::Slice const& slice) {
  return ::createSystemCollection(&vocbase, "_modules");
}

bool UpgradeTasks::setupAnalyzers(TRI_vocbase_t& vocbase,
                                  arangodb::velocypack::Slice const& slice) {
  return ::createSystemCollection(&vocbase, "_iresearch_analyzers");
}

bool UpgradeTasks::createRouting(TRI_vocbase_t& vocbase,
                                 arangodb::velocypack::Slice const& slice) {
  return ::createSystemCollection(&vocbase, "_routing");
}

bool UpgradeTasks::insertRedirections(TRI_vocbase_t& vocbase,
                                      arangodb::velocypack::Slice const& slice) {
  std::vector<std::string> toRemove;  // remove in a different trx
  auto cb = [&toRemove](VPackSlice const& doc) {
    TRI_ASSERT(doc.isObject());
    VPackSlice url = doc.get("url"), action = doc.get("action");
    if (url.isObject() && action.isObject() && action.get("options").isObject()) {
      VPackSlice v = action.get("options").get("destination");
      if (v.isString()) {
        std::string path = v.copyString();
        if (path.find("_admin/html") != std::string::npos ||
            path.find("_admin/aardvark") != std::string::npos) {
          toRemove.push_back(doc.get(StaticStrings::KeyString).copyString());
        }
      }
    }
  };

  auto res = methods::Collections::all(vocbase, "_routing", cb);

  if (res.fail()) {
    THROW_ARANGO_EXCEPTION(res);
  }

  auto ctx = transaction::StandaloneContext::Create(vocbase);
  SingleCollectionTransaction trx(ctx, "_routing", AccessMode::Type::WRITE);

  res = trx.begin();

  if (!res.ok()) {
    THROW_ARANGO_EXCEPTION(res);
  }

  OperationOptions opts;

  opts.waitForSync = true;

  for (std::string const& key : toRemove) {
    VPackBuilder b;
    b(VPackValue(VPackValueType::Object))(StaticStrings::KeyString, VPackValue(key))();
    trx.remove("_routing", b.slice(), opts);  // check results
  }

  std::vector<std::string> paths = {"/", "/_admin/html",
                                    "/_admin/html/index.html"};
  std::string dest = "/_db/" + vocbase.name() + "/_admin/aardvark/index.html";
  OperationResult opres;

  for (std::string const& path : paths) {
    VPackBuilder bb;
    bb.openObject();
    bb.add("url", VPackValue(path));
    bb.add("action", VPackValue(VPackValueType::Object));
    bb.add("do", VPackValue("@arangodb/actions/redirectRequest"));
    bb.add("options", VPackValue(VPackValueType::Object));
    bb.add("permanently", VPackSlice::trueSlice());
    bb.add("destination", VPackValue(dest));
    bb.close();
    bb.close();
    bb.add("priority", VPackValue(-1000000));
    bb.close();
    opres = trx.insert("_routing", bb.slice(), opts);
    if (opres.fail()) {
      THROW_ARANGO_EXCEPTION(opres.result);
    }
  }

  res = trx.finish(opres.result);

  if (!res.ok()) {
    THROW_ARANGO_EXCEPTION(res);
  }

  return true;
}

bool UpgradeTasks::setupAqlFunctions(TRI_vocbase_t& vocbase,
                                     arangodb::velocypack::Slice const& slice) {
  return ::createSystemCollection(&vocbase, "_aqlfunctions");
}

bool UpgradeTasks::createFrontend(TRI_vocbase_t& vocbase,
                                  arangodb::velocypack::Slice const& slice) {
  return ::createSystemCollection(&vocbase, "_frontend");
}

bool UpgradeTasks::setupQueues(TRI_vocbase_t& vocbase,
                               arangodb::velocypack::Slice const& slice) {
  return ::createSystemCollection(&vocbase, "_queues");
}

bool UpgradeTasks::setupJobs(TRI_vocbase_t& vocbase, arangodb::velocypack::Slice const& slice) {
  return ::createSystemCollection(&vocbase, "_jobs");
}

bool UpgradeTasks::createJobsIndex(TRI_vocbase_t& vocbase,
                                   arangodb::velocypack::Slice const& slice) {
  ::createSystemCollection(&vocbase, "_jobs");
  ::createIndex(&vocbase, "_jobs", Index::TRI_IDX_TYPE_SKIPLIST_INDEX,
                {"queue", "status", "delayUntil"},
                /*unique*/ false,
                /*sparse*/ false);
  ::createIndex(&vocbase, "_jobs", Index::TRI_IDX_TYPE_SKIPLIST_INDEX,
                {"status", "queue", "delayUntil"},
                /*unique*/ false,
                /*sparse*/ false);

  return true;
}

bool UpgradeTasks::setupApps(TRI_vocbase_t& vocbase, arangodb::velocypack::Slice const& slice) {
  return ::createSystemCollection(&vocbase, "_apps");
}

bool UpgradeTasks::createAppsIndex(TRI_vocbase_t& vocbase,
                                   arangodb::velocypack::Slice const& slice) {
  return ::createIndex(&vocbase, "_apps", Index::TRI_IDX_TYPE_HASH_INDEX, {"mount"},
                       /*unique*/ true,
                       /*sparse*/ true);
}

bool UpgradeTasks::setupAppBundles(TRI_vocbase_t& vocbase,
                                   arangodb::velocypack::Slice const& slice) {
  return ::createSystemCollection(&vocbase, "_appbundles");
}

bool UpgradeTasks::persistLocalDocumentIds(TRI_vocbase_t& vocbase,
                                           arangodb::velocypack::Slice const& slice) {
  if (EngineSelectorFeature::engineName() != MMFilesEngine::EngineName) {
    return true;
  }
  Result res = basics::catchToResult([&vocbase]() -> Result {
    MMFilesEngine* engine = static_cast<MMFilesEngine*>(EngineSelectorFeature::ENGINE);
    return engine->persistLocalDocumentIds(vocbase);
  });
  return res.ok();
}

bool UpgradeTasks::renameReplicationApplierStateFiles(TRI_vocbase_t& vocbase,
                                                      arangodb::velocypack::Slice const& slice) {
  if (EngineSelectorFeature::engineName() == MMFilesEngine::EngineName) {
    return true;
  }
  
  StorageEngine* engine = EngineSelectorFeature::ENGINE;
  std::string const path = engine->databasePath(&vocbase);
  
  std::string const source = arangodb::basics::FileUtils::buildFilename(
      path, "REPLICATION-APPLIER-STATE");
    
  if (!basics::FileUtils::isRegularFile(source)) {
    // source file does not exist
    return true;
  }

  bool result = true;
 
  // copy file REPLICATION-APPLIER-STATE to REPLICATION-APPLIER-STATE-<id> 
  Result res = basics::catchToResult([&vocbase, &path, &source, &result]() -> Result {
    std::string const dest = arangodb::basics::FileUtils::buildFilename(
        path, "REPLICATION-APPLIER-STATE-" + std::to_string(vocbase.id()));

    LOG_TOPIC(TRACE, Logger::STARTUP) << "copying replication applier file '" << source << "' to '" << dest << "'";

    std::string error;
    if (!TRI_CopyFile(source.c_str(), dest.c_str(), error)) {
      LOG_TOPIC(WARN, Logger::STARTUP) << "could not copy replication applier file '" << source << "' to '" << dest << "'";
      result = false;
    }
    return Result();
  });
  if (res.fail()) {
    return false;
  }
  return result;
}