////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS 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 Kaveh Vahedipour
////////////////////////////////////////////////////////////////////////////////

#include "RestServer/ArangoServer.h"
#include "Rest/HttpRequest.h"
#include "Rest/Version.h"
#include "RestAgencyPrivHandler.h"

#include "Agency/Agent.h"

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

#include <typeinfo>

#include "Logger/Logger.h"

using namespace arangodb;

using namespace arangodb::basics;
using namespace arangodb::rest;
using namespace arangodb::consensus;

////////////////////////////////////////////////////////////////////////////////
/// @brief ArangoDB server
////////////////////////////////////////////////////////////////////////////////

extern ArangoServer* ArangoInstance;


RestAgencyPrivHandler::RestAgencyPrivHandler(HttpRequest* request, Agent* agent)
  : RestBaseHandler(request), _agent(agent) {
}

bool RestAgencyPrivHandler::isDirect() const { return false; }

inline HttpHandler::status_t RestAgencyPrivHandler::reportErrorEmptyRequest () {
  LOG(WARN) << "Empty request to agency!";
  generateError(HttpResponse::NOT_FOUND,404);
  return HttpHandler::status_t(HANDLER_DONE);
}

inline HttpHandler::status_t RestAgencyPrivHandler::reportTooManySuffices () {
  LOG(WARN) << "Agency handles a single suffix: vote, log or configure";
  generateError(HttpResponse::NOT_FOUND,404);
  return HttpHandler::status_t(HANDLER_DONE);
}

inline HttpHandler::status_t RestAgencyPrivHandler::reportBadQuery () {
  generateError(HttpResponse::BAD,400);
  return HttpHandler::status_t(HANDLER_DONE);
}

inline HttpHandler::status_t RestAgencyPrivHandler::reportMethodNotAllowed () {
  generateError(HttpResponse::METHOD_NOT_ALLOWED,405);
  return HttpHandler::status_t(HANDLER_DONE);
}

HttpHandler::status_t RestAgencyPrivHandler::execute() {
  try {
    VPackBuilder result;
    result.add(VPackValue(VPackValueType::Object));
    arangodb::velocypack::Options opts;
    if (_request->suffix().size() == 0) { // empty request
      return reportErrorEmptyRequest();
    } else if (_request->suffix().size() > 1) { // request too long
      return reportTooManySuffices();
    } else {
      term_t term, prevLogTerm;
      id_t id; // leaderId for appendEntries, cadidateId for requestVote
      index_t prevLogIndex, leaderCommit;
    	if (_request->suffix()[0] == "appendEntries") {  // appendEntries
        if (_request->requestType() != HttpRequest::HTTP_REQUEST_POST)
          return reportMethodNotAllowed();
        if (readValue("term", term) &&
            readValue("leaderId", id) &&
            readValue("prevLogIndex", prevLogIndex) &&
            readValue("prevLogTerm", prevLogTerm) && 
            readValue("leaderCommit", leaderCommit)) { // found all values
          priv_rpc_ret_t ret = _agent->recvAppendEntriesRPC(
            term, id, prevLogIndex, prevLogTerm, leaderCommit,
            _request->toVelocyPack(&opts));
          if (ret.success) {
            result.add("term", VPackValue(ret.term));
            result.add("success", VPackValue(ret.success));
          } else {
            // Should neve get here
            TRI_ASSERT(false);
          }
        } else {
          return reportBadQuery(); // bad query
        }
    	} else if (_request->suffix()[0] == "requestVote") { // requestVote
        if (readValue("term", term) &&
            readValue("candidateId", id) &&
            readValue("prevLogIndex", prevLogIndex) &&
            readValue("prevLogTerm", prevLogTerm)) {
          priv_rpc_ret_t ret = _agent->requestVote (
            term, id, prevLogIndex, prevLogTerm, nullptr);
          result.add("term", VPackValue(ret.term));
          result.add("voteGranted", VPackValue(ret.success));
        }
      } else if (_request->suffix()[0] == "notifyAll") { // notify
        if (_request->requestType() != HttpRequest::HTTP_REQUEST_POST)
          return reportMethodNotAllowed();
        if (readValue("term", term) && readValue("agencyId", id)) {
          priv_rpc_ret_t ret = _agent->requestVote (
            term, id, 0, 0, _request->toVelocyPack(&opts));
          result.add("term", VPackValue(ret.term));
          result.add("voteGranted", VPackValue(ret.success));
        } else {
          return reportBadQuery(); // bad query
        }
      } else {
        generateError(HttpResponse::NOT_FOUND,404); // nothing else here
        return HttpHandler::status_t(HANDLER_DONE);
      }
    }
    result.close();
    VPackSlice s = result.slice();
    generateResult(s);
  } catch (...) {
    // Ignore this error
  }
  return HttpHandler::status_t(HANDLER_DONE);
}