/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

#include "tmanager/src/cpp/manager/stats-interface.h"
#include <iostream>
#include <string>
#include "manager/tmanager.h"
#include "manager/tmetrics-collector.h"
#include "metrics/tmanager-metrics.h"
#include "basics/basics.h"
#include "errors/errors.h"
#include "threads/threads.h"
#include "network/network.h"
#include "proto/tmanager.pb.h"

namespace heron {
namespace tmanager {

StatsInterface::StatsInterface(std::shared_ptr<EventLoop> eventLoop, const NetworkOptions& _options,
                               shared_ptr<TMetricsCollector> _collector, TManager* _tmanager)
    : metrics_collector_(_collector), tmanager_(_tmanager) {
  http_server_ = make_unique<HTTPServer>(eventLoop, _options);
  // Install the handlers
  auto cbHandleStats = [this](IncomingHTTPRequest* request) { this->HandleStatsRequest(request); };

  auto cbHandleException = [this](IncomingHTTPRequest* request) {
    this->HandleExceptionRequest(request);
  };

  auto cbHandleExceptionSummary = [this](IncomingHTTPRequest* request) {
    this->HandleExceptionSummaryRequest(request);
  };

  auto cbHandleStmgrsRegistrationSummary = [this](IncomingHTTPRequest* request) {
    this->HandleStmgrsRegistrationSummaryRequest(request);
  };

  auto cbHandleUnknown = [this](IncomingHTTPRequest* request) {
    this->HandleUnknownRequest(request);
  };

  http_server_->InstallCallBack("/stats", std::move(cbHandleStats));
  http_server_->InstallCallBack("/exceptions", std::move(cbHandleException));
  http_server_->InstallCallBack("/exceptionsummary", std::move(cbHandleExceptionSummary));
  http_server_->InstallCallBack("/stmgrsregistrationsummary",
      std::move(cbHandleStmgrsRegistrationSummary));
  http_server_->InstallGenericCallBack(std::move(cbHandleUnknown));
  CHECK(http_server_->Start() == SP_OK);
}

StatsInterface::~StatsInterface() {}

void StatsInterface::HandleStatsRequest(IncomingHTTPRequest* _request) {
  LOG(INFO) << "Got a stats request " << _request->GetQuery();
  // get the entire stuff
  unsigned char* pb = _request->ExtractFromPostData(0, _request->GetPayloadSize());
  proto::tmanager::MetricRequest req;
  if (!req.ParseFromArray(pb, _request->GetPayloadSize())) {
    LOG(ERROR) << "Unable to deserialize post data specified in StatsRequest";
    http_server_->SendErrorReply(_request, 400);
    delete _request;
    return;
  }
  auto res = metrics_collector_->GetMetrics(req, tmanager_->getInitialTopology());
  sp_string response_string;
  CHECK(res->SerializeToString(&response_string));
  auto response = make_unique<OutgoingHTTPResponse>(_request);
  response->AddHeader("Content-Type", "application/octet-stream");
  response->AddHeader("Content-Length", std::to_string(response_string.size()));
  response->AddResponse(response_string);
  http_server_->SendReply(_request, 200, std::move(response));
  delete _request;
  LOG(INFO) << "Done with stats request ";
}

void StatsInterface::HandleExceptionRequest(IncomingHTTPRequest* _request) {
  LOG(INFO) << "Request for exceptions" << _request->GetQuery();
  // Get the Exception request proto.
  unsigned char* request_data = _request->ExtractFromPostData(0, _request->GetPayloadSize());
  heron::proto::tmanager::ExceptionLogRequest exception_request;
  if (!exception_request.ParseFromArray(request_data, _request->GetPayloadSize())) {
    LOG(ERROR) << "Unable to deserialize post data specified in ExceptionRequest" << std::endl;
    http_server_->SendErrorReply(_request, 400);
    delete _request;
    return;
  }
  unique_ptr<heron::proto::tmanager::ExceptionLogResponse> exception_response =
      metrics_collector_->GetExceptions(exception_request);
  sp_string response_string;
  CHECK(exception_response->SerializeToString(&response_string));
  auto http_response = make_unique<OutgoingHTTPResponse>(_request);
  http_response->AddHeader("Content-Type", "application/octet-stream");
  http_response->AddHeader("Content-Length", std::to_string(response_string.size()));
  http_response->AddResponse(response_string);
  http_server_->SendReply(_request, 200, std::move(http_response));
  delete _request;
  LOG(INFO) << "Returned exceptions response";
}

void StatsInterface::HandleExceptionSummaryRequest(IncomingHTTPRequest* _request) {
  LOG(INFO) << "Request for exception summary " << _request->GetQuery();
  unsigned char* request_data = _request->ExtractFromPostData(0, _request->GetPayloadSize());
  heron::proto::tmanager::ExceptionLogRequest exception_request;
  if (!exception_request.ParseFromArray(request_data, _request->GetPayloadSize())) {
    LOG(ERROR) << "Unable to deserialize post data specified in ExceptionRequest" << std::endl;
    http_server_->SendErrorReply(_request, 400);
    delete _request;
    return;
  }
  auto exception_response = metrics_collector_->GetExceptionsSummary(exception_request);
  sp_string response_string;
  CHECK(exception_response->SerializeToString(&response_string));
  auto http_response = make_unique<OutgoingHTTPResponse>(_request);
  http_response->AddHeader("Content-Type", "application/octet-stream");
  http_response->AddHeader("Content-Length", std::to_string(response_string.size()));
  http_response->AddResponse(response_string);
  http_server_->SendReply(_request, 200, std::move(http_response));
  delete _request;
  LOG(INFO) << "Returned exceptions response";
}

void StatsInterface::HandleStmgrsRegistrationSummaryRequest(IncomingHTTPRequest* _request) {
  LOG(INFO) << "Request for stream managers registration summary " << _request->GetQuery();
  unsigned char* request_data =
    _request->ExtractFromPostData(0, _request->GetPayloadSize());
  heron::proto::tmanager::StmgrsRegistrationSummaryRequest stmgrs_reg_request;
  if (!stmgrs_reg_request.ParseFromArray(request_data, _request->GetPayloadSize())) {
    LOG(ERROR) << "Unable to deserialize post data specified in" <<
      "StmgrsRegistrationSummaryRequest" << std::endl;
    http_server_->SendErrorReply(_request, 400);
    delete _request;
    return;
  }
  auto stmgrs_reg_summary_response = tmanager_->GetStmgrsRegSummary();
  sp_string response_string;
  CHECK(stmgrs_reg_summary_response->SerializeToString(&response_string));
  auto http_response = make_unique<OutgoingHTTPResponse>(_request);
  http_response->AddHeader("Content-Type", "application/octet-stream");
  http_response->AddHeader("Content-Length", std::to_string(response_string.size()));
  http_response->AddResponse(response_string);
  http_server_->SendReply(_request, 200, std::move(http_response));
  delete _request;
  LOG(INFO) << "Returned stream managers registration summary response";
}

void StatsInterface::HandleUnknownRequest(IncomingHTTPRequest* _request) {
  LOG(WARNING) << "Got an unknown request " << _request->GetQuery();
  http_server_->SendErrorReply(_request, 400);
  delete _request;
}
}  // namespace tmanager
}  // namespace heron