/**
 * 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.
 **/

/* A standalone command-line interface to QuickStep */

#include <chrono>
#include <cstddef>
#include <cstdio>
#include <exception>
#include <memory>
#include <string>
#include <utility>
#include <vector>
#include <fstream>

// TODO(jmp): If filesystem shows up in C++-17, we can switch to just using that.
#ifdef QUICKSTEP_OS_WINDOWS
#include <filesystem>
#else
#include <stdlib.h>
#endif

#include "cli/CliConfig.h"  // For QUICKSTEP_USE_LINENOISE, QUICKSTEP_ENABLE_GOOGLE_PROFILER.
#include "cli/CommandExecutor.hpp"
#include "cli/DropRelation.hpp"

#ifdef QUICKSTEP_USE_LINENOISE
#include "cli/LineReaderLineNoise.hpp"
typedef quickstep::LineReaderLineNoise LineReaderImpl;
#else
#include "cli/LineReaderDumb.hpp"
typedef quickstep::LineReaderDumb LineReaderImpl;
#endif

#ifdef QUICKSTEP_ENABLE_GOOGLE_PROFILER
#include <gperftools/profiler.h>
#endif

#include "cli/DefaultsConfigurator.hpp"
#include "cli/InputParserUtil.hpp"
#include "cli/PrintToScreen.hpp"
#include "parser/ParseStatement.hpp"
#include "parser/SqlParserWrapper.hpp"
#include "query_execution/AdmitRequestMessage.hpp"
#include "query_execution/ForemanSingleNode.hpp"
#include "query_execution/QueryExecutionTypedefs.hpp"
#include "query_execution/QueryExecutionUtil.hpp"
#include "query_execution/Worker.hpp"
#include "query_execution/WorkerDirectory.hpp"
#include "query_execution/WorkerMessage.hpp"
#include "query_optimizer/QueryHandle.hpp"
#include "query_optimizer/QueryPlan.hpp"
#include "query_optimizer/QueryProcessor.hpp"
#include "storage/StorageConfig.h"  // For QUICKSTEP_HAVE_FILE_MANAGER_HDFS.

#ifdef QUICKSTEP_HAVE_FILE_MANAGER_HDFS
#include "storage/FileManagerHdfs.hpp"
#endif

#include "storage/PreloaderThread.hpp"
#include "threading/ThreadIDBasedMap.hpp"
#include "utility/ExecutionDAGVisualizer.hpp"
#include "utility/Macros.hpp"
#include "utility/PtrVector.hpp"
#include "utility/SqlError.hpp"
#include "utility/StringUtil.hpp"

#include "gflags/gflags.h"

#include "glog/logging.h"

#include "tmb/address.h"
#include "tmb/id_typedefs.h"
#include "tmb/message_bus.h"
#include "tmb/message_style.h"

namespace quickstep {
class CatalogRelation;
}

using std::fflush;
using std::fprintf;
using std::printf;
using std::string;
using std::vector;

using quickstep::Address;
using quickstep::AdmitRequestMessage;
using quickstep::CatalogRelation;
using quickstep::DefaultsConfigurator;
using quickstep::DropRelation;
using quickstep::ForemanSingleNode;
using quickstep::InputParserUtil;
using quickstep::MessageBusImpl;
using quickstep::MessageStyle;
using quickstep::ParseCommand;
using quickstep::ParseResult;
using quickstep::ParseStatement;
using quickstep::PrintToScreen;
using quickstep::PtrVector;
using quickstep::QueryExecutionUtil;
using quickstep::QueryHandle;
using quickstep::QueryPlan;
using quickstep::QueryProcessor;
using quickstep::SqlParserWrapper;
using quickstep::Worker;
using quickstep::WorkerDirectory;
using quickstep::WorkerMessage;
using quickstep::kAdmitRequestMessage;
using quickstep::kPoisonMessage;
using quickstep::kWorkloadCompletionMessage;

using tmb::client_id;

namespace quickstep {

#ifdef QUICKSTEP_OS_WINDOWS
static constexpr char kPathSeparator = '\\';
static constexpr char kDefaultStoragePath[] = "qsstor\\";
#else
static constexpr char kPathSeparator = '/';
static constexpr char kDefaultStoragePath[] = "qsstor/";
#endif

DEFINE_bool(profile_and_report_workorder_perf, false,
    "If true, Quickstep will record the exceution time of all the individual "
    "normal work orders and report it at the end of query execution.");
DEFINE_int32(num_workers, 0, "Number of worker threads. If this value is "
                             "specified and is greater than 0, then this "
                             "user-supplied value is used. Else (i.e. the"
                             "default case), we examine the reported "
                             "hardware concurrency level, and use that.");
DEFINE_bool(preload_buffer_pool, false,
            "If true, pre-load all known blocks into buffer pool before "
            "accepting queries (should also set --buffer_pool_slots to be "
            "large enough to accomodate the entire database).");
DEFINE_string(storage_path, kDefaultStoragePath,
              "Filesystem path to store the Quickstep database.");
DEFINE_string(worker_affinities, "",
              "A comma-separated list of CPU IDs to pin worker threads to "
              "(leaving this empty will cause all worker threads to inherit "
              "the affinity mask of the Quickstep process, which typically "
              "means that they will all be runable on any CPU according to "
              "the kernel's own scheduling policy).");
DEFINE_bool(initialize_db, false, "If true, initialize a database.");
DEFINE_bool(print_query, false,
            "Print each input query statement. This is useful when running a "
            "large number of queries in a batch.");
DEFINE_string(profile_file_name, "",
              "If nonempty, enable profiling using GOOGLE CPU Profiler, and write "
              "its output to the given file name. This flag has no effect if "
              "ENABLE_GOOGLE_PROFILER CMake flag was not set during build. "
              "The profiler only starts collecting samples after the first query, "
              "so that it runs against a warm buffer pool and caches. If you want to profile "
              "everything, including the first query run, set the "
              "environment variable CPUPROFILE instead of passing this flag.");
              // Here's a detailed explanation of why we skip the first query run
              // during profiling:
              // Unless you’ve preloaded the buffer pool (which is not always a good
              // idea), the first run of the query results in disk I/O and other overhead
              // that significantly skews the profiling results. It’s the same reason we don’t
              // include the first run time in our benchmarking: when profiling query
              // execution, it makes more sense to get numbers using a warm buffer pool and
              // warm caches. This is not *always* the right thing to do: it’s obviously
              // wrong for profiling the TextScan operator. In those cases, you might want
              // to put in your own Profiler probes (just follow the start/stop pattern used
              // in this file) or just run quickstep with the CPUPROFILE environment variable
              // set (as per gperftools documentation) to get the full profile for the
              // entire execution.
              // To put things in perspective, the first run is, in my experiments, about 5-10
              // times more expensive than the average run. That means the query needs to be
              // run at least a hundred times to make the impact of the first run small (< 5 %).
DEFINE_bool(visualize_execution_dag, false,
            "If true, visualize the execution plan DAG into a graph in DOT "
            "format (DOT is a plain text graph description language) which is "
            "then printed via stderr.");

}  // namespace quickstep

int main(int argc, char* argv[]) {
  google::InitGoogleLogging(argv[0]);
  gflags::ParseCommandLineFlags(&argc, &argv, true);

  // Detect the hardware concurrency level.
  const std::size_t num_hw_threads =
      DefaultsConfigurator::GetNumHardwareThreads();

  // Use the command-line value if that was supplied, else use the value
  // that we computed above, provided it did return a valid value.
  // TODO(jmp): May need to change this at some point to keep one thread
  //            available for the OS if the hardware concurrency level is high.
  if (quickstep::FLAGS_num_workers <= 0) {
    LOG(INFO) << "Quickstep expects at least one worker thread, switching to "
                 "the default number of worker threads";
  }
  const int real_num_workers = quickstep::FLAGS_num_workers > 0
                                   ? quickstep::FLAGS_num_workers
                                   : (num_hw_threads != 0 ? num_hw_threads : 1);

  DCHECK_GT(real_num_workers, 0);
  printf("Starting Quickstep with %d worker thread(s) and a %.2f GB buffer pool\n",
         real_num_workers,
         (static_cast<double>(quickstep::FLAGS_buffer_pool_slots) * quickstep::kSlotSizeBytes)/quickstep::kAGigaByte);

#ifdef QUICKSTEP_HAVE_FILE_MANAGER_HDFS
  if (quickstep::FLAGS_use_hdfs) {
    LOG(INFO) << "Using HDFS as the default persistent storage, with namenode at "
              << quickstep::FLAGS_hdfs_namenode_host << ":"
              << quickstep::FLAGS_hdfs_namenode_port << " and block replication factor "
              << quickstep::FLAGS_hdfs_num_replications << "\n";
  }
#endif

  // Initialize the thread ID based map here before the Foreman and workers are
  // constructed because the initialization isn't thread safe.
  quickstep::ClientIDMap::Instance();

  MessageBusImpl bus;
  bus.Initialize();

  // The TMB client id for the main thread, used to kill workers at the end.
  const client_id main_thread_client_id = bus.Connect();
  bus.RegisterClientAsSender(main_thread_client_id, kAdmitRequestMessage);
  bus.RegisterClientAsSender(main_thread_client_id, kPoisonMessage);
  bus.RegisterClientAsReceiver(main_thread_client_id, kWorkloadCompletionMessage);

  // Setup the paths used by StorageManager.
  string fixed_storage_path(quickstep::FLAGS_storage_path);
  if (!fixed_storage_path.empty()
      && (fixed_storage_path.back() != quickstep::kPathSeparator)) {
    fixed_storage_path.push_back(quickstep::kPathSeparator);
  }

  string catalog_path(fixed_storage_path);
  catalog_path.append("catalog.pb.bin");
  if (quickstep::FLAGS_initialize_db) {  // Initialize the database
    // TODO(jmp): Refactor the code in this file!
    LOG(INFO) << "Initializing the database, creating a new catalog file and storage directory\n";

    // Create the directory
    // TODO(jmp): At some point, likely in C++-17, we will just have the
    //            filesystem path, and we can clean this up
#ifdef QUICKSTEP_OS_WINDOWS
    std::filesystem::create_directories(fixed_storage_path);
    LOG(FATAL) << "Failed when attempting to create the directory: " << fixed_storage_path << "\n";
    LOG(FATAL) << "Check if the directory already exists. If so, delete it or move it before initializing \n";
#else
    {
      string path_name = "mkdir " + fixed_storage_path;
      if (std::system(path_name.c_str())) {
        LOG(FATAL) << "Failed when attempting to create the directory: " << fixed_storage_path << "\n";
      }
    }
#endif

    // Create the default catalog file.
    std::ofstream catalog_file(catalog_path);
    if (!catalog_file.good()) {
      LOG(FATAL) << "ERROR: Unable to open catalog.pb.bin for writing.\n";
    }

    quickstep::Catalog catalog;
    catalog.addDatabase(new quickstep::CatalogDatabase(nullptr, "default"));

    if (!catalog.getProto().SerializeToOstream(&catalog_file)) {
      LOG(FATAL) << "ERROR: Unable to serialize catalog proto to file catalog.pb.bin\n";
      return 1;
    }

    // Close the catalog file - it will be reopened below by the QueryProcessor.
    catalog_file.close();
  }

  // Setup QueryProcessor, including CatalogDatabase and StorageManager.
  std::unique_ptr<QueryProcessor> query_processor;
  try {
    query_processor.reset(new QueryProcessor(catalog_path, fixed_storage_path));
  } catch (const std::exception &e) {
    LOG(FATAL) << "FATAL ERROR DURING STARTUP: "
               << e.what()
               << "\nIf you intended to create a new database, "
               << "please use the \"-initialize_db=true\" command line option.";
  } catch (...) {
    LOG(FATAL) << "NON-STANDARD EXCEPTION DURING STARTUP";
  }

  // Parse the CPU affinities for workers and the preloader thread, if enabled
  // to warm up the buffer pool.
  const vector<int> worker_cpu_affinities =
      InputParserUtil::ParseWorkerAffinities(real_num_workers,
                                             quickstep::FLAGS_worker_affinities);

  const std::size_t num_numa_nodes_system = DefaultsConfigurator::GetNumNUMANodes();

  if (quickstep::FLAGS_preload_buffer_pool) {
    std::chrono::time_point<std::chrono::steady_clock> preload_start, preload_end;
    preload_start = std::chrono::steady_clock::now();
    printf("Preloading the buffer pool ... ");
    fflush(stdout);
    quickstep::PreloaderThread preloader(*query_processor->getDefaultDatabase(),
                                         query_processor->getStorageManager(),
                                         worker_cpu_affinities.front());

    preloader.start();
    preloader.join();
    preload_end = std::chrono::steady_clock::now();
    printf("in %g seconds\n",
           std::chrono::duration<double>(preload_end - preload_start).count());
  }

  // Get the NUMA affinities for workers.
  vector<int> cpu_numa_nodes = InputParserUtil::GetNUMANodesForCPUs();
  if (cpu_numa_nodes.empty()) {
    // libnuma is not present. Assign -1 as the NUMA node for every worker.
    cpu_numa_nodes.assign(worker_cpu_affinities.size(), -1);
  }

  vector<int> worker_numa_nodes;
  PtrVector<Worker> workers;
  vector<client_id> worker_client_ids;

  // Initialize the worker threads.
  DCHECK_EQ(static_cast<std::size_t>(real_num_workers),
            worker_cpu_affinities.size());
  for (std::size_t worker_thread_index = 0;
       worker_thread_index < worker_cpu_affinities.size();
       ++worker_thread_index) {
    int numa_node_id = -1;
    if (worker_cpu_affinities[worker_thread_index] >= 0) {
      // This worker can be NUMA affinitized.
      numa_node_id = cpu_numa_nodes[worker_cpu_affinities[worker_thread_index]];
    }
    worker_numa_nodes.push_back(numa_node_id);

    workers.push_back(
        new Worker(worker_thread_index, &bus, worker_cpu_affinities[worker_thread_index]));
    worker_client_ids.push_back(workers.back().getBusClientID());
  }

  // TODO(zuyu): Move WorkerDirectory within Shiftboss once the latter is added.
  WorkerDirectory worker_directory(worker_cpu_affinities.size(),
                                   worker_client_ids,
                                   worker_numa_nodes);

  ForemanSingleNode foreman(
      main_thread_client_id,
      &worker_directory,
      &bus,
      query_processor->getDefaultDatabase(),
      query_processor->getStorageManager(),
      -1,  // Don't pin the Foreman thread.
      num_numa_nodes_system,
      quickstep::FLAGS_profile_and_report_workorder_perf || quickstep::FLAGS_visualize_execution_dag);

  // Start the worker threads.
  for (Worker &worker : workers) {
    worker.start();
  }

  foreman.start();

  LineReaderImpl line_reader("quickstep> ",
                             "      ...> ");
  std::unique_ptr<SqlParserWrapper> parser_wrapper(new SqlParserWrapper());
  std::chrono::time_point<std::chrono::steady_clock> start, end;

#ifdef QUICKSTEP_ENABLE_GOOGLE_PROFILER
  bool started_profiling = false;
#endif
  for (;;) {
    string *command_string = new string();
    *command_string = line_reader.getNextCommand();
    if (command_string->size() == 0) {
      delete command_string;
      break;
    }

    if (quickstep::FLAGS_print_query) {
      printf("\n%s\n", command_string->c_str());
    }

    parser_wrapper->feedNextBuffer(command_string);

    bool quitting = false;
    // A parse error should reset the parser. This is because the thrown quickstep
    // SqlError does not do the proper reset work of the YYABORT macro.
    bool reset_parser = false;
    for (;;) {
      ParseResult result = parser_wrapper->getNextStatement();
      const ParseStatement &statement = *result.parsed_statement;
      if (result.condition == ParseResult::kSuccess) {
        if (statement.getStatementType() == ParseStatement::kQuit) {
          quitting = true;
          break;
        }

        if (statement.getStatementType() == ParseStatement::kCommand) {
          try {
            quickstep::cli::executeCommand(
                statement,
                *(query_processor->getDefaultDatabase()),
                main_thread_client_id,
                foreman.getBusClientID(),
                &bus,
                query_processor->getStorageManager(),
                query_processor.get(),
                stdout);
          } catch (const quickstep::SqlError &sql_error) {
            fprintf(stderr, "%s",
                    sql_error.formatMessage(*command_string).c_str());
            reset_parser = true;
            break;
          }
          continue;
        }

        std::unique_ptr<QueryHandle> query_handle(
            std::make_unique<QueryHandle>(query_processor->query_id(),
                                          main_thread_client_id,
                                          statement.getPriority()));
        try {
          query_processor->generateQueryHandle(statement, query_handle.get());
        } catch (const quickstep::SqlError &sql_error) {
          fprintf(stderr, "%s", sql_error.formatMessage(*command_string).c_str());
          reset_parser = true;
          break;
        }

        DCHECK(query_handle->getQueryPlanMutable() != nullptr);
        std::unique_ptr<quickstep::ExecutionDAGVisualizer> dag_visualizer;
        if (quickstep::FLAGS_visualize_execution_dag) {
          dag_visualizer.reset(
              new quickstep::ExecutionDAGVisualizer(*query_handle->getQueryPlanMutable()));
        }

        start = std::chrono::steady_clock::now();
        QueryExecutionUtil::ConstructAndSendAdmitRequestMessage(
            main_thread_client_id,
            foreman.getBusClientID(),
            query_handle.get(),
            &bus);

        try {
          QueryExecutionUtil::ReceiveQueryCompletionMessage(
              main_thread_client_id, &bus);
          end = std::chrono::steady_clock::now();

          const CatalogRelation *query_result_relation = query_handle->getQueryResultRelation();
          if (query_result_relation) {
            PrintToScreen::PrintRelation(*query_result_relation,
                                         query_processor->getStorageManager(),
                                         stdout);
            PrintToScreen::PrintOutputSize(
                *query_result_relation,
                query_processor->getStorageManager(),
                stdout);

            DropRelation::Drop(*query_result_relation,
                               query_processor->getDefaultDatabase(),
                               query_processor->getStorageManager());
          }

          query_processor->saveCatalog();
          std::chrono::duration<double, std::milli> time_ms = end - start;
          printf("Time: %s ms\n",
                 quickstep::DoubleToStringWithSignificantDigits(
                     time_ms.count(), 3).c_str());
          if (quickstep::FLAGS_profile_and_report_workorder_perf) {
            // TODO(harshad) - Allow user specified file instead of stdout.
            foreman.printWorkOrderProfilingResults(query_handle->query_id(),
                                                   stdout);
          }
          if (quickstep::FLAGS_visualize_execution_dag) {
            const auto &profiling_stats =
                foreman.getWorkOrderProfilingResults(query_handle->query_id());
            dag_visualizer->bindProfilingStats(profiling_stats);
            std::cerr << "\n" << dag_visualizer->toDOT() << "\n";
          }
        } catch (const std::exception &e) {
          fprintf(stderr, "QUERY EXECUTION ERROR: %s\n", e.what());
          break;
        }
      } else {
        if (result.condition == ParseResult::kError) {
          fprintf(stderr, "%s", result.error_message.c_str());
        }
        reset_parser = true;
        break;
      }
#ifdef QUICKSTEP_ENABLE_GOOGLE_PROFILER
      // Profile only if profile_file_name flag is set
      if (!started_profiling && !quickstep::FLAGS_profile_file_name.empty()) {
        started_profiling = true;
        ProfilerStart(quickstep::FLAGS_profile_file_name.c_str());
      }
#endif
    }

    if (quitting) {
      break;
    } else if (reset_parser) {
      parser_wrapper.reset(new SqlParserWrapper());
      reset_parser = false;
    }
  }

#ifdef QUICKSTEP_ENABLE_GOOGLE_PROFILER
  if (started_profiling) {
    ProfilerStop();
    ProfilerFlush();
  }
#endif

  // Kill the foreman and workers.
  QueryExecutionUtil::BroadcastPoisonMessage(main_thread_client_id, &bus);

  for (Worker &worker : workers) {
    worker.join();
  }

  foreman.join();
  return 0;
}