/**
 * 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 "cli/CommandExecutor.hpp"

#include <algorithm>
#include <cstddef>
#include <cstdint>
#include <cstdio>
#include <memory>
#include <string>
#include <vector>

#include "catalog/CatalogAttribute.hpp"
#include "catalog/CatalogDatabase.hpp"
#include "catalog/CatalogRelation.hpp"
#include "catalog/CatalogRelationSchema.hpp"
#include "catalog/CatalogRelationStatistics.hpp"
#include "cli/DropRelation.hpp"
#include "cli/PrintToScreen.hpp"
#include "expressions/aggregation/AggregateFunctionMax.hpp"
#include "expressions/aggregation/AggregateFunctionMin.hpp"
#include "parser/ParseStatement.hpp"
#include "parser/ParseString.hpp"
#include "parser/SqlParserWrapper.hpp"
#include "query_optimizer/QueryHandle.hpp"
#include "query_optimizer/QueryPlan.hpp"
#include "query_optimizer/QueryProcessor.hpp"
#include "storage/StorageBlock.hpp"
#include "storage/StorageBlockInfo.hpp"
#include "storage/StorageManager.hpp"
#include "storage/TupleIdSequence.hpp"
#include "storage/TupleStorageSubBlock.hpp"
#include "types/Type.hpp"
#include "types/TypeID.hpp"
#include "types/TypedValue.hpp"
#include "utility/PtrVector.hpp"
#include "utility/SqlError.hpp"

#include "glog/logging.h"

#include "tmb/id_typedefs.h"

using std::fprintf;
using std::fputc;
using std::fputs;
using std::size_t;
using std::string;
using std::vector;

namespace tmb { class MessageBus; }

namespace quickstep {
namespace cli {
namespace {

namespace C = ::quickstep::cli;

void ExecuteDescribeDatabase(
    const PtrVector<ParseString> *arguments,
    const CatalogDatabase &catalog_database,
    StorageManager *storage_manager,
    FILE *out) {
  // Column width initialized to 6 to take into account the header name
  // and the column value table
  int max_column_width = C::kInitMaxColumnWidth;
  vector<std::size_t> num_blocks;
  const CatalogRelation *relation = nullptr;
  if (arguments->size() == 0) {
    for (const CatalogRelation &rel : catalog_database) {
      max_column_width =
          std::max(static_cast<int>(rel.getName().length()), max_column_width);
      num_blocks.push_back(rel.size_blocks());
    }
  } else {
    const ParseString &table_name = arguments->front();
    const std::string &table_name_val = table_name.value();
    relation = catalog_database.getRelationByName(table_name_val);

    if (relation == nullptr) {
      THROW_SQL_ERROR_AT(&(arguments->front())) << " Unrecognized relation " << table_name_val;
    }
    max_column_width = std::max(static_cast<int>(relation->getName().length()),
                                    max_column_width);
    num_blocks.push_back(relation->size_blocks());
  }
  // Only if we have relations work on the printing logic.
  if (catalog_database.size() > 0) {
    const std::size_t max_num_blocks = *std::max_element(num_blocks.begin(), num_blocks.end());
    const int max_num_blocks_digits = std::max(PrintToScreen::GetNumberOfDigits(max_num_blocks),
                                      C::kInitMaxColumnWidth+2);
    vector<int> column_widths;
    column_widths.push_back(max_column_width +1);
    column_widths.push_back(C::kInitMaxColumnWidth + 1);
    column_widths.push_back(max_num_blocks_digits + 1);
    fputs("       List of relations\n\n", out);
    fprintf(out, "%-*s |", max_column_width+1, " Name");
    fprintf(out, "%-*s |", C::kInitMaxColumnWidth, " Type");
    fprintf(out, "%-*s\n", max_num_blocks_digits, " Blocks");
    PrintToScreen::printHBar(column_widths, out);
    //  If there are no argument print the entire list of tables
    //  else print the particular table only.
    vector<std::size_t>::const_iterator num_blocks_it = num_blocks.begin();
    if (arguments->size() == 0) {
      for (const CatalogRelation &rel : catalog_database) {
        fprintf(out, " %-*s |", max_column_width, rel.getName().c_str());
        fprintf(out, " %-*s |", C::kInitMaxColumnWidth - 1, "table");
        fprintf(out, " %-*lu\n", max_num_blocks_digits - 1, *num_blocks_it);
        ++num_blocks_it;
      }
    } else {
      fprintf(out, " %-*s |", max_column_width, relation->getName().c_str());
      fprintf(out, " %-*s |", C::kInitMaxColumnWidth -1, "table");
      fprintf(out, " %-*lu\n", max_num_blocks_digits - 1, *num_blocks_it);
      ++num_blocks_it;
    }
    fputc('\n', out);
  }
}

void ExecuteDescribeTable(
    const PtrVector<ParseString> *arguments,
    const CatalogDatabase &catalog_database, FILE *out) {
  const ParseString &table_name = arguments->front();
  const std::string &table_name_val = table_name.value();
  const CatalogRelation *relation =
      catalog_database.getRelationByName(table_name_val);
  if (relation == nullptr) {
    THROW_SQL_ERROR_AT(&(arguments->front())) << " Unrecognized relation "  << table_name_val;
  }
  vector<int> column_widths;
  int max_attr_column_width = C::kInitMaxColumnWidth;
  int max_type_column_width = C::kInitMaxColumnWidth;

  for (const CatalogAttribute &attr : *relation) {
    // Printed column needs to be wide enough to print:
    //   1. The attribute name (in the printed "header").
    //   2. Any value of the attribute's Type.
    max_attr_column_width =
        std::max(max_attr_column_width,
            static_cast<int>(attr.getDisplayName().length()));
    max_type_column_width =
        std::max(max_type_column_width,
            static_cast<int>(attr.getType().getName().length()));
  }
  // Add room for one extra character to allow spacing between the column ending and the vertical bar
  column_widths.push_back(max_attr_column_width+1);
  column_widths.push_back(max_type_column_width+1);

  fprintf(out, "%*s \"%s\"\n", C::kInitMaxColumnWidth, "Table", table_name_val.c_str());
  fprintf(out, "%-*s |", max_attr_column_width+1, " Column");
  fprintf(out, "%-*s\n", max_type_column_width+1, " Type");
  PrintToScreen::printHBar(column_widths, out);
  for (const CatalogAttribute &attr : *relation) {
    fprintf(out, " %-*s |", max_attr_column_width,
            attr.getDisplayName().c_str());
    fprintf(out, " %-*s\n", max_type_column_width,
            attr.getType().getName().c_str());
  }
  // TODO(rogers): Add handlers for partitioning information.
  if (relation->hasIndexScheme()) {
    fprintf(out, "%*s\n", C::kInitMaxColumnWidth+2, " Indexes");
    const quickstep::IndexScheme &index_scheme = relation->getIndexScheme();
    for (auto index_it = index_scheme.begin(); index_it != index_scheme.end();
         ++index_it) {
      fprintf(out, "  \"%-*s\" %s", static_cast<int>(index_it->first.length()),
              index_it->first.c_str(),
              index_it->second.IndexSubBlockType_Name(
                  index_it->second.sub_block_type()).c_str());
      fputc(' ', out);
      fputc('(', out);
      fprintf(out, "%s", relation->getAttributeById(index_it->second.indexed_attribute_ids(0))
                             ->getDisplayName().c_str());
      for (std::size_t i = 1; i < static_cast<std::size_t>(index_it->second.indexed_attribute_ids_size()); ++i) {
        const char *attribute_display_name = relation->getAttributeById(
                                                 index_it->second.indexed_attribute_ids(i))
                                                     ->getDisplayName().c_str();
        fprintf(out, ", %s", attribute_display_name);
      }
      fputc(')', out);
      fputc('\n', out);
    }
  }
}

/**
 * @brief A helper function that executes a SQL query to obtain a row of results.
 */
inline std::vector<TypedValue> ExecuteQueryForSingleRow(
    const tmb::client_id main_thread_client_id,
    const tmb::client_id foreman_client_id,
    const std::string &query_string,
    tmb::MessageBus *bus,
    StorageManager *storage_manager,
    QueryProcessor *query_processor,
    SqlParserWrapper *parser_wrapper) {
  parser_wrapper->feedNextBuffer(new std::string(query_string));

  ParseResult result = parser_wrapper->getNextStatement();
  DCHECK(result.condition == ParseResult::kSuccess);

  const ParseStatement &statement = *result.parsed_statement;
  const CatalogRelation *query_result_relation = nullptr;

  {
    // Generate the query plan.
    auto query_handle =
        std::make_unique<QueryHandle>(query_processor->query_id(),
                                      main_thread_client_id,
                                      statement.getPriority());
    query_processor->generateQueryHandle(statement, query_handle.get());
    DCHECK(query_handle->getQueryPlanMutable() != nullptr);
    query_result_relation = query_handle->getQueryResultRelation();
    DCHECK(query_result_relation != nullptr);

    // Use foreman to execute the query plan.
    QueryExecutionUtil::ConstructAndSendAdmitRequestMessage(
        main_thread_client_id, foreman_client_id, query_handle.release(), bus);
  }

  QueryExecutionUtil::ReceiveQueryCompletionMessage(main_thread_client_id, bus);

  // Retrieve the scalar result from the result relation.
  std::vector<TypedValue> values;
  {
    std::vector<block_id> blocks = query_result_relation->getBlocksSnapshot();
    DCHECK_EQ(1u, blocks.size());

    BlockReference block = storage_manager->getBlock(blocks[0], *query_result_relation);
    const TupleStorageSubBlock &tuple_store = block->getTupleStorageSubBlock();
    DCHECK_EQ(1, tuple_store.numTuples());

    const std::size_t num_columns = tuple_store.getRelation().size();
    if (tuple_store.isPacked()) {
      for (std::size_t i = 0; i < num_columns; ++i) {
        values.emplace_back(tuple_store.getAttributeValueTyped(0, i));
        values[i].ensureNotReference();
      }
    } else {
      std::unique_ptr<TupleIdSequence> existence_map(tuple_store.getExistenceMap());
      for (std::size_t i = 0; i < num_columns; ++i) {
        values.emplace_back(
            tuple_store.getAttributeValueTyped(*existence_map->begin(), i));
        values[i].ensureNotReference();
      }
    }
  }

  // Drop the result relation.
  DropRelation::Drop(*query_result_relation,
                     query_processor->getDefaultDatabase(),
                     storage_manager);

  return values;
}

/**
 * @brief A helper function that executes a SQL query to obtain a scalar result.
 */
inline TypedValue ExecuteQueryForSingleResult(
    const tmb::client_id main_thread_client_id,
    const tmb::client_id foreman_client_id,
    const std::string &query_string,
    tmb::MessageBus *bus,
    StorageManager *storage_manager,
    QueryProcessor *query_processor,
    SqlParserWrapper *parser_wrapper) {
  std::vector<TypedValue> results =
      ExecuteQueryForSingleRow(main_thread_client_id,
                               foreman_client_id,
                               query_string,
                               bus,
                               storage_manager,
                               query_processor,
                               parser_wrapper);
  DCHECK_EQ(1u, results.size());
  return results[0];
}

/**
 * @brief A helper function for escaping quotes (i.e. ' or ").
 */
std::string EscapeQuotes(const std::string &str, const char quote) {
  std::string ret;
  for (const char c : str) {
    ret.push_back(c);
    if (c == quote) {
      ret.push_back(c);
    }
  }
  return ret;
}

void ExecuteAnalyze(const PtrVector<ParseString> *arguments,
                    const tmb::client_id main_thread_client_id,
                    const tmb::client_id foreman_client_id,
                    MessageBus *bus,
                    StorageManager *storage_manager,
                    QueryProcessor *query_processor,
                    FILE *out) {
  const CatalogDatabase &database = *query_processor->getDefaultDatabase();

  std::unique_ptr<SqlParserWrapper> parser_wrapper(new SqlParserWrapper());
  std::vector<std::reference_wrapper<const CatalogRelation>> relations;
  if (arguments->size() == 0) {
    relations.insert(relations.begin(), database.begin(), database.end());
  } else {
    for (const auto &rel_name : *arguments) {
      const CatalogRelation *rel = database.getRelationByName(rel_name.value());
      if (rel == nullptr) {
        THROW_SQL_ERROR_AT(&rel_name) << "Table does not exist";
      } else {
        relations.emplace_back(*rel);
      }
    }
  }

  // Analyze each relation in the database.
  for (const CatalogRelation &relation : relations) {
    fprintf(out, "Analyzing %s ... ", relation.getName().c_str());
    fflush(out);

    CatalogRelation *mutable_relation =
        query_processor->getDefaultDatabase()->getRelationByIdMutable(relation.getID());
    CatalogRelationStatistics *mutable_stat =
        mutable_relation->getStatisticsMutable();

    const std::string rel_name = EscapeQuotes(relation.getName(), '"');

    // Get the number of distinct values for each column.
    for (const CatalogAttribute &attribute : relation) {
      const std::string attr_name = EscapeQuotes(attribute.getName(), '"');
      const Type &attr_type = attribute.getType();
      bool is_min_applicable =
          AggregateFunctionMin::Instance().canApplyToTypes({&attr_type});
      bool is_max_applicable =
          AggregateFunctionMax::Instance().canApplyToTypes({&attr_type});

      // NOTE(jianqiao): Note that the relation name and the attribute names may
      // contain non-letter characters, e.g. CREATE TABLE "with space"("1" int).
      // So here we need to format the names with double quotes (").
      std::string query_string = "SELECT COUNT(DISTINCT \"";
      query_string.append(attr_name);
      query_string.append("\")");
      if (is_min_applicable) {
        query_string.append(", MIN(\"");
        query_string.append(attr_name);
        query_string.append("\")");
      }
      if (is_max_applicable) {
        query_string.append(", MAX(\"");
        query_string.append(attr_name);
        query_string.append("\")");
      }
      query_string.append(" FROM \"");
      query_string.append(rel_name);
      query_string.append("\";");

      std::vector<TypedValue> results =
          ExecuteQueryForSingleRow(main_thread_client_id,
                                   foreman_client_id,
                                   query_string,
                                   bus,
                                   storage_manager,
                                   query_processor,
                                   parser_wrapper.get());

      auto results_it = results.begin();
      DCHECK(results_it->getTypeID() == TypeID::kLong);

      const attribute_id attr_id = attribute.getID();
      mutable_stat->setNumDistinctValues(attr_id,
                                         results_it->getLiteral<std::int64_t>());
      if (is_min_applicable) {
        ++results_it;
        mutable_stat->setMinValue(attr_id, *results_it);
      }
      if (is_max_applicable) {
        ++results_it;
        mutable_stat->setMaxValue(attr_id, *results_it);
      }
    }

    // Get the number of tuples for the relation.
    std::string query_string = "SELECT COUNT(*) FROM \"";
    query_string.append(rel_name);
    query_string.append("\";");

    TypedValue num_tuples =
        ExecuteQueryForSingleResult(main_thread_client_id,
                                    foreman_client_id,
                                    query_string,
                                    bus,
                                    storage_manager,
                                    query_processor,
                                    parser_wrapper.get());

    DCHECK(num_tuples.getTypeID() == TypeID::kLong);
    mutable_stat->setNumTuples(num_tuples.getLiteral<std::int64_t>());

    mutable_stat->setExactness(true);

    fprintf(out, "done\n");
    fflush(out);
  }
  query_processor->markCatalogAltered();
  query_processor->saveCatalog();
}

}  // namespace

void executeCommand(const ParseStatement &statement,
                    const CatalogDatabase &catalog_database,
                    const tmb::client_id main_thread_client_id,
                    const tmb::client_id foreman_client_id,
                    MessageBus *bus,
                    StorageManager *storage_manager,
                    QueryProcessor *query_processor,
                    FILE *out) {
  const ParseCommand &command = static_cast<const ParseCommand &>(statement);
  const PtrVector<ParseString> *arguments = command.arguments();
  const std::string &command_str = command.command()->value();
  if (command_str == C::kDescribeDatabaseCommand) {
    ExecuteDescribeDatabase(arguments, catalog_database, storage_manager, out);
  } else if (command_str == C::kDescribeTableCommand) {
    if (arguments->size() == 0) {
      ExecuteDescribeDatabase(arguments, catalog_database, storage_manager, out);
    } else {
      ExecuteDescribeTable(arguments, catalog_database, out);
    }
  } else if (command_str == C::kAnalyzeCommand) {
    ExecuteAnalyze(arguments,
                   main_thread_client_id,
                   foreman_client_id,
                   bus,
                   storage_manager,
                   query_processor, out);
  } else {
    THROW_SQL_ERROR_AT(command.command()) << "Invalid Command";
  }
}
}  // namespace cli
}  // namespace quickstep