/*
 * Copyright (c) 2015, 2021, Oracle and/or its affiliates.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2.0,
 * as published by the Free Software Foundation.
 *
 * This program is also distributed with certain software (including
 * but not limited to OpenSSL) that is licensed under separate terms,
 * as designated in a particular file or component or in included license
 * documentation.  The authors of MySQL hereby grant you an additional
 * permission to link the program and your derivative works with the
 * separately licensed software that they have included with MySQL.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License, version 2.0, for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "find_statement_builder.h"
#include "ngs_common/protocol_protobuf.h"
#include "xpl_error.h"
#include <algorithm>


void xpl::Find_statement_builder::build(const Find &msg) const
{
  if (!is_table_data_model(msg) && msg.grouping_size() > 0)
    add_document_statement_with_grouping(msg);
  else
    add_statement_common(msg);
}


void xpl::Find_statement_builder::add_statement_common(const Find &msg) const
{
  m_builder.put("SELECT ");
  if (is_table_data_model(msg))
    add_table_projection(msg.projection());
  else
    add_document_projection(msg.projection());
  m_builder.put(" FROM ");
  add_collection(msg.collection());
  add_filter(msg.criteria());
  add_grouping(msg.grouping());
  add_grouping_criteria(msg.grouping_criteria());
  add_order(msg.order());
  add_limit(msg.limit(), false);
}


namespace
{
const char* const DERIVED_TABLE_NAME = "`_DERIVED_TABLE_`";
} // namespace


void xpl::Find_statement_builder::add_document_statement_with_grouping(const Find &msg) const
{
  if (msg.projection_size() == 0)
    throw ngs::Error_code(ER_X_BAD_PROJECTION, "Invalid empty projection list for grouping");

  m_builder.put("SELECT ");
  add_document_object(msg.projection(), &Find_statement_builder::add_document_primary_projection_item);
  m_builder.put(" FROM (");
  m_builder.put("SELECT ");
  add_table_projection(msg.projection());
  m_builder.put(" FROM ");
  add_collection(msg.collection());
  add_filter(msg.criteria());
  add_grouping(msg.grouping());
  add_grouping_criteria(msg.grouping_criteria());
  add_order(msg.order());
  add_limit(msg.limit(), false);
  m_builder.put(") AS ").put(DERIVED_TABLE_NAME);
}


void xpl::Find_statement_builder::add_table_projection(const Projection_list &projection) const
{
  if (projection.size() == 0)
  {
    m_builder.put("*");
    return;
  }
  m_builder.put_list(projection, ngs::bind(&Find_statement_builder::add_table_projection_item, this, ngs::placeholders::_1));
}


void xpl::Find_statement_builder::add_table_projection_item(const Projection &item) const
{
  m_builder.put_expr(item.source());
  add_alias(item);
}


void xpl::Find_statement_builder::add_document_projection(const Projection_list &projection) const
{
  if (projection.size() == 0)
  {
    m_builder.put("doc");
    return;
  }

  if (projection.size() == 1 &&
      !projection.Get(0).has_alias() &&
      projection.Get(0).source().type() == Mysqlx::Expr::Expr::OBJECT)
  {
    m_builder.put_expr(projection.Get(0).source()).put(" AS doc");
    return;
  }

  add_document_object(projection, &Find_statement_builder::add_document_projection_item);
}


void xpl::Find_statement_builder::add_document_object(const Projection_list &projection,
                                                      const Object_item_adder &adder) const
{
  m_builder.put("JSON_OBJECT(")
      .put_list(projection, ngs::bind(adder, this, ngs::placeholders::_1))
      .put(") AS doc");
}


void xpl::Find_statement_builder::add_document_projection_item(const Projection &item) const
{
  if (!item.has_alias())
    throw ngs::Error(ER_X_PROJ_BAD_KEY_NAME,
                     "Invalid projection target name");

  m_builder.put_quote(item.alias()).put(", ").put_expr(item.source());
}


void xpl::Find_statement_builder::add_document_primary_projection_item(const Projection &item) const
{
  if (!item.has_alias())
    throw ngs::Error(ER_X_PROJ_BAD_KEY_NAME,
                     "Invalid projection target name");

  m_builder.put_quote(item.alias()).put(", ")
      .put(DERIVED_TABLE_NAME).dot().put_identifier(item.alias());
}


void xpl::Find_statement_builder::add_grouping(const Grouping_list &group) const
{
  if (group.size() > 0)
    m_builder.put(" GROUP BY ").put_list(group, &Generator::put_expr);
}


void xpl::Find_statement_builder::add_grouping_criteria(const Grouping_criteria &criteria) const
{
  if (criteria.IsInitialized())
    m_builder.put(" HAVING ").put_expr(criteria);
}
