query/include/matador/sql/query_intermediates.hpp

#ifndef QUERY_QUERY_INTERMEDIATES_HPP
#define QUERY_QUERY_INTERMEDIATES_HPP

#include "matador/sql/column_definition.hpp"
#include "matador/sql/column_definition_generator.hpp"
#include "matador/sql/column_generator.hpp"
#include "matador/sql/key_value_generator.hpp"
#include "matador/sql/key_value_pair.hpp"
#include "matador/sql/placeholder_generator.hpp"
#include "matador/sql/query_result.hpp"
#include "matador/sql/query_data.hpp"
#include "matador/sql/record.hpp"
#include "matador/sql/statement.hpp"
#include "matador/sql/schema.hpp"
#include "matador/sql/value_extractor.hpp"

#include <string>

namespace matador::sql {

class basic_condition;
class connection;

class basic_query_intermediate
{
public:
  explicit basic_query_intermediate(connection &db, const sql::schema &schema);

protected:
  connection &connection_;
  const sql::schema &schema_;
};

class query_intermediate : public basic_query_intermediate
{
public:
  query_intermediate(connection &db, const sql::schema &schema, const std::shared_ptr<query_data> &data);

protected:
  std::shared_ptr<query_data> data_;
};

class query_execute_finish : public query_intermediate
{
public:
  using query_intermediate::query_intermediate;

  size_t execute();
  statement prepare();
  [[nodiscard]] query_context build() const;
};

class query_select_finish : public query_intermediate
{
protected:
  using query_intermediate::query_intermediate;

public:
  template < class Type >
  query_result<Type> fetch_all()
  {
    return query_result<Type>(fetch());
  }
  query_result<record> fetch_all();

  template < class Type >
  std::unique_ptr<Type> fetch_one()
  {
    auto result = query_result<Type>(fetch());
    auto first = result.begin();
    if (first == result.end()) {
      return nullptr;
    }

    return std::unique_ptr<Type>{first.release()};
  }
  std::optional<record> fetch_one();

  template<typename Type>
  std::optional<Type> fetch_value()
  {
    const auto result = fetch_one();
    if (result.has_value()) {
      return result.value().at(0).as<Type>().value();
    }
    return std::nullopt;
  }

  statement prepare();

  [[nodiscard]] query_context build() const;

private:
  std::unique_ptr<query_result_impl> fetch();
};

class query_offset_intermediate;

class query_limit_intermediate : public query_select_finish
{
public:
  using query_select_finish::query_select_finish;

  query_offset_intermediate offset(size_t offset);
};

class query_offset_intermediate : public query_select_finish
{
public:
  using query_select_finish::query_select_finish;

  query_limit_intermediate limit(size_t limit);
};

class query_order_direction_intermediate : public query_select_finish
{
public:
  using query_select_finish::query_select_finish;

  query_limit_intermediate limit(size_t limit);
};

class query_order_by_intermediate;

class query_group_by_intermediate : public query_select_finish
{
public:
  using query_select_finish::query_select_finish;

  query_order_by_intermediate order_by(const column &col);
};

class query_order_by_intermediate : public query_intermediate
{
public:
  using query_intermediate::query_intermediate;

  query_order_direction_intermediate asc();
  query_order_direction_intermediate desc();
};

class query_where_intermediate : public query_select_finish
{
public:
  using query_select_finish::query_select_finish;

  query_group_by_intermediate group_by(const column &col);
  query_order_by_intermediate order_by(const column &col);
};

class query_join_intermediate;

class query_on_intermediate : public query_select_finish
{
public:
  using query_select_finish::query_select_finish;

  query_join_intermediate join_left(const table &t);
  template<class Condition>
  query_where_intermediate where(const Condition &cond)
  {
    return where_clause(std::make_unique<Condition>(std::move(cond)));
  }
  query_where_intermediate where(std::unique_ptr<basic_condition> &&cond)
  {
    return where_clause(std::move(cond));
  }
  query_group_by_intermediate group_by(const column &col);
  query_order_by_intermediate order_by(const column &col);

private:
  query_where_intermediate where_clause(std::unique_ptr<basic_condition> &&cond);
};

class query_join_intermediate : public query_intermediate
{
public:
  using query_intermediate::query_intermediate;

  template<class Condition>
  query_on_intermediate on(const Condition &cond)
  {
    return on_clause(std::make_unique<Condition>(std::move(cond)));
  }
  query_on_intermediate on(std::unique_ptr<basic_condition> &&cond)
  {
    return on_clause(std::move(cond));
  }

private:
  query_on_intermediate on_clause(std::unique_ptr<basic_condition> &&cond);
};

class query_from_intermediate : public query_select_finish
{
public:
  using query_select_finish::query_select_finish;

  query_join_intermediate join_left(const table &t);
  template<class Condition>
  query_where_intermediate where(const Condition &cond)
  {
    return where_clause(std::make_unique<Condition>(std::move(cond)));
  }
  query_where_intermediate where(std::unique_ptr<basic_condition> &&cond)
  {
    return where_clause(std::move(cond));
  }
  query_group_by_intermediate group_by(const column &col);
  query_order_by_intermediate order_by(const column &col);

private:
  query_where_intermediate where_clause(std::unique_ptr<basic_condition> &&cond);
};

class query_start_intermediate : public basic_query_intermediate
{
public:
  explicit query_start_intermediate(connection &db, const sql::schema &schema);

protected:
  std::shared_ptr<query_data> data_ { std::make_shared<query_data>() };
};

class query_select_intermediate : public query_start_intermediate
{
public:
  query_select_intermediate(connection &db, const sql::schema &schema, const std::vector<column>& columns);

  query_from_intermediate from(const table& t);
};

template < class Type >
std::vector<any_type> as_placeholder(const Type &obj)
{
  placeholder_generator generator;
  matador::utils::access::process(generator, obj);

  return generator.placeholder_values;
}

class query_into_intermediate : public query_intermediate
{
public:
  using query_intermediate::query_intermediate;

  query_execute_finish values(std::initializer_list<any_type> values);
  query_execute_finish values(std::vector<any_type> &&values);
  template<class Type>
  query_execute_finish values()
  {
    Type obj;
    return values(std::move(as_placeholder(obj)));
  }
  template<class Type>
  query_execute_finish values(const Type &obj)
  {
    return values(std::move(value_extractor::extract(obj)));
  }
};

class query_create_intermediate : public query_start_intermediate
{
public:
  explicit query_create_intermediate(connection &db, const sql::schema &schema);

  query_execute_finish table(const sql::table &table, std::initializer_list<column_definition> columns);
  query_execute_finish table(const sql::table &table, const std::vector<column_definition> &columns);
  template<class Type>
  query_execute_finish table(const sql::table &table)
  {
    return this->table(table, column_definition_generator::generate<Type>(schema_));
  }
};

class query_drop_intermediate : query_start_intermediate
{
public:
  explicit query_drop_intermediate(connection &db, const sql::schema &schema);

  query_execute_finish table(const sql::table &table);
};

class query_insert_intermediate : public query_start_intermediate
{
public:
  explicit query_insert_intermediate(connection &db, const sql::schema &schema);

  query_into_intermediate into(const sql::table &table, std::initializer_list<column> column_names);
  query_into_intermediate into(const sql::table &table, std::vector<column> &&column_names);
  query_into_intermediate into(const sql::table &table);
};

class query_execute_where_intermediate : public query_execute_finish
{
public:
  using query_execute_finish::query_execute_finish;

  query_order_by_intermediate order_by(const column &col);
};

class query_set_intermediate : public query_execute_finish
{
public:
  using query_execute_finish::query_execute_finish;

  template<class Condition>
  query_execute_where_intermediate where(const Condition &cond)
  {
    return where_clause(std::make_unique<Condition>(std::move(cond)));
  }

private:
  query_execute_where_intermediate where_clause(std::unique_ptr<basic_condition> &&cond);
};

class query_update_intermediate : public query_start_intermediate
{
public:
  query_update_intermediate(connection &db, const sql::schema &schema, const sql::table& table);

  query_set_intermediate set(std::initializer_list<key_value_pair> columns);
  query_set_intermediate set(std::vector<key_value_pair> &&columns);
  template<class Type>
  query_set_intermediate set(const Type &obj)
  {
    return set(key_value_generator::generate(obj));
  }
};

class query_delete_from_intermediate : public query_execute_finish
{
public:
  using query_execute_finish::query_execute_finish;

  template<class Condition>
  query_execute_where_intermediate where(const Condition &cond)
  {
    return where_clause(std::make_unique<Condition>(std::move(cond)));
  }

private:
  query_execute_where_intermediate where_clause(std::unique_ptr<basic_condition> &&cond);
};

class query_delete_intermediate : public query_start_intermediate
{
public:
  explicit query_delete_intermediate(connection &db, const sql::schema &schema);

  query_delete_from_intermediate from(const sql::table &table);
};

}
#endif //QUERY_QUERY_INTERMEDIATES_HPP