query/include/matador/sql/column.hpp

#ifndef QUERY_COLUMN_HPP
#define QUERY_COLUMN_HPP

#include "matador/sql/any_type.hpp"
#include "matador/sql/any_type_to_visitor.hpp"
#include "matador/sql/types.hpp"

#include "matador/utils/field_attributes.hpp"

#include <optional>
#include <vector>

namespace matador::sql {

class column {
public:
  column(sql_function_t func, std::string name);
  column(const char *name, std::string alias = ""); // NOLINT(*-explicit-constructor)
  column(std::string name, std::string alias = ""); // NOLINT(*-explicit-constructor)

  column(const column&) = default;
  column& operator=(const column&) = default;
  column(column&&) noexcept = default;
  column& operator=(column&&) noexcept = default;

  template<typename Type>
  explicit column(std::string name, utils::field_attributes attr = utils::null_attributes)
  : column(std::move(name), data_type_traits<Type>::builtin_type(attr.size()), attr)
  {}

  template<typename Type>
  column(std::string name, const Type &, utils::field_attributes attr = utils::null_attributes)
  : column(std::move(name), data_type_traits<Type>::builtin_type(attr.size()), attr)
  {}

  column(std::string name, data_type_t type, utils::field_attributes attr = utils::null_attributes);
  template<typename Type>

  column(std::string name, std::string ref_table, std::string ref_column, utils::field_attributes attr = utils::null_attributes)
  : column(std::move(name), data_type_traits<Type>::builtin_type(attr.size()), ref_table, ref_column, attr)
  {}

  column(std::string name, data_type_t type, size_t index, std::string ref_table, std::string ref_column, utils::field_attributes attr = utils::null_attributes);

  [[nodiscard]] const std::string& name() const;
  [[nodiscard]] size_t index() const;
  [[nodiscard]] const utils::field_attributes& attributes() const;
  [[nodiscard]] data_type_t type() const;
  [[nodiscard]] const std::string& alias() const;
  [[nodiscard]] const std::string& ref_table() const;
  [[nodiscard]] const std::string& ref_column() const;

  void type(data_type_t type);
  void alias(const std::string &as);

  template< typename Type >
  [[nodiscard]] bool is_type_of() const {
    return std::holds_alternative<Type>(value_);
  }

  [[nodiscard]] std::string str() const;

  template<typename Type>
  void set(const Type &value, const utils::field_attributes &attr = utils::null_attributes)
  {
    type_ = data_type_traits<Type>::builtin_type(attr.size());
    attributes_ = attr;
    value_ = value;
  }

  void set(const std::string &value, const utils::field_attributes &attr)
  {
    type_ = data_type_traits<std::string>::builtin_type(attr.size());
    attributes_ = attr;
    value_ = value;
  }

  void set(const char *value, const utils::field_attributes &attr)
  {
    type_ = data_type_traits<std::string>::builtin_type(attr.size());
    attributes_ = attr;
    value_ = value;
  }

  template<class Type>
  Type as() const
  {
    const Type* ptr= std::get_if<Type>(&value_);
    if (ptr) {
      return *ptr;
    }
    any_type_to_visitor<Type> visitor;
    std::visit(visitor, const_cast<any_type&>(value_));
    return visitor.result;
  }

  [[nodiscard]] bool is_function() const;
  [[nodiscard]] sql_function_t function() const;

private:
  template<class Operator>
  void process(Operator &op)
  {
    op.on_attribute(name_.c_str(), value_, type_, attributes_);
  }

  using data_type_index = std::vector<data_type_t>;

private:
  friend class record;

  static const data_type_index data_type_index_;

  std::string name_;
  size_t index_{};
  utils::field_attributes attributes_;
  data_type_t type_{data_type_t::type_unknown};
  any_type value_;
  sql_function_t function_{sql_function_t::NONE};
  std::string alias_;
  std::string ref_table_;
  std::string ref_column_;
};

/**
 * User defined literal to have a shortcut creating a column object
 * @param name Name of the column
 * @param len Length of the column name
 * @return A column object with given name
 */
column operator "" _col(const char *name, size_t len);

column make_column(const std::string &name, data_type_t type, utils::field_attributes attr = utils::not_null_attributes);

template < typename Type >
column make_column(const std::string &name, utils::field_attributes attr = utils::not_null_attributes)
{
    return make_column(name, data_type_traits<Type>::builtin_type(0), attr);
}
template <>
column make_column<std::string>(const std::string &name, utils::field_attributes attr);

template < typename Type >
column make_pk_column(const std::string &name, size_t size = 0)
{
    return make_column<Type>(name, { size, utils::constraints::PRIMARY_KEY | utils::constraints::NOT_NULL});
}

template <>
column make_pk_column<std::string>(const std::string &name, size_t size);

template < typename Type >
column make_fk_column(const std::string &name, size_t size, const std::string &ref_table, const std::string &ref_column)
{
    return {name, data_type_traits<Type>::builtin_type(size), ref_table, ref_column, { size, utils::constraints::FOREIGN_KEY }};
}

template < typename Type >
[[maybe_unused]] column make_fk_column(const std::string &name, const std::string &ref_table, const std::string &ref_column)
{
    return {name, data_type_traits<Type>::builtin_type(0), 0, ref_table, ref_column, { 0, utils::constraints::FOREIGN_KEY }};
}

template <>
column make_fk_column<std::string>(const std::string &name, size_t size, const std::string &ref_table, const std::string &ref_column);

}
#endif //QUERY_COLUMN_HPP