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#pragma once
#include <database/query.hpp>
#include <database/engine.hpp>
using namespace std::string_literals;
template <class T, class... Tuple>
struct Index;
template <class T, class... Types>
struct Index<T, std::tuple<T, Types...>>
{
static const std::size_t value = 0;
};
template <class T, class U, class... Types>
struct Index<T, std::tuple<U, Types...>>
{
static const std::size_t value = Index<T, std::tuple<Types...>>::value + 1;
};
struct UpdateQuery: public Query
{
template <typename... T>
UpdateQuery(const std::string& name, const std::tuple<T...>& columns):
Query("UPDATE ")
{
this->body += name;
this->insert_col_names_and_values(columns);
}
template <typename... T>
void insert_col_names_and_values(const std::tuple<T...>& columns)
{
this->body += " SET ";
this->insert_col_name_and_value(columns);
this->body += " WHERE "s + Id::name + "=$" + std::to_string(this->current_param);
}
template <int N=0, typename... T>
typename std::enable_if<N < sizeof...(T), void>::type
insert_col_name_and_value(const std::tuple<T...>& columns)
{
using ColumnType = std::decay_t<decltype(std::get<N>(columns))>;
if (!std::is_same<ColumnType, Id>::value)
{
this->body += ColumnType::name + "=$"s + std::to_string(this->current_param);
this->current_param++;
if (N < (sizeof...(T) - 1))
this->body += ", ";
}
this->insert_col_name_and_value<N+1>(columns);
}
template <int N=0, typename... T>
typename std::enable_if<N == sizeof...(T), void>::type
insert_col_name_and_value(const std::tuple<T...>&)
{}
template <typename... T>
void execute(DatabaseEngine& db, const std::tuple<T...>& columns)
{
auto statement = db.prepare(this->body);
this->bind_param(columns, *statement);
this->bind_id(columns, *statement);
statement->step();
}
template <int N=0, typename... T>
typename std::enable_if<N < sizeof...(T), void>::type
bind_param(const std::tuple<T...>& columns, Statement& statement, int index=1)
{
auto&& column = std::get<N>(columns);
using ColumnType = std::decay_t<decltype(column)>;
if (!std::is_same<ColumnType, Id>::value)
actual_bind(statement, column.value, index++);
this->bind_param<N+1>(columns, statement, index);
}
template <int N=0, typename... T>
typename std::enable_if<N == sizeof...(T), void>::type
bind_param(const std::tuple<T...>&, Statement&, int)
{}
template <typename... T>
void bind_id(const std::tuple<T...>& columns, Statement& statement)
{
static constexpr auto index = Index<Id, std::tuple<T...>>::value;
auto&& value = std::get<index>(columns);
actual_bind(statement, value.value, sizeof...(T));
}
};
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