/**
 * @file mix_cc/sql/set.h
 * @brief 设值 语句
 * @author Cat (null.null.null@qq.com)
 * @version 0.1
 * @date 2021-09-17
 * 
 * Copyright: Baosight Co. Ltd.
 * DO NOT COPY/USE WITHOUT PERMISSION
 * 
 */
#pragma once
#include "mix_cc/sql/public.h"
#include "mix_cc/sql/statement.h"
#include "mix_cc/sql/where.h"
#include <algorithm>
#include <string>

namespace mix_cc {
namespace sql {
namespace detail {

template <typename PrevStatement, typename Enable, typename... Values>
struct set_t_impl;

template <typename PrevStatement, typename... Values>
struct set_t_impl<
    PrevStatement,
    std::enable_if_t<PrevStatement::s_text == op::cmd_t::insert_into>,
    Values...> : public prev_statement_t<PrevStatement>,
                 public statement_t {
  static constexpr auto s_text = op::cmd_t::set;
  constexpr explicit set_t_impl(PrevStatement prev_st, Values... values)
      : prev_statement_t<PrevStatement>(prev_st),
        values_(hana::make_tuple(values...)) {}

  constexpr auto get_command() {
    std::string op1_str = "VALUES";
    auto col_names =
        hana::transform(values_, [](auto val) { return val.get_col_name(); });
    auto r_str_c = hana::fold_left(
        col_names, [](auto col1, auto col2) { return col1 + "," + col2; });
    auto vals =
        hana::transform(values_, [](auto val) { return val.get_value(); });
    auto r_str_c2 = hana::fold_left(
        vals, [](auto val1, auto val2) { return val1 + "," + val2; });
    return std::string("(") + r_str_c + ")" + op1_str + "(" + r_str_c2 + ")";
  }

 public:
  hana::tuple<Values...> values_;
};

template <typename PrevStatement, typename... Values>
struct set_t_impl<PrevStatement,
                  std::enable_if_t<PrevStatement::s_text == op::cmd_t::update>,
                  Values...> : public prev_statement_t<PrevStatement>,
                               public statement_t {
  static constexpr auto s_text = op::cmd_t::set;
  constexpr explicit set_t_impl(PrevStatement prev_st, Values... values)
      : prev_statement_t<PrevStatement>(prev_st),
        values_(hana::make_tuple(values...)) {}

  constexpr auto get_command() {
    auto vals_str =
        hana::transform(values_, [](auto val) { return val.get_str(); });
    auto r_str_c = hana::fold_left(
        vals_str, [](auto val1, auto val2) { return val1 + "," + val2; });
    return std::string(" ") + s_text.c_str() + " " + r_str_c;
  }

  template <typename... Conditions>
  auto where(Conditions... conditions) {
    return where_t(*this, conditions...);
  }

 public:
  hana::tuple<Values...> values_;
};
}  // namespace detail

template <typename PrevStatement, typename... Values>
struct set_t : public detail::set_t_impl<PrevStatement, void, Values...> {
  constexpr explicit set_t(PrevStatement prev_st, Values... values)
      : detail::set_t_impl<PrevStatement, void, Values...>(prev_st, values...) {
  }
};

}  // namespace sql

}  // namespace mix_cc