eis/mix_cc/sql/exec.h

/**
 * @file mix_cc/sql/exec.h
 * @brief 执行 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/debug.h"
#include "mix_cc/exception.h"
#include "mix_cc/fp.h"
#include "mix_cc/sql/op/cmd.h"
#include "mix_cc/sql/select.h"
#include "mix_cc/sql/sqlapi_warpper.h"
#include "mix_cc/sql/statement.h"
#include <string>
#include <vector>
namespace mix_cc {
namespace sql {

namespace detail {
template <typename Tp>
constexpr auto parse_statement(Tp statement) {
  return hana::flatten(
      hana::make_tuple(statement.parse_prev(), hana::make_tuple(statement)));
}

template <typename SpeficDB, typename Row, typename Tp>
auto exec_special(Tp statement) -> maybe<std::vector<Row>> {
  using row_t = Row;
  SpeficDB sql_engine;
  std::vector<row_t> results;
  try {
    if (!sql_engine.connect()) {
      return {};
    }
    std::string statement_str;
    hana::for_each(statement,
                   [&](auto st) { statement_str += st.get_command().c_str(); });
    statement_str += ";";
    sql_engine.cmd_.execute(_TSA(statement_str.c_str()));
    if (sql_engine.cmd_.is_result_set() &&
        sql_engine.cmd_.rows_affacted() != 0) {
      while (sql_engine.cmd_.fetch_next()) {
        row_t row_data;
        hana::for_each(
            statement[0_c].cols_, [&row_data, &sql_engine](auto col) {
              hana::for_each(hana::keys(row_data), [&](auto key) {
                if constexpr (col.col_name == key) {
                  hana::at_key(row_data, key) = sql_engine.cmd_.field(col);
                }
              });
            });
        results.emplace_back(row_data);
      }
    }
  } catch (const SAException& e) {
    DEBUG_PRINT_MIX_CC(std::string(e.ErrText().GetMultiByteChars()) +
                       " sql is: " + sql_engine.cmd_.command_text());
  } catch (const std::exception& e) {
    DEBUG_PRINT_MIX_CC(std::string(e.what()) +
                       " sql is: " + sql_engine.cmd_.command_text());
  } catch (...) {
    DEBUG_PRINT_MIX_CC("sql query exec error");
  }
  return results;
}

template <typename SpeficDB, typename Tp>
constexpr maybe<size_t> exec_general(Tp statement) {
  SpeficDB sql_engine;
  try {
    if (!sql_engine.connect()) {
      return {};
    }
    std::string statement_str;
    hana::for_each(statement,
                   [&](auto st) { statement_str += st.get_command().c_str(); });
    statement_str += ";";
    sql_engine.cmd_.execute(_TSA(statement_str.c_str()));
    return sql_engine.cmd_.rows_affacted();
  } catch (const SAException& e) {
    DEBUG_PRINT_MIX_CC(std::string(e.ErrText().GetMultiByteChars()) +
                       " sql is: " + sql_engine.cmd_.command_text());
  } catch (const std::exception& e) {
    DEBUG_PRINT_MIX_CC(std::string(e.what()) +
                       " sql is: " + sql_engine.cmd_.command_text());
  } catch (...) {
    DEBUG_PRINT_MIX_CC("sql query exec error");
  }
  return {};
}

}  // namespace detail

template <typename SpeficDB, typename T, typename Tp,
          std::enable_if_t<!std::is_same_v<T, size_t>, bool> = true>
constexpr auto exec(Tp statement)
    -> maybe<std::vector<typename T::DataStruct>> {
  auto parsed_statement = detail::parse_statement(statement);
  return detail::exec_special<SpeficDB, typename T::DataStruct>(
      parsed_statement);
}

template <typename SpeficDB, typename T, typename Tp,
          std::enable_if_t<std::is_same_v<T, size_t>, bool> = true>
constexpr maybe<size_t> exec(Tp statement) {
  auto parsed_statement = detail::parse_statement(statement);
  return detail::exec_general<SpeficDB>(parsed_statement);
}

}  // namespace sql
}  // namespace mix_cc