#include "cppScratch/dal/dal.hpp"
#include "dal/secret.hpp"

using namespace std;

void dal_func() {
    cout << "hello from dal" << endl;
    dal_secret();

    try
    {
        // Connect to the database.  You can have multiple connections open
        // at the same time, even to the same database.
        pqxx::connection c;
        std::cout << "Connected to " << c.dbname() << '\n';

        // Start a transaction.  A connection can only have one transaction
        // open at the same time, but after you finish a transaction, you
        // can start a new one on the same connection.
        pqxx::work tx{c};

        // Query data of two columns, converting them to std::string and
        // int respectively.  Iterate the rows.
        for (auto [name, salary] : tx.query<std::string, int>(
            "SELECT name, salary FROM employee ORDER BY name"))
        {
            std::cout << name << " earns " << salary << ".\n";
        }

        // For large amounts of data, "streaming" the results is more
        // efficient.  It does not work for all types of queries though.
        //
        // You can read fields as std::string_view here, which is not
        // something you can do in most places.  A string_view becomes
        // meaningless when the underlying string ceases to exist.  In this
        // one situation, you can convert a field to string_view and it
        // will be valid for just that one iteration of the loop.  The next
        // iteration may overwrite or deallocate its buffer space.
        for (auto [name, salary] : tx.stream<std::string_view, int>(
            "SELECT name, salary FROM employee"))
        {
            std::cout << name << " earns " << salary << ".\n";
        }

        // Execute a statement, and check that it returns 0 rows of data.
        // This will throw pqxx::unexpected_rows if the query returns rows.
        std::cout << "Doubling all employees' salaries...\n";
        tx.exec0("UPDATE employee SET salary = salary*2");

        // Shorthand: conveniently query a single value from the database.
        int my_salary = tx.query_value<int>(
            "SELECT salary FROM employee WHERE name = 'Me'");
        std::cout << "I now earn " << my_salary << ".\n";

        // Or, query one whole row.  This function will throw an exception
        // unless the result contains exactly 1 row.
        auto [top_name, top_salary] = tx.query1<std::string, int>(
            R"(
                SELECT name, salary
                FROM employee
                WHERE salary = max(salary)
                LIMIT 1
            )");
        std::cout << "Top earner is " << top_name << " with a salary of "
                    << top_salary << ".\n";

        // If you need to access the result metadata, not just the actual
        // field values, use the "exec" functions.  Most of them return
        // pqxx::result objects.
        pqxx::result res = tx.exec("SELECT * FROM employee");
        std::cout << "Columns:\n";
        for (pqxx::row_size_type col = 0; col < res.columns(); ++col)
            std::cout << res.column_name(col) << '\n';

        // Commit the transaction.  If you don't do this, the database will
        // undo any changes you made in the transaction.
        std::cout << "Making changes definite: ";
        tx.commit();
        std::cout << "OK.\n";
    }
    catch (std::exception const &e)
    {
        std::cerr << "ERROR: " << e.what() << '\n';
    }
}