#include <stdio.h>
#include <libpq-fe.h>
#include <stdlib.h>


PGresult * run_query(PGconn *conn, char * query)
{
    PGresult *res = PQexec(conn, query);

    ExecStatusType resStatus = PQresultStatus(res);

    printf("Query Status: %s\n", PQresStatus(resStatus));

    if (resStatus != PGRES_TUPLES_OK) {
        fprintf(stderr, "Error while executing query: %s\n", PQerrorMessage(conn));

        PQclear(res);
        PQfinish(conn);

        exit(1);
    }

    return res;
}

void print_query(PGresult * res)
{
    int rows = PQntuples(res);
    int cols = PQnfields(res);

    for (int i = 0; i < rows; ++i) {
        for (int j = 0; j < cols; ++j) {
            printf("%s\t", PQgetvalue(res, i, j));
        }
        puts("");
    }
}

int main(void)
{
    char *conninfo = "dbname=postgres user=postgres password=postgres host=localhost port=5432";
    PGconn *conn = PQconnectdb(conninfo);

    if (PQstatus(conn) != CONNECTION_OK) {
        fprintf(stderr, "Error while connetinning in postgresSQL.\n");
        PQfinish(conn);

        exit(1);
    }

    char *query = "select * from nivel";

    PGresult *res = run_query(conn, query);

    print_query(res);

    PQclear(res);
    PQfinish(conn);

    return 0;
}