//example of C++ database access by Lin Jensen 2006, updated November 2020
#include <iostream>
#include <string>
using namespace std;
/*
 *  to compile:
g++ -lpq fruitstand.cc
  */
//#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <libpq-fe.h>
#define CONNINFO "dbname=fruitstand"

static void
exit_nicely(PGconn *conn)
{
    PQfinish(conn);
    exit(1);
}

void askfruits(PGconn *conn);   		//prototypes
void displayorder(PGconn *conn, char  *saleid);

int
main(int argc, char **argv)
{
    const char *conninfo;
    PGconn     *conn;
    PGresult   *res;
    int         nFields;
    int         i,
                j;
    char       *saleid;  // will point to string in a resultSet
    char	id[10];  // we make a copy  

    const char *paramValues[1];  // for queryParams 
    
    /*   NOTE: everything going to and from SQL is a string  */
		/*  for our fruit input values, no spaces!  */

	conninfo = CONNINFO;

	if (argc < 2)
	{printf("USAGE: %s 'Cust Name'\n", argv[0]);
	 exit(1);
	} 

    /* Make a connection to the database */
    conn = PQconnectdb(conninfo);

    /* Check to see that the backend connection was successfully made */
    if (PQstatus(conn) != CONNECTION_OK)
    {
        fprintf(stderr, "Connection to database failed: %s",
                PQerrorMessage(conn));
        exit_nicely(conn);
    }
    
/* Now we will insert a row in sales for this customer, 
	with default date and serial saleid */    
    paramValues[0] = argv[1];

    res = PQexecParams(conn,
                       "insert into sales values ($1) returning saleid",
                       1,       /* one param */
                       NULL,    /* let the backend deduce param type */
                       paramValues,
                       NULL,    /* don't need param lengths since text */
                       NULL,    /* default to all text params */
                       0);      /* ask for text results */

    if (PQresultStatus(res) != PGRES_TUPLES_OK)
    {
        fprintf(stderr, "INSERT failed: %s", PQerrorMessage(conn));
        PQclear(res);
        exit_nicely(conn);
    }
    saleid = PQgetvalue(res, 0, 0); 
    printf ("Sale ID = %s for %s\n", saleid, argv[1]);
    
    strncpy(id, saleid,9);	// copy this for rest of sale
        PQclear(res);		// now clear the resultSet
    
    
/****  Now we shall loop asking for fruits, until we get an empty fruit
	inserts may fail if the fruit isn't in the database
	or if the quantity isn't a valid integer to SQL. 
Well, we'll expect this, and just keep asking (On error, IGNORE)
*/
    askfruits(conn);
    displayorder(conn, id);
    
    PQfinish(conn);		// close connection
    return 0;
}
/*-------------------------------------------------------*/
void askfruits(PGconn *conn)
{
    string	fruit;	/*varchar(12), and \0  */
    string  qty;		/* up to 4 digits */
    
    PGresult    *res;
    const char	*fvalues[2];

    res = PQprepare(conn, "ordins" ,
	"insert into sold values($1,$2)",
	2, NULL);
    if (PQresultStatus(res) != PGRES_COMMAND_OK)
    {
        fprintf(stderr, "PQprepare failed: %s", PQerrorMessage(conn));
//        exit_nicely(conn);
    }
        PQclear(res);

    cout << "Fruit Quantity (^D for done): \n";
    cin >> fruit >> qty;
while(cin.good() ) { 
    cout << "You want " << qty <<" " << fruit << "s -- ";
	fvalues[0]=fruit.c_str();
	fvalues[1]=qty.c_str();
  res = PQexecPrepared(conn,"ordins",
	  2, fvalues, NULL,NULL,0);
    if (PQresultStatus(res) != PGRES_COMMAND_OK)
    {
        fprintf(stderr, "INSERT failed: %s", PQresultErrorMessage(res));
    }
    else
    {
      puts("row inserted");
    }
    PQclear(res);
  
    cin >> fruit >> qty;    // next input (or ^D)
    
}  /* end while - on break */  
}  // end askfruits
/*--------------------------*/

void displayorder(PGconn *conn, char  *saleid)
{
    PGresult   *res;
    const char *paramValues[1];   
    int row, col;

    paramValues[0] = saleid;
    cout << "-----  Your Order -----\n";

    res = PQexecParams(conn,
"select fruit, quantity, price, price*quantity as amt, who, date, total from fruit, sold natural join sales where name=fruit and saleid=$1",
                       1,       /* one param */
                       NULL,    /* let the backend deduce param type */
                       paramValues,
                       NULL, NULL, 0);
    if (PQresultStatus(res) != PGRES_TUPLES_OK)
    {
        fprintf(stderr, "SELECT failed: %s", PQerrorMessage(conn));
        exit_nicely(conn);
    }
/*--- Display customer, date, and total ---*/
    cout<< "Customer : "<< PQgetvalue(res, 0, PQfnumber(res, "who"))<<endl;
    printf("Date     : %s\n", PQgetvalue(res, 0, PQfnumber(res, "date")));
    printf("Total Due: %s\n", PQgetvalue(res, 0, PQfnumber(res, "total")));
    
/*--- Display details for each fruit ---*/
     puts ("\n\t------------------------------");
       puts ("\tFruit        Qty  Price    Amt");
       puts ("\t------------------------------");
     for (row=0; row<PQntuples(res); row++)
        printf ("\t%12s%4s%7s%7s\n",
		  PQgetvalue(res,row,0),
		  PQgetvalue(res,row,1),
		  PQgetvalue(res,row,2),
		  PQgetvalue(res,row,3) );
     puts ("\t------------------------------");

     PQclear(res);
}  // end displayorder