Improving my AWK skills

Question

This program works as I intended but I feel like I used some clumsy methods to get the out put I desired(especially with my use of print commands and variable declarations)

Could some one improve this script so I can see where I could improve?
Does some one want to show me some crazy bummed version of this?
Is setting variables in the BEGIN block which "runs every line !@#!#@!" how you are supposed to set a variable in AWK?

#!/usr/bin/awk -f
BEGIN{
FS=",";
recordsCursor=1;
number=0;
#spacer="_";
#copies=3;
}
{
    while(number++ <=copies){
        while(recordsCursor <= NF){
            if(recordsCursor==1){
            printf($recordsCursor);
            printf(spacer);
            printf("%.3d,",number);
            }else if(NF != recordsCursor){
                printf("%s," , $recordsCursor);
                }else{
                printf("%s" , $recordsCursor);
                }
        recordsCursor++;
        }
    recordsCursor=1;
    print "";
    }
print "";
number=0;
}

Command: ./test.awk -v copies=3 -v spacer=_ input

Given input:

madison_Leaderboard_728x90,728x90,Leaderboard ads for Madison,no,,,,,,,_blank,image,web
madison_Bullseye_300x250,300x250,Bullseye ads for Madison,no,,,,,,Bullseye,_blank,image,web
madison_Button_155x155,155x155,Button ads for Madison,no,,,,,,,_blank,image,web

Correct output:

madison_Leaderboard_728x90_001,728x90,Leaderboard ads for Madison,no,,,,,,,_blank,image,web
madison_Leaderboard_728x90_002,728x90,Leaderboard ads for Madison,no,,,,,,,_blank,image,web
madison_Leaderboard_728x90_003,728x90,Leaderboard ads for Madison,no,,,,,,,_blank,image,web
madison_Leaderboard_728x90_004,728x90,Leaderboard ads for Madison,no,,,,,,,_blank,image,web

madison_Bullseye_300x250_001,300x250,Bullseye ads for Madison,no,,,,,,Bullseye,_blank,image,web
madison_Bullseye_300x250_002,300x250,Bullseye ads for Madison,no,,,,,,Bullseye,_blank,image,web
madison_Bullseye_300x250_003,300x250,Bullseye ads for Madison,no,,,,,,Bullseye,_blank,image,web
madison_Bullseye_300x250_004,300x250,Bullseye ads for Madison,no,,,,,,Bullseye,_blank,image,web

madison_Button_155x155_001,155x155,Button ads for Madison,no,,,,,,,_blank,image,web
madison_Button_155x155_002,155x155,Button ads for Madison,no,,,,,,,_blank,image,web
madison_Button_155x155_003,155x155,Button ads for Madison,no,,,,,,,_blank,image,web
madison_Button_155x155_004,155x155,Button ads for Madison,no,,,,,,,_blank,image,web

Answer 1

awk -v copies=3 -v spacer=_ '
  BEGIN {OFS=FS=","} 
  {
    field1 = $1
    for (i=1; i <= copies+1; i++) {
      $1 = sprintf("%s%s%03d", field1, spacer, i)
      print
    }  
    print ""
  }
'

This takes advantage of awk recalculating $0 if any of the fields change value.