#!/usr/bin/perl
use strict;
use warnings;

# config
my $FileA = $ARGV[0] || 'FileA.txt';
my $FileB = $ARGV[1] || 'FileB.txt';
my $FileC = "result.csv";

# read in smaller file key1,key2,key3,count
# example l103709,bbbbbbb,c_0200,929
# and create lookup hash_B
my %hash_B = ();
open FB, '<', $FileB or die "File $FileB Not Found!";
my $countB = 0;
while ( <FB> ) {
  next unless /\S/; # skip blank lines
  chomp;
  my ($look, $sec, $cls, $max) = split ",";
  my $key = join ',',$look, $sec, $cls;
  
  if ( exists $hash_B{$key} ){
    warn "WARNING : Duplicate key [$key] in $FileB at line $.\n";
  } else {
    $hash_B{$key} = $max;
    ++$countB;
  }
}
close FB;
printf "%d lines read from %s\n",$countB,$FileB;

# scan larger FileA to match with smaller FileB
# example l103709,bbbbbbb,c_0200,loc,10,1
open FA, '<', $FileA or die "File $FileA Not Found!";

my $countA = 0;
my $sum_qtd = 0;
my %hash_A = ();
my @match = ();

while ( <FA> ) {
  next unless /\S/; # skip blank lines
  chomp;
  my ($look, $sec, $cls, $att, $idx, $qtd) = split ",";
  my $key = join ',',$look, $sec, $cls;
  
  if (exists $hash_B{$key}){
    # match found
    my $max = $hash_B{$key};
    $hash_A{$key} += $qtd; 
    $sum_qtd += $qtd;  # use to check output  
    my $record = join ',',$look,$sec,$att,$idx,$max;
    push @match,[$record,$qtd]; # store for output
  }
  ++$countA;
}
close FA;
printf "%d lines read from %s\n",$countA,$FileA;
printf "%d matches with %s\n",scalar @match,$FileB;

# check total of qtd in FileA 
# equals max in FileB for each matched key
my $error = 0;
for my $key (keys %hash_A){
  if ($hash_A{$key} != $hash_B{$key}){
    ++$error;
    printf "WARNING $key fileA = %d ; fileB = %d\n",$hash_A{$key},$hash_B{$key};
  }
}
if ($error== 0){
  print "OK - no errors\n";
} else {
  printf "ERROR - see %d warnings\n",$error;
}

# output records
printf "%d lines expected\n",$sum_qtd;
open FC, '>', $FileC or die "File $FileC Not Found!";
my $count_zero = 0;
my $countC  = 0;
while ($count_zero < @match ){
  for (@match){
    my ($record,$qtd) = @$_;
    if ($qtd > 0){
      --$qtd;
      ++$count_zero if $qtd == 0;
      $_->[1] = $qtd ; # update qtd in array
      print FC join ',',$record,$qtd."\n"; 
      ++$countC;
    }
  }
}
close FC;
printf "%d lines written to %s\n",$countC,$FileC;