package Ernad::Eval;

use strict;
use warnings;

use Carp qw(cluck longmess shortmess croak confess);
use Data::Dumper;

sub init_outcome {
  my $rela=shift or confess "I need a rela number here.";
  my $nobs=shift or confess "I need a nobs number here.";
  ## take the larger to be the n
  if($rela>$nobs) {
    confess "parameter order is rela, nobs";
  }
  my $start=1;
  my $out;
  $out->[0]=$nobs; 
  my $count=1;
  while($count<=$rela) {
    $out->[$count]=$count;
    $count++;
  }
  return $out;
}

sub print_outcome {
  my $in=shift;
  my $indent=shift // 0;
  my $to_print=&show_outcome($in,$indent);
  print $to_print, "\n";
}

sub show_outcome {
  my $in=shift;
  my $indent=shift // 0;
  my $print='';
  my $count=0;
  while($count++<=$indent) {
    $print.=' ';
  }    
  $print.=&show_in($in).' ';
  $print.=&expand($in);
  return $print;
}

sub create_simul_outcomes {
  my $rela=shift or confess "I need a rela number here.";
  my $nobs=shift or confess "I need a nobs number here.";
  if($rela>$nobs) {
    confess "parameter order is rela, nobs";
  }
  my $s;
  my $count=0;
  my $outcome=&init_outcome($rela,$nobs);
  my $c=0;
  while(defined($outcome->[$c])) {
    $s->[$count]->[$c]=$outcome->[$c];
    $c++;
  }
  while($outcome=&next_outcome($outcome)) {  
    $count++;
    my $c=0;
    while(defined($outcome->[$c])) {
      $s->[$count]->[$c]=$outcome->[$c];
      $c++;
    }
  }
  return $s;
}

sub expand {
  my $in=shift;
  my @obs=@{$in};
  my $nobs=shift @obs;
  my $rela=scalar(@obs);
  ## create a hash
  my $rel;
  my $count;
  $count=0;
  while($count<$rela) {
    $rel->{$obs[$count]}=1;
    $count++;
  }
  $count=1;
  my $out='[';
  while($count<$nobs+1) {
    if(defined($rel->{$count})) {
      $out.='1,';
    }
    else {
      $out.='0,';
    }
    $count++;
  }
  chop $out;
  $out.=']';
  return $out;
}

sub simul_outcomes {
  my $rela=shift or confess "I need a rela number here.";
  my $nobs=shift or confess "I need a nobs number here.";
  my $funref=shift or confess "I need a function reference here.";
  my $verbose=shift // 1;
  if($rela>$nobs) {
    confess "parameter order is rela, nobs";
  }
  my $outcome=&init_outcome($rela,$nobs);
  my $old_result;
  my $result=&{$funref}($outcome,$verbose);
  my $sum=$result;
  while($outcome=&next_outcome($outcome)) {  
    if(not defined($old_result)) {
      $old_result=1;
    }
    ## funref takes the outcome and a verbosity
    ## with valiues 0,1 or 2
    my $result=&{$funref}($outcome,$verbose);
    $sum+=$result;
    if($result>$old_result) {
      die "violation of natural order";
    }
    $old_result=$result;
  }
  print "sum is $sum\n";
}

sub show_simuls  {
  my $rela=shift or confess "I need a rela number here.";
  my $nobs=shift or confess "I need a nobs number here.";
  if($rela>$nobs) {
    confess "parameter order is rela, nobs";
  }
  my $outcome=&init_outcome($rela,$nobs);
  my $show_in=&show_in($outcome);
  my $expand=&expand($outcome);
  print "$show_in $expand\n";
  my $old_result;
  my $count_simul=1;
  while($outcome=&next_outcome($outcome)) {  
    $count_simul++;
    my $show_in=&show_in($outcome);
    my $expand=&expand($outcome);
    print "$show_in $expand\n";
  }
  my $count_in_set=&count_in_set($rela,$nobs);
  if($count_in_set != $count_simul) {
    die "count_in_set $count_in_set, count_simul $count_simul";
  }
}

sub factorial {
  my $n=shift;
  my $count=0;
  my $result=1;
  while($count++<$n) {
    $result=$result*$count;
    print "count $count result $result\n";
  }
  return $result;
}

sub count_in_set {
  my $rela=shift or confess "I need a rela number here.";
  my $nobs=shift or confess "I need a nobs number here.";
  if($rela>$nobs) {
    confess "parameter order is rela, nobs";
  }
  return factorial($nobs)/factorial($rela)/factorial($nobs-$rela);
}

sub next_outcome {
  my $in=shift or confess "I need in input to increment from.";
  my @obs=@{$in};
  my $nobs=shift @obs;
  my $rela=scalar(@obs);
  my $count=1;
  my $done='';
  while($count<$rela) {
    ## maximum number 
    if($obs[$count-1]>$nobs-$rela+$count-1) {
      return '';
    }    
    my $delta=$obs[$count]-$obs[$count-1];
    if($delta == 1) {
      $count++;
      next;
    }
    if($obs[$count-1]<$nobs) {
      $obs[$count-1]++;
      my $c=1;
      ## reset the lower parts
      while($c<$count) {
        $obs[$c-1]=$c;
        $c++;
      }
      $done=1;
      last;
    }
    $count++;
  }
  if(not $done and $obs[$rela-1]<$nobs) {
    $obs[$rela-1]++;
    my $c=1;
    ## reset the lower parts
    while($c<$rela) {
      $obs[$c-1]=$c;
      $c++;
    }
    $done=1;
  }
  ## nothing found any more
  if(not $done) {
    return '';
  }
  $count=1;
  while(defined($in->[$count])) {
    $in->[$count]=$obs[$count-1];
    $count++;
  }
  return $in;
}

sub show_in {
  my $in=shift;
  my $in_print=Dumper $in;
  $in_print=~s|\n||g;
  $in_print=~s|\s+||g;
  $in_print=~s|;||g;  
  $in_print=~s|\$VAR1\s*=\s*||; 
  return $in_print;
}

1;


# [5,1,2,3] [1,1,1,0,0]
# [5,1,2,4] [1,1,0,1,0]
# [5,1,3,4] [1,0,1,1,0]
# [5,2,3,4] [0,1,1,1,0]
# [5,1,2,5] [1,1,0,0,1]
# [5,1,3,5] [1,0,1,0,1]
# [5,2,3,5] [0,1,1,0,1]
#*[5,1,4,5] [1,0,0,1,1]
# [5,2,4,5] [0,1,0,1,1]
# [5,3,4,5] [0,0,1,1,1]