#!/usr/bin/perl

# Make a pool of random players with known true ratings between 1000 to 2000
# Set the calculated ratings to be the same as the true ratings
# Play games between randomly selected players with the outcome
#     determined by the true ratings
# Calculate the system error

require "func.pl";

runTests();

sub makePlayers{
  local($i);

  for($i=0;$i<$MaxPlayers;$i++){
    $Tr[$i] = int(rand(1000)) + 1000;
    $Or[$i] = $Tr[$i];
    $Wp[$i] = 0.5;
  }
}

sub setCalc2True{
  @Cr = @Tr;
  @Cor = @Or;
  @Cwp = @Wp;
}

sub setCalc2Init{
  local($i);

  for($i=0;$i<$MaxPlayers;$i++){
    $Cr[$i] = 1500;
    $Cor[$i] = 1500;
    $Cwp[$i] = 0.5;
  }
}

sub updateRatings{
  local($p1, $p2, $w1) = @_;
  local($r1, $r2, $or1, $or2, $wp1, $wp2);

  ($r1, $or1, $wp1) = newRating($Cr[$p1], $Cr[$p2], $w1, $Cor[$p1], $Cwp[$p1]);
  ($r2, $or2, $wp2) = newRating($Cr[$p2], $Cr[$p1], 1 - $w1, $Cor[$p2], $Cwp[$p2]);
  $Cr[$p1] = $r1;
  $Cr[$p2] = $r2;
  $Cor[$p1] = $or1;
  $Cor[$p2] = $or2;
  $Cwp[$p1] = $wp1;
  $Cwp[$p2] = $wp2;
}

sub newRating{
  local($mr, $or, $iwon, $aor, $mwp) = @_;
  local($rdiff, $k, $nr);
  local($cf, $nor, $nwp);

  $rdiff = ($or - $mr)/400;
  $wp = 1.0/(1.0 + 10.0**$rdiff);

  $cf = $wp - 0.5;
  $cf = 1 - 4*$cf*$cf;

  $nor = (25*$aor + $cf*$or)/(25+$cf);
  $nwp = (25*$mwp + $cf*$iwon)/(25+$cf);
#  if ($nwp < 0.01){ $nwp = 0.01; }
#  if ($nwp > 0.99){ $nwp = 0.99; }
#print "  $nwp = (15*$wp + $cf*$iwon)/(15+$cf); \n";

#print "$nwp  $wp  $cf\n";

  $k = 1.0/$nwp - 1.0;
  $nr = $nor - 400*log($k)/log(10);

  return ($nr, $nor, $nwp);
}