#!/usr/bin/perl

use strict;
use Data::Dumper;

my( $matches, $games, $forced_moves, $total_moves, $analysed_pos, $diff_best );
my( $file1, $file2 );
my( $line );
my( $dir1, $dir2 );
my ($gno, $mno);

# array of sum of discrepencies
# win, wing, winbg, loseg, loseb, equity
my @diffs;
my @squares;

# as above, but only for moves where best move decision differs
my @best_diffs;
my @best_squares;

open( BEST, "> /tmp/bestdata" ) or die "Can't open /tmp/best: $!";

# called with one line from a file and a hash reference (either empty
# or the returned value from a call of this routine from another file
# parameter update simply toggles so that only one file is used to count
# moves and forced moves.
# returns "" if there is no move in the input line (double/take/drop
# otherwise the input hash will have a set of keys for each move analysed
# (the key is one to four letter pairs indicating the source and destination
# of one chequer moved
# the value for each key will be a hash with keys rank - the rank, 1=best
#  of the move corresponding to the key and key 'ana' which is an array
#  reference - the array has the elements win, wing, winbg, loseg, losebg,
#     equity

sub doline {
    my( $l, $moves, $update ) = @_;
    my $key;

    # exit early if not a move
    return "" if( $l !~ /;[BW]\[([^\]]*)\]/);
    # extrace dice roll
    my $m = $1;
    # not a dice roll, exit early
    return "" if( $m =~ /^\d+$/ );
    $total_moves++ if( $update );
    # look for the analysis of the move - it will be form
    # A[n][rank of move made 0 = best][move encoded as letter string
    # src/dst (there will be between 1 and 4 such pairs of source dest
    # letters, then the evaluation
    # force moves aren't analysed, so we simply record it as forced
    if( $l !~ /^.*A\[\d+\](.*)/ ) {
	++$forced_moves if( $update );
	return "";
    }
    $l = $1;
    # discard the leading '['
    $l =~ s/\[//g;
    then break the move evaluations into separate strings
    my @evals = split( /\]/, $l );
    my $rank = 0;
    # the list of evaluations are in order best to worst
    while( my $e = shift @evals ) {
	# rank of move 1 = best
	++$rank;
	# skip if we can't make sense of it
	next if( not $e =~ /^([a-z]+) E (.*) 2C .*/ );
	# key is encoding of move, $e is the series of values
        # win, wing, winbg, loseg, losebg, equitey
	($key, $e) = ($1, $2);
	$$moves{ $key }->{ 'rank' } = $rank;
	$$moves{ $key }->{ 'ana' } = [ split( /\s+/, $e ) ];
    }

    return $m;
}
	   
# called with one move from each of the two files to be compared

sub domove {
    my( $l1, $l2 ) = @_;
    my( $m1, $m2, %move1, %move2 );

    # we count all lines as moves unless they are takes (don't know
    # why I did this
    ++$mno if( $l1 !~ /^;[BW]\[take\]/ );
    # get a hash from each file's line
    $m1 = doline( $l1, \%move1, 0 );
    $m2 = doline( $l2, \%move2, 1 );
    # comparision is shallow, actually only checks that they have the
    # the same first level keys, meaning each file analysed the same set
    # of moves
    if( $m1 ne $m2 ) {
	die "mismatched moves at line $line of $file1\n";
    }
    # exit early if it's not a move or it's a forced move
    return if( $m1 eq "" );

    # now compare the ranks and analyses of the moves
    foreach my $k1 (sort ( keys %move1 ) ) {
	my ($r1, $r2);
	$r1 = $move1{ $k1 }->{ 'rank' };
	$r2 = $move2{ $k1 }->{ 'rank' };
	# processing if best mvoe from file1 isn't the best mvoe in file2
	if( ( $r1 == 1 ) and ( $r1 != $r2 ) ) {
	    if (  $move2{ $k1 }->{ 'rank ' } != 1 ) {
#		print "Move1:\n";
#		print Dumper($move1{ $k1 });
#		print "Move2:\n";
#		print Dumper($move2{ $k1 });
		++$diff_best;
		# find the best move in file 2
		foreach my $k2 ( sort ( keys %move2 ) ) {
		    next if( $move2{ $k2 }->{ 'rank' } != 1 );
		    # see what rank it had in file 1
		    $r1 = $move1{ $k2 }->{ 'rank' };
		    my $d;
		    # if the best move in file 2 was analysed in file 1...
		    if( defined( $move1{ $k2 } ) ) {
			# update stats on difference between file1's analysis
			# of file1's best move with file1's analysis of the
			# best move according to file2
			my $max = 0;
			for( my $i = 0; $i < 6; ++$i ) {
			    $d = $move1{ $k1 }->{ 'ana' }[ $i ] -
				$move1{ $k2 }->{ 'ana' }[ $i ];
			    $best_diffs[ $i ] += abs  $d ;
			    $best_squares[ $i ] += $d * $d;
			    $max = abs $d if(((abs $d) > $max) and ($i != 5));
#			    printf BEST "%g ", abs $d;
			}
			# report difference in equities between best move
			# in file1 vs. file1's equitie for best mvoe according
			# to file2
			printf BEST "%5.5f %s %d:%d\n", $d, $file1, $gno,$mno;
		    }
		    # report files disagree on best move
		    print STDERR "Wrong rank $k1 ($r2, $r1) at game $gno, ".
			"move $mno - $file1:$line\n$l1\n$file2:$line\n$l2\n";
		}
	    }
	}
	next if( !defined( $move2{ $k1 }->{ 'ana' } ) );
	++$analysed_pos;
	# accumulate differences in the various figures for every move
	# which was analysed in both matches
	for( my $i = 0; $i < 6; ++$i ) {
	    my $d = $move1{ $k1 }->{ 'ana' }[ $i ] - 
		$move2{ $k1 }->{ 'ana' }[ $i ];
	    $diffs[ $i ] += abs  $d ;
	    $squares[ $i ] += $d * $d;
	}
    }

}

# called after the first line of a game has been read, $fh1, $fh2 are
# the input handles for the files being compared, the next read will
# get a move line, the first line of the next game, or eof returns
# TRUE if there are more games to read

sub dogame {
    my( $fh1, $fh2 ) = @_;
    my( $l1, $l2 );
    ++$games;
    ++$gno;
    $mno = 0;
    while( $l1 = <$fh1> ) {
	++$line; 
	$l1 =~ s/\s+$//;
	$l2 = <$fh2> or die 
	    "Mismatched games - eof at $line of $file2";
	if( $l1 =~ /^\(/ ) {
	    return 1 if( $l2 =~ /^\(/ );
	    die "End of game at $line of $file1 but not in $file2";
	}
	die "End of game at $line of $file2 but not in $file1"
	    if ( $l2 =~ /^\(/ );
	domove( $l1, $l2 );
    }

    while ( $l2 = <$fh2> ) {
	die "Eof at $line of $file1, not in $file2";
    }

    return 0;
}

# process an entire match out of an sgf file	
sub domatch {
    my( $file ) = @_;

    ++$matches;
    $gno = -1;
    $file1 = "$dir1/$file";
    $file2 = "$dir2/$file";
    $line = 0;
    open( FILE1, "< $file1" ) or die "Can't open $file1: $!";
    open( FILE2, "< $file2" ) or die "Can't open $file2: $!";
    while( dogame( \*FILE1, \*FILE2 ) ) {
	# no body
    }

    close( FILE1 );
    close( FILE2 );
}

sub usage {
    print <<EOM
Usage: $0 path0 path1
   compare sgf files named on stdin in the two directories
EOM
;
}

sub main {
    usage if $#ARGV != 1;
    $dir1 = $ARGV[ 0 ];
    $dir2 = $ARGV[ 1 ];
    while( <STDIN> ) {
	s/\s+$//;
	next if( /^$/ );
	domatch( $_ );
    }

    print "$matches matches, $games games, $total_moves moves\n";
    print "$forced_moves forced moves, $analysed_pos positions\n";
    print "The best move was different in $diff_best cases\n";
    print "Average Diff/Std Err\n";
    for( my $i = 0; $i < 6; ++$i ) {
	printf "%1.5f ", $diffs[ $i ] / $analysed_pos;
    }
    print "\n";
    for( my $i = 0; $i < 6; ++$i ) {
	printf "%1.5f ", sqrt( $squares[ $i ] / $analysed_pos );
    }
    print "\n";
    if( $diff_best > 0 ) {
	print 
	"Where best moves differed, $dir1 match evaluations of the choices\n";
	print "Average Diff/Std Err\n";
	for( my $i = 0; $i < 6; ++$i ) {
	    printf "%1.5f ", $best_diffs[ $i ] / $diff_best;
	}
	print "\n";
	for( my $i = 0; $i < 6; ++$i ) {
	    printf "%1.5f ", sqrt( $best_squares[ $i ] / $diff_best );
	}
	print "\n";
    }
}


main;