#!/usr/bin/perl -w

# Reference:
# The Scottish Local Government Elections Order 2007

use strict;

# Data structures:
#
# vote is
#   { Voter => opaque,
#     Prefs => [ list ],
#     Weight => 1.0 }
# We edit Prefs as we go

# $cands{CAND}{Desc}
# $cands{CAND}{Votes}

our $stage=0;

our $seats=0;

sub unkopt ($$) {
    my ($what,$opt) = @_;
    if ($opt =~ m/^[A-Z]/) {
	die "unknown option $_ for $what";
    } elsif ($opt =~ m/^[a-z]/) {
	print STDERR "warning (line $.): unknown option $_ for $what\n";
    }
}

for (;;) {
    $_ = <>;
    if (m/^\| /) {
	foreach $_ (split / /, $') {
	    if (m/^_?[Ss]eats=(\d+)/) {
		$seats = $1;
	    } else {
		unkopt "election", $_;
	    }
	}
    } elsif (m/^(\w+) = (\S*) \|/) {
	my ($cand,$desc) = @_;
	unkopt "candidate $cand", $_ foreach split / /, $';
	$cands{$cand}{Desc} = $desc;
    } elsif (m/^(\w*) :\s*(.*)\s*\|(.*)/) {
	my ($voter,$prefs,$opts) = ($1,$2,$3);
	$v = { Voter => $voter };
	push @{ $v->{Prefs} }, [ $_ =~ m/\w+/g ]
	    foreach split /\s+/, $prefs;
	foreach $_ (split / /, $opts) {
	    if (m/^_?[Ww]eight=(\d+)/(\d+)$/) {
		$v->{Weight} = $1 / $2;
	    } elsif (m/^_?[Ww]eight=([0-9.]+)$/) {
		$v->{Weight} = new Math::BigRat $1;
	    } else {
		unkopt "voter $v->{Voter}", $_;
	    }
	}
	push @allvotes, $v;
    } elsif (m/^\.$/) {
	last;
    } else {
	die "$_ ?";
    }
}

sub sortballots (@) {
    # Takes each argument, which should be a ballot, sorts
    # it into $cand{CAND}{Votes} according to first preference.
    # Strips that first preference from the ballot.
    # If the first preference has been eliminated, strips it
    # and looks for further preferences.
    foreach my $v (@_) {
	my $firstprefs = shift @{ $v->{Prefs} };
	if (!$firstprefs || !@$firstprefs) {
	    vlog $v, "no more preferences, non transferable";
	    push @non_transferable, $v;
	    next;
	}
	if (@$firstprefs > 1) {
	    vlog $v, "splitting due to several equal first preferences";
	    foreach my $fpref (@$firstprefs) {
		my $v2 = {
		    %$v,
		    Weight => $v->{Weight} / @$firstprefs,
		    Prefs => [ [ $fpref ], @{ $v->{Prefs} } ],
			 };
		vlog $v, "split for $fpref";
		
			
		    Voter => $
	    
	my @prefs 
	my $nprefs = scalar @{ $v->{Prefs}
    my @input = @_;
    

# $cands

for (;;) {