#!/usr/bin/perl -w
my %mailmap = ();
open I, "<", ".mailmap";
while (<I>) {
        chomp;
        next if /^#/;
        if (my ($author, $mail) = /^(.*?)\s+<(.+)>$/) {
                $mailmap{$mail} = $author;
        }
}
close I;

my %mail2author = ();
open I, "git log --pretty='format:%ae   %an' |";
while (<I>) {
        chomp;
        my ($mail, $author) = split(/\t/, $_);
        next if exists $mailmap{$mail};
        $mail2author{$mail} ||= {};
        $mail2author{$mail}{$author} ||= 0;
        $mail2author{$mail}{$author}++;
}
close I;

while (my ($mail, $authorcount) = each %mail2author) {
        # %$authorcount is ($author => $count);
        # sort and show the names from the most frequent ones.
        my @names = (map { $_->[0] }
                sort { $b->[1] <=> $a->[1] }
                map { [$_, $authorcount->{$_}] }
                keys %$authorcount);
        if (1 < @names) {
                for (@names) {
                        print "$_ <$mail>\n";
                }
        }
}