#!/usr/bin/perl -w

use strict;
use Text::Wrap;

my $kernel_auth = "Upstream Kernel Changes";

my (%map, @reverts);
my $pstate = 1;
my $no_kern_log = 0;
my $print_shas = 0;
my $first_print = 1;

while (@ARGV) {
	my $opt = $ARGV[0];
	shift;
	if ($opt eq "--no-kern-log") {
		$no_kern_log = 1;
	} elsif ($opt eq "--print-shas") {
		$print_shas = 1;
	} else {
		print STDERR "Unknown options: $opt\n";
		exit(1);
	}
}

sub check_reverts($) {
	my ($entry) = @_;
	my ($check);

	foreach $check (reverse @reverts) {
		my $desc = "Revert \"" . $entry->{'desc'} . "\"";
		if ($check->{'desc'} eq $desc) {
			@reverts = grep($_->{'desc'} ne $desc, @reverts);
			return 1;
		}
	}

	return 0;
}

sub add_entry($) {
	my ($entry) = @_;
	my $key = $entry->{'author'};

        # store description in array, in email->{desc list} map
        if (exists $map{$key}) {
                # grab ref
                my $obj = $map{$key};

                # add desc to array
                push(@$obj, $entry);
        } else {
                # create new array, containing 1 item
                my @arr = ($entry);

                # store ref to array
                $map{$key} = \@arr;
        }
}

sub shortlog_entry($$$$$) {
	my ($name, $desc, $bug, $cve, $commit) = @_;
	my $entry;

	$desc =~ s#/pub/scm/linux/kernel/git/#/.../#g;
	$desc =~ s#\[PATCH\] ##g;

	$desc =~ s#^\s*##g;
	$desc =~ s# *UBUNTU: ##g;

	$entry->{'desc'} = $desc;
	if ($bug ne '') {
		$entry->{'bugno'} = $bug;
	}
	$entry->{'cve'} = $cve;
	$entry->{'commit'} = $commit;
	$entry->{'author'} = $name;

	if ($desc =~ /^Revert "/) {
		push(@reverts, $entry);
		return;
	}

	return if check_reverts($entry);

	add_entry($entry);
}

# sort comparison function
sub by_name($$) {
	my ($a, $b) = @_;

	uc($a) cmp uc($b);
}

sub shortlog_output {
	my ($obj, $key, $entry);

	foreach $key (sort by_name keys %map) {
		next if $key eq $kernel_auth and $no_kern_log;

		print "\n" unless $first_print;
		$first_print = 0;

		# output author
		printf "  [ %s ]\n\n", $key;

		# output author's 1-line summaries
		$obj = $map{$key};
		foreach $entry (reverse @$obj) {
			print wrap("  * ", "    ", $entry->{'desc'}) . "\n";
			# For non upstream changes, add other info.
			if ($key ne $kernel_auth) {
				if ($print_shas) {
					print "    - GIT-SHA " . $entry->{'commit'} .
						"\n";
				}
			}
			if (defined($entry->{'bugno'})) {
				print "    - LP: #" .  $entry->{'bugno'} . "\n";
			}
			if (defined($entry->{'cve'})) {
				print "    - " . $entry->{'cve'} . "\n";
			}
		}
	}
}

sub changelog_input {
	my ($author, $desc, $commit, $entry, $cve);

	while (<STDIN>) {
		# get commit
		if ($pstate == 1) {
			next unless /^commit (.*)/;

			$commit = $1;

			$pstate++;
		}

		# get author and email
		elsif ($pstate == 2) {
			my ($email);

			next unless /^[Aa]uthor:?\s*(.*?)\s*<(.*)>/;

			$author = $1;
			$email = $2;
			$desc = undef;
			$cve = undef;

			# cset author fixups
			if (!$author) {
				$author = $email;
			}
			$pstate++;
		}

		# skip to blank line
		elsif ($pstate == 3) {
			next unless /^\s*$/;
			$pstate++;
		}

		# skip to non-blank line
		elsif ($pstate == 4) {
			next unless /^\s*?(.*)/;
			my $ignore = 0;
			my $do_ignore = 0;
			my $bug = undef;
			my %bugz = ();
			my $k;

			# skip lines that are obviously not
			# a 1-line cset description
			next if /^\s*From: /;

			chomp;
			$desc = $1;

			if ($desc =~ /^ *(Revert "|)UBUNTU:/) {
				$do_ignore = 1;
			} else {
				$do_ignore = 0;
				$author = $kernel_auth;
				$ignore = 1 if $desc =~ /Merge /;
			}
			while (<STDIN>) {
				$ignore  =  1 if ($do_ignore && /^ *Ignore: yes/i);
				if    (/^ *Bug: *(#|)([0-9#,\s]*)\s*$/i) {
					foreach $k (split('(,|\s)\s*(#|)', $2)) {
						$bugz{$k} = 1 if (($k ne '') and ($k =~ /[0-9]+/));
					}
				}
				elsif (/^ *BugLink: *http.*:\/\/.*\/([0-9]+)/i) {
					$bugz{$1} = 1;
				}
				elsif (/^ *(CVE-.*)/) {
					$cve = $1
				}
				last if /^commit /;
			}

                        $bug = join(", #", sort keys(%bugz));
			if (!$ignore) {
				&shortlog_entry($author, $desc, $bug,
						$cve, $commit, 0);
			}

			$pstate = 1;
			if ($_ && /^commit (.*)/) {
				$commit = $1;
				$pstate++;
			}
		}

		else {
			die "invalid parse state $pstate";
		}
	}

	foreach $entry (@reverts) {
		add_entry($entry);
	}
}

&changelog_input;
&shortlog_output;

exit(0);