#!/usr/bin/env perl
#
# InspIRCd -- Internet Relay Chat Daemon
#
#   Copyright (C) 2020-2024 Sadie Powell <sadie@witchery.services>
#
# This file is part of InspIRCd.  InspIRCd is free software: you can
# redistribute it and/or modify it under the terms of the GNU General Public
# License as published by the Free Software Foundation, version 2.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#


use v5.26.0;
use strict;
use warnings FATAL => qw(all);

use File::Basename qw(dirname);
use File::Util     ();
use FindBin        qw($RealDir);
use List::Util     qw(uniq);
use POSIX          qw(strftime);

use lib dirname $RealDir;
use make::common;
use make::console;

my @ignored_revisions = (
	'46a39046196f55b52336e19662bb7bac85b731ac', # adding copyright headers
	'4a6fedd9324d87349a806c9c1d0ae6e7d3c1fd38', # mass-updating descriptions
	'bab14f0dd2345c9d7dcbc47c918563709e1ac094', # peavey breaking line endings
	'de6d4dbd1e8845e08c2d87cd89a919e5b21ba619', # jsoref fixing a ton of typos
	'f2acdbc3820f0f4f5ef76a0a64e73d2a320df91f', # peavey fixing line endings
);

sub make_range($@) {
	my ($separator, @nums) = @_;
	my ($last_num, $start_num, @num_ranges);
	for my $num (uniq sort { $a <=> $b } @nums) {
		if (!defined $last_num) {
			$start_num = $last_num = $num
		} elsif ($num == $last_num + 1) {
			$last_num = $num;
		} else {
			if ($last_num == $start_num) {
				push @num_ranges, $last_num;
			} else {
				push @num_ranges, "$start_num$separator$last_num";
			}
			$start_num = $last_num = $num;
		}
	}
	if (defined $last_num) {
		if ($last_num == $start_num) {
			push @num_ranges, $last_num;
		} else {
			push @num_ranges, "$start_num$separator$last_num";
		}
	}
	return @num_ranges;
}

my @paths = File::Util->new->list_dir(dirname($RealDir) => { recurse => 1 });
my @updated;
for my $path (@paths) {
	next unless -f $path;
	next if $path =~ /\/\./;
	next if $path =~ /\/build\//;
	next if $path =~ /\/vendor\//;

	if (system "git ls-files --error-unmatch -- $path 1>/dev/null 2>/dev/null") {
		say STDERR console_format "Skipping <|YELLOW $path|> as it has not been committed." if defined $ENV{MKHEADERS_VERBOSE};
		next;
	}

	open(my $fh, $path) or print_error "unable to read from $path: $!";
	my ($copyright, $indent, $linenum, @linenums, @lines);
	for my $line (<$fh>) {
		$linenum += 1;
		chomp $line;
		if ($line =~ /^([^0-9A-Za-z]+\s)Copyright\s+\(C\)\s+[^<]+(\s+<[^>]+>)?[\r\s]*$/) {
			$copyright = scalar @lines;
			$indent = $1;
		} else {
			push @lines, $line;
			push @linenums, $linenum;
		}
	}
	close $fh;

	if (defined $copyright) {
		say console_format "Updating copyright headers in <|GREEN $path|>." if defined $ENV{MKHEADERS_VERBOSE};
		my (%authors, $commit, %commits);
		my $ignored_args = join ' ', map { "--ignore-rev $_" } @ignored_revisions;
		my $line_args = join ' ', map { "-L $_" } make_range ',', @linenums;
		for my $line (split /\n+/, `git blame $ignored_args $line_args --incremental -M -w HEAD -- $path`) {
			if ($line =~ /^([0-9a-f]{40})(?:\s\d+){3}$/) {
				$commit = $1;
				$commits{$commit} //= {};
			} elsif ($line =~ /^author (.+)/) {
				$commits{$commit}->{NAME} = $1;
			} elsif ($line =~ /^author-mail <(.+)>/) {
				next if $1 eq 'unknown@email.invalid';
				next if $1 =~ /\@users.noreply.github.com$/;
				$commits{$commit}->{EMAIL} = $1;
			} elsif ($line =~ /^author-time (.+)/) {
				$commits{$commit}->{YEAR} = strftime '%Y', gmtime $1;
			} elsif ($line =~ /^filename /) {
				my $display = $commits{$commit}->{NAME};
				if (exists $commits{$commit}->{EMAIL}) {
					$display .= sprintf " <%s>", $commits{$commit}->{EMAIL};
				}
				$authors{$display} //= [];
				push @{$authors{$display}}, $commits{$commit}->{YEAR};
				my $details = `git rev-list --format=%B --max-count=1 $commit`;
				while ($details =~ /co-authored-by: ([^<]+<[^>]+>)/gi) {
					open(my $fh, '-|', 'git', 'check-mailmap', $1);
					chomp(my $coauthor = <$fh>);
					close $fh;
					my $year = $details =~ /co-authored-year: (\d+)/i ? $1 : $commits{$commit}->{YEAR};
					$authors{$coauthor} //= [];
					push @{$authors{$coauthor}}, $year;
				}
				undef $commit;
			}
		}

		my @copyrights;
		while (my ($display, $years) = each %authors) {
			next if $display eq 'InspIRCd Robot <noreply@inspircd.org>';
			my @year_ranges = make_range '-', @$years;
			my $joined_years = join ', ', @year_ranges;
			push @copyrights, "${\$indent}Copyright (C) $joined_years $display";
		}

		splice @lines, $copyright, 0, reverse sort @copyrights;
		open(my $fh, '>', $path) or print_error "unable to write to $path: $!";
		for my $line (@lines) {
			say $fh $line;
		}
		close $fh;
		push @updated, $path;
	} else {
		say STDERR console_format "Skipping <|YELLOW $path|> as it contains no copyright headers." if defined $ENV{MKHEADERS_VERBOSE};
	}
}

if ($ENV{MKHEADERS_COMMIT} // 1) {
	execute 'git', 'commit',
		'--author', 'InspIRCd Robot <noreply@inspircd.org>',
		'--message', 'Update copyright headers.',
		'--', @updated;
}