#!/usr/bin/perl -w
# Copyright (C) 2019-2021 all contributors <meta@public-inbox.org>
# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
#
# Used for editing messages in a public-inbox.
# Supports v2 inboxes only, for now.
use strict;
use warnings;
use Getopt::Long qw(:config gnu_getopt no_ignore_case auto_abbrev);
use PublicInbox::AdminEdit;
use File::Temp 0.19 (); # 0.19 for TMPDIR
use PublicInbox::ContentHash qw(content_hash);
use PublicInbox::MID qw(mid_clean mids);
PublicInbox::Admin::check_require('-index');
use PublicInbox::Eml;
use PublicInbox::InboxWritable qw(eml_from_path);
use PublicInbox::Import;

my $help = <<'EOF';
usage: public-inbox-edit -m MESSAGE-ID [--all] [INBOX_DIRS]

  destructively edit messages in a public inbox

options:

  --all               edit all configured inboxes
  -m MESSAGE-ID       edit the message with a given Message-ID
  -F FILE             edit the message matching the contents of FILE
  --force             forcibly edit even if Message-ID is ambiguous
  --raw               do not perform "From " line escaping

See public-inbox-edit(1) man page for full documentation.
EOF

my $opt = { verbose => 1, all => 0, -min_inbox_version => 2, raw => 0 };
my @opt = qw(mid|m=s file|F=s raw C=s@);
GetOptions($opt, @PublicInbox::AdminEdit::OPT, @opt) or die $help;
if ($opt->{help}) { print $help; exit 0 };
PublicInbox::Admin::do_chdir(delete $opt->{C});

my $cfg = PublicInbox::Config->new;
my $editor = $ENV{MAIL_EDITOR}; # e.g. "mutt -f"
unless (defined $editor) {
	my $k = 'publicinbox.mailEditor';
	$editor = $cfg->{lc($k)} if $cfg;
	unless (defined $editor) {
		warn "\`$k' not configured, trying \`git var GIT_EDITOR'\n";
		chomp($editor = `git var GIT_EDITOR`);
		warn "Will use $editor to edit mail\n";
	}
}

my $mid = $opt->{mid};
my $file = $opt->{file};
if (defined $mid && defined $file) {
	die "the --mid and --file options are mutually exclusive\n";
}

my @ibxs = PublicInbox::Admin::resolve_inboxes(\@ARGV, $opt, $cfg);
PublicInbox::AdminEdit::check_editable(\@ibxs);

my $found = {}; # chash => [ [ibx, smsg] [, [ibx, smsg] ] ]

sub find_mid ($$$) {
	my ($found, $mid, $ibxs) = @_;
	foreach my $ibx (@$ibxs) {
		my $over = $ibx->over;
		my ($id, $prev);
		while (my $smsg = $over->next_by_mid($mid, \$id, \$prev)) {
			my $ref = $ibx->msg_by_smsg($smsg);
			my $mime = PublicInbox::Eml->new($ref);
			my $chash = content_hash($mime);
			my $tuple = [ $ibx, $smsg ];
			push @{$found->{$chash} ||= []}, $tuple
		}
		PublicInbox::InboxWritable::cleanup($ibx);
	}
	$found;
}

sub show_cmd ($$) {
	my ($ibx, $smsg) = @_;
	" GIT_DIR=$ibx->{inboxdir}/all.git \\\n    git show $smsg->{blob}\n";
}

sub show_found ($) {
	my ($found) = @_;
	foreach my $to_edit (values %$found) {
		foreach my $tuple (@$to_edit) {
			my ($ibx, $smsg) = @$tuple;
			warn show_cmd($ibx, $smsg);
		}
	}
}

if (defined($mid)) {
	$mid = mid_clean($mid);
	find_mid($found, $mid, \@ibxs);
	my $nr = scalar(keys %$found);
	die "No message found for <$mid>\n" unless $nr;
	if ($nr > 1) {
		warn <<"";
Multiple messages with different content found matching
<$mid>:

		show_found($found);
		die "Use --force to edit all of them\n" if !$opt->{force};
		warn "Will edit all of them\n";
	}
} else {
	my $eml = eml_from_path($file) or die "open($file) failed: $!";
	my $mids = mids($eml);
	find_mid($found, $_, \@ibxs) for (@$mids); # populates $found
	my $chash = content_hash($eml);
	my $to_edit = $found->{$chash};
	unless ($to_edit) {
		my $nr = scalar(keys %$found);
		if ($nr > 0) {
			warn <<"";
$nr matches to Message-ID(s) in $file, but none matched content
Partial matches below:

			show_found($found);
		} elsif ($nr == 0) {
			$mids = join('', map { "  <$_>\n" } @$mids);
			warn <<"";
No matching messages found matching Message-ID(s) in $file
$mids

		}
		exit 1;
	}
	$found = { $chash => $to_edit };
}

my %tmpopt = (
	TEMPLATE => 'public-inbox-edit-XXXX',
	TMPDIR => 1,
	SUFFIX => $opt->{raw} ? '.eml' : '.mbox',
);

foreach my $to_edit (values %$found) {
	my $edit_fh = File::Temp->new(%tmpopt);
	$edit_fh->autoflush(1);
	my $edit_fn = $edit_fh->filename;
	my ($ibx, $smsg) = @{$to_edit->[0]};
	my $old_raw = $ibx->msg_by_smsg($smsg);
	PublicInbox::InboxWritable::cleanup($ibx);

	my $tmp = $$old_raw;
	if (!$opt->{raw}) {
		my $oid = $smsg->{blob};
		print $edit_fh "From mboxrd\@$oid Thu Jan  1 00:00:00 1970\n"
			or die "failed to write From_ line: $!";
		$tmp =~ s/^(>*From )/>$1/gm;
	}
	print $edit_fh $tmp or
		die "failed to write tempfile for editing: $!";

	# run the editor, respecting spaces/quote
retry_edit:
	if (system(qw(sh -c), $editor.' "$@"', $editor, $edit_fn)) {
		if (!(-t STDIN) && !$opt->{force}) {
			die "E: $editor failed: $?\n";
		}
		print STDERR "$editor failed, ";
		print STDERR "continuing as forced\n" if $opt->{force};
		while (!$opt->{force}) {
			print STDERR "(r)etry, (c)ontinue, (q)uit?\n";
			chomp(my $op = <STDIN> || '');
			$op = lc($op);
			goto retry_edit if $op eq 'r';
			if ($op eq 'q') {
				# n.b. we'll lose the exit signal, here,
				# oh well; "q" is user-specified anyways.
				exit($? >> 8);
			}
			last if $op eq 'c'; # continuing
			print STDERR "\`$op' not recognized\n";
		}
	}

	# reread the edited file, not using $edit_fh since $EDITOR may
	# rename/relink $edit_fn
	open my $new_fh, '<', $edit_fn or
		die "can't read edited file ($edit_fn): $!\n";
	defined(my $new_raw = do { local $/; <$new_fh> }) or die
		"read $edit_fn: $!\n";

	if (!$opt->{raw}) {
		# get rid of the From we added
		$new_raw =~ s/\A[\r\n]*From [^\r\n]*\r?\n//s;

		# check if user forgot to purge (in mutt) after editing
		if ($new_raw =~ /^From /sm) {
			if (-t STDIN) {
				print STDERR <<'';
Extra "From " lines detected in new mbox.
Did you forget to purge the original message from the mbox after editing?

				while (1) {
					print STDERR <<"";
(y)es to re-edit, (n)o to continue

					chomp(my $op = <STDIN> || '');
					$op = lc($op);
					goto retry_edit if $op eq 'y';
					last if $op eq 'n'; # continuing
					print STDERR "\`$op' not recognized\n";
				}
			} else { # non-interactive path
				# unlikely to happen, as extra From lines are
				# only a common mistake (for me) with
				# interactive use
				warn <<"";
W: possible message boundary splitting error

			}
		}
		# unescape what we escaped:
		$new_raw =~ s/^>(>*From )/$1/gm;
	}

	my $new_mime = PublicInbox::Eml->new(\$new_raw);
	my $old_mime = PublicInbox::Eml->new($old_raw);

	# make sure we don't compare unwanted headers, since mutt adds
	# Content-Length, Status, and Lines headers:
	PublicInbox::Import::drop_unwanted_headers($new_mime);
	PublicInbox::Import::drop_unwanted_headers($old_mime);

	# allow changing Received: and maybe other headers which can
	# contain sensitive info.
	my $nhdr = $new_mime->header_obj->as_string;
	my $ohdr = $old_mime->header_obj->as_string;
	if (($nhdr eq $ohdr) &&
	    (content_hash($new_mime) eq content_hash($old_mime))) {
		warn "No change detected to:\n", show_cmd($ibx, $smsg);

		next unless $opt->{verbose};
		# should we consider this machine-parseable?
		PublicInbox::AdminEdit::show_rewrites(\*STDOUT, $ibx, []);
		next;
	}

	foreach my $tuple (@$to_edit) {
		$ibx = PublicInbox::InboxWritable->new($tuple->[0]);
		$smsg = $tuple->[1];
		my $im = $ibx->importer(0);
		my $commits = $im->replace($old_mime, $new_mime);
		$im->done;
		unless ($commits) {
			warn "Failed to replace:\n", show_cmd($ibx, $smsg);
			next;
		}
		next unless $opt->{verbose};
		# should we consider this machine-parseable?
		PublicInbox::AdminEdit::show_rewrites(\*STDOUT, $ibx, $commits);
	}
}