+# Copyright (C) 2018 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+package PublicInbox::MsgTime;
+use strict;
+use warnings;
+use base qw(Exporter);
+our @EXPORT_OK = qw(msg_timestamp);
+use Date::Parse qw(str2time);
+use Time::Zone qw(tz_offset);
+
+sub msg_timestamp ($) {
+ my ($hdr) = @_; # Email::MIME::Header
+ my ($ts, $zone);
+ my $mid;
+ my @recvd = $hdr->header_raw('Received');
+ foreach my $r (@recvd) {
+ $zone = undef;
+ $r =~ /\s*(\d+\s+[[:alpha:]]+\s+\d{2,4}\s+
+ \d+\D\d+(?:\D\d+)\s+([\+\-]\d+))/sx or next;
+ $zone = $2;
+ $ts = eval { str2time($1) } and last;
+ $mid ||= $hdr->header_raw('Message-ID');
+ warn "no date in $mid Received: $r\n";
+ }
+ unless (defined $ts) {
+ my @date = $hdr->header_raw('Date');
+ foreach my $d (@date) {
+ $zone = undef;
+ $ts = eval { str2time($d) };
+ if ($@) {
+ $mid ||= $hdr->header_raw('Message-ID');
+ warn "bad Date: $d in $mid: $@\n";
+ } elsif ($d =~ /\s+([\+\-]\d+)\s*\z/) {
+ $zone = $1;
+ }
+ }
+ }
+ $ts = time unless defined $ts;
+ return $ts unless wantarray;
+
+ $zone ||= '+0000';
+ # "-1200" is the furthest westermost zone offset,
+ # but git fast-import is liberal so we use "-1400"
+ if ($zone >= 1400 || $zone <= -1400) {
+ warn "bogus TZ offset: $zone, ignoring and assuming +0000\n";
+ $zone = '+0000';
+ }
+ ($ts, $zone);
+}
+
+1;