#!/usr/bin/env perl
#
-# Copyright © 2019-2020 Nick Bowler
+# Copyright © 2019-2021 Nick Bowler
#
# Replace the current MPD play queue with a saved playlist, by rearranging
# existing queue entries when possible. This avoids losing the current
my $sock;
+my $pl_current_length;
+
# Returns a hash reference mapping filenames to an array reference listing
# the queue IDs for that file in the current play queue.
sub get_tracks_in_play_queue {
- my %matches;
- my $entry;
+ my (%matches, %idmap, $entry);
+ my $pos = -1;
MPD::exec("playlistinfo");
while (<$sock>) {
if (/^(\w+): (.*)$/) {
if ($1 eq "file") {
$entry = $matches{$2} //= [];
+ $pos++;
} elsif ($1 eq "Id") {
push @$entry, $2;
+ $idmap{$2} = $pos;
}
}
}
- return \%matches;
+ $pl_current_length = $pos+1;
+
+ return (\%matches, \%idmap);
}
# Given an MPD playlist name, returns a reference to an array containing
# Retrieve the current play queue and target play queue.
MPD::run("tagtypes", "clear");
-my $current = get_tracks_in_play_queue();
+my ($current, $idmap) = get_tracks_in_play_queue();
my $target = get_playlist_files($ARGV[0]);
+my $add_start;
+
+sub load_tracks($$) {
+ my ($seq, $dst) = @_;
+ my ($newlen, $count);
+
+ my $start = $add_start // $seq;
+ my $add_position = $pl_current_length;
+ my $end = $seq+1;
+
+ $dst //= $start;
+
+ MPD::exec("load", $ARGV[0], "$start:$end");
+ MPD::exec("status");
+ MPD::exec("command_list_end");
+
+ while (<$sock>) {
+ last if (/^OK/);
+ die($_) if (/^ACK/);
+
+ if (/^(\w+): (.*)$/) {
+ if ($1 eq "playlistlength") {
+ $newlen = int($2);
+ }
+ }
+ }
+
+ $count = $newlen - $pl_current_length;
+
+ MPD::exec("command_list_begin");
+ if ($newlen > $pl_current_length) {
+ MPD::exec("move", "$add_position:$newlen", $dst)
+ if ($add_position != $dst);
+ }
+
+ $pl_current_length = $newlen;
+ undef $add_start;
+
+ return $count;
+}
+
MPD::exec("command_list_begin");
+my ($num_added, $num_failed) = (0, 0);
for (my $i = 0; $i < @$target; $i++) {
my $f = $target->[$i];
my $id = shift @{ $current->{$f} };
+ if (defined $id and defined $add_start) {
+ my $n = $i - $add_start;
+ my $m = load_tracks($i-1, $add_start - $num_failed);
+
+ $num_added += $m;
+ $num_failed += $n - $m;
+ }
+
if (defined $id) {
- MPD::exec("moveid", $id, $i);
+ # Try not to move tracks already in the right place.
+ MPD::exec("moveid", $id, $i - $num_failed)
+ if ($i - $num_failed != $idmap->{$id} + $num_added);
} else {
- MPD::exec("addid", $f, $i);
+ $add_start //= $i;
}
}
-# Remove any tracks left from the old play queue.
-MPD::exec("deleteid", $_) foreach (map { @$_ } values %$current);
+# Now all unwanted tracks from the original playqueue have been moved to the
+# end and can be deleted all at once.
+
+my $pos = ($add_start // @$target) - $num_failed;
+MPD::exec("delete", $pos . ":") if map { @$_ } values %$current;
+MPD::exec("load", $ARGV[0], "$add_start:") if defined $add_start;
MPD::run("command_list_end");