[PATCH 12/12] lei forget-external: bash completion support

[Eric Wong <e@80x24.org>]

The tricky bit was getting around word splitting bash
does on URLs.  This may work with other shells, too.
---
 lib/PublicInbox/LEI.pm         |  4 ++++
 lib/PublicInbox/LeiExternal.pm | 17 +++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/lib/PublicInbox/LEI.pm b/lib/PublicInbox/LEI.pm
index 9c3d7279..ef3f90fc 100644
--- a/lib/PublicInbox/LEI.pm
+++ b/lib/PublicInbox/LEI.pm
@@ -655,6 +655,10 @@ sub lei__complete {
 	} elsif ($cmd eq 'config' && !@argv && !$CONFIG_KEYS{$cur}) {
 		puts $self, grep(/$re/, keys %CONFIG_KEYS);
 	}
+	$cmd =~ tr/-/_/;
+	if (my $sub = $self->can("_complete_$cmd")) {
+		puts $self, $sub->($self, @argv, $cur);
+	}
 	# TODO: URLs, pathnames, OIDs, MIDs, etc...  See optparse() for
 	# proto parsing.
 }
diff --git a/lib/PublicInbox/LeiExternal.pm b/lib/PublicInbox/LeiExternal.pm
index 21071058..59c3c367 100644
--- a/lib/PublicInbox/LeiExternal.pm
+++ b/lib/PublicInbox/LeiExternal.pm
@@ -93,4 +93,21 @@ sub lei_forget_external {
 	}
 }
 
+# shell completion helper called by lei__complete
+sub _complete_forget_external {
+	my ($self, @argv) = @_;
+	my $cfg = $self->_lei_cfg(0);
+	my $cur = pop @argv;
+	# Workaround bash word-splitting URLs to ['https', ':', '//' ...]
+	# Maybe there's a better way to go about this in
+	# contrib/completion/lei-completion.bash
+	my $colon = ($argv[-1] // '') eq ':';
+	my $re = $cur =~ /\A[\w-]/ ? '' : '.*';
+	map {
+		my $x = substr($_, length('external.'));
+		# only return the part specified on the CLI
+		$colon && $x =~ /(\Q$cur\E.*)/ ? $1 : $x;
+	} grep(/\Aexternal\.$re\Q$cur/, @{$cfg->{-section_order}});
+}
+
 1;