#!/usr/bin/perl -w
use strict;

use Fcntl qw(:DEFAULT :flock);
use File::Temp qw(tempfile);
use File::Spec::Functions qw(tmpdir);
use File::Basename;

my $editor = $ENV{EDITOR} || 'vi';

File::Temp->safe_level(2);
my ($tfh, $fname) = tempfile(
    basename($0).".XXXXXXX",
    DIR => tmpdir(),
    UNLINK => 1,
);

select((select($tfh), $|++)[0]);

print $tfh <<"INTRO";
Default text to appear in editor.
INTRO

# File::Temp locks the file by default
# which is not productive with external editors
flock $tfh, LOCK_UN;

my $status = system $editor, $fname;

die($status != -1
    ? "external editor $editor failed with $?\n"
    : "couldn't launch external editor $editor: $!\n"
) unless $status == 0;

seek $tfh, 0, 0 or die "Error seeking on temp file: $!\n";
my $data = do { local $/; <$tfh> };