#!/usr/bin/perl

# xre - perl script to rename version-controlled files with PERL expressions
# (c) 2009 by Fantasai <http://fantasai.inkedblade.net/>
# Interface based on Larry Wall's wonderful 'rename' command
# This is version 3.
#
# This script is open source under the BSD License:
#   Redistribution and use in source and binary forms, with or without
#   modification, are permitted provided that the following conditions
#   are met:
#     * Redistributions of source code must retain the above copyright notice,
#       this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above copyright
#       notice, this list of conditions and the following disclaimer in the
#       documentation and/or other materials provided with the distribution.
#     * Neither the name of the original author nor the names of any contributors
#       may be used to endorse or promote products derived from this software
#       without specific prior written permission.
#   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
#   AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
#   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
#   ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
#   LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
#   CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
#   SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
#   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
#   CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
#   ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
#   POSSIBILITY OF SUCH DAMAGE.

if (!@ARGV || "-h" eq $ARGV[0] || "-help" eq $ARGV[0] || "--help" eq $ARGV[0]) {
  print "Extended Rename:\n";
  print "  xre [OPTION] COMMAND PERLEXPR [list of strings]\n";
  print "COMMAND is a command to run.\n";
  print "PERLEXPR is a perl expression that modifies the \$_ string.\n";
  print "For each argument after PERLEXPR that is modified by the perl\n" .
        "expression, the command will be executed with the original\n" .
        "argument and the argument as altered by the perl expression.\n" .
        "Alternatively, the list of strings may be given on stdin.\n";
  print "The -v option prints the command in addition to executing it.\n";
  print "  eRename -v 'svn mv' 's/perl/expr/' *\n";
  print "The -p option prints the command instead of executing it.\n";
  print "  eRename -p 'svn mv' 's/perl/expr/' *\n";
  exit;
}

if ('-v' eq $ARGV[0]) {
  $print = 1;
  $exec = 1;
  shift @ARGV;
}
elsif ('-p' eq $ARGV[0]) {
  $print = 1;
  $exec = 0;
  shift @ARGV;
}
else {
  $print = 0;
  $exec = 1;
}

$cmd = shift @ARGV;
$expr = shift @ARGV;

if (@ARGV) {
  @strings = @ARGV;
}
else {
  @strings = ();
  while (<STDIN>) {
    chomp;
    push @strings, $_;
  }
}

foreach (@strings) {
  $old = $_;
  eval $expr;
  if ($old ne $_) {
    print "$cmd $old $_\n" if $print;
    print `$cmd $old $_` if $exec;
  }
}