#!/usr/bin/env perl

use warnings;
use strict;

use Getopt::Std;

my %opt; getopts('he:',\%opt);

$opt{'h'}
  and &help;

my $expr = $opt{'e'}
  or &help('no -e option specified');

@ARGV
  or &help('no filename(s) specified');

sub help
{
  warn join(' ', @_), "\n\n"
    if @_;

  print STDERR <<ZZ;

Usage: $0 -e expr sqlfile1 [sqlfile2 [...]]

to reproduce on output a version of the input file(s),
which are supposed to be MySQL database dumps in SQL format,
in which all tables have been renamed according to expr.

Option:

  -e expr

  A Perl expression (operating on \$_) that specifies how the
  table name is to be modified.  This option is required.

Example:

  $0 -e 's/^/foo_/' dbdump.sql > dbdump_foo.sql

prefixes all table names with the string foo_.

ZZ

  exit(!!@_);
}

foreach my $f (@ARGV)
{
  if (!open(F, '<', $f))
  {
    warn "cannot read file, skipped: $f\n";
    next;
  }

  my @f = <F>;
  close(F);

  my %table_name =
    map { $_ => 1 }
      map { /^\s*CREATE TABLE `([^`]+)`/i ? ($1) : () } @f;

  #warn "table names: ", join(', ', keys %table_name), "\n";

  foreach my $l (@f)
  {
    my @l = split(/`/, $l, -1);
    if (@l > 2)
    {
      my @newl = map { if (defined $table_name{$_}) { eval $expr; }; $_ } @l[1 .. @l-2];
      splice(@l, 1, @l-2, @newl);
    }

    print join('`', @l);
  }
}