#!/usr/bin/perl
use FileHandle;
use File::Basename;

if (($#ARGV + 1) < 4){die <<EOS ;}
*** Copyright 2012, Gamma Remote Sensing, v1.3 23-May-2012 clw ***
*** Generate SLC_tab, MLI_tab, or RAW_list for processing  ***

usage: $0 <dir> <ext-1> <ext-2> <tab>
    dir   (input) directory including paths that contain the data files
    ext-1 (input) pattern to select data files (examples: slc, raw...), (enter - for all files in the directory)
    ext-2 (input) pattern to select parameter files that match the data (enter -  for none, examples: slc.par, raw_par, raw.par)
    tab   (output) list of data filenames and associated parameter files (including paths) (text)

    NOTE: The current directory is denoted using . 
       
EOS

$ddir = $ARGV[0];
$ext1 = $ARGV[1];
$ext2 = $ARGV[2];

open (TAB, ">$ARGV[3]") or die "ERROR: cannot open the output tab file: $ARGV[3]\n\n";
-e $ddir or die "\nERROR $0: directory containing data does not exist: $ddir\n";
print "output tab file: $ARGV[3]\n";

if ($ext1 ne "-"){
  @files1 = <$ddir/*$ext1>;
}
else {
  @files1 = <$ddir/*>;
}
$len1 = $#files1 + 1;

if ($ext2 ne "-") {
  @files2 = <$ddir/*$ext2>;
  $len2 = $#files2 + 1;
  if ($len1 != $len2) {
    print "ERROR: the number of files in the directory differ for the two extensions: $len1 $len2\n";
    print "@files1\n";
    print "@files2\n";
    exit -1;
  }
  for ($i = 0; $i < $len1; $i++) {
    print "$files1[$i]  $files2[$i]\n";
    print TAB "$files1[$i]  $files2[$i]\n";
  }
}
else {
  for ($i = 0; $i < $len1; $i++) {
    print "$files1[$i]\n";
    print TAB "$files1[$i]\n";
  }
}

exit 0;