## Copyright (C) 2006-2015 Bill Denney
##
## This file is part of Octave.
##
## Octave is free software; you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 3 of the License, or (at
## your option) any later version.
##
## Octave is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Octave; see the file COPYING.  If not, see
## <http://www.gnu.org/licenses/>.

## -*- texinfo -*-
## @deftypefn  {Function File} {@var{files} =} unpack (@var{file})
## @deftypefnx {Function File} {@var{files} =} unpack (@var{file}, @var{dir})
## @deftypefnx {Function File} {@var{files} =} unpack (@var{file}, @var{dir}, @var{filetype})
## Unpack the archive @var{file} based on its extension to the directory
## @var{dir}.
##
## If @var{file} is a list of strings, then each file is unpacked
## individually.  Shell wildcards in the filename such as @samp{*} or
## @samp{?} are accepted and expanded.
##
## If @var{dir} is not specified or is empty (@code{[]}), it defaults to the
## current directory.  If a directory is in the file list, then @var{filetype}
## must also be specified.
##
## The specific archive filetype is inferred from the extension of the file.
## The @var{filetype} may also be specified directly using a string which
## corresponds to a known extension.
##
## Valid filetype extensions:
##
## @table @code
## @item  bz
## @itemx bz2
## bzip archive
##
## @item gz
## gzip archive
##
## @item tar
## tar archive
##
## @item  tarbz
## @itemx tarbz2
## @itemx tbz
## @itemx tbz2
## tar + bzip archive
##
## @item  targz
## @itemx tgz
## tar + gzip archive
##
## @item z
## compress archive
##
## @item zip
## zip archive
## @end table
##
## The optional return value is a list of @var{files} unpacked.
## @seealso{bunzip2, gunzip, unzip, untar, bzip2, gzip, zip, tar}
## @end deftypefn

## Author: Bill Denney <denney@seas.upenn.edu>

function filelist = unpack (file, dir = ".", filetype = "")

  if (nargin < 1 || nargin > 3)
    print_usage ();
  endif

  if (! ischar (file) && ! iscellstr (file))
    error ("unpack: FILE must be a string or cell array of strings");
  endif

  ## Convert char arrays to cell strings to simplify further processing
  if (ischar (file))
    file = cellstr (file);
  endif
  if (numel (file) == 1)
    gfile = glob (file);
    if (isempty (gfile))
      error ('unpack: file "%s" not found', file{1});
    else
      file = gfile;
    endif
  endif

  ## Recursively unpack cellstr arrays one file at a time
  if (numel (file) > 1)
    files = {};
    for i = 1:numel (file)
      tmpfiles = unpack (file{i}, dir);
      files = {files{:} tmpfiles{:}};
    endfor

    ## Return output if requested.
    if (nargout > 0)
      filelist = files;
    endif
    return;

  else
    file = file{1};
  endif

  if (isdir (file))
    if (isempty (filetype))
      error ("unpack: FILETYPE must be given for a directory");
    elseif (! any (strcmpi (filetype, "gunzip")))
      error ('unpack: FILETYPE must be "gunzip" for a directory');
    endif
    ext = ".gz";
  else
    [pathstr, name, ext] = fileparts (file);

    ## Check to see if it's .tar.gz, .tar.Z, etc.
    if (any (strcmpi ({".gz" ".Z" ".bz2" ".bz"}, ext)))
      [~, tmpname, tmpext] = fileparts (name);
      if (strcmpi (tmpext, ".tar"))
        name = tmpname;
        ext = [tmpext ext];
      endif
    endif

    ## If the file is a URL, download it and then work with that file.
    if (! isempty (strfind (file, "://")))
      ## FIXME: The above code is not a perfect test for a URL
      urlfile = file;
      tmpfile = [tempname ext];
      [file, success, msg] = urlwrite (urlfile, tmpfile);
      if (! success)
        error ('unpack: could not fetch "%s": %s', urlfile, msg);
      endif
    endif

  endif

  file = make_absolute_filename (file);

  ## Instructions on what to do for any extension.
  ##
  ## The field names are the file extension without periods.
  ## The first cell is what is executed to unpack an archive verbosely.
  ## The second cell is what is executed to unpack an archive quietly.
  ## The third cell is the function to execute on output to get the files list.
  ## The fourth cell indicates if the files may need to be manually moved
  ##   (i.e., tar and unzip decompress into the current directory while
  ##    bzip2 and gzip decompress the file at its location).
  persistent commandlist;
  if (isempty (commandlist))
    commandlist.gz = {'gzip -d -v -r "%s"', ...
                      'gzip -d -r "%s"', ...
                      @__parse_gzip__, true};
    commandlist.z = commandlist.gz;
    commandlist.bz2 = {'bzip2 -d -v "%s"', ...
                       'bzip2 -d "%s"', ...
                       @__parse_bzip2__, true};
    commandlist.bz = commandlist.bz2;
    commandlist.tar = {'tar xvf "%s"', ...
                       'tar xf "%s"', ...
                       @__parse_tar__, false};
    commandlist.targz = {'gzip -d -c "%s" | tar xvf -', ...
                         'gzip -d -c "%s" | tar xf -', ...
                         @__parse_tar__, false};
    commandlist.tgz = commandlist.targz;
    commandlist.tarbz2 = {'bzip2 -d -c "%s" | tar xvf -', ...
                          'bzip2 -d -c "%s" | tar xf -', ...
                          @__parse_tar__, false};
    commandlist.tarbz = commandlist.tarbz2;
    commandlist.tbz2 = commandlist.tarbz2;
    commandlist.tbz = commandlist.tarbz2;
    commandlist.zip = {'unzip -n "%s"', ...
                       'unzip -nq "%s"', ...
                       @__parse_zip__, false};
  endif

  ## Unzip doesn't actually care about the extension
  if (strcmpi (filetype, "unzip"))
    nodotext = "zip";
  else
    nodotext = ext(ext != '.');
  endif

  if (ispc && strcmp (nodotext, "tar"))
    ## Change file pathname into a mingw style acceptable for tar
    file = __w2mpth__ (file);
  endif

  if (isfield (commandlist, tolower (nodotext)))
    [commandv, commandq, parsefcn, move] = deal (commandlist.(nodotext){:});
    origdir = pwd ();
    if (move)
      startdir = fileparts (file);
    else
      startdir = origdir;
    endif
    cstartdir = make_absolute_filename (startdir);
    cenddir = make_absolute_filename (dir);
    needmove = move && ! strcmp (cstartdir, cenddir);
    if (nargout > 0 || needmove)
      command = commandv;
    else
      command = commandq;
    endif
  else
    warning ("unpack: unrecognized FILETYPE <%s>", ext);
    files = file;
    return;
  endif

  ## Create the directory if necessary.
  s = stat (dir);
  if (isempty (s))
    [status, msg] = mkdir (dir);
    if (! status)
      error ("unpack: mkdir failed to create %s: %s", dir, msg);
    endif
  elseif (! S_ISDIR (s.mode))
    error ("unpack: %s: not a directory", dir);
  endif

  unwind_protect
    cd (dir);
    [status, output] = system (sprintf ([command " 2>&1"], file));
  unwind_protect_cleanup
    cd (origdir);
  end_unwind_protect

  if (status)
    error ("unpack: unarchiving program exited with status: %d\n%s",
           status, output);
  endif

  if (nargout > 0 || needmove)
    ## Trim the last CR or NL if needed.
    files = parsefcn (ostrsplit (output, "\r\n", true))';

    ## Move files if necessary.
    if (needmove)
      [st, msg] = movefile (files, cenddir);
      if (! st)
        error ('unpack: unable to move files to "%s": %s', dir, msg);
      endif

      ## Fix the names of the files since they were moved.
      files = strrep (files, cstartdir, cenddir);
    endif

    ## Return output if requested.
    if (nargout > 0)
      filelist = files;
    endif
  endif

endfunction

function files = __parse_zip__ (output)
  ## Parse the output from zip and unzip.

  ## Skip first line which is Archive header.
  files = char (output(2:end));
  ## Trim constant width prefix and return cell array.
  files = cellstr (files(:,14:end))
endfunction

function output = __parse_tar__ (output)
  ## This is a no-op, but it makes things simpler for other cases.
endfunction

function files = __parse_gzip__ (output)
  ## Parse the output from gzip and gunzip returning the files
  ## commpressed (or decompressed).

  files = regexprep (output, '^.+ with (.*)$', '$1');
endfunction

function files = __parse_bzip2__ (output)
  ## Parse the output from bzip2 and bunzip2 returning the files
  ## commpressed (or decompressed).

  ## Strip leading blanks and .bz2 extension from file name
  files = regexprep (output, '^\s+(.*)\.bz2: .*', '$1');
endfunction


%!test
%! ## Create temporary directory and file for packing and unpacking
%! dirname = tempname ();
%! assert (mkdir (dirname));
%! filename = tempname ();
%! fid = fopen (filename, "wt");
%! assert (fid >= 0);
%! fprintf (fid, "Hello World\n");
%! fprintf (fid, "123 456 789\n");
%! fclose (fid);
%! unwind_protect
%!   copyfile (filename, [filename ".orig"]);
%!   gzip (filename, dirname);
%!   [~, f] = fileparts (filename);
%!   filelist = unpack (fullfile (dirname, [f ".gz"]), P_tmpdir);
%!   assert (filelist{1}, filename);
%!   fid = fopen ([filename ".orig"], "rb");
%!   assert (fid >= 0);
%!   orig_data = fread (fid);
%!   fclose (fid);
%!   fid = fopen (filename, "rb");
%!   assert (fid >= 0);
%!   new_data = fread (fid);
%!   fclose (fid);
%!   if (orig_data != new_data)
%!     error ("unpack: Unpacked file does not equal original");
%!   endif
%! unwind_protect_cleanup
%!   unlink (filename);
%!   unlink ([filename ".orig"]);
%!   rmdir (dirname);
%! end_unwind_protect

## Test input validation
%!error unpack ()
%!error unpack (1,2,3,4)
%!error <FILE must be a string or cell array of strings> unpack (1)
%!error <file "_%NOT_A_FILENAME%_" not found> unpack ("_%NOT_A_FILENAME%_")
%!error <file "_%NOT_A_FILENAME%_" not found> unpack ({"_%NOT_A_FILENAME%_"})
%!error <file "_%NOT_A_FILENAME%_" not found> unpack ({"_%NOT_A_FILENAME%_", "2nd_filename"})
%!error <FILETYPE must be given for a directory>
%! if (isunix || ismac)
%!   unpack ("/");
%! else
%!   unpack ('C:\');
%! endif
%!error <FILETYPE must be "gunzip" for a directory>
%! if (isunix || ismac)
%!   unpack ("/", [], "foobar");
%! else
%!   unpack ('C:\', [], "foobar");
%! endif